Subject: GLOWBUGS digest 369

From: [email-masked]
Date: Sun, 1 Dec 1996 10:23:19 -0600 (CST)

GLOWBUGS Digest 369

Topics covered in this issue include:

  1) 6T9 schematic
	by [email-masked]
  2) Re: new member
	by Jeffrey Herman <[email-masked]>
  3) Not T9...
	by [email-masked] (Stephen M Smith)
  4) Bad tubes :-(
	by Bob <[email-masked]>
  5) No handkey?
	by Jeffrey Herman <[email-masked]>
  6) Re: Not T9...
	by "Brian Carling" <[email-masked]>
  7) Bare Essentials+6T9
	by [email-masked]
  8) Re: Bad tubes :-(
	by [email-masked] (michael silva)
  9) Looking for ...
	by Jeffrey Herman <[email-masked]>
 10) new email address
	by [email-masked]
 11) Just got a receiver chassis - What to do?
	by Dave <[email-masked]>

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Date: Sat, 30 Nov 1996 12:03:10 -0600
From: [email-masked]
To: [email-masked]
Subject: 6T9 schematic
Message-ID: <[email-masked]>

THANKS FOR THE WELCOME
I got the 6T9 schematics from ARRL book" Understanding Amateur Radio"
printed in 1977

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

Date: 	Sat, 30 Nov 1996 08:37:05 -1000
From: Jeffrey Herman <[email-masked]>
To: Brian Carling <[email-masked]>
Subject: Re: new member
Message-ID: <Pine.GSO.3.93.961130083329.20850C-100000@uhunix3>

Hey Brian! Sounds like you're working magic with that MOPA rig!
The 6T9er appeared in the early 70s ARRL Handbook. It's in my
'74 edition. And someone told me AES is selling 6T9s for around
$2 or $3.
73 from Hawaii,
Jeff KH2PZ

On Sat, 30 Nov 1996, Brian Carling wrote:
> That 6T9 xmtr sounds great! Where did you get the schematic for it?

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

Date: Sat, 30 Nov 1996 17:03:03 EST
From: [email-masked] (Stephen M Smith)
To: [email-masked]
Subject: Not T9...
Message-ID: <[email-masked]>

Group,

I've been massaging The Scounger this weekend.  I replaced the filter
capacitors and installed 100K bleeders on the input and output caps so
now the B+ is clean at 220 Volts key down.  I've figured out which tap on
the pi net coil is optimum for a 50 Ohm load and I get about 5 Watts out
for 9 Watts input, not bad.  However,  I've run into a few problems that
have me scratching my head.  

The note is not T9.  I can't really say that it's chirp, more of a short
warble upon key down, then a clean note (now that I have good filter
caps. installed!).  This happens no matter what crystal I'm using and
doesn't seem to be affected by the plate or loadig controls (until the
tube drops out of oscillation).  Now for a strange one :  When I grab the
FT-243 case with my fingers, the warble goes away.  It's replaced by
something that sounds like key clicks.  

This circuit is the classic crystal controlled Colpits.  My feedback
network is a 7-45 pf trimmer in series with 750 pf.  When I adjust the
trimmer, nothing is affected except the frequency.   The power output
varies slightly with max. power output occuring when the trimmer is at
minumum capacitance (there is no peak).  Seems to me that I should get a
peak in p/out by adusting the trimmer since that changes the amount of
feedback (?).

Here's what I tried to fix the warble:  I installed bleeders, only 100K,
not real stiff, more for safety.  The screen was being fed right off the
B+, so I added 22K in series and bypassed with .005 uf.  I figured that
would stiffen up the screen supply, even if the B+ moved around with the
plate load.  No dice.  Everything the same except that the max. power
output dropped about 1/2 Watt (I expected that).  I guess that the B+
plus might not be settling right away upon key down but I haven't checked
it with a 'scope.  Maybe my tube is "soft" and doing wierd things.  

Any ideas?  Thanks.

73.......Steve, WB6TNL (formerly WN6TNL)

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

Date: Sat, 30 Nov 1996 23:18:57 +0000
From: Bob <[email-masked]>
To: [email-masked]
Subject: Bad tubes :-(
Message-ID: <19961130231845.AAC23001@LOCALNAME>

I recently got hold of some old tubes and finally got a chance to look them
over carefully.  Many have been damged (loose parts inside) from rough
handling over the years.  Among the casualties are two VT-4's (the military
version of the 211) .  It is very discouraging because these would have been
quite beautiful sitting in the middle of well built homebrew project.  

Oh well, there are some other possibilities in the bottom of the box.

73 es TNX
KE4QOK 
Bob
136 Hermitage Rd.
Newport News, Va. 23606

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

Date: 	Sat, 30 Nov 1996 13:20:16 -1000
From: Jeffrey Herman <[email-masked]>
To: Glowbugs List <[email-masked]>
Subject: No handkey?
Message-ID: <Pine.GSO.3.93.961130130433.3477A-100000@uhunix3>

One of our valued list members has publicly admitted that he doesn't
own a handkey, and is fumbling in an attempt to connect a CMOS keyer
to his homebrewed xmtr. That the poor fellow was brave enough to 
admit this and face public ridicule means there is a fair amount
of hope to salvage his reputation and bring him back into the
good graces of the list. As a pre-Christmas gift I suggest that
anyone who has a spare hand key (not of too much value - we don't
want to spoil the old boy) send it to him (COD the postage though)
so he can at least participate in SKN on New Years Day.

I'm willing to send him a portion of a hacksaw blade and give him the
option of either assembling a straight key or a Sideswiper with it.

That he attempted to key his newly built xmtr with a pair of alligator
clips and actually carried on a QSO in that manner shows that even
though he strayed with the CMOS, he still has a good heart.

Jeff KH2PZ

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

Date: Sat, 30 Nov 1996 16:40:02 +0000
From: "Brian Carling" <[email-masked]>
To: [email-masked]
Subject: Re: Not T9...
