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Re: New S Band Converter



In Australia, Ian MacKenzie, VK2ZIM, can be contacted at Comsys on +61 2
9878 1188 and he can supply Conifer grid dish (24dbi) antennas  and modified
Conifer down converters. Choose the IF you want. These units have a good
interdigital input filter and a noise figure of about 0.7db.
    The disadvantage is that they do cost money but so does anything else
that works well.

Murray Peterson
VK2KGM

----- Original Message -----
From: "Tony Langdon" <tlangdon@atctraining.com.au>
To: "'Howard Long'" <howard@howardlong.com>; "Roy Welch"
<rdwelch@swbell.net>
Cc: <amsat-bb@AMSAT.Org>
Sent: Tuesday, January 16, 2001 11:31 AM
Subject: RE: [amsat-bb] New S Band Converter


> > *** 2m 23cm IF, 70cm 13cm IF
>
> Probably the most common scenario.
>
> >
> > Pro's:
> >
> > o Easy to find 23cms uplink trasmit converters on 2m.
> >
> > o Fairly wide 13cm sub-band available to you.
>
> In some areas (e.g. Australia), may simplify choices for 13cm Rx (common
> converters from defunct pay TV systems here have a LO of 1951 MHz, so 2400
> MHz becomes 449 MHz, which could be reached with a slightly modified 70cm
> Rx.
>
> > Con's:
> >
> > o Your expensive 23cm Transmit converter will likely be very
> > narrow band on
> > 2m and be limited to the satellite sub-band (1268MHz).
>
> You will need separate xtals for satellite and terrestrial, unless you can
> mod your IF Tx/Rx to go out of band.
>
> > Pro's:
> >
> > o Nice wide band transmit, likely to be able to use TX converter for
> > terrestrial 23cm too. (You'll need to mod your FT-847).
>
> Generally, this is the case, most rigs only cover 10 MHz out of the box
> here.
>
> > o May be difficult to find 70cm IF TX converters. I think
> > there may be a
> > technical consideration in using a 70cm IF due to local oscillator
> > considerations and in band transmit mixing products.
>
> I'd imagine this is a similar scenario to 2m -> 70cm, but I happen to have
a
> 2m - 70cm transverter.  It uses double conversion, down to 10m, then back
up
> to 70, to avoid any spurious products leaking through the chain.
>
> > o Very limited sub-band of 13cm available to you.
>
> In VK, not an issue.  only need to cover 2400 - 2404 MHz for terrestrial
and
> satellite operation (our terrestrial is conveniently on 2403 MHz).
> ----
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>

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