[Amps] 144 MHz GS35B update

[gudguyham at aol.com]

At 3500 volts the GS-35b is on par with a pair of 3-500's

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-----Original Message-----
From: Carl <km1h at jeremy.qozzy.com>
To: 'Amps' <Amps at contesting.com>; N1BUG <paul at n1bug.com>
Sent: Mon, May 1, 2017 06:30 PM
Subject: Re: [Amps] 144 MHz GS35B update


That tube also neeeds 3000-3500V before it shows good efficiency.
My 2M 3CX1000A7 needs 80W for 1800 out at 3000V but it was a pull when I got 
it with socket 35 years ago and still runs the same.

Carl



----- Original Message ----- 
From: "N1BUG" <<a href="mailto:paul at n1bug.com">paul at n1bug.com</a>>
To: "'Amps'" <<a href="mailto:Amps at contesting.com">Amps at contesting.com</a>>
Sent: Monday, May 01, 2017 4:50 PM
Subject: Re: [Amps] 144 MHz GS35B update


> There we go. After reviewing pictures of several other amplifiers using 
> this tube I removed one more turn from the coil on the tube side of the T 
> match. Input SWR is 1:1 and the amp is making over 600 watts out with 25 
> watts in. I plan to run it this way for a while before I go for the real 
> QRO.
>
> Paul
>
>
> On 05/01/2017 02:40 PM, N1BUG wrote:
>> I'm seeing more RF output with the new configuration, about 500W for
>> somewhere around 25W drive. It appears I am going to have some fun
>> getting the input SWR down but I guess everyone does. That's
>> probably why there are so many slight variations on coil dimensions
>> among the various plans.
>>
>> My first try with both coils having 5 turns 15mm ID, 20mm long
>> resulted in minimum SWR of 3:1. My second try with 4 turns 15mm ID,
>> 20mm long got it down to about 2.6:1. I am not sure whether to take
>> another turn off both coils or perhaps just the one on the tube
>> side. Many pictures of amps I have seen appeared to have less L on
>> the tube side although I don't see this mentioned in any
>> accompanying text.
>>
>> Paul
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