[amsat-bb] Re: VO-52

Louis House, KD5GM kd5gm at sbcglobal.net
Sat Jun 12 18:06:05 PDT 2010

>Message: 2
>Date: Fri, 11 Jun 2010 18:41:37 -0700
>From: Clint Bradford <clintbradford at mac.com>
>Subject: [amsat-bb]  VO-52 - OK to Work in FM?
>To: AMSAT BB <amsat-bb at amsat.org>
>Message-ID: <783B57E0-1B8C-4F72-A695->ACD09E6AE27E at mac.com>
>Content-Type: text/plain; charset=us-ascii

>The Bengal ham club posted about five years ago >instructions for working V)-52 in FM mode. Is that still >OK to do?

>"HAMSAT or VO-52 is a satellite intended for 
>SSB/CW operation. However as in VU land very few 
>of us can afford multimode VHF/UHF radios we are 
>accessing Hamsat on FM for which it is best to stick to
 >the centre frequencies (435.250 uplink and 145.900 >downlink). It is also best to simultaneously monitor your 
>own signals on the downlink using a separate radio. >Hamsat requires around 100 watt ERP for solid 59 
>signals. So if you are using 10 watts RF the 
>recommended antenna gain is around 10 db. However 
>Hamsat or VO-52 have been  accessed  on high 
>elevation passes using 25 watts ERP. If you want to use 
>omni directional antennas you can build a turnstile or an 
>eggbeater antenna which has a dome shaped radiation 
>pattern with circular polarisation. Separate 10 element 
>UHF and 5 element VHF crossed yagis with 
>circular .polarisation would give excellent results. Only 
>keep the transmission line loss (particularly on UHF) 
>minimum. Use hardline CATV cable if transmission line 
>is more than!
> 100 feet. Otherwise if you use RG-213 keep the 
>feeder length to around 20 - 30 feet. I have been using a 
>handheld arrow yagi antenna with RG-58U cable of 
>around 1 meter length. Doppler compensation is needed 
>particularly on the UHF uplink where the signal will shift a
>round 10 KHz. So for the uplink it is best to start from 
>435.240 MHz during AOS and end at 435.260 MHz at 
>LOS and on the downlink start receiving 5 KHz up at 
>145.905 MHz and end at 145.895 MHz. Currently the 
>VU transponder is on and it has a beacon (continuous 
>carrier) on 145.936 MHz though we have not yet r
>eceived the beacon from Calcutta / Kolkata."

>Clint, K6LCS

It is very exciting to work VO-52 in the CW mode. She is a strong bird and hears well. I work her often on only 2 watts CW and a 12 dbi gain vertical yagi on the uplink and 10d bi for the V down link and can hear her down to about 5 degrees on most passes.  

CW, The original digital mode

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