WW2 HF aerial distribution amplifiers - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Radio Wrangler · 30th Dec 2019, 10:48 pm

Quote:

Originally Posted by G6Tanuki

I can't but avoid thinking that this 'back-feed' of LO signals must have also been an issue with the early cable-TV networks? Seems that the immediately post-WWII Abingdon "cable-TV" network used 'distributed amplifiers' using twelve EF95 valves and a sort-of travelling-wave-line to couple them together in order to drive the coax that fed the downstream dwellings...

http://www.aeolian-hall.myzen.co.uk/circuit.gif

THat's a distributed amplifier, but all the valves run with the same amount of g-k bias without any self-bias from cathode resistors. THey'd need to be carefully matched - and stay that way.

David

John KC0G · 15th May 2020, 6:18 am

I had concluded that from the previous posts that there was not much else to be learned. The main information had come from Dud Charman via Pat Hawker, and that was about it. But recently I was going through Pat's columns looking for other information and came across a piece which he wrote in the April 1991 issue of Radcom, pp 32-34. In it he referred to an article by Dud Charman in the January 1991 issue of OTNews, No. 22, published by RAOTA. If anybody has a copy and could scan it, I would love to see it.

Pat also briefly mentioned Hanslope Park in his column in October 1996, p. 76, and included three small photographs in February 2000, pp. 56-57.

In post #5, Jon expressed an interest in the splitting networks. Hopefully the article will shed some light on them. In the USA the use of multi-transformer coupling circuits to extend bandwidth seems to have started in the 1930's. Harold Wheeler and others at the Hazeltine Corp developed an all-wave radio receiver in the 1930's which covered medium and short waves. Details can be found in H. A. Wheeler, "The Early Days of Wheeler and Hazeltine Corporation - Profiles in Electronics", Hazeltine Corporation, 1982, pp 263-276, and in H. A. Wheeler and V. E. Whitman, "The Design of Doublet Antenna Systems," in Proc. of the Institute of Radio Engineers, vol. 24, no. 10, pp. 1257-1275, Oct. 1936. Patents were obtained for some of this work. The most relevant seem to be US2081861 and US2239136. The others were US2064774, US2064775, US2092709, US2204712 and US2206990.

73 John

15th May 2020, 6:18 am	#22
John KC0G Hexode Join Date: Mar 2009 Location: Minneapolis, Minnesota, USA. Posts: 278	Re: WW2 HF aerial distribution amplifiers I had concluded that from the previous posts that there was not much else to be learned. The main information had come from Dud Charman via Pat Hawker, and that was about it. But recently I was going through Pat's columns looking for other information and came across a piece which he wrote in the April 1991 issue of Radcom, pp 32-34. In it he referred to an article by Dud Charman in the January 1991 issue of OTNews, No. 22, published by RAOTA. If anybody has a copy and could scan it, I would love to see it. Pat also briefly mentioned Hanslope Park in his column in October 1996, p. 76, and included three small photographs in February 2000, pp. 56-57. In post #5, Jon expressed an interest in the splitting networks. Hopefully the article will shed some light on them. In the USA the use of multi-transformer coupling circuits to extend bandwidth seems to have started in the 1930's. Harold Wheeler and others at the Hazeltine Corp developed an all-wave radio receiver in the 1930's which covered medium and short waves. Details can be found in H. A. Wheeler, "The Early Days of Wheeler and Hazeltine Corporation - Profiles in Electronics", Hazeltine Corporation, 1982, pp 263-276, and in H. A. Wheeler and V. E. Whitman, "The Design of Doublet Antenna Systems," in Proc. of the Institute of Radio Engineers, vol. 24, no. 10, pp. 1257-1275, Oct. 1936. Patents were obtained for some of this work. The most relevant seem to be US2081861 and US2239136. The others were US2064774, US2064775, US2092709, US2204712 and US2206990. 73 John