[Lowfer] 6 MHz Canadian Medfers?

[John Andrews]

Bill,

Sorry for the delay. I copied a few snips of the 6776.8 signal on 
Sunday, but with no improvement over Saturday's results.

Regarding modes -- With the Doppler shift, etc., WOLF would pretty much 
be a line to line thing, with no real build-up of copy expected. I 
remember Lyle running it on 160m, with ho-hum results. We also tried it 
up at 13.5 MHz, but it was awful. I'm told that the PSK63F mode is 
useful with static crashes and fast fades. They use the extra overhead 
for FEC, but I haven't bothered to look up the coding scheme. If you can 
figure it out, the eprom method should work. BW is double the straight 
PSK31, but that's hardly an issue!

The advantage of PSK31 is the very quick re-sync. If a character is shot 
out, then the next one may be OK. FEC will probably mean longer holes in 
copy, but hopefully a deeper trough will result. Some of the FEC modes 
that Jay and I tried were very slow to sync, and required some patience.

John, W1TAG

On 7/16/2016 11:42 PM, Bill de Carle wrote:
> John, Jay, Kurt:
>
> Thanks for the reports.  I know PSK31 isn't very robust but still it's
> kind of amazing that such
> a low power signal gets copied some 550 Km away on a band full of other
> unrelated signals as well
> as static crashes.  After watching the corrupted but repeating text on
> the screen for a while
> the human brain will figure out (guess) what the actual transmitted
> message must be.
>
> One could try other BPSK modes - the beacon box consists of an
> oscillator (at 4x final freq),
> EEprom for the bitstream (loadable via a serial port) and timing
> generator with some flexibility
> in the clocking options but everything derived from the one epson
> oscillator module running at
> a nominal 27,107,200 Hz.  I could upload a WOLF bitstream and run it at
> one of these speeds:
> 25, 31.25, 50, 100, 200, 400 bps or any of them divided by 10.  That
> means the standard WOLF
> decoder software would work, but we'd probably want to run it faster for
> HF.  We used to run
> BPSK at MS25 (40 bits per second) quite successfully on HF all those
> years ago.  The box can
> generate either BPSK or CW.  You fellas did a lot of work comparing the
> various modes under
> many different conditions so not much new to be learned by repeating
> that.  Paul Nicholson's
> ebNaut tests are of interest here but probably more suited to VLF or lower.
>
> Thanks also to Warren for the query about the Canadian 6 Mhz band - I
> thought it would be fun
> to dig out the old QRP beacon and see if it still worked and if there
> was still any interest.
> I'll leave it running for another 24H or longer if someone asks.  Wonder
> if Warren managed
> to copy it?
>
> 73,
> Bill VE2IQ
>
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