[Amps] Peter Dahl / Harbach SB-220 transformer

[Jim Thomson]

Date: Sat, 12 Jun 2010 07:03:51 EDT
From: Gudguyham at aol.com
Subject: Re: [Amps] Peter Dahl / Harbach SB-220 transformer
:




##  A buddy across town   built a single 3-500z  for 6m.. works good... abt 
500w .   He  wiped out the neighbourhood
CATV... and that amp was relegated to FD  use.  He also wiped out the 49.9 
mhz  cordless phone freqs at the  time.  This
was 10 yrs ago. 

***** Well, if it only made 500 watts nothing was tuned right, there is  
still another 500 watts in there.  Tune it right and you'll get the power  in 
the right place not on cordless phones and CATV.

####  That was a HB  SINGLE  3-500Z  6m RF deck.    The tube was
semi flat.. and he had 100 w icon to drive it.    500w  from a flat
3-500Z is not too bad. 

## the amp was tuned correctly, LP filters, shorted 1/4 wave stubs et all. 
The problem is... you stuff 500 W  into a 5 over 5 stacked array... and it's
always gonna be pointed at one or more neighbours homes.   Back then, those
baby monitor's could be heard [across the street]  on 49.990 mhz.   I doubt those
things will reject the low end of 6m.   Ch-2 TV is another similar problem... none of em
have HP filters in em... and bye-bye ch-2.   Then toss in the 49 mhz  cordless phone band. 
Do those things cut of 6m ?? 

No wonder he wiped out the neighbourhood.   I looked around my neighbourhood... and dumped
the notion of installing the 9-el  6m yagi.[+ 2 kw]   A buddy 1 mile away is up on a ledge/hilltop.   At the
time his icom had 6m.   He installed an inverted vee on his flat roof... abt 10'  above the roof.
[and 400' ASL]  ..with no balun.. and fed with 80' ofr RG-58.    One afternoon... the 6m band was
hopping. He had a 3 hr pile up into the east coast.. with lots of 60 over S-9 sigs in both directions. 
Then the band went dead.   He stayed dead for months.   His next rig did not have 6m .
 That was his 1st and last 6m experience. 

if I had more room.. 6m might  be an option... but as is... I have no room for 10/12m. 

Later.... Jim   VE7RF 







later.... Jim   VE7RF