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The best way to measure a transformer gut temp is measure the winding resistance cold then hot and determine the real temperature rise by the copper constant. I think it is about .4%/degreeC. wa1gfz R

All, I hate to say that some dumb a$$ deleted almost everything I had written except some corrections about the windings. I'd about bet they were the one who wrote the screwed up stuff I had to

During an ahhhhhhhh, I see about 1/3 of A0 anode current. If one transmits half the time, that's a duty-cycle of 1/6.

All, I finally did finish all I was going to do on Wikipedia about power transformers. I found I also had to edit a few stubs and others. The definition of Oersted was completely screwed and they had

Jim, I forgot to add, the calculations about voltage arcing I'm thinking of are for only up to say 3 kVA in size. When you get on up in size, the volts per turn, and per layer can raise due to the

No, the one in mention was Hal Mandel W4HBM. He had Dahl design a transformer for him, and I can't remember if it was a anode or a heater, but in two tries, Dahl got it wrong, both transformers went

different than RTTY. ### Dream On.... unless you chopped all the audio off below 350 hz..... or the plate current meter ballistics are out to lunch. ### see above. [and inte

Hello Thomas, A couple of suggestions for your amplifier... First, I would float the B- to make metering of plate and grid current readily available to you. It takes no more than two resistors and a

A Dahl 4500va-rated transformer

Yeah, that's correct. If you compare them then you would see that I have copyed part's of it. I think that the Ameritron amp. is running the tubes a bit to hard. An other thing i have done is that i

SSB has a duty cycle of less than 20%, so it's quite different than RTTY.

You dont need matched tubes -- just put some resistance in the cathodes and they self match -- rich knows more about how to get the right values of resistance -- im still learning Steven Grant W4IIV

Very good English Anyway I had a Ameratron (sp) AL 811H This was a 4 tube 811 amp. Try researching it for CKT diagrams and ideas. I think the schematic is on the Ameratron web page. la3pna wrote:

Hi group. I'm Thomas, La3PNA and I'm in the progress of starting to build an HF amplifier with 4 811A tubes. I'm gone to use 4 of them because, I got the tubes, sockets and Plate caps for 4. I have

I increases. ### agreed. ### Those 253 lb Dahl's are a bargain..... on SSB because one of his 68-pounders will do 15k out. 8910/4cx15,000J. ### I find that hard to believe !... but I may well be

Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the ham_amplifiers group. File : /LA3PNA 811 Amplifier/811.jpg Uploaded by : la3pna

them too! other very good companies who make some gem dandy transformers, and for a way better price. I'll dig up a couple of address for you later today. ### someone listed on 'amp's.. think it was

all ### The way around that problem on 10/12m is this.....[a] Use a 10-1000 pf ceranic vac cap for 160-10m.... the other cap is a 12- 500 pf jennings... also good.... IE: use a low min C cap. ### [b]

RMS cathode-grid potential multiplied by - meter indicated - DC grid current is an okay approximation. The actual dissipation calculation involves integral calculus. Drive And degree of loading

Tom gets some things pretty much right. However, VHF parasites isn't one of them. A Q of 15 on 10m is quite common.