[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[linrad] SSB

Hi, Kohjin, Conrad, et al!

> My first glance was a surprise especially on 40m CW and VLF.
> In comparison to my KK7B's R2, I firstly observed it's 
> quieter than mine. 'Time Machine' has a front end bandpass 
> filter and your PTS is doing better than my setup of course. 
> My setup consists of no filter in front of mixers, noisy 
> HP8640B as an LO and not modified diplexers.

I found that the front end filters made a very big difference in
performance.  Without them the SRA-386 preamp gets overwhelmed.  There
is a separate plug in filter for each band for the Time Machine. Each
band's filter and crystal are sold as a separate (form the Time Machine)

> I assume you use PTS-040, phase noise -135dBc/Hz @1KHz is 
> supreme! I leave URL for other's reference; 
> http://www.programmedtest.com/

Well, I don't yet have a PTS-040, though a couple are on the way.  I am
currently using PTS 500 for LO.  

> By the way, you have provided 
> phone band and I could realize they are SSB. Current Linrad 
> doesn't support SSB yet, does it?

Linrad can be used for SSB, although I don't think Leif has optimized it
for SSB yet.  If you go to mode D "SSB" it will remember the filter
settings, screen and other parameter choices you make and store them
separately from those for mode A "narrow cw".  Then you can just flip
back and forth between the modes with minimal effort.  I find that
Linrad does quite well on SSB.  It takes a bit of fiddling with the
vertical red bars in the baseband to get the bfo right and the station
centered within the filter passband, but once its done its set till you
want to change sidebands.  Then you must fiddle again.  Remember to turn
off the AFC when you go to SSB ;)  Of course you can even listen to
shortwave broadcasters this way.

If you are calibrating your receiver, you should know that it expects to
be calibrated for each mode that you are going to use.  This is not a
big deal to do.  When I do it for A, I always just go ahead and do it
for D as well.

I agree with both of you on the importance of power supply quality.
What I can get is a vey high grade medical equipment commercial power
supply with 0.05% regulation, less than 5 mV ripple, and essentially no
leakage.  It is of course a linear supply and supplies + and - 15 volts.
For this application I don't want a switcher. 

Have a great day, all!

I am off to work here...


Roger Rehr
W3SZ   FN20ah
2 Merrymount Road
Reading, PA  19609-1718