[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Microwave signal generator



I also have an 8616B and I concur with John. The frequency stability, even
after many hours of warmup, is not suitable for a L.O.. From what I can see,
the signal purity is not so great either. It makes allot more sense to use
the 8616 for it's intended purpose and brew up one of the simple crystal
based harmonic multiplier circuits floating around as your L.O..

add my 2 cents to the pot.....
Howie
AB2S

----- Original Message -----
From: "John Stephensen, KD6OZH" <kd6ozh@gte.net>
To: "Bruce Nolte" <brucenol@abs.net>; <amsat-bb@AMSAT.Org>
Sent: Wednesday, June 13, 2001 11:03 PM
Subject: Re: [amsat-bb] Microwave signal generator


> If I remember correctly, the 8616 uses a klystron oscillator which isn't
> stable enough for SSB. It will be useful for antenna tuning if you have a
> directional coupler. The LO for any receiving converter needs to be
crystal
> controlled.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message -----
> From: "Bruce Nolte" <brucenol@abs.net>
> To: <amsat-bb@AMSAT.Org>
> Sent: Thursday, 14 June 2001 01:50 UTC
> Subject: [amsat-bb] Microwave signal generator
>
>
> > Greetings, I am contemplating the path I will need to take to receive
> > S-band on AO-40, and on a hunch I picked up a surplus HP 8616B microwave
> > signal generator at a recent hamfest for $20. I figure if nothing else,
> > it might be useful for testing and alignment purposes of whatever
> > downconverter I end up getting to feed my FT-736.
> >
> > I was discussing my plans for it with the guy I got it from, and he
> > suggested that the signal generator could prove useful as a local
> > oscillator for my S-band receiver by tuning it the appropriate frequency
> > needed to produce a mixing product in the 2 meter band.  I have only a
> > vague idea how to do this, I can probably map out a block diagram, but
> > am a bit intimidated about the practical aspects of making it work.
> >
> > A couple of practical concerns about the generator are also on my mind
> > as well. First, any receiver would have to be at or near the antenna,
> > since line loss over a nominal 75 foot run of coax, or even 7/8 CATV
> > hardline would be enormous at 2.4 gig.  Since the generator is a large
> > rack mounted piece of 1960's high technology, it is not practical to
> > mount it near the feedpoint of the antenna.  I would have to run coax
> > from the generator out to the downconverter at the antenna, and expect
> > from 20 to 30 dB of loss, even with top quality feedline. The signal
> > source is probably strong enough to overcome this, but I really have no
> > idea how much signal I need.  The 145 Mhz downlink should be fine with
> > 9913, LDF4-50 or whatever decide to use.  Another concern is the
> > stability of  the signal source, for even a 0.1 percent drift at those
> > frequencies is a couple of Mhz.
> >
> > It is an intresting concept, but before I invest any serious amount of
> > time or cash into a project, I want to see if this proposal passes the
> > practicality test.
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home