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Title: Stylized 200 watt phone transmitter from 1940 Post by: WQ9E on October 31, 2012, 08:28:28 PM From Radio News April 1940.
Title: Re: Stylized 200 watt phone transmitter from 1940 Post by: N0WEK on October 31, 2012, 11:51:53 PM Cool transmitter!
Those transmitters sure loved their transformer iron. Where would you find TZ-40s, all the other tubes are common. I like the parallel push pull modulator! You could cut the transformer count in half with solid state rectifiers. Title: Re: Stylized 200 watt phone transmitter from 1940 Post by: kb3ouk on November 01, 2012, 07:32:11 AM 811's will work in place of the TZ-40's.
Title: Re: Stylized 200 watt phone transmitter from 1940 Post by: KM1H on November 01, 2012, 03:09:36 PM Thats with the original 811's. 811A's would also work but would be seriously loafing at 200W.
Make a few changes and use 572B's for a bit more punch, use 811A's for mods. I guess that mag didnt get on the 813 wagon yet. Carl Title: Re: Stylized 200 watt phone transmitter from 1940 Post by: N0WEK on November 01, 2012, 04:30:55 PM Turns out that there are currently 4 TZ-40 tubes available (cheap) in two different auctions.
Title: Re: Stylized 200 watt phone transmitter from 1940 Post by: KM1H on November 01, 2012, 04:50:35 PM The Z means zero bias up to 1000V but the 7.5V filament is a PITA. They also take more drive than the 811. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Might make good replacements for 807/6146 mods in some rigs if there is room for a fil xfmr and enough drive can be cobbled up. |