[Amps] New SB-200 owner

[Roger Halstead]

>I am a new subscriber to this list and soon to be an ex-subscriber.

Welcome and don't let the current signal to noise...er... high noise to 
signal ratio discourage you.
Like any newsgroup/reflector I've seen, on occasion a topic will arise that 
raises a bit of conflict with different camps of thought.

The 572 may not be the best tube, or even a good tube (YMMV) but the 
conversion can be done and made to work fairly well.  Whether it's good 
"engineering practice" and those taking exception to it is what raised the 
noise ratio.

 For most of us doing a conversion to get something running is far from good 
engineering practice any way. OTOH some of us want to build or buy the best 
engineered equipment we can find.  There is a place for both, but like 
computer operating systems some may take exception and some do not like to 
have flaws pointed out even though they exist.... Ah, well...

Were it me, I'd start with a search for articles on such conversions.  They 
may or may not be on the net. I don't recall seeing any in the ham 
magazines, but I wasn't interested in doing a conversion until recently.  As 
I recall the ARRL Handbook and amplifier books deal with complete builds. I 
don't know about QEX.

More than likely I'd move on to the ARRL Handbook and build a PI-L network 
for the desired Q at the operating frequency which in this case is 50 to 54 
MHz. OTOH I used to teach electronics so it's not a route I'd expect many to 
take.

There is a way to cheat a bit, but it's not guranteed for all situations. 
If you can find a project or design that uses the same plate current and 
voltage try their PI-L design.  Just remember circuit layout is much more 
important at 50 Mhz than at 3.5 Mhz.  On a homebrew project there may be 
more than a little "cut-and-try" involved.

Now I need to get back to my shop and figure out why my computer won't boot 
when all I did was change the heatsink/cooler.  I know, I probably 
disconnected something, somewhere, but I sure can't find it.  OTOH the one 
beside this one has a bad MoBo.  Seems like I spend more time fixing stuff 
than using it lately and that includes my antennas and rigs.  This is my 
oldest computer, so I hope it holds out until I get the two multi core 
units back up and running.

73 and good luck,

Roger (K8RI)


>
>
>
> I have recently bought a used SB-200 and plan on converting it to 6M
> monoband use.  I do not plan to pay someone to do it even thought they 
> might
> do a better job.
>
>
>
> I thought I would get some useful information on this reflector.  Not so
> far!