mw dish surplus

Wed May 3 11:32:00 CDT 2017

If you look at the pictures, these appear to be part of terrestrial microwave systems, NOT satellite.  They appear to operate on various terrestrial microwave bands, according to the labels on the equipment.  11/10gHz, 23gHz, 18gHz.  Probably from an old government point-to-point microwave system.

ODU is a generic term for OutDoor Unit, not always associated with satellite equipment.  This stuff could be of interest to hams.  A dish is a dish, and a different feed could be installed at the focal point, for example.  To a point...

Looks like fun to play with, but don’t expect to hit any satellites with this stuff.....
73, Terry, N4TLF

From: Samudra Haque 
Sent: Wednesday, May 03, 2017 10:20 AM
To: tacos at amrad.org 
Subject: Re: mw dish surplus

Just in case one (anyone) would like to experiment with satellite ODU, there are a variety of flavors: C-band (much desired), Ku-band, and Ka-band (desired). All of the upconversion takes place at the ODU. However, commercially, I have owned and operated large fleet of VSAT (Very Small Aperture Terminals) which typicaly use a modem (either 70 MHz, 140 MHz or L-band as intermediate frequency), and the TX upconversion and RX conversion (both!) take place in a single housing, that is the ODU in common parlance. Ex: Anacom transceivers (https://www.anacominc.com/prod_anasat.html). So if you see a large box, that includes: up/down converters, psu, HPA, dual synthesizers etc. good for lots of microwave parts and waveguides. 

On the other hand, most fixed satellite service TWO-WAY terminals have a polarizer (either linear or circular) which has taps, and transducers with different feeds- so that they TX signals are attenuated from the RX signals. There you would use either a waveguide/coax to the "ODU" as described above, for the RX path, and a higher power waveguide/coax for the TX path.  Or, if you had a simple block up converter (L-band to Ku-, Ka-, C-band) only, then a separate block down-converter (e.g., Ku-, Ka-, C-, band to L-band) would be required.

Note: old "L-band" 950-1450 MHz, new "L-band" upto around 2000 MHz. Not specific, look at the specs.
Also, there are often test bands on the GEO satellite transceivers for carrier/tx/rx/loop back tests ... 

/samudra

On 5/2/2017 4:12 PM, Tad wrote:

  That is what is typically called an "ODU" or out door unit. It is often coupled to the IDU over coax and runs an IF (intermediate frequency) and dc over that coax. The odu upconverts to the over the air frequency and amplifies the signal.  

  Some manufacturers just have a form of Ethernet and power to the ODU instead and have the radio not just an amount and frequency converter outside.  

  Tad

  On May 2, 2017 11:15 AM, "Alex Fraser" <beatnic at comcast.net> wrote:

    Saw these on a gov auction.  They are in Loudoun county VA.
    2 of the antennas are on 10 GHZ and 4 are on 17GHz.  The pictures show a heat sink on the smaller antennas.  Perhaps there is a transceiver built in?

    https://www.publicsurplus.com/sms/auction/view?auc=1844379&trackId=50

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