The 4X1 can get quite squirrely at times, especially 10-15M and over 5KV. Do
your grid connections with copper strap to a single point ground. I wound
the P.S. with strap also.
Use a big glitch resistor at the base of the plate choke and out of sight of
the chimney. Dont skimp on the bypass either.
Carl
KM1H
Carl
KM1H
----- Original Message -----
From: "Rob Atkinson" <ranchorobbo@gmail.com>
To: "Carl" <km1h@jeremy.mv.com>
Cc: "DAVE WHITE" <mausoptik@btinternet.com>; <amps@contesting.com>
Sent: Thursday, July 15, 2010 6:45 PM
Subject: Re: [Amps] parasitic suppressor voodoo
> Okay! From Carl and Dave's lips to God's ears, or is it the other way
> around. The authorities have spoken and I now proceed with
> confidence....
>
> tnx
>
> Rob
> K5UJ
>
> p.s. to the original poster--pse accept my appology for intruding on
> the "voodoo" thread....I shall now step out of the way....
>
>
> On Thu, Jul 15, 2010 at 3:00 PM, Carl <km1h@jeremy.mv.com> wrote:
>> Agree with Dave. In the past I turned out many 1-2 holers grid or cathode
>> driven to order; most covered 160 or 80-10M. Then I used 20-25W Globars
>> or
>> surplus 68 Ohm 50W Carborundums which I bought almost 100 in sealed
>> packages
>> for real cheap.
>>
>> Stopped that when all the local AM stations used the tubes until they
>> were
>> even almost dead as modulators or went SS. I did about 10 3CX3000A7's and
>> a
>> few 4CX5000A's after that.
>>
>> Carl
>> KM1H
>>
>>
>>
>> ----- Original Message ----- From: "DAVE WHITE"
>> <mausoptik@btinternet.com>
>> To: <amps@contesting.com>; "Rob Atkinson" <ranchorobbo@gmail.com>
>> Sent: Thursday, July 15, 2010 3:34 PM
>> Subject: Re: [Amps] parasitic suppressor voodoo
>>
>>
>> On a 2 times 4-1000A amp (5.5kv, grounded grid, cathode driven) I used
>> two
>> separate parasitic suppressors, each with 3 paralleled 50 ohm carbon
>> resistors inside a 15mm diamater two-turn coil of 2mm copper wire over
>> about
>> 10mm length. The amp has worked flawlessly (80 thru 10m) for many years.
>>
>> If yours is a low band amp, you could probably make REALLY certain by
>> increasing the number of turns on the coil. Initially with four turns the
>> resistors smoked a little on 10m. I guessed "too much L". There was no
>> science to building these suppressors - it was a case of looking at the
>> W6SAI "Radio Handbook" and seeing if it worked. Voodoo? Maybe.
>>
>> I didn't try the amp without parasitic chokes but it seemed to work and
>> "if
>> it ain't broke, don't fix it"....
>>
>> Hope this helps
>> Dave G0OIL
>>
>> --- On Thu, 15/7/10, Rob Atkinson <ranchorobbo@gmail.com> wrote:
>>
>> From: Rob Atkinson <ranchorobbo@gmail.com>
>> Subject: Re: [Amps] parasitic suppressor voodoo
>> To: amps@contesting.com
>> Date: Thursday, 15 July, 2010, 18:40
>>
>> I would love to know what if any p.s. is needed on a pair 4-1000A at
>> 4.5 KV triode connected cathode driven for 160, 75 and 40 m.
>>
>> rob
>> K5UJ
>> _______________________________________________
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>>
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