Sunday, May 31, 2009

Summer Means Its Time to Fool with Antennas


I saw one of these on QTH.com virtually unused for a nice price, so I bought it. I'm not a big antenna tuner kind of guy. I pretty much build my antennas to provide a proper load to the coax. I do use some antenna that have wild impedance, but I I usually put some kind of matching network at the base of the antenna to bring it into line. My 160 ant for example has a base impedance of about ten ohms so I have a little network that brings that up to something around 45 ohms. I have a 40M vertical that has an impdeance of about 2000 ohms. I have a tuner at the base of the vertical that brings the antenna down to 53 ohms. All of my antennas have their own dedicated matching device that is built precisely to give me the most efficiency in my system. I have one antenna thats a 135ft flat top fed with 300 ohm transmitting line that comes into my Johnson Matchbox and I use the flat top all the way to 6M. On 6 I built a separate link coupled tuner so I just pull the Johnson out of line and plug in the 6M job and have at it. Again each band is optimized.

I recently put up a RX only vertical to play with the diversity branch of the test code. N4HY has added an interesting feature to PowerSDR that allows very impressive diversity peaking or notching that is steerable from the software. I have 2 full size 80M/40M/30M verticals already on the property, but I wanted to try a triangular array switching between any pair of 3 verticals to see if I could improve steering. The answer to that question by the way is yes. There are noise sources that you can null better on one pair than on the other 2.

My thrid vertical consists of a 45 ft piece of #14 that is suspended by a tree. When I first moved to this QTH in the mid 90's I had a tree man climb a few of my pines and put big old eye bolts into the tree, and I ran some steel cable through the eyebolts to the ground. This way I can use the trees to hoist up my antenna pipe dreams at will. For this antenna I merely tied an insulator to one side of the halyard tied the wire to the other and hoisted up the vertical. At the base of the tree I pounded a stake into the ground and to the stake I mounted a bracket that has a SO239 and some bolts which to hook radials to. Since this is a RX antenna I only put out 3 radials. So I have a 45ft piece of wire that is virtually invisible suspended from a tree in the front yard.

Of course I could not resist pumping some RF into this vertical. It didn't match very well, so I put the new little auto tuner in the line. This little tuner will tune automatically if the SWR is greater than some present number like 2:1. To see if this thing would even work I brought up WEBSDR.org and proceeded to send some CW on 80 40 and 30. On 80M the antenna is down several dBm compared to my full size 1/4 wave vertical with a very well characterized ground. The base impedance of that antenna is about 33 ohms which is near perfect. With the Flex 5K since I can rapidly change antennas I was able to switch back and forth using WEBSDR as my field strength meter 4500 miles away. Both signals were barely out of the noise as it was clear there is a lot of summertime static over in PA3 land. Band noise was running -100dBm over there an I was hitting as much as -93dBm. (I love being able to talk about signal strenght in terms of dBm instead of dorky S-Units) The full size super efficient 80M was louder by maybe 3-5 dB on the average than the front yard kluge but I could copy both antenna at 100W, and there were some QSB peaks where the antennas were were equal on the WEBSDR dBm meter. On 40 there was at best 1-3 dB difference between my 1/2 wave end fed super efficient flame thrower and this 45 ft piece of wire (about 3/8 wave on 40). On 40 this antenna should really shine, so what I am seeing is the poor efficiency of my front yard gound plane. On 30 I was able to tune up fine. After I was past my terminator and it got good and dark, I was able to hear both my 5/8 wave 30M vertical AND the 45ft antenna (which would behave like a 1/2 wave end fed on this band). The 5/8 wave vertical with the really good ground was louder. I was feeding the 45 ft piece of wire with about 75 ft of coax so it doesn't surprise me. My hope is to move the tuner out to the antenna thereby removing the "coax behaving as a attenuator instead of a feedline" from the equation.

So what's the upshot of all this? Well I've read a lot of hubub about those 43ft verticals. A lot of people swear by them and a lot of people swear at them. Mostly I think people are talking out of their sleves without ever actually trying one. This 45 ft invisible piece of wire (which is virtually the same as a 43ft aluminum pipe) is a hell of an antenna. You basically head down to the home depot and buy a 500ft roll of #14, spread all that wire out, and hire some joker to put an eyebolt in the tree. That's maybe 50 bux. Since this tuner has batteries, and the batteries that I have in there are slated to last about 4 years, and this thing is automatic, I am going to find a water tight box and put that sucker out at the tree and see what it does. I bet it will do quite nicely. I may add a few more radials as well. This antenna could well be the answer to those among us that suffer covenants and desire to put up a very good antenna that also can NOT easily be spotted. Basically someone would have to actually be in your yard up close to the tree to get a load of this antenna. At the base of the antenna I wound a loose coil about 4" in dia maybe 4 turns for strain relief so if the wind blows the tree around it just stretches out the coil a little. After all tomorrow is the first day of hurricane season.

I tried to load the antenna on 160 but even with the monumental ground loss I could not get a match. HOWEVER, there is nothing that precludes you from running a second wire up the tree in an inverted-L kind of scenario and switch between the 2. I use a coax switch out at the antenna to switch between 4 antenna using the coax as the means to control the antennas. Here is a home brew version by Phil Salas AD5X that allows for switching 2 antennas and it would be easy enough to increase this simple switch to 3 outputs.

REMOTE ANT SWITCH

To add a third position just add another relay and use diode steering on the relay coils. For position 1 use a + 12V, for position 2 reverse the polarity and use a -12V, and for position 3 use Zero volts. You would have to pick off the control voltages before the feed line went into the remote tuner, but you would want the antenna switch AFTER the tuner so you could use the tuner on all antennas. This sticks with my philosophy of tuning the antenna AT THE ANTENNA where ever possible. Also by using the outputs available via DDUTIL you could make the band switch to be controlled by PowerSDR as well, making band change virtually point and shoot!!! I wont go into what is involved there but it certainly is do-able.

