Friday, October 16, 2009

K4M/KH4 on 80

Given the amount of time it took me to work them on 40 yesterday ( a little over an hour), I got up an hour early to see if I could bag them on 80. As you can see the pileup is dramatically smaller, BUT I had storm static that was out of control. My S meeter spent most of its time at -90dBm about the same level as K4M. I live on the central east coast of FL and here is a map of my noise sources:

In a word UGLY!!! I'm virtually surrounded by storms.

It was the first time I needed ALL the noise reduction goodies to make the contact. I turned the AGC-T way down so the static fell into the background and only peaks got through. The Static is limiting so there is no reason to run the static way into AGC. The way you do this is to set AGC-T so the average static level is just audible. Crashes will of course poke through but the static will NOT dominate the AGC action of the radio. When you hear people speak of signals "popping out of the noise" this adjustment of AGC threshold is why. The noise was still too loud however so I kicked on BIN. BIN stands for bin-aural and it splits the audio into a low pass and a high pass so one ear gets the low passed audio and the other gets the high. I was running only 50hz bandwidth on the filters so there isn't a lot of "low" and "'high" to filter, but it did seem to improve copyability so left it active. Next I turned on NR. The NR in this radio actually does something

Here is an MP3 with AGC-T set to 85 (towards the high end)

Here is an MP3 with AGC-T set to 56

An MP3 with BIN added

An MP3 with BIN and NR added

The last 2 are subtle and probably require headphones to really appreciate but each step in the noise reduction scheme of this radio combined to make the signal quite readable through the din. There was considerable QSB to contend with. I made several trail recordings of these settings and kept the ones with peak signals to try and avoid QSB as a factor in the recordings.

During AGC 56 there was a -70dbm signal (aka loud) station calling about 40 hz off freq it can not be heard except for a few of his key clicks.

One thing that was a blessing is that the pile up was VERY well behaved. Almost no tuner uppers and almost no jokers calling on freq, and only one ahole sending strings of dits.

The operator today was running a much more traditional pileup. He was pretty much +2 to +3 and not drifting all over the place, which is why the pileup was nice and compact. He was working a lot of JA's and some Russians in-between US contacts, as the day to night gray line was just washing over Japan and the night to day end of the gray line was still an hour away from the east coast. All in all I had him in the log in under ten minutes TOO MUCH FUN