[amsat-bb] Re: 2 meter to 10 meter downconverter?
kl7uw at acsalaska.net
Fri Apr 6 08:23:57 PDT 2007
At 03:58 AM 4/6/2007, Tyler Harpster wrote:
>What's a good source of 2 meter to 10 meter down converters? I just need to
>receive 2 meters, but my 706 is doing uplink duty on 435. I have an old
>shortwave receiver that can do the listening to the AO-7 mode B downlink
>with a receive converter.
I can recommend the DEMI 144/28. I just completed building the
144/28K, which is the low-power xvtr kit. It outputs 10mw in
transmit for use with other xvtrs an designed to drive microwave
units. But I am using it in Rx-only to drive my SDR-IQ on 28-30
MHz. The receive-only version is identical without the transmit
components and sold assembled for $170 (the kit I bought is also $170).
I had a couple boo-boos in the construction: my first LO coil was
too many turns and the oscillator would not run. I apparently blew
both the preamp and second receive mmic. Replacing them I got -124
dBm (0.14 uv) sensitivity in FM-mode. My FT-817 is only -119 dBm
(0.25 uv), so you can see this is pretty hot! DEMI rates the
converter at 1 dB NF and 17 dB conversion gain. The LO uses a PTC
heater and I have freq. stability as good as I can measure with an
IFR-120 service monitor (1-Hz).
If wanting cheaper, you might check out TenTec. They made a line of
convertors and xvtrs at around $100 at one time.
Ed - KL7UW
BP40IQ 50-MHz - 10-GHz www.kl7uw.com
144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
DUBUS Magazine USA Rep dubususa at hotmail.com
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