[Lowfer] BPSK31

[Ed Phillips]

John Andrews wrote:
> 
> Ed,
> 
> > Question:  How is TAG generating the BPSK31 signal?
> 
> It's actually a phasing SSB exciter. The carrier is generated by a DDS chip,
> then buffered and fed to two SBL-3 mixers. The output of my sound card is
> routed through a 90 degree audio phase shift network to the mixers, and the
> combined mixer output is amplified and sent to the PA. It's a pretty broad
> signal, since the PA runs in the usual lowfer switching mode. But for this
> application, there's nobody to bother.
> 

	Thanks for the dope.  I guess the phase-shift network is simple since
you're working over a limited range of tones.  I'm still looking for an
"easier" way.  I built an SSB exciter back in the 1980's which used a
200 kHz crystal filter I happened to have.  Never went the rest of the
way to mix it down to 180 kHz but intend to take it out and have a
look.  I agree with you on the broad signal but at least one of us guys
is a purist and wants to do it right.  Low power on a noisy band?  Who
cares?

Ed