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Title: Two transmitters, one article. Post by: WA4WAX on July 26, 2016, 09:14:40 AM ......Take your pick. It all starts on page 816.
http://www.americanradiohistory.com/Archive-Practical/Wireless/60s/PW-1963-01.pdf Title: Re: Two transmitters, one article. Post by: W3RSW on July 26, 2016, 11:13:38 AM Perused the circuits, but as usual the rest of the magazine was fun too. Ads for stuff like gangedd potentiometers, log/log, Log/anti log, log/Lin, etc. for Mullard circuits, ....just fascinating imagining the audio circuits these fit. Title: Re: Two transmitters, one article. Post by: DMOD on July 26, 2016, 01:37:02 PM From Page 819:
Quote The modulating impedance of the P.A. can be found from: Z= P.A. H.T. voltage/P.A. current (mA) x 1000. Assuming that the P.A. draws 40mA at 250V, the impedance will be approximately 6200. Actually it's 6250, but where did the x 1000 come from? Phil - AC0OB Title: Re: Two transmitters, one article. Post by: W3GMS on July 26, 2016, 02:25:45 PM From Page 819: Quote The modulating impedance of the P.A. can be found from: Z= P.A. H.T. voltage/P.A. current (mA) x 1000. Assuming that the P.A. draws 40mA at 250V, the impedance will be approximately 6200. Actually it's 6250, but where did the x 1000 come from? Phil - AC0OB Normally you convert the current to ampere's, but if you don't and just use MA then the answer comes to 6.25. When you multiply that times 1000 your back to the correct answer! Joe-GMS Title: Re: Two transmitters, one article. Post by: DMOD on July 26, 2016, 02:49:48 PM thanks Joe.
Guess I am just to literal. :D Phil Title: Re: Two transmitters, one article. Post by: W3GMS on July 26, 2016, 11:47:29 PM thanks Joe. Guess I am just to literal. :D Phil The 1000 was a giveaway for me. I though amps vs ma and then 1000 fit into place! I understand very well about being literal ;). Been there done that..... 73, Joe |