My Station

 

 

 


 

Antenna

The antenna is a 1.4 prime focus dish from www.satellitesuperstore.com . Technical information: The ratio of focal length to aperture size (F/D Ratio) is 0.41, Gain at 10.95GHz 41.8dB.

As you see, the stand is kept in place with ~ 280kg of lintel, breeze block and slab.

The dish was aligned using the sun on March 1st, 2019 because at 10:16 the sun's azimuth and elevation was the same as Es'Hail 2, so the shadow of the feed would be directly over the center of the dish.

LNB

Testing with an Octagon 0.1db Quad High Gain HD Ready Universal low-noise block downconverter (LNB). This is very sensitive but drifts - for SSB / CW it must be modifed, either change the crystal to a TCXO or add support for an external reference such as the Leo Bodnar GPSDO. Drift is much worse in the daylight for obvious reasons.

There is a special feature in SDR Console which locks the receiver to the digital beacon on the narrow-band transponder, so reception is perfect. 

The output frequency of the LNB is ~739MHz, the LNB also has considerable gain - up to 65dB!

A LNB must be powered, the supply voltage determines the polarisation. Typically 13v for vertical and 18v for horizontal polarisation. Power supplies are not expensive, for example Labgear PSUFC on Amazon.

SDR

Receiver

There are many options, the most popular being:

  • Airspy R2,
  • SDRplay RSP1A, RSP2,
  • RTL Dongles.

The output of the LNB is ~ 739MHz, so the receiver must cover this frequency.

Transceiver

The transceiver must support transmit at 2.4GHz and receive at 739MHz, preferably at the same time (full duplex).The currently supported options are:

Both work well, the recommended solution is Pluto:

  • Price,
  • TX output power,
  • Ease of programming.

 

Comparison Table
Feature LimeSDR Pluto
Price $299 £110
RF chip LMS7002M AD9363 (hack to AD9364).
Frequency range 100 kHz – 3.8 GHz
 

325 MHz to 3.8 GHz
70 MHz to 6.0 GHz (AD9364hack)

Ext. reference Yes With modification
RX sensitivity Good Good
Stability Good Good
Bandwidth 50Mhz 5MHz (200 MB/s)
TX power -6dBm +6dBm
Case included No, eBay Plastic, metal available from eBay
Software API Good Very good
Other   USB noise - needs a very good cable or metal case