Re: LF: 630m JT9-2 last night

[N1BUG <paul@n1bug.com>]

Thanks Jay,

That sounds like a very good approach. I will see if I can find
someone within daytime range who has accurate power control and is
interested in doing that. It is not easy for me to adjust power in
small steps on the fly. Signals tend to be very stable during the
day. It might be interesting to start with JT9-1, decreasing power
in 1 dB steps until it stops reliably decoding, then switch to JT9-2
and keep going down in 1 dB steps until it stops decoding, then
switch to JT9-5 and keep going down. As you say, night time is more
tricky. I think we need some kind of test like this to compare one
submode against another in real world conditions.

73,
Paul N1BUG


On 11/13/18 7:29 AM, jrusgrove@comcast.net wrote:
> Paul
> 
> John, W1TAG and I found a good way to evaluate software was to
> run controlled testing between our two stations. The transmit end
> was configured to easily change power in 1 dB steps so that
> accurate measurements could be made. We would run the first set
> of tests during mid day so there was low noise, phase shift and
> skywave interference. The second test was during nightime
> conditions ... with all of the above anomolies. We would test for
> weak signal performance, static immunity and decoder recovery
> time after loss of signal during the transmission. While we often
> couldn't put 'precise' numbers on the various modes (especially
> at night) we could usually resolve things to a couple dB.
> Comparing one mode against another during these tests definately
> gave a 'feel' for what modes worked well up to expectation ...
> and those that didn't.
> 
> Jay W1VD