[Amps] SB200 on 6M

[Carl]

> Subject: Re: [Amps] SB200 on 6M
>
>>
>> I'm converting a SB200 for 6M. What's the best configuration for the
>> Anti-Parasitic Choke?
>>
>> Thanks
>>
>> - 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.
>
> Carl
> KM1H
>
> ###  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.

Carl
KM1H