Re: [amsat-bb] Newbie Post: Rig Choice, 23cm Capability Importance

["Edward R. Cole" <al7eb@xxxxxxxxxxxxx>]

At 09:19 PM 2/27/2003 -0600, Jon Ogden wrote:
>on 2/27/03 6:00 PM, rmidgett@bellsouth.net at rmidgett@bellsouth.net wrote:
>
>> It appears that AO-40 is accessed primarily by 23cm, with DL via mode S.
With
>> that in mind, am I correct that I could utilize the 2m band in a 2m/70cm
rig
>> to drive a 23cm transverter for the uplink to AO-40, and monitor the S
band DL
>> via a seperate RX (like my PCR-1000)?
>
>AO-40 is accessed both by U band and L band.  From what I think I have read,
>the L band antennas are higher gain and if squint is bad, then L band is
>harder to use.  I could be wrong, but I think I remember reading that.
>
>Given that then your choices are as follows:
>
>1.) Purchase a rig with 23 cm (IC-910 or TS-2000).
> 
>Personally, I would rather have a mast mounted 23 cm converter.  The amount
>of loss in even good coax is rather high at 1.2 GHz.  You'll get more power
>to the antenna with the L band transverter at the antenna.
>
>2.) Purchase a VHF/UHF rig (ie: FT-847) and an L band transceiver.
>
>In this case, I would use the UHF side as my IF for L band.  Why?  The
>reason is that this way, I could then use either L or U for my uplink
>depending on conditions.  Then use the 2m side as the IF for S band.
>
>
>Personally, I would prefer option #2 as it gives you the transverter at the
>mast and more flexibility.  There aren't really any other active satellites
>that use L band at this time, but there are 2 more being built right now
>that will.  
>
>Even if you purchased a 910 or TS-2000, you could still buy the transverter
>for L band as I think L band is an optional module on each radio anyhow.
>
>But I would DEFINITELY use 432 for the L band IF.
>
>73,
>
>Jon
>NA9D

Jon,

I am probably repeating myself, but I think you will find that most xvtrs
for 1.2 GHz will utilize an IF of 144 MHz.  You might special order a unit
with an IF of 432 MHz.

Instead I think it easier and about the same cost for using:
mode-L:  use 144/1268  (Downeast, ssb, and Kuhne make them).  BTW it is
only a Tx conv.

So how do you receive AO-40 when operating mode-LS?  I bought an extra
Drake.  One has an IF of 144 MHz; the other an IF of 435 MHz.  I use a
common LNA (preamp) which drives both converters thru a coax tee!  To
switch modes I connect the appropriate IF cable to the FT-847.  This way I
use common equipment to minimize the difficulty or expense.

My Downeast Microwave Tx convertor,  does not have receiving equipment such
as offered in a full xvtr.  It converts the FT-847 144 MHz Tx signal to
1268 MHz at 18w.  The Tx-converter mounts at the antenna and I don't need a
second receiver.

Ed - AL7EB

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