This 45ft wire works great for 80, 40, and 30. It gets too long to be a good DX antenna above 30, and its too short to match on 160. I usually don't operate above 30M, but if you added a second wire to one of the positions of that antenna switch about 15 ft long you should be able to tune that second wire from 20 through 10 with good result, and if you could sneak a third wire up, some kind of inv-L about 130 ft in total length, or a T antenna you could get on 160 as well. You may need to buy a second roll of #14 for a few more radials if your going all out 160-10. (Actually I'm a fan of something around 3000ft in total radial lenght)

If your anygood with a fishing pole this antenna would be very easy to put up as a portable antenna as well. Just pop some line over the canopy of some unsuspecting tree and hoist and string out a few radials. Hook up the tuner and have a blast.

I've been measuring the distance between my trees. One is 60 ft away, another is 30ft away, one is about 100ft away. In fact I have 4 trees 60 ft apart!! Just the ticket for some invisible vertical arrays!! If I can only figure out how to get the coax UNDER the driveway. And I can even make DDUTIL control that from the computer!!

Covenants? What covenants?

73

Image Rejection and ten thousand page views


Well this blog has been active now since Feb 15th and in that time I have had over ten thousand unique page views. I've had many interesting emails as well. I've taught myself something about web pages and HTML coding. All in all I'm amazed at the response, and I think it just shows the interest in this cutting edge aspect of ham radio. I would like to thank you for your support and I find the interest heartening. When you hear some old buzzard squawking about the death of ham radio, just remember, he's the one that's dead, not ham radio. Not by a long shot!!

Me?? I'm just having a gas! (Anesthesiologist's joke)

I thought it might be interesting to see a clip of the Image Rejection protocol in action in the production test screen. Above you can see the test forms for both the main radio and second RX

I only did the Image test, but as you can see you can test virtually every aspect of the radio

Here is the clip there is no audio

video

This test allows for a starting value for each band to be stored in memory. Notice how quickly the image is notched. The adaption in each band is a fine tuning of these initial values. This radio aligns itself. Just plug in a dummy load and PowerSDR does the rest. Every rejection value for each band is greater than 100dB

73

Thursday, May 28, 2009

WBIR

What in the heck is that? WBIR stands for Wide Band Image Rejection. The Flex system is a 4th method phasing system, so it looses the images by mathematically canceling the image. Filter rigs rely on the filter to choke out the image and to the extent the filter can act as a choke is the extent you get canceling. If the filter is a crummy choke you get crummy canceling and there isn't anything you can do about it. We generally don't think much about this because the filters do a fair job and if you can't do anything about it why worry? On the other hand the Flex radio can do something about it. An equation can be tuned to within an inch of its life. It is not a piece of physical hardware like a filter. It is plastic and can be shaped.


The above picture (a) represents a signal split into 2 components, component A and component B. In (b) component B is phase shifted 90 degrees from A. In (c) the two components are vectorily added together. The result in picture is A2 cancels B2, and you are left with A1 and B1 adding together. If A2 and B2 are perfect opposites their sum equals zero. If A1 and B1 are perfectly the same you wind up with a signal that is twice the value of either one alone. This is how a phasing radio works. In the computer it is possible to as Picard on Star Trek used to say "make it so". It is possible to make A2 and B2 the same but opposite in sign so you get very deep canceling.

Here are a couple of slides from Gerals's Dayton presentation this year that shows what this means practically.

In the above picture you see some quite strong signals on the left side of the screen. On the right side you see their images.

In this picture we see the same strong signals on the left, but NO signals on the right. The difference is WBIR. When WBIR was engaged it analyzed the signals and essentially made A2=-B2 and the images perfectly canceled.

In the early SDR-1000 code you had to do this adjustment by hand. You would feed in a signal generator signal and then proceed to adjust phase and gain control to cancel the image. On a single freq you could get quite deed nulls, over 100dBm, but as you moved off frequency that null would deteriorate. You might set the null at 3750 for example and be 100dBm down, and move to the bottom of the band and have that deteriorate by many tens of dB. The next move was to remember the image numbers on a per band basis. Each band would have its own null. The system was automated. Code was developed so the radio would null itself on each band, but still only at one point, so there was a variability in image rejection across the band. This was an improvement.

Now we come with what is essentially just in time image rejection across the band. N4HY along with KE5DTO have once again merged their enormous brains and have come up with an algorithm that adapts the image rejection to near perfect on the fly. The algorithm is a very very fast adapting system that nulls the radio to "best null" as you tune to a frequency. If you tune to a new freq the algorithm kicks on and once again you are living in the land of best null. If you are on the same freq for a while, the radio occasionally checks the null, so you are always living in the land of best null. This algorithm is now working in both the main RX and the second RX, and is also going to address TX. This means the radio will always be "best tuned" and perfectly aligned for both TX and RX, no matter where you are in the spectrum including if you are using the radio to drive VHF/UHF/SHF transverters. You will be assured of the cleanest signals both on TX and RX.

Just sit back and think about how cool this is. In the old days you needed a room full of equipment to align your radio. Now all you need is an equation!!

73

Tuesday, May 26, 2009

WK remote


This is not exactly software defined radio but I think its very cool and is certaily related to our recent discussoin. I was looking over K1EL's site reviewing the features of WinKey. I have a couple of WinKeys, V1 and V2 USB. Winkey is a full featured CW keyer, that also allows for computer control of the keyer. There are some contest programs like N1MM that have integrated winkey into the program. I presently use my Winkey V2 as my memory keyer. The internal keyer in PowerSDR is connected to my paddle, but I have a little outborad switchbox that was made for me by Begali that I use to run memories for DX contacts. I prefer the action of the internal keyer for QSO's, so over all it works for me.

