>Ok, Rich: that should be an interesting experiment.!!
> I had tried a transmission line transformer, 4:1 , 100 ohms to 25 ohms ,
>with the input on the 100 ohm side, and paralled with 100ohms , 100 watt
>resistor. that design was given to me by another ham who said his setup
>worked just fine ,
** Maybe just fine with a radio with a built-in tuner.
>but I could never get it to work for me..
** ... makes sense since there is nothing to balance out the
asymmetrical cathode input-Z
> I also tried to make a 2:1 xfmr. from a book, 50 ohms down to 25 ohms, but
>can't get that to work either, but then I'm not too sure of my capabilities
>in that respect.
> Oh,! well, Lets try your experiment, it seems relatively simple, what
>could go wrong??
> carl / kz5ca
>----- Original Message -----
>From: "2" <2@vc.net>
>To: "carl seyersdahl" <carlseye@tampabay.rr.com>; " AMPS"
><amps@contesting.com>
>Sent: Friday, May 02, 2003 12:31 PM
>Subject: Re: [Amps] G-G Amplifiers With No Tuned Input.
>
>
>
>
>>Roger, Rich; I'm still where I have been :
>> I think the only question is what wattage rating to use for the resistor,
>>and I don't have anything of that nature anyway. Seems it might have to be
>>at least 50 watts, maybe more.!! However, considering the "on " time , for
>>SSB maybe not.!!!
>
>** The typical duty-cycle for SSB 2-way is c. 15%. I stock some
>low-L,3W-CCS @70?C Matsushita MOF resistors that will easily do 15w each
>in SSB service. With the ultra-fast diode shipment, I will include
>enough of these resistors to series/parallel and make a 50-ohm, or
>60-ohm, or 70-ohm termination at 100w pep SSB. // These resistors are so
>durable they can be operated glowing dull-red in the dark, which is 12w
>continuous diss.//
>.
>> what's your guess??
>> carl / kz5ca
>>----- Original Message -----
>>From: "2" <2@vc.net>
>>To: "carl seyersdahl" <carlseye@tampabay.rr.com>; " AMPS"
>><amps@contesting.com>
>>Sent: Friday, May 02, 2003 10:06 AM
>>Subject: Re: [Amps] G-G Amplifiers With No Tuned Input.
>>
>>
>>>
>>>
>>> >Rich: that sounds like an interesting idea.!!
>>> > I'm working on a gla1000, plain model, modified with
>>> >EL509's, and would love to test such an idea. I have tried several other
>>> >things, like tuned inputs, a broadband input transformer, and not had
>>much
>>> >luck . what is the no. of the diode you mentioned.???
>>>
>>> ** I purchased ten of 'em to distribute free for R and D. Are you still
>>> at 7509 Wakulla Dr. ?
>>> -- My guess is that the input terminator R that the diode goes in series
>>> with should be 50 - 75 ohms. If you try the idea, please post your
>>> findings on AMPS. Need a termination R ?
>>>
>>> have phun, Carl
>>>
>>> > carl / kz5ca
>>> >----- Original Message -----
>>> >From: "2" <2@vc.net>
>>> >To: " AMPS" <amps@contesting.com>
>>> >Sent: Thursday, May 01, 2003 3:27 PM
>>> >Subject: [Amps] G-G Amplifiers With No Tuned Input.
>>> >
>>> >
>>> >> Amplifiers such as the MLA-2500, SB-230, 374, 78, and 76PA have no
>>tuned
>>> >> input. This is not a problem when such a g-g amplifier is driven by a
>>> >> tube-output radio such as the TS-830S. The reason is that although
>the
>>> >> input Z of a cathode-driven triode fluctuates from roughly 1/3 of the
>>> >> average driving Z on negative peaks to a virtual open circuit on
>>positive
>>> >> peaks, the Pi-network tuned circuit in a tube-output radio acts as a
>>> >> flywheel to smooth out the Z fluctuation at the cathode/s. However,
>>with
>>> >> modern solid-state radios there is no tuned output, so something is
>>> >> needed to smooth the Z fluctuation. A possible workaround, short of
>>> >> adding a bank of tuned input circuits, might be to put a ultra fast
>>> >> recovery diode in series with the input terminating R. The diode is
>>> >> oriented so that the terminating R conducts only when the driving
>>> >> potential is positive -- which is when the tube is not conducting..
>>> >> Thus, on the negative half of the driving cycle, when the tube has a
>>low
>>> >> driving Z, no driving power is lost in the terminating R and the
>driver
>>> >> should see a lower SWR.
>>> >> - - Unfortunately, I do not own such an amplifier to test the idea
>on.
>>> >> If anyone out there has such an amplifier and is willing to test this
>>> >> idea, please inform me and I will send you a freebee 2A, 35nS, 300v
>>> >> switch diode.
>>> >>
>>>
>>>
>>> - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>>> www.vcnet.com/measures.
>>> end
>>>
>>
>>
>>
>
>
>- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>www.vcnet.com/measures.
>end
>
>
>
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
end
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