Tuesday, May 24, 2011

PP0T Trinadade & Martin Vaz

This morning I couldn't sleep so I decided to brave the static and flipped on the radio. The static was out of OK and AR this morning


I saw the expedition on Trinidade spotted on 40 and decided to give a listen.


He was in the mud until I got diversity adjusted and then he was Q5 but still with a lot of static and QSB typical of summer time conditions. He was working one-zeez and two-zeez up one mostly EU. Here are the stats and location for Trinadade


It's about 4700 miles SE. Here is a google shot of the island


The pics shot off and around the island are stunning and worth the google trip. A little after I worked him he QRT'd and I was hoping he might show up down on 80M so I hung around for a bit to write this blog post and see what might develop, but no such luck. Trinadade has an interesting history and you can read more on the PP0T web site

There is only one op on this expedition as his transport was a Brazilian Navy ship and it headed out at the end of April to return in June. Pretty exciting to contemplate operating from a place like this for a month or more



73

Monday, April 25, 2011

FJ/OH2YL






I've been off the radio for a few weeks and flipped on 80M and there was FJ/OH2YL Anne is on DX pedition on St Barts operating 160-10 CW

She was an easy chip shot from FL


When I first heard her she was working the gray line across EU and Russia. According to the web site she is running a pair of phased HF-2V butternut verticals. She was probably beaming EU as her strength was such that I probably worked her off the side of her array


She was in direct competition with the storms over Louisiana. The storms are about -95dBm, summer time cdx are certainly here.

I flipped on diversity and was able to null the static down to about -102 dBm making the listening much more pleasant.



I listened to her knock off station after station as I wrote this post. She is one fine operator. Wish she would QSY to 40 :)

73

Sunday, April 10, 2011

The Amazing World of Ham Radio



So no sooner did I write about the "Knob Project" than did I start to receive email from others who have been involved in developing similar ideas.

James KS4JU editor of HamRadioScience wrote about development of computer cases with built in screens


His comment is that some of these cases also contain remote controllers



I can see the brain flashes going off all over radio land!!!

This morning before I even got my Latte I got a note from Tobias DH1TW about his project


This guy has developed a complete control surface for PSDR using a DJ console that is in Beta testing!!

I haven't had the chance to review either of these developments in detail, but I think its GREAT!! It shows the versitility of a plastic radio, that is a radio that can be molded by the user to fit the user's needs. In my case I wanted a radio station that was highly integrated. I wanted a radio station that would do my will and follow my needs without my having to do much in the way of knob twisting and button pushing. I wanted a radio station with a high degree of efficiency and I had a blast creating that all based around PSDR and DDUTIL. To acheive my goal I needed this

A 19 dollar board from Unified Microsystems and the support of K5FR and DDUTIL

I also wanted to try to bring to ham radio the promise of SO2R based in software as an extension of the automated station, and to a very large extent we have created this also using N1MM as the contest interface.

James is interested in a radio in a box kind of approach YET the radio looses none of its flexibility. It gives up nothing but gains in its individual expression of character. On the other end I have seen PSDR displayed on 40 inch TV screens at the Orlando hamfest


A few of us got together and built a Knob



as a foray into a different means of control for use in contesting and DXing, and the Knob was turned into a commercial product

And now other hams from around the world are revealing their own additions and variations and ingenuity!! What fun this hobby is!!

73


Friday, April 8, 2011

The Knob becomes a FlexControl

Flex is announcing a commercial version of the Knob by K6TU and K6TD. Here is a recap on Stu's website regarding bringing this product to market

Contest Knob – Announcing the Product

I didn't really have anything to do with bringing this concept to market except for my input in helping design how the Knob does its "Control" thing, which I think it does VERY WELL. For $129.95 the "Flexibility" this device brings to the radio is well worth it. It is much much more than a contest controler, but makes a whole panoply of features readily available to the finger tips.

The argument has always been either/or. EITHER it's point and shoot OR it's a Knob that is needed. This device makes it BOTH/AND since it is seamlessly integrated into the operation of the radio. Its presence brings a whole new level of integration to managing the radio, and in my operation it has become indispensable. It was a lot of fun being involved in this project, and it shows once again the ingenuity of hams in solving their own problems and in coming together to devise a "corporate" solution. Corporate comes from the Latin: corporātus which means to "form into a body" and that is what happened. Many came together to create something useful for all involved.