I run my paddle into the F5K or the F3K's CW jack. PowerSDR also scans a comport for CW, if you turn that feature on. So I run the output of my winkey through a PNP transistor across a couple of pins on the COM-1 of my computer. This allows me to use the keyer on the F5K or the F3K or the SDR-1000 without changing any plugs, since the keyer is talking to PowerSDR in every case. If there was a way to run the winkey from remote this would allow me to use the keyer on any of the radios.

As I was poking around I found this!! It's a set up to connect 2 winkey keyers together over the internet, so you can paddle your little heart out from thousands of miles away, or from poolside at your hacienda. This looks like the perfect solution for the CW nut who wants to do remote base CW The program also allows a distant keyboard to control a single winkey connected to the transceiver. As well as control the memories Here is a shot of the control panel



What will Steve K1EL think of next?

73

Sunday, May 24, 2009

Atlantis Returns



Its been 3 days and the WX has been terrible here in FL. Today it's gorgeous, but I guess it's prettier in California so Atlantis will be touching down at Edwards instead of Kennedy. The de-orbit burn has just been completed and the die is cast. However they get her home safely is that matters but I do love those twin sonic booms as the shuttle passes over my house on its final approach. The first is from the leading edge and the second is from a trailing edge.


I got up early to listen to Niue again. Not as loud as yesterday but still very respectable. He was on 40M and I was hoping for 80 or 160, but I am in the log so what the heck. In the mean time I am at work listening to 40CW on WEBSDR The crew is almost home and life is good on the east coast of FL!

73

Friday, May 22, 2009

Niue was Newy for me on 40

can you spot the spot?

I guess there has been a sunspot cited in the past couple days. I haven't really noticed a downturn in the bands because I operate the low bands, but this morning I heard Niue ZK2 boiling through on 40M CW.

Set my DX pea shooter up (F5K, DDUTIL, CW Skimmer, AL80B, 1//2 wave end fed vertical) and bagged him in 2 calls. It was great because I was already 2 minutes late for heading out the door to work when I heard him. I haven't heard squat on 40, 80, or 160 in a couple weeks so maybe Niue, or that (newy) pimple on sol's mug is a good omen!!!



73

Remote part deux

Scott responded to my recent blog post on Remote control of the F5K. he kindly consented to publication of his thoughts and experience.

The iPhone thing is old news I should have guessed...if you can think it you can do it

Lee,

Just wanted to thank you for including my experience in your post! I think a lot of people think remote operation is a lot harder than it really is. The fact is, it's not, and I GREATLY increase my operating time by being able to operate remote.

You mentioned using an iPhone... I'm already doing that too! Last month or two, Apple rolled out Skype on the iPhone, and it works great although the lag does increase a little bit. I assume this is from the slower processor. There is also 'RDP' and 'VNC' applications to control the rig. All three are free! If your iPhone is jailbroken (i.e. hacked to run unauthorized software), you can also install a program called 'Backgrounder', that will allow any application to run in the background while you switch to another application. This allows you to start your Skype connection, then flip over to VNC/RDP to control the rig. I planted my tomato plants this year while following a local 80M traffic net, followed by a DX pileup. Very cool!!

As far as my experienc with RDP and VNC goes... The SDR machine is the only Windows computer in the house. Everything else is Mac OSX. The only VNC mac client I've found is called "Chicken of the VNC", and no matter how I set it up, the screen updates about every 5-7 seconds, even when wired on my gigabit home network. It might be the mac's implementation of the VNC protocol; I hadn't tested it from any other hosts. But in my situation, Microsoft's RDP client far outpaces Chicken Of The VNC. I also used TightVNC when I tested it last. I whole-heartedly agree with you about the Microsoft Bloat, and this is one of the very rare times I favor an MS application! :)

73 and have a great weekend!
Scott, N5KRC

This makes applications like DDUTIL even more useful. WIth DDUTIL you can design a really remote-able station including beam pointing and antenna selection and amplifier control

73

Thursday, May 21, 2009

Compander Revisited


There was a recent discussion on EHAM regarding what the SDR sounded like when using the compander and the DX compander. I decided to make a couple of .avi clips to demonstrate what the compander does. Power SDR has built in a scope function that operates on both receive and transmit. Above is an example of what the signal looks like on transmit. You will also note near the bottom of the screen is a function called Gate. Next to Gate is a VU meter that represents the mic signal. I used this meter to keep the speech levels essentially constant during all runs. Watch the scope to clearly see what differences the various compander settings make. I made 3 runs one at 3 on each compander, one at 5 on each compander and one at 10 on each compander. You can judge for yourself how the compander works. If you watch you can see me switch each compander off and on.

level 3 run

level 5 run

level 10 run

The audio in these runs are without any pre-emphasis, which I usually add. My normal setup is to use just the compander with a setting of 2 and some upward sloping pre-emphasis. This increases the talk power without significant added distortion, but even at 10 the signal is very well behaved.

73

Remote


There is a thread that has developed over on the Flex reflector that I think is worth writing about. I have run my flex radios remotely on my local network. It is dead easy to do. For remote duties I use a program called tightVNC. There are others out there. Another popular program is UltraVNC which I have also used. Windows has a built-in VNC called remote desktop that I can not recommend. Its typical MS bloatware, clunky and slow.

The tight VNC server on my ham computer can be accessed by the VNC client on my linux computer in my office so I am able to run all my favorite stuff remotely from my linux box. For audio duties I use IP-sound. I have also used skype to good avail. Many are using 2 skype accounts, one for transmit audio and one for receive audio. This speeds things up considerably.

With these tools and VAC it is dead easy to set up remote operation. If you know how to bore a secure hole in your firewall you can have this remote operation all over the world. I have done remote both on SSB and CW using the keyboard. On CW the lag is enough of a problem that it would be hard to work a DX pileup with the rythm required, but for rag chew not so much and no problem on SSB.

