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Re: [Amps] SB200 on 6M

To: "Jim Thomson" <>, <>
Subject: Re: [Amps] SB200 on 6M
From: "Carl" <>
Date: Tue, 4 Jun 2013 09:48:47 -0400
List-post: <">>

Subject: Re: [Amps] SB200 on 6M

I'm converting a SB200 for 6M. What's the best configuration for the
Anti-Parasitic Choke?


- Paul

## dunno. BUT if the 2 watt carbon comp resistors heat up, use more of em in parallel, OR use a small 7-10-15 watt GLOBAR. You can still buy the small globars with wire leads out each end..still on their website. Dunno what the min order is though.

## On several 4-1000 HF amps from years ago, we would use five of those carbon comp resistors
in parallel...end of heating problems.

Jim  VE7RF

Having to use a high wattage resistor on such a small tube as a 572B means
you havent a clue about suppressor design, and simply use a generic brute
force method.


### Use JUST enough L to make the suppressor work. If you use too little L, it wont work. Use too much L the resistorS will overheat, so it's a delicate balancing act. If you use MOX type resistors, they have too much L inside the resistor, so then you gotta put a cap in series with the MOX, to cancel out the internal L of the MOX.

** Yeah, after I told you a few times. That was something I did back in the late 80's or so and later copied by your buddy. Works OK for a kluge.

## A U shaped suppressor, made of cu or brass will work, as will heavy gauge wire. 3 turns around a 2 watt CC will
also work, but the 2 watt CC will run hot.

** Not very well

## In an ideal world, IE: building from scratch, the chinese 572B would not even be on my list....for a tube for 6m, or even HF. A SB-200 6m conversion would be the ONLY time one would use a 572B on 6M.

** Or several other 2-4 572B amps running 2 tubes. Ive even put a Clipperton L on 6M with 3 tubes but not efficiently. If 572B's were on hand then its worth the attempt at HB as are 813's and some other oldies. OTOH its easier using various tetrodes in GG such as the 4-125/250/400 as they are often very cheap even NIB at hamfests.

## since doing all of this since 1972, and 38 amps later, I think I have a reasonable concept of how all of this works carl.

** Its easy when you start with stable tubes and/or can copy what others did. The thousands of HB 4-1000A amps are proof. The 813 and 4-400A are other stable GG amps.

## two GS35B tubes will do an easy 5kw + on 6M......and no suppressor required. Its already been done and pix posted..
on the yahoo amp reflector.

later... Jim   VE7RF

** I dont think we should be bragging about a CB mentality power level on here. Nor most of your other amps for that matter.

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