Subject: GLOWBUGS digest 398

From: [email-masked]
Date: Mon, 30 Dec 1996 07:51:33 -0600 (CST)

GLOWBUGS Digest 398

Topics covered in this issue include:

  1) Re: Which VFO to build?
	by [email-masked]
  2) Book Needed
	by Doug <[email-masked]>
  3) Re: Ocean Hopper, cont.
	by "Robert M. Bratcher Jr." <[email-masked]>

----------------------------------------------------------------------

Date: Sun, 29 Dec 1996 20:13:46 -0500 (EST)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] (), [email-masked]
Subject: Re: Which VFO to build?
Message-ID: <[email-masked]>

> Which would give the best output when multiplied?  I don't think I could
> ever get a stable VFO if I tried to bandswitch the coils.
> 
> Dave WB7AWK

Dave and other vfo builders.....

Regarding vfo's, the use of a Dow electron coupled circuit is recommended,
unless you are out on a tour de force, for the fun of it.

Bandswitching works very well, generally.  You just need to use good
solid switches of ceramic rather than fibre or phenolic stuff.  Size
the switch to handle a 100 watt load and on a vfo it will be quite
effective.  Space the coils about 2 inches apart minimally for reduced
interaction.  Use coils about 1 inch in diameter and 2.5 inches long
in a series tuned Colpitts AKA Clapp oscillator, as probably the best.
A Hartley is usually second best, with a Colpitts third best.  Use
larger coils if you have space.  Wire with no. 14 wire, minimally,
and use good solid mounts, everywhere.  On the capacitor shaft, use
a double shaft coupling to minimize torsional shaft twisting problems
due to shaft misalignments.  Make sure the capacitor is a good double
bearinged one, with heavy bearings and wipers, and likewise 100 watt
sized.

It is more advantageous to use multipliers, rather than switching for
ultimate stability, but switches, if properly sized and constructed
do a fine job in my hands.  A heterodyne system is the best if you
want rock stability, but hey, on a glowbug, some slight character
is tolerable in the signal, and right nice.  Character in a multiplier
system gets multiplied as the frequency goes up, so still make the
oscillator section rock stable, if possible.

If using a multiplier system, use a 100 watt final coil minimally for
the oscillator coil, and GOOD ceramics as padders, and a very good
100 watt sized capacitor for tuning.  Don't ever use underrated
components for best stability.  Such a coil for 160M can be 2 inches
in diameter and about 6 inches long, wound of no. 12 or 14 wire.
No. 16 will do in a pinch.  Don't use standard miniductor stock, unless
it is 100 watt rated.  A coil of about 25 turns should do, well, padded
with transmitting micas or ceramics to bring it down to 160 and with
a 50pf variable or at most a 100pf variable as the tuning cap (I prefer
to use a 25 pf size, or at most a 35pf size, since most of 160 is
not used, and doubling up to 80 one gets good coverage from a small
capacitor).

Hint.... think OVERKILL in rating vfo stuff, and that is usually always
         best.

73/ZUT DE NA4G/Bob UP

------------------------------

Date: Sun, 29 Dec 1996 20:34:57 -0700
From: Doug <[email-masked]>
To: [email-masked]
Subject: Book Needed
Message-ID: <[email-masked]>

Hi fellow Glowbuggers...I need a copy of the 15th edition of the Radio
Handbook, by Bill Orr, Editors and Engineers.  There is a couple
articles in there I'd like to look through and possibly build the amps
they are about.  So, if someone out there has a copy and would be 
willing to part with it, or loan it for a while, I'd be glad to pay
UPS both ways and if you'd like to sell it, we can work out a deal.

I've quit getting any postings from the group...I hope it's not
something serious.  So, if all is going well, let me know and I'll 
re-subscribe.

Thanks, Happy New Year

Doug Dunn, K7YD
Livingston, MT

------------------------------

Date: Mon, 30 Dec 1996 06:38:52 -0600
From: "Robert M. Bratcher Jr." <[email-masked]>
To: [email-masked]
Cc: Multiple recipients of list <[email-masked]>
Subject: Re: Ocean Hopper, cont.
Message-ID: <[email-masked]>

I've got a large Allied book (dark red & brown cover) which has the ocean
hopper as one of the projects. Never got around to building it though...

Robert M. Bratcher Jr.
E-mail to:
[email-masked]
Record collector, 8mm, super 8, 16 and 35mm Film collector.
I like old radio's too.
Collins, Hallicrafters, National & Hammurland are my Favorites!

------------------------------

End of GLOWBUGS Digest 398
**************************