Here are a few comments off the reflector

Re: [Flexradio] Excellent results

with remote operation

Steve Floyd
Wed, 20 May 2009 11:00:11 -0700

I have been using my Flex 5K remote over the internet
with the same excellent success. I use UltraVNC to
access the computer desktop, and Skype with VAC for
audio. Works great from remote locations in Alaska
and the west coast; all with my station in VA. The
audio reports are so good that people cannot tell
that I am operating remote. Great fun!

Internet remote operation of the Flex radios is
becoming an important required feature!

73'
Steve
W4YHD

[Flexradio] Excellent results with

remote operation

Dave
Wed, 20 May 2009 04:01:46 -0700

Hi All, I was recently in California for two weeks running
my Flex 5000A remotely
(radio back in NJ).
Using a Plantronics HS650 headset into my laptop and
using the hotel's
crowded wifi network I was able to use
the radio successfully. People could
not believe I was
running remote. People stated the audio running remote
was
better than most station's local microphones. Setup
for remote was Skype for the VoIP audio transport
(two accounts),
Virtual Audio Cable to "patch" the
Skype audio in and out of PowerSDR, and
TightVNC for
remote desktop access.
Latency was very acceptable
except during some evenings when the hotel's
wifi
network bandwidth was saturated.
73 Dave wo2x

Re: [Flexradio] Excellent results with remote operation

Edwin Marzan
Wed, 20 May 2009 10:43:06 -0700

I spoke with Dave on his remote setup and it was truly
amazing! If he hadn't mentioned it over the air I never
would have known. I'm wondering if anyone else tried
this with any success. Edwin Marzan AB2VW

Re: [Flexradio] Excellent

results with remote operation

Scott Chrestman
Wed, 20 May 2009 11:30:17 -0700

95% of my operation is remote. Even if I'm home,
I'm typically in my easy chair in the living room
controlling the SDR-1000 computer from my
Dell Mini 9 laptop over wifi with a bluetooth headset
paired to it. I use Microsoft's Remote Desktop
client as it gives me better panadapter-response
than VNC does. I also use Skype for the audio transport.
I monitor the bands almost all day while at the office over
a dedicated IPSEC tunnel back to my house (cable
broadband at home, dual-T1 office connection). I have
even had sucsess in operating "remote mobile", using
the Mini 9 with a Verizon broadband USB card. On my
last trip to New Orleans, I operated (as a passenger!)
the majority of the way. That was the ONLY time that
anyone had questioned how I was operating, as apparently
my audio was dropping out due to the limited upstream
bandwidth. Turning the panadapter completely off resolved
that issue as it wasn't constantly streaming data to update
the screen. I could not live without my Flex-Radio!! 73,
Scott, N5KRC

Many of us will never bother to play with a remote base, but it is fun to experiment and its fun to know how easy it is to be able to access your fully functional radio station from afar. The internet has done truly amazing things in terms of what we are capable of today. In 1998 I took a 3 week trip to China. At that time I was doing some day trading. I brought a little cheap laptop along. I was able to day trade (actually night trade since China is 13 hours ahead) from all over China. It was amazing and I made enough money to pay for the trip a couple times over. Now just as easily I can take my ham radio hobby along and make QSO's and I can listen to a receiver at the university of Twente in the Netherlands from anywhere I can grab an internet connection!

Now N5KRC is running remote mobile!! I bet if Scott reverted to something like tightVNC he would be able to look AND listen as one of the advantages of those programs is to be able to pare down the bandwidth needed on the remote link. It just cracks me up where ham radio has gone and how easy it is to implement the future with these Flex radios. It also cracks me up that the old fossils continue to screech KNOB KNOB.

I was in a discussion on EHAM a couple weeks ago and I was describing the advantages of the F3K including its ability to interface with software like skimmer and DX lab to a guy who was interested in buying a new radio. Some joker made it it his mission to point out that the Flex NEEDED a computer, as if that made it somehow inferior for portable or mobile. My point to him was it was not a disadvantage in the least, but in fact an advantage. With the laptop I had a fully featured radio station complete with all the digital formats log books etc etc. Its the perfect setup for quick and dirty field day for example. Power, antenna, flex radio, paddle, laptop, logging software, beer, hot dog, chili, lawn chair way too much coffee... all completely integrated. Now I come to find its the perfect mobile radio to boot!! No punching holes in the car or wacky verticals with huge coils and guying systems knocking on tree limbs. No porcupine of 3 dozen antennas sticking out of every surface, and bumper. Just a laptop and a roving internet connection

All of the fun, none of the hassle and its so easy to do. In years past to get a legacy radio to remote base was a real chore. Not anymore.

So when do we get the iPHONE app? Stuck in the airport? Maybe a little 20CW will help pass the time
73


One last note. I made the trip between the Netherlands and FL once
again last night on 80M This time I was Q5 on one watt. I also went
down to 160 and listened to a LZ station having a QSO on both my
receiver and the WEBSDR. I never would have found him in the static
on my receiver. We have been having non stopped thunder storms here in
FL for that past 3 days and last night was no exception. After I
located the LZ on my F5K with the WEBSDR assist, with considerable
fiddling with the F5K's controls I was able to copy the LZ station on
my receiver. He was -114dBm and copiable in the middle of May in the
middle of a thunder storm. How fun is that?

Tuesday, May 19, 2009

Of Course its Irresitable


So of course I had to hear myself half way around the world. This is a shot from Google Earth of my QTH about 1/3 the way down the coast of FL, and the University of Twente. You can see the University as a little orange balloon near the lower right corner of the display.

On 30M using a 5/8 wave vert I was Q5 with 50W

On 40M using a 1/2 wave end fed vert I was Q5 on 3 watts

On 80M using a 1/4 wave full size vertical I was Q5 at 10 watts

On 160M using an inv-L I needed 1000W to make the trip

This is a shot of the terminator at the time of my test


This is way too much fun. After listening to myself I tuned in a YT1 in Serbia on 3508 khz. I could hear him at my FL QTH on the F5K and on the RX in the Netherlands/ There was considerable lag from the internet RX but it was very cool listening to this QSO using receivers that are 5200 miles apart.

