A dozen folks have written me, privately and on the List - with advice
about my loop antenna. The consensus is: it doesn't matter much - so I
connected the balanced feedline to the loop with no 'spread'.
First off - there have been a couple of 'why do you want to do *that*??"
questions - and the answer is of course - brand new housing development,
and CC&Rs. Now, here in No. Nevada - folks are pretty much live and let
live - and I do have a VHF/UHF stick up on a 35' pole - but putting up a
'real' antenna is not a good idea... so I have run mine around the
perimeter of my back yard, just under the top of my 6' wooden fence. Until
I shift QTHs - perhaps as soon as this spring - this is what I have to
work with. I had considered an all-band vertical, and have owned a couple
of Butternuts in years gone by - but the Loop must do for now.
At 100W RF output on 80M - the Loop is tunable to 1:1.1 using an
Ameritron ATR-15 tuner. Before I had a chance to try a Real QSO on that,
or any other bands, the Valiant puked up Yet Another Capacitor.
Which brings me to: The Valiant.
I have recieved much helpful advice and experience from many folks as I
have been involved in electrically refurbing my Valiant I. Of course I
couldn't have finished the Project w/out the help I have recieved - so my
thanks to all of you who have been so kind with your advice and
experience!!
And this much I have learned: just because a capacitor is a certain
value and voltage, doesn't mean it's going to be able to stand RF
current... ;}
There is a fine reason the Johnson engineers used the capacitor configs
they did in the pi-net and coupling circuits - it's the "divide and
conquer" strategy. Now, I imagine a few folks are rolling their eyes and
saying things on the order of "No shit, Sherlock!" - but I have next to no
RF repair or design experience - most of my work professionally and
privately has been in audio and music and film systems... even hi-power
PA-amp output coupling caps don't have to stand the gaff that occurs in RF
work.
And even though I rebuilt the bandswitch stacks twice - I didn't use the
topology that existed - two 'series pairs' in parallel - mainly due to not
having the right units and to getting 4 350pF micas that are marked on the
package "350" - the color code is '350' - but they're 560pF every one of
'em. No wonder they were surplused! Imagine the hours of Fun that
caused... now I just check 'em no matter what.
So the Valiant is putting out 100 - 130 watts into my load or antenna on
all bands - I put it back in it's cabinet (mistake..) and cabled it up.
Having previously set the mod bias, I tuned 'er up, opened the Audio pot,
gave a couple of whistles and the 160/80 M capacitor stack "deviated from
spec" in a rather spectacular and stinky fashion. O well - at least I
understand completely what needs to be done - and about $60 worth of the
correct RF units will be delivered to me on Tuesday. Wouldn't have been
so much, but I bought heavier than required and also spares, just in
case....
Thats where it lies as of this Weekend - if I have paid my dues
sufficiently I oughta be on the air by the weekend - and I'll be happy,
until I set my fence on fire - snowing or not. ;}
Cheers
John KB6SCO