I haven't had the chance to give the commercial version a whirl, but given what I know of the prototype, I would not hesitate for a second to recommend it to anyone who is interested.

73

Tuesday, March 29, 2011

More Knob

Origins & Refinement of the Contest Knob - II

Stu continues with part 2 of his recap of the development of this fine contraption. Just for the record I am never satisfied but I am willing to be bounded :)

73

Sunday, March 27, 2011

4K8M UN3F


I was doing a little correspondence when UN3F in Kazakhstan popped up on 30M. Recently I have increased my 30M operating. I am usually on 40, 80 and 160 and had only worked about 100 countries on 30M till about a month ago, so I have been trying to pick things up on 30 since not too much new in the way of spots comes across the cluster for the other bands. I could do a lot more on 160 but my antennas are still down on that band.

Just as I tuned him in he was working a WB8 and I was getting set to work him and he seemed to disappear, probably going QRT. He was past his sunrise so he was probably heading out to work. At the same time I saw 4K8M in Azerbaijan spotted so I loaded up the memories and had at it, clicking back and forth.

Unfortunately UF3F was truly gone but I had 4k8M in the log first call.


I have 3 antennas available for 30M and none of them are great. I have a 135ft flat top at about 50 ft fed with open wire to a Johnson KW matchbox. That antenna has as pattern that looks like this on 30M (north is strait up)


This antenna was not a very good match for UN3F but a better match for 4K8M

The second antenna is my 65ft 80M vertical. On 30M this antenna approximates a 5/8 wave vertical. This antenna has an extensive radial system and exhibits a SWR of about 2:1 on 30M. I better match that with an Ameritron tuner. This is the antenna I use the most on 30M


Finally I have a 45 ft vertical wire out of a tree that has a MFJ 929 auto tuner at the base of the tree. It has a beautiful pattern:


unfortunately the ground system on this antenna is abysmal since I mostly use it as a RX probe antenna for diversity, so I don't transmit on it much. UN3F is on fairly often so I'm sure I will have another shot at him before summer

73

Saturday, March 26, 2011

Filters





My old buddy K3RR and I were corresponding and he mentioned the difference between his cascaded 250hz filters and my 12hz DSP filters. The theoretical difference is 10log 250/12 =13.2 dBm. I was sitting on 80M seeing if I could hear anything out of A52J:

(after all hope springs eternal) and since the band was so quiet I decided to measure the difference and make a little document.

Here is the radio with 12hz filters:


The RX2 receiver's vertical antenna has a little less output than the full size vertical on 80M connected to RX1. Best case today is in the -118dB range. For the 250hz case:


-107 dBm was the best I could do which is about 11 dBm difference. So the filter difference extends me another 11 dB into the noise floor. I decided to look at 500hz filters as well:


Predicted is 16.2 dBm and I got 14dBm difference, very consistent with the data point above. Some of the difference between predicted and measured could be due to AGC action since certainly by the time I get 16dB above the noise there is some AGC starting to flatten out the signal. I had "best" AGC-T (agc threshold, or the point at which the AGC just starts to reduce gain) set on the 12hz filters:


When I readjusted on the wider filters it didn't make any difference. The AGC-T adjustment is one of the best features of this radio. The AGC is designed to effectively turn down the sensitivity of the radio. If the AGC is not active the radio is most sensitive. By adjusting the AGC-T you can set the AGC to turn on at some point considerably higher than the band noise. This is a big deal when working DX since in most radios the AGC is already well engaged and turning down the sensitivity due to the band noise itself, so you are never really able to realize the full sensitivity of the radio or the full dynamic range. Since you don't need the radio to be more sensitive than band conditions allow by adjusting the AGC-T your chances of hearing someone right at the noise are improved.

Here is a shot at 500hz with the noise blankers turned off

-83dBm

and now at 500hz with the blankers turned on


Without the noise blankers, the AGC-T and the 12hz filters (and diversity) I basically would only be working G's, OK's and DL's on the bands.

Here is a shot of the radio on 10M with a resonant vertical attached

and here is a shot with no antenna connected to RX1

Still no Bhutan but VU4PB just showed up on 40 to tease me:

A nice European pile up and a K1 who is hearing him. It's the K1's gray line time so maybe tonight is the night:


73