73

I Bet You Guys Think I'm Kidding!!! Or Man's Best Productivity Killer

I write a lot about how different SDR is from "normal" radio (as if SDR is abnormal every cell phone is basically a SDR) In fact it is going to become the norm. I write about a lot of stuff that kind of sounds like science fiction or it belongs in Star Trek. This post will blow your mind!!! And its reality. All the jokers with their ROOFING FILTERS are going to be off the radar. In the October 2008 CQ review of the Flex 5000 I wrote a side bar that is reprinted below

User Perspective: Paradigm Shift

By Lee Crocker,* W9OY

I recently was asked, “Is SDR ready for prime time?” Let me

answer that with some personal ham history. My first rig: homebrew transmitter, Hallicrafters S-40B receiver, and a Navy flameproof key.


Paradigm shift: I had two “big iron” boxes, Hallicrafters and

Hammarlund.


Paradigm shift: Japanese companies entered the U.S. market

with a wide variety of simple transceivers. My big iron went the

way of the dodo. Transceivers made more sense—lighter, cheaper,

ever more features in ever smaller boxes. Next came “transition rigs”: part traditional transceiver and part proprietary SDR (software defined radio).

The latest paradigm shift, full SDR, has already occurred. SDR

is of the present; the others, in my view, have become of the past.

SDR is cheaper to build and more feature-packed. Old-time radios

are basically etched in stone. Change is at the margins (add a filter

or two), not much more. The SDR can be changed radically in

form and function simply by changing the computer code. The

SDR can be perfectly customized to your station’s need, be it

ragchewing, DXing, contesting, etc. Upgrading involves a download,

not a soldering iron; entire radio fleets can be upgraded by

simple download.


Another paradigm shift: open source licensing. While others

use proprietary code, FlexRadio freely promotes experimentation

within the code among hams. Multiple branches of individually

developed code reside on the Flex servers for download. As good

ideas come to fruition they are readily included into the main trunk

of the SDR code, giving each owner a better radio experience. A

hundred enthusiasts’ brains are far more creative than one factory

engineer making all the decisions. It’s a critical mass of hobbyist

brain power, super-charging the future of our hobby.

Freedom and flexibility: We are almost at the point of “if you

can think it, you can do it.” These paradigm shifts are not “future.”

The results sit on my desk today, with performance that is as good

as or better than anything else the market offers. Today,

my desk holds only SDRs, radios that are not “of the future.” The

paradigm shift has already occurred.


The Paradigm shift HAS happened in spades!!! In this mornings email I received a note from Rich WB2JBS regarding this web site:

http://www.websdr.org/

If you go into the first site you are greeted with this


This is a partial display of an 8 band SDR available over the internet that is usable by multiple users. This picture displays 40M 30M 20M and 17M as well as the control panel. I always wanted to see what 40M SWBC looked like in Europe. If you look at the 40M band it looks like the sky is on fire. This is what 40M SWBC looks like in Europe. The sky is on fire with RF!! I placed the filter on the strongest station in the pass band. Just take a look at the S-meter! -26 dBm is a true 47dB over S-9. I never see this kind of signal on my Flex stuff even in the strongest contest situation. The strongest stations on my Flex radios are in the -50 dBm range.

With this receiver you are able to see the activity on 8 bands, and all users can see that activity. Recall that the output of the SDR is some bandwidth like 96khz. The hardware acts like a data engine. It sucks in a slice of the RF spectrum (like 96khz) and spits out that 96 khz as data. This radio on the other hand is a data engine on steroids!! It uses a very fast A/D converter that sucks in the entire shortwave band up through 18mhz. The A/D then spits out the data as a 18mhz digital base band. This raw 18mhz digital base band is further displayed, processed, filtered and demodulated in a FPGA.

In fact within this bandwidth you can place dozens of individual "filter/demodulator" (what Flex calls a "watch receiver"), and this is how this radio works. When you sign in, a watch receiver is assigned to your IP address. It is that watch receiver that you can slide around the various bands. Moving the filter, by left clicking on the black of the band of interest moves your freq up and down the band. You also can grab the filter and slide that up and down the band by left clicking and holding. If you put the cursor in the waterfall of the band of interest you can zoom in and out by using the wheel on the mouse. Once you do the zoom you can move up and down in the band by click and grab within the waterfall, and move the freq of the water fall up and down. Once you have a station tuned in you can adjust the bandwidth of the filter, each side independently. By judiciously adjusting you can center the filter according to the CW offset to which you like to listen. You can also grab focus on the filter and tune by moving that up and down. Your watch receiver is represented by a little icon that looks like a filter. To change bands you simply click the new band. Its very intuitive and ergonomic. PowerSDR also allows for dozens of receivers but the problem is there is no easy way to allow all that data coming from many receivers to be interpreted. After about 2 receivers the brain starts flashing OVERLOAD OVERLOAD. This of course is the solution. If you have many receivers sucking in tons of data, you need many ham operator brains to understand the data!! PA3FWM's program will allow receiver numbers of 100 or more!

There is also a display that shows who is using the "radio" along with you. Below is a partial display:



If you put your callsign in the box at the top where your watch receiver will be displayed with your call sign, and it will show what band and where in the band you are listening. If you don't supply the call you will be displayed by your IP address. If you look in the 40M box you will find my call sign. On the 8 bands there is a total of 68 watch receivers aka users in the entire bandwidth of the digital base band

How cool is this? The software was written by PA3FWM and the "radio" resides at the University of Twente in the Netherlands. This thing is cooler than a box of softrocks. If you go to his webpage you can see for yourself the hardware associated with the signals to which you are listening.

