[amsat-bb] Re: RS-15 satellite.

i8cvs domenico.i8cvs at tin.it
Fri Sep 22 09:23:56 PDT 2006

----- Original Message -----
From: <Garyatlnt at aol.com>
To: <amsat-bb at amsat.org>
Cc: <Garyatlnt at aol.com>
Sent: Thursday, September 21, 2006 6:09 PM
Subject: [amsat-bb] RS-15 satellite.

> I was reading recently about the status of RS-15 which was declared
> semi-operational.  Nevertheless I thought I would give it a try.  I would
> sporadically hear the beacon and then try to access the transponder and
> remained persistant in trying for several days, then about 3 days ago
> I turned on my rig to try and forgot the uplink frequency and wrongly
> entered 144.958 to 144.998 [rather than the listed uplink of 144.858 to
> 144.898] and the transponder responded with the downlink still in the
> listed range of 29.354-29.394.  I have continued to be able to get the
> transponder to respond by useing the "wrong" uplink of  144.958-144.998.
> I hope others will try the same as I sure would like to make some contacts
> rather than simply hearing my own signal.  Thanks.  Gary DeMunbrun
> [ WA4RKS].

Hi Gary, WA4RKS

The listed frequency for the uplink Mode-A of RS-15 is 145.858 to
145.898 MHz and not as you writes 144.858 to 144.898 MHz

Now if you wrongly entered 145.958 to 145.998 MHz (as I believe)
and the transponder responded with the downlink still in the listed range
29.354 to 29.394 MHz it is possible that the local oscillator in the
down-converter on board of RS-15 changed the nominal frequency
increasing it by about 100 KHz because of crystal aging and this is

If instead you really entered 144.958 to 144.998 MHz as you writes for
the uplink it is more difficult to accept that the local oscillator on RS-15
down-converter decreases its nominal frequency by 900 KHz

Anyway while listening RS-15 using your claimed anomalous uplink you
should verify if you have doppler shift, if you have QSB, if you get the
downlink only when RS-15 is in range or if you get your own signal at
any time.

In addition you should verify if transmitting in the anomalous uplink from
144.958 to 144.998 MHz you get your own signal from 29.354 to
29.394 MHz because of some unwanted mixing product between your

For your information on 3 august 2006 at 13:33 UTC orbit 47788 I have
received the 29.353 MHz beacon of RS-15 as a 4.5 sec. intermittent and
unmodulated carrier with QSB but uplinking in the official listed frequency
range any attemp to get my downlink was unsuccesfull.

73" de

i8CVS Domenico

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