s-band
Specialist Contributor
- Joined
- Feb 7, 2016
- Messages
- 1,189
- Reaction score
- 1,846
- Points
- 113
- My Satellite Setup
-
1.5m IRTE PF, Octagon OSLO external Ref., TBS6983,
Various L, S, C, X & Ka bits. 1.2m S/X/Ku/Ka Prodelin on Az-El (being refurbished)
- My Location
- Essex
There have been a few iterations along the way but here is some info on the X band stuff that I'm using.
The feeds are based on 28mm plumbing for 8.4GHz and 35mm for 7.5GHz. Whilst the 28mm works at 7GHz, it is a bit close to cut off for my liking. I started off with squashed pipe polarisers but switched to a more professional one for DSN from uhf-satcom. The LNA is a single CE3512K2-C1 GaAsFET from CEL which has an NF around 0.8dB (should be better). That's followed by a Miteq AFS3-08500960 from Ebay. That's got a NF of about 1.6dB. The overall system NF is about 1dB on 8.4 and 1.2dB on 7.5.
7GHz offset feed, polariser & transition
7GHz Scalar, polariser & LNA
The BDC comprises: An isolator to improve the match, a Wessex surplus 2 stage amp with all fets replaced by MGF 4949, 3dB splitter to feed an analyser, surplus filter, WJ M14A mixer, 2250MHz LPF & an IF amp. The LO is uses a synth from a Gilat band B Ka LNB with external reference fed from a signal generator. Initially it used the original crystal giving an LO of 9125MHz. I swap the isolators and filters to switch between bands.
For the back end I use an SDR (AD-Pluto, Airspy or Lime Mini) or a TBS 6983.
Useful links:
https://uhf-satcom.com/
Microwave and Millemeter-wave Experiments - L. Cupido
Madrid Deep Space Communications Complex - NASA Seguimiento Online
HORIZONS Web-Interface
The feeds are based on 28mm plumbing for 8.4GHz and 35mm for 7.5GHz. Whilst the 28mm works at 7GHz, it is a bit close to cut off for my liking. I started off with squashed pipe polarisers but switched to a more professional one for DSN from uhf-satcom. The LNA is a single CE3512K2-C1 GaAsFET from CEL which has an NF around 0.8dB (should be better). That's followed by a Miteq AFS3-08500960 from Ebay. That's got a NF of about 1.6dB. The overall system NF is about 1dB on 8.4 and 1.2dB on 7.5.
7GHz offset feed, polariser & transition
7GHz Scalar, polariser & LNA
The BDC comprises: An isolator to improve the match, a Wessex surplus 2 stage amp with all fets replaced by MGF 4949, 3dB splitter to feed an analyser, surplus filter, WJ M14A mixer, 2250MHz LPF & an IF amp. The LO is uses a synth from a Gilat band B Ka LNB with external reference fed from a signal generator. Initially it used the original crystal giving an LO of 9125MHz. I swap the isolators and filters to switch between bands.
For the back end I use an SDR (AD-Pluto, Airspy or Lime Mini) or a TBS 6983.
Useful links:
https://uhf-satcom.com/
Microwave and Millemeter-wave Experiments - L. Cupido
Madrid Deep Space Communications Complex - NASA Seguimiento Online
HORIZONS Web-Interface