[amsat-bb] Re: Phelps Dodge Cavity Resonator 406-512 MHz for mode J. Also request for info.
domenico.i8cvs at tin.it
Mon Nov 5 22:58:16 PST 2012
Hi Bill, NJ1H
This 432 MHz filter and protection device has a fraction of dB losses
and so if fitted in front of a 70 cm preamplifier do not degrade very
much it's Noise Figure.
You can build it very easily at home.
----- Original Message -----
From: "Bill Bordy, NJ1H " <nj1h at comcast.net>
To: <amsat-bb at amsat.org>
Sent: Tuesday, November 06, 2012 5:04 AM
Subject: [amsat-bb] Phelps Dodge Cavity Resonator 406-512 MHz for mode J.
Also request for info.
> I am now on mode J with a transverter and my Flex-5000A. I picked up a
> Downeast 144-28 transverter at the local hamfest, and experienced
> overload on the 435 MHz downlink when transmitting on 2M. I had seen
> this before with my FT-736R
> At a previous hamfest, I saw a Phelps Dodge Cavity Resonator marked
> 406-512 MHz and bought it for $1 thinking that it may resolve the
> overload problem. Well, I finally tried it in path for the 435 MHz .
> Wow, great fix. I have it in front of my 435 MHz preamp and now have no
> movement of noise floor when transmitting on the 2M uplink.
> It also has CAT NO 495-509 marked on it. Not sure about the second 5,
> could be a 3 since number is worn badly.
> I did a WEB search and didn't find any technical information specific to
> this model. If anyone has information, would you supply me with a link
> or info?
> If you can find one of these, don't pass it up. A single tuning
> adjustment on top. I peaked it during a FO-29 pass. I then discovered a
> local 435 MHz noise source, I think a cable distribution box, than I
> could peak on also. Fortunately it is only in one direction and beam has
> to be right on to see.
> There may be other cavity resonators that would work.
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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