How would you like to know what your signal looks like in the Netherlands? Set up a few of these around the country and you will always have a different take on propagation. Imagine being in a contest where you could just change the position of your receiver across the face of the earth. Oh I bet those grumpy old contesters that hate anything new are peeing into their boot right now at the prospect!!! I can hear 'em now crowing ROOFING FILTER ROOFING FILTER BEAM BEAM (If you crow this in a small group it will sounds like the angry crowd chasing after Frankenstein) That mental picture is kind of the picture I get when the contesters get a load of this!!!


This is a picture of the hardware!!! Look at how simple this looks. It points out once again that the money shot for this kind of radio IS IN THE SOFTWARE

Just remember if you get fired for listening to the radio from your desk all day long it isn't MY FAULT

Check this out soon as the 8 band version is going off line in a few days and will be replaced by a 3 band version that uses 3 RX's with 48khz bandwidth

Beam me up Scotty this sucker ROCKS

73



Monday, May 18, 2009

Sell in May and Go Away


The old stock market refrain is sell in May and go away and it refers to the fact traditionally stocks are in the doldrums in the summer. It also seems to be true of summer time low band ham radio operation.

I swung through the bands this morning and the results were dismal. Only 4 stations were visible on the low end of 40. Eventually I scrubbed the noise and found a German 1dBm out of the noise. My band noise was -126 with static to -100dBm. NO stations were visible on 80M. There wasn't one station on 80 in the DX area. There was one lone QSO going on in the QRP part of the band

For the first time in weeks I saw one lone JA station calling on 160, and a "one lander" bravely calling CQ about 4 khz below him. Too bad they were on different frequencies. Its also too bad they don't have a panadapter so they could see each other. It was obvious they were both pining for a QSO. My band noise on 160 was in the -117 dBm area with static up -97 dBm.

If you look closely at the above skimmer screen you can see the 2 stations on 160M

73

Sunday, May 17, 2009

Another F3K User Speaks


My buddy Greg AB4GO wrote me a review of his shiny new F3K. Greg lives about 25 miles south of me and is part of the Florida Contest Group and the Local DX club. He is a bit of a rocket scientist as he designs antennas for satellites among other things, when he isn't busy pursuing his avocations. I saw Greg at the Orlando hamfest when I stopped by Gerald's talk down there. By the end of the talk I swear he was drooling over the new radio.

Greg lives in a deed restricted community. Its a beautiful community except it is anathma to ham radio. As McGuire said to Ben in the graduate: I have one word for you

Covenants

This is something that affects many hams these days, so view Greg's experience through the lens of what it's like for a ham with covenents.

As McMahan used to say And HEEER'S Greg!!

AB4GO Experiences With the Flex-3000 May 17, 2009

My experiences turning on the Flex-3000 have been very pleasant. Let me introduce myself as Greg O’Neill, AB4GO. I am a radio development engineer currently focusing on Wireless Antenna Products. At home, I am just a ham. I live in a covenant restricted neighborhood with antenna restrictions. There are a few embedded disguised antennas here and there. I believe I represent a great number of HAMS that enjoy operating their radios in a modest environment.

I became interested in the Flex-3000 when I saw the advertisements in QST last fall. I mentioned it to my wife back then. Well, at the Orlando HamCation, when we heard K5SDR talk about the radio, my interest peaked. I ordered the radio. The anticipation of receiving the radio has been fun. I read some background articles and subscribed to the reflector. The reflector is somewhat intense and may not be worth the time for the casually interested person. It is great if you want to follow all the nuances that can come up.

At my station, I have a newer model laptop computer with a Core 2 Duo processor at 1.66 GHz and only 1 GB of RAM. I should update the RAM. There have been no hesitations in the operation of the radio. The computer seems to take the radio in stride with QRZ.com and the Flex Owners Manual running in the background. The CPU generally operates between 15 and 25 percent, sometimes higher. The Flex-3000 comes with a nice IEEE 1394 6 pin to 6 pin cable. Nice ferrite cores are on the cable meant to be placed near the radio. My computer has a small 4 pin IEEE 1394 connector. Lee suggested I get a 4 pin to 6 pin cable. So I visited Radio Shack and Walmart with no joy. The BITs computer store in town had the cable. Apparently, the Firewire is not widely used on today’s computers.

In preparation, I took the time to terminate the power cables with lugs. A good solid ground wire is run to a single ground rod outside my radio shack. I positioned the Flex-3000 on top of a 1995 ARRL Handbook, used as a spacer, and then on my shelf above my 2 ft by 4 ft radio table. Finally I was ready for installation. I have a 12 volt powered amplified speaker and an excellent pair of MFJ-392B headphones. I decided to power the radio from my Astron RS-35M to ensure sufficient power for the transmitter. I choose to use my Heil Goldline microphone. I purchased the adapting cable from Flex with my initial order. The cabinet is cool and quiet during transmit.
The Quick Start Guide installation was straight forward. I did not study the PowerSDR presentation on the screen before receiving the radio. I wanted to listen to some signals while I began to read the Owners Manual. There was a moment or two of now knowing what I was doing to try to tune a signal. Once I began reading the manual I became comfortable tuning a signal. I enjoy 20 meter SSB and some 80 meter SSB.

My philosophy about this radio is to enjoy discovery. There is no need to conquer it immediately. After poking around a little with the receiver, I began reading the Owners Manual. The manual is very easy reading. It is set up just right, but in Chapter 6 OPERATION, we really get into the operating technique.

I listen to many folks talk about strong signal rejection for their radios. I sort of have the opposite problem. I need to be able to hear the weak signals. There aren’t any strong signals to reject here. Flex has made an advancement in the way we will make signal level measurements. A basic signal, say an S4 signal reads S4 whether the receiver pre-amplifier is on or off or the attenuator is used. The signal just gets clearer if the pre-amp is needed. I really appreciate having the panadapter calibrated in dBm. That is better than having some arbitrary 10 dB/division scale. I believe we hams will, in the near future, talk more about high frequency path loss. Flex allows us to adjust the vertical scale of the display in other than 10 dB/divisions. That will be nice for finding weak signals. I like to use the AVG (Average) display of the swept signals. I have listened mostly on 20 meters using my Buddipole antenna set up as a ½ wave vertical.


