Re: [amsat-bb] Mode S Downconverter IF

[Estes Wayne-W10191 <W10191@xxxxxxxxxxxx>]

Jerry, K5OE wrote:

<snip> I believe a 2 m IF for the 13 cm downconverter and 70 cm uplink will be safe from harmonics, as will a 23 cm uplink.

Wayne replies:

You had me confused and worried there for a minute.  Fortunately, almost all of us plan to use a 2m IF for our 13cm downconverters because that IF is the most widely available from Drake, TranSystem, DEM, SSB and others.

If I ever decided to add 23 cm uplink capability, I would by default want to use a 70 cm IF (which would require helical filters to remove the 3rd harmonic of the IF signal).  Possibly the Kuhne MKU13OTX transmit converter with 70cm IF option, plus a mast-mounted DEM 20W amplifier.  That setup would cost so much money that I won't even consider it unless I used mode U/S for a while and was unhappy with the U uplink (or the AO40 U receiver dies).

I dream of someday car-camping with an AO40 mode L/S setup using helical antennas mounted to a camera tripod.

Wayne Estes W9AE
Mundelein, IL, USA
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