Rich: thanks for the tune-up on amplifier tank circuitry. I do enjoy this list,
I do. Make me sit back and think about what I know (vaguely of) vs. what I
thought I forgot.
73...73's
Gary, WA6FGI
----- Original Message -----
From: R. Measures
To: Gary Smith
Cc: Martin J. Morgenbesser ; Kim Elmore ; AMPS@contesting.com
Sent: Saturday, December 04, 2004 4:33 AM
Subject: Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000
On Dec 3, 2004, at 8:35 PM, Gary Smith wrote:
> Good friend of mine Marion, KJ6DB, has my old 811H, sez it works so
> well he forgets about it. Amp is three or so years old, I had it
> wired on 220v, sent it to him he returned the jumpers on the xfrmr
> input board to 117v, operates it on 10 mtrs sees about 600 watts or so
> out, he drives it with an Icom 756, first model.
>
> My .02 on this amp vs. say, the Heathkit: the SB-220 will operate 80
> thru 10 (if it has the 10m mod kit in it) while the entire Ameritron
> line will operate 160 thru 15, warc bands included, 12/10 mtrs, owner
> modifiable.
>
> To answer this question before you ask it , operating the SB-220 on
> 17/12 meters will strain the dickens out of the tank circuits with a
> severe loss of power output. This is what I asked Jim Harbach the
> heathkit mods guy, I am repeating what he told me.
Hello, Gary -- There is an approximate 10% increase in tank circulating
current through the bandswitch by operating a SB-220, TL-922, L4, et
cetera on 12m (using 10m position) or operating on 17m (using 15m
position) -- but the strain is easily offset by decreasing the anode
supply V -- i. e., using the CW tap on the HV to reduce the RF
current..
- note - due to skin effect, the additional heat is greater on 12m
operation
>
> I know I maybe accused of beating the Ameritron drum too hard, but
> they are a fairly modern design assembled with modern (read easily
> available) components for the bands we have available to us at what I
> consider a more than fair price.
- Unless Ameritron amplifiers use more tank L for 12m than they use for
10m, they have the same tradeoff on 12m as the SB-220, TL-922, et
cetera.
- The Ameritron amplifiers that I have seen use no forced air cooling
on the bandswitch or tank L, and they use tank L conductor sizes that
do not adequately compensate for skin effect on 20m - 10m.
>
>
> 73 and so-forth,
> Gary, WA6FGI
>
> Oh how I wish for an new Alpha 99 and a Christmas tree full of neon
> bulbs so I could light them up with no wires attached.
An 8171 does a better job -- and you can light up the neighbors'
Christmas trees too.
>
> ...
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|