It has been fun to exercise the MultiRX listening to two QSO’s which should be good for working pileups. I am sure there are many other features that I have not yet experienced. I have used the ANF (Auto Noise Filter) to reduce in passband tones and the NR (Noise Reduction). I have played around with the AGC-T which is similar to an RF Gain control. Having read Lee’s piece about this control suggests I have more to learn about the fine points of this control. I have played with the receive filter selections a bit. It is nice to have such a wide selection readily available. One thing I need to learn more about is how to set the filters to receive the low bass voice of some of my 80 meter broadcast quality friends under strong signal conditions. This may be in part due to the speaker I am using.
For transmitting, I followed the procedure for setting the Microphone gain. I have found that on 20 meters, during less than strong signal conditions, the receiving stations have recommended for me to use the DX feature for mic operation. That has increased the received power level significantly. I am just now experimenting with the GATE control. It seems to take out any extraneous noises. The internal Antenna Tuning Unit has worked nicely.

I have made several contacts. My reports are similar to my other radio. These contacts have been to Europe from my location in Florida. I had a nice rag chew with a station in Illinois. The radio is operating flawlessly. It is a pleasant experience. Later today, I hope to make some CW contacts and get familiar with the internal keyer. These are my first impressions, with many more to discover.




Buddipole

This is a pic of Greg's Buddipole out in his yard.

Regarding the reflector, it can be a little intense as Greg says, but to a large extent that is because this technology conceptually tends to be kind of foreign to the ham experience and the "lingo" is a bit unfamiliar. In fact that is the major thrust of this blog to try and introduce these concepts in normal situations that hams experience in their operating lives. To that extent it is very worth while to read the Flex reflector. Over time repeated exposure to the terminology and concepts start to make more and more sense.

73

Friday, May 15, 2009

Notes from Underground

Today I received a note from a buddy who received his F3K yesterday. He is running a laptop and the plug between his laptop and his flex didn't mate. The laptop uses a 4 pin and the F3K uses 6 pins. So I advised a 4 pin to 6 pin cable. These are very commonly used to mate firewire video cameras to computers.

He wrote back and said the install was uneventful once he got the cable and he was impressed at how well he was hearing weak signals on 20M. I wanted to just say a word about how easy it was for him to get his new radio up and running. I hope to I can have him write a little more about his initial experience so I can publish it for you all.

I later received a note from a ham who stopped by for the shuttle launch this week. and when he found out I lived here is shuttle country he dropped me a note. He is a retired communications engineer who was showing his grandson the shuttle up close. It is spectacular to see the launch up close. You can see it from a couple hundred miles away, but when its up close the experience is entirely different, just the noise is deafening

Any way he is a F5K owner and his big thing was how his radio is basically a collection of test equipment for him (as well as a damn good radio). In other words the "linearity of the S meter and its dBm readout and the panadapter and its use as a narrow band signal analyzer etc etc. He is also enjoying playing around with the various SVN threads including the diversity thread I have written about. He is both amazed and jazzed to see what happens when he plays various antennas one against the other in the diversity setting.

So I wanted to take a few minutes to relay some of their experiences so you all know I'm not the only one having a total gas (anesthesiologist joke) with my flex experience

73

Tuesday, May 12, 2009

There's More Than One Way to Skin a F5K, or F3K


Well the cat is out of the bag. The boys at Flex especially Matt Youngblood KD5FGE and Beppe IK3VIG have been collaborating to Skin PowerSDR for a couple of months or so in time for Dayton!!! The results are in, and according to a post by Gerald K5SDR on the reflector this is just the beginning.

Here is an example called: Default


and one called military


and this one is called IK3VIG Black


All told there are 12 different skins presently available in this SVN repository. Of the new skins black is probably my favorite. Many of the features of these skins can be customized in the Setup menu






This is the URL to the SVN repository

svn://206.216.146.154/svn/repos_sdr_windows/PowerSDR/
branches/ke5dto/PrettyBetty

To download you need tortoise SVN loaded on your
computer.

If you are unfamiliar with this technology you can
review the Knowledge Base article

In order to make the new skins work the .Net framework needs to be updated to the latest ver 3.51.

Pretty Cool!!! errr Pretty Betty

73

Ken N9VV had put up examples of all of the new skins on his website He also has a movie of the new PowerSDR skins available on this site

Saturday, May 9, 2009

Triangle Diversity


I decided that 2 antennas for diversity reception was not adequate. I have 2 verticals in the back of my property with good ground planes. In the front there is a pine with an eyebolt at about 45 ft. and a rope that goes through the bolt. I decided to cobble together a third vertical for RX. I made a little feed point bracket so I could attach a wire for the vertical element and added two radials at 180 degrees. At 45 ft the wire is a little long on 40 and a little short on 80 but should give pretty good output on either band.

The triangle is not a perfect equilateral triangle. It is 100ft on the base and about 180ft on each remaining side. With the F5K I didn't even need to make any kind of switching arrangement. I merely plugged one vert into ant 1, one vert into ant 3 and one vert into RX2. With this arrangement I can choose 1-rx2, 3-rx2, and 1,3 from the antenna control panel in the F5K

It happens there is some kind of contest happening in EU so the low end of 80M is quite active and its just a few minutes past the terminator flying over my head as I write.

Here is a clip of a HA8 station on 3503,

HA8

The effect is somewhat subtle but there is definite improvement is readability using the diversity set up.

