Wednesday, March 4, 2009

The bleeding Edge

This morning I woke up early and toddled into the shack with an ice cold bottle of Arizona Green Tea. As I was quenching my thirst I heard RW0CN on 3503. I first set up all the controls including the AGC, played with the NB and started narrowing the filter down to 50hz. The band was relatively quiet but he was only a few dB out of the noise. By the time I was done tuning him in he was watery weak, but Q5. I worked him in a couple of calls and here is an audio file of my report.


A bit later I was tuning 160 and heard what I guess is a Chinese beacon 3L6P (3LBP?) on 1831.010. Its cold here in FL this morning and I'm sure there are a number of space heaters on all across the land, and my usually quiet band had a buzz. Not much of a buzz, my band noise was down about -105 dBm, but the Chinese station was below my noise around -109 dBm. This next clip is of my bringing the Chinese station out from under my noise. I first narrow the filters down to 50hz, adjust the AGC-T and play with the AGC decay and decide "long" is the ticket, I turn on one of the 2 noise blankers. I had previously determined what combination of noise reduction would be best for this band on this morning, and NB1 was the correct choice here. Listen as I tune this station in:


Near the end I turn between 500hz and 50hz so you can hear the difference in copyability

PowerSDR has a group of noise reduction features as you can see in this pic

This shot was taken while 3L6P was transmitting and as you can see he is barely visible in my noise. The controls are NB, NB2, NR and ANL. The corresponding set up screen is:

The controls on the front panel turn off and on what is shown in this second screen. The ANL (auto notch) works very well, but since I'm mostly CW it is counter productive for me. Its really hard to work CW when you notch out your contact. The noise blankers are fantastic, and each works on a little differnt kind of noise, and together they are number 1 with a bullet. The NR works but it adds enough artifact that I don't care much for it, but there are occasions where it makes the difference. Also there is the RX EQ which surprisingly enough can make a dramatic difference in some noise conditions. NR and RX EQ are not very effective on CW, as the bald headed man with the sun glasses and the Louisiana accent said "its the filters stupid". Today it was the filters, the NB, and the AGC tunability that made the difference. SR is spur reduction and if there is a spur in the radio, you can move that spur out of the way by clicking this button. I never use it, but its there on the odd chance. BIN is a means to turn a signal into a binaural signal. It was all the rage a few years ago to have the band separated into a low pass filter into the left ear, and a high pass into the left ear and the signal center in the middle of knee of both filters giving your brain the sense of becoming the filter. I think there were also versions that changed the phase between one ear and the other. I built one of these years ago and I never found it to be of much use in terms of increased readability. It clearly makes a difference in what you hear, it kind of gives a presence but I read em as good with BIN as without. 40+ years of 80M static has fried my brain just fine thank you very much and I don't need any help from someone named BIN.

For grins here is WH12E an 80M beacon I guess on KH1. Now this sucker is weak, but with headphones he can be copied.

I tried to look for more info on these beacons and so far have come up short. It would be interesting to know something about the equipment, antennas and power levels of these stations

My buddy K3RR thinks these are both fishing buoys on drift nets and that could well be the case. What ever they are it was fun to pull them out of the noise

W8JI confirms these are net beacons so I guess instead of me hearing a new one I was caught in the net!!