Re: LF: SSB modulation for WSPR

[LineOne <dhchurch@lineone.net>]

Unequal in amplitude Andy. the cure was simple but ridiculous. I had set the internal preset balance with the I & Q gain pots about halfway but what I didn't check was that  I & Q remained identical at different gain settings. In using many second-hand components, including a 2-gang 10k log pot on the I & Q input which came from a sound mixer I made about 20 years ago. Since that time I'd forgotten that these pots were log/antilog as they were stereo pan pots. Say no more.

Hugh

On 21/10/2015 11:13, Andy Talbot wrote:

Need to ask the obvious - is the frequency recorded in Joe's spots the actual one you were transmitting on?  Exactly, spot on, to the Hz ?

When you say I and Q are "somewhat different",  do you mean, the wrong way round, or unequal amplitued, or not in quadrature. All would contribute to a component on the wrong sideband and / or frequency  as well as the correct one

Seems a bit odd that your one actual decoded spot was quite weak copy at a respectable distance.   Judging from my dual mode transmission the other day, there are quite a few monitoring stations closer.

Andy

On 21 October 2015 at 10:15, LineOne <dhchurch@lineone.net> wrote:

So far the only person to decode my WSPR transmissions is Joe, DF2JP.

I made a drive unit for 136kHz to utilise 4 different methods of modulation including quadrature switching for SSB. Having just discovered that a fault caused the I and Q channels to be somewhat different I wondered what the effect would be and why Joe was the only one to decode it?

The carrier frequency is never more than 0.8Hz out, time is spot on via GMT (UTC) and the sound card is perfectly accurate so receive decoding is good.

Hugh, M0DSZ.

(P.S. I have no intention of signing up to Yahoo).