[Amps] SB200 on 6M

[Jim Thomson]

-----Original Message----- 
From: Carl
Sent: Monday, June 03, 2013 11:27 AM
To: Jim Thomson ; amps at contesting.com
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.

##  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.

##  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.

##  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.

##  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