23cm transverter for 1267-1269

  • I am interested in working and receiving the telemetry from satellites on 23cm, to do that I will need a transverter.

    Can someone please give me details of where I can purchase a suitable transverter and hopefully some idea of cost.

    (Unfortunately most 23cm transverters are set up for EME, not satellites. I dont want to have to go back to a rasberry pi or similar, as I am using a Flexradio 6600 and transverters for telemetry on 2m and 70cm.)

    Thanks and best wishes the forum is a good idea.



  • Yes thanks, my mistake, but that is why I need a transverter to give me the 1267 uplink. Without the uplink I cannot turn on the downlink telemetry on 145.880 for AO-92 when it has been commanded to a 23cm uplink and not the normal 70cm uplink.

    Alternatively does anyone have any suggestion to get a suitable 23cm uplink?

    If it was EME that would be easy, as there are lots of transverters for 23cm EME.

    Also what suggestions are there for suitable antennas for the 23cm satellite uplink frequency.



  • Hi Ross

    It sounds like you have an interest in telemetry, but you also say working the satellites on 23cm. The picture to the left is ESEO (European Student Earth Orbiter). It will have an uplink on 1263.5MHz, so when you select the IF frequency on your transverter it may be worthwhile getting TX capability on 1267 and 1263. - Perhaps 70cm to 23cm as Fox and ESEO have 2m downlinks.
    Currently, it's at ESTEC in Holland, but hopefully will be on it's way to the launch site shortly. (The definition of shortly is always open to interpretation!)

    73 David G0MRF

  • Hi Thomas.

    For power budget reasons, it's important to either shut off the transmitter on ESEO when there is no one on the uplink, or change from transponder to telemetry, which uses less power. As L band is full of radar signals, we could not use 'squelch' based on signal level. The 67Hz detector is a very reliable way to trigger timers to control the transponder. Once a 67Hz tone is detected, the transponder is active. If the tone is lost, the transmitter continues for 20 seconds. In practice you may be able to have a QSO if only one person has CTCSS....but don't chat for more than 20 seconds...

  • Thanks for your comments David, sorry I have been a few days in replying.

    Can I ask why you picked 1263 as an uplink frequency. With the SG-lab transverter I can get 1266 to 1268 easily enough, but it looks like 1263 is impossible.

    Yes I do have an interest in telemetry and have been downloading data from all 3 Fox satellites and soon , of course next month when the Falcon 9 launches hopefully Fox 1 Cliff as well.

    My email address is ross.biggar@outlook .com

    I would like to hear from you.



  • I don't know, if I can feed such a low tone from PC's soundcard to the microfone input, a higher subtone would be better, eg 151.4 Hz is possible.

    Adding CTCSS to older transceivers is a topic that has been on the terresteral repeater usergroups for years. It isn't difficult: a typical FM transmitter has a mic pre-amplifier, clipper (limiting the deviation), low-pass filter (to remove the harmonics from the clipper and then a potmeter going to the FM-modulated oscillator. Since the clipper limits the maximal audio signal, the setting of the pot defined the max deviation the transmitter can make.

    Best place to inject CTCSS is on the runner of this potmeter, typically with a high resistor (100k) in series.

    How to generate a tone - you should use a sine wave! - these days one uses a small PIC or ATMEL processor. I use a high frequency, 100kHz or so, and pulsewith modulation. The output looks nasty, but a single RC filter then delivers a nice sine wave.

    Many years ago I made a design that would be used for fundraising for a hamradio meuseum but for various reasons this never materialized. If you can program a 12HV615 yourself it is really easy, I may have a spare chip left. All you need is a crystal, 4 capacitors, 3 resistors and a piece of breadboard.

    There are also various kits out there, for instance on ebay, many of these do have more components than my design (grin).