I rotated around between the 3 antenna pairs and there was a definate advantage with ant 1.3 vs the other 2 pairs, both in signal to noise and in fading. I switched to 160 and there was only one domestic station calling CQ in 4 land and I was not able to get much diversity on him no matter what combo I chose. I switched to 40 and listend to some Russians in the contest and a completely different set of antennas gave the best response. This time RX2, 1 was best with RX2, 3 close behind. I have a lot more evaluation to do, but I think a triangle is a good first start for actually honing this receiving technique. At some point I may phase 2 of the antennas by making a phasing box, or possibly using my MFJ 1026 and feed that box's output against a single antemma

So much playing to do, such little time, and all it took was flipping another wire up in a tree.

73

Tuesday, May 5, 2009

Phase 3

I made a couple more examples. of audio files. The first is a CW QSO between a VP2 and a FM2 station. The phasing was tuned to notch as much static as possible. The effect is subtle but improves the intelligibility of the weaker station by at least 3 dB. Sometimes 3dB is the difference between go and no go on a weak station. The band noise was running around -114 and the stations were in the -108 range.

40-E

In the next clip I was monitoring a SWBC station well below the noise source.


40-F

You may need headphones but this station is completely covered by noise until the phasing is turned on. The effect is best heard toward the end of the clip when you can just make out the female voice.

Here is a clip of a local broadcast. Bob N4HY wanted to hear this one


40-G

Note the strength of this station -30dBm aka LOUD. The station is completely eliminated, almost like turning on a mute button. The tuning to remove this station is very critical.

I spent some time last night trying to separate WWVB from WWVH on 10mhz. For me the angles between the 2 stations are incident enough that I could not effectively separate the two. This is a job for someone on the west coast. Because WWVH uses a female voice 7.5 seconds before the male voice its easy to tell the two apart.

This feature is way too fun to play with. I find myself spending all my time listening to noise!!!! To what have I devolved???

73

Monday, May 4, 2009

Phase 2


Here is a shot of PowerSDR with Bob's DSP test form open. I decided to run some tests on this thing. I have a pair of 80 and 40M verticals that are spaced about 100ft. I fed one vertical into ANT-1 on the F5K, and I fed the other into RX-2. I turned on the DSP Test Form, as shown above.

First I tuned to a broadcast station that is about 4 miles north of me. The signal on my pair of 80/40M verticals were -20 dBm on one vertical and -23 dBm on the other. (aka about 50 over S-9.) In other words its one friggin strong signal. By judicious tuning I was able to completely null this strong signal. This signal is about 30dB stronger than the strongest of signals I ever encounter on the air. Next I tuned to 40M to hear what I could hear. These are a few samples I recorded of QSO's and noise being nulled.

40-A 40-B 40-C 40-D

In A you can hear the noise reduction. I tuned to best signal quality and then just clicked enable off and on a few times. This means my noise is a point source comming from a specific location.

In B In this clip you can hear the station fade down into the noise and when I click on the noise canceling he become readable again. The effect was more pronounced at different times during the QSO, but if I record a long QSO the files become huge.

In C is a classic situation. This "maddening" kind of digital noise is completely eliminated from the background.

In D another noise is eliminated virtually completely in a very noisy band

As you can see on the console I have no other noise abatement turned on for this demonstration.

I did run across 2 QSO's on the same freq, and I was able to eliminate one of the QSO's while copying the other using this diversity technique, and then do the opposite, eliminate the other QSO and listen to the QSO I had just notched. Amazing!!! I didn't make a clip of that because the QSO ended just as I got the hang of the tuning and was moving toward the "rec" button.

I am very excited about this development

73

Entering a New Phase

I've been out to the beach for a while and all I have is really unreliable dial-up out there so I've been incommunibloggo. Next time I go, I'm going to throw in F3K and a collapsible fiberglass 40M vertical and see what kind of trouble I can get into running "portable" from the edge of the Atlantic. I got up yesterday and went down to the water to watch the sun rise. As looked out at the horizon waiting for 6:41 to arrive, I noticed a band of dark opaque clouds maybe 100 miles off shore. As I looked I realized I was looking at probably the most common source of the static I hear every morning in the summer.

N4HY last week started a new SVN series around the F5K's diversity feature. I have a MFJ 1026 "Noise Canceller" and it works by mixing signals from 2 antennas and adjusting the phase and amplitude one against the other to get either a peak or a null.

The F5K allows for dual diversity reception when you have both receivers installed. Since the data that comes out of these are sync'd, Bob decided to do a 1026 in software, that is you can adjust the phase and amplitude of one receiver against the other. In addition you have the advantage of dual diversity and AGC polling with this kind of set up. I haven't had the chance to give this console a whirl yet but hopefully soon I will get the chance. It should be very interesting. I presume the tuning could be made to be automatic.

This morning I was listening to the V88 on 40 CW. He was weak in my summer time static (band noise in the -112dBm range) and it would have been very interesting to listen with this kind of set up and try and dig him out of the noise, either notching out some of the storm activity or peaking his signal. The storms would be exactly opposite from his desired direction, and I have 2 40M verticals that are about 100ft apart that would be ideal to give this kind of noise canceling a try. I don't know if the storms are "point source" enough to get a deep null on them. I never had that much luck with the 1026, but it was a big enough pain in the patootie to use with all the TR relays etc it had in the line to make it more trouble than it was worth. Also I never really saw deep nulls using the 1026, this implamentation should prove to be mucy more interesting

This is what I find so interesting about SDR. Dual diversity noise reduction done in software. Just plug in 2 antennas and have at it

Many people have been wondering what is the "difference" between the F5K and the F3K, and this is an example of the difference. There is probably nothing you couldn't hear with the F5K that you could't hear with the F3K when running a simple single antenna topology. Both receivers are superb. However when it comes to more exotic implamentations such as dual diversity with noise canceling, this is where the F5K simply runs away from the pack. The radio was designed with this kind of exotic implemantation in mind.

73