Hello Steve,
Tuesday, September 20, 2005, 10:02:13 AM, you wrote:
ST> Can't see a problem with trying it as an experiment - I'd been thinking
ST> along the lines of whether part of the coil was left shorted by the
ST> bandswitch.
>>
>> The HT runs at 2100 off load and 1950 on load. As I've said in other
>> replies I have a spare set of valves and switching them around hasn't
>> helped.
ST> I don't know the amp, but from what I read that looks about right.
>>
>> Gain and output seems to be OK, although I've seen that some say they
>> get more output, on 80 & 40m 80w in gets around 625 - 650w out. As far
>> as the anode current, dip it is deepest at max rf out.
>>
ST> I forgot to ask - what's the anode current / efficiency?
ST> In the end, if it's all about right and output power and linearity are
ST> ok, then you could do worse than leave it alone. In your place I
ST> couldn't, but I spend much more time fiddling with equipment than
ST> actually using it!
ST> There's a good looking set of notes at mods.dk if you put in sb200 on
ST> the article search.
ST> Steve
Firstly Steve thanks for your help.
The next time the thing is on the bench I'll maybe add a turn or two
on the tank coil and see what happens.
The anode current reads, for 500w out, 340mA so that works out to be
around 75%. Of course all these readings have a little + or - about
them as I have no idea how accurate the meter is.
The amp has had all the standard mods and updates done to it already,
but this problem has been there from the start.
So I'll leave it for now, it's linear, it's giving a reasonable output
and it does it's job, but just like you I want to get it sorted, so
I'll try the tank coil addition sometime.
Thanks again.
--
Best regards,
John mailto:kvp@bigfoot.com
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|