A great video! Far too technical for my schoolboy level understanding of electronics, but all the more impressive for that. This should be in the national archives as evidence of British engineering prowess. (I have to say I enjoyed hearing the domestic background sound of a young Birkill gurgling away!)
What a nice satellite spectrum analyzer, and on it you could see analogue satellite television transponders of bygone days, it’s interesting to look at the circuit diagram, whether it was implemented on transistors or microcircuits
As far as I can recall, a mix of analogue & digital ICs, with some discrete transistor stages. Composite 625-line sync & blanking (for all timings, sync reinsertion and framing for noise & spectrum display) were from a Plessey single-chip digital SPG. Narrow-band FM video demod used a Signetics NE561 PLL chip, wide-band a different PLL (was it NE564?) The SA IF amp and log detector were also Plessey chips -- the UK company (later GEC-Plessey, then acquired by Mitel, later Zarlink) made a range of very useful analogue and RF chips, since long obsolete, and also some of the earliest microwave GaAs FETs -- I used a couple of free sample GAT5's in the Ku-Band LNB. I guess (watching the video) the first mixer would have been a single-balanced diode affair (H-P Schottky diodes) in microstrip. The Gunn LO was a surplus cavity-to-coax job, possibly Mullard. Back to the indoor unit: SA display was implemented via a simple analogue comparator, gating filtered (1.5MHz @ 3dB?) log amp output at line (15.625kHz horizontal scan) frequency to generate the SA video signal, the second downconverter (to 36MHz in the Mk.1 RX, based on a UHF TV tuner) being swept by a sawtooth waveform derived from field sync (50Hz). Monitor was a BBC-surplus studio type, 405/525/625-line B&W composite video. The DOG at upper left came from a clutch of standard (74-series) TTL logic ICs. The wide-band block first IF (450 - 950MHz) amplifier (quadrature balanced Kurakawa configuration using 'wireline' hybrids) prominently visible on the head unit for both bands, was based on a microstrip design I did for the BBC to replace an unreliable tri-plate amplifier used in their 200W TV relay-station transposers, ironically a Plessey product.
ruclips.net/user/shorts5lnaOlxhEKk?si=LJgjQl0OLlGI3x09 Hi Steve, Happy new year! I was very impressed with your spectrum analyzer and decided to make my own ,on a small CRT monitor and an analog satellite tunner (TBCE220IT Samsung)I also used an LM311 comparator and an op amp LM741 ,the B/B signal from th tuner goes to LM 741 and after to the input one at LM311 and horizontal "sawtooth" (16.625 hz) to second input ,from LM311 the B/B signal goes to the CRT video input ,also the frame" sawtooth" 50Hz goes at the tuner VT (to varicaps) and it works !😂
Many thanks for sharing this fascinating video. He was an amazing pioneer.
Cheers from VK2, Sydney, Australia.
A great video! Far too technical for my schoolboy level understanding of electronics, but all the more impressive for that. This should be in the national archives as evidence of British engineering prowess. (I have to say I enjoyed hearing the domestic background sound of a young Birkill gurgling away!)
What a nice satellite spectrum analyzer, and on it you could see analogue satellite television transponders of bygone days, it’s interesting to look at the circuit diagram, whether it was implemented on transistors or microcircuits
As far as I can recall, a mix of analogue & digital ICs, with some discrete transistor stages. Composite 625-line sync & blanking (for all timings, sync reinsertion and framing for noise & spectrum display) were from a Plessey single-chip digital SPG. Narrow-band FM video demod used a Signetics NE561 PLL chip, wide-band a different PLL (was it NE564?) The SA IF amp and log detector were also Plessey chips -- the UK company (later GEC-Plessey, then acquired by Mitel, later Zarlink) made a range of very useful analogue and RF chips, since long obsolete, and also some of the earliest microwave GaAs FETs -- I used a couple of free sample GAT5's in the Ku-Band LNB. I guess (watching the video) the first mixer would have been a single-balanced diode affair (H-P Schottky diodes) in microstrip. The Gunn LO was a surplus cavity-to-coax job, possibly Mullard. Back to the indoor unit: SA display was implemented via a simple analogue comparator, gating filtered (1.5MHz @ 3dB?) log amp output at line (15.625kHz horizontal scan) frequency to generate the SA video signal, the second downconverter (to 36MHz in the Mk.1 RX, based on a UHF TV tuner) being swept by a sawtooth waveform derived from field sync (50Hz). Monitor was a BBC-surplus studio type, 405/525/625-line B&W composite video. The DOG at upper left came from a clutch of standard (74-series) TTL logic ICs. The wide-band block first IF (450 - 950MHz) amplifier (quadrature balanced Kurakawa configuration using 'wireline' hybrids) prominently visible on the head unit for both bands, was based on a microstrip design I did for the BBC to replace an unreliable tri-plate amplifier used in their 200W TV relay-station transposers, ironically a Plessey product.
@midvodian This is very impressive, thank you for your answer and Merry Christmas to you
ruclips.net/user/shorts5lnaOlxhEKk?si=LJgjQl0OLlGI3x09
Hi Steve, Happy new year! I was very impressed with your spectrum analyzer and decided to make my own ,on a small CRT monitor and an analog satellite tunner (TBCE220IT Samsung)I also used an LM311 comparator and an op amp LM741 ,the B/B signal from th tuner goes to LM 741 and after to the input one at LM311 and horizontal "sawtooth" (16.625 hz) to second input ,from LM311 the B/B signal goes to the CRT video input ,also the frame" sawtooth" 50Hz goes at the tuner VT (to varicaps) and it works !😂
P.s the strongest transponders on the SA is from 28.2 East ,in Ireland this satelite can be caught on a pot lid😂😂