Re: [amsat-bb] MMDS converters and 2.4ghz projects

["Frederick M. Spinner" <fspinner@xxxxxxxxxxx>]

Hey.. thanks.. I ordered four of those cool hairpin filters.

I wonder about PLL sources.  The latest issue of EE Times has an ad
for the Maxim MAX2751-- 2120 to 2260 MHz VCO (eight pin surface mount 
device), runs on +5V. Its too new to have data online apparently, though.

I imagine it could provide a small, simple and cheap (the VCO is $3.55 from 
Arrow) device to make a 2256 MHz PLL.  With a single frequency lock, and a 
"slow" loop filter I imagine a PLL can be devised that was more than 
suitable (phase noise) for SSB.

Interestingly enough I have a couple of the San Diego Microwave Group 2.4 
GHz Qualcomm PLL's. (Like the old 73 article) One I never got working, the 
other I never tried to get working.  Maybe I can cobble something up.  I 
have the old DEMI Mode-S converter, but I've never been to terribly 
impressed with it.

The old DEMI preamp worked fine at CSVHF in Winnipeg this year-- 0.64 dBNF 
with 12.5 dB of gain.  So I should be getting close to having a
good Mode-S receiver.

Fred W0FMS


>From: Mike Kana <cosmo224@execpc.com>
>Reply-To: cosmo224@execpc.com
>To: amsat-bb@AMSAT.Org
>Subject: [amsat-bb] MMDS converters and 2.4ghz projects
>Date: Sun, 31 Dec 2000 17:42:16 -0600
>
>Greetings all
>
>In one of the earlier emails regarding the vanishing surplus and the
>options of buying
>from the established kit/finished product dealers, there is still the
>time honored
>approach of homebrew - There is an outfit called 'ElectroMaven' which
>had a
>large supply of filters in a neat metal enclosure with sma in and out.
>Remove the
>lid and what do you find?  A hair pin filter for 2.4ghz!  Ok, now build
>up a couple
>of 1 stage mmic blocks and bolt them in line with this filter and hook
>up to a
>mixer that covers the 2.4 ghz frequency range - The daring can build up
>the LO chain or
>possibly modify a Qualcomm PLL synth and there ya go.  Now, I know that
>you can probably get a nice kit for a reasonable price and all the parts
>will be
>there but there is something almost illegally fun about gathering
>various and
>sundry parts and ending up with a mode S down converter.
>
>Cheers es 73
>de AA9IL
>Mike Kana
>
>Happy Millenium
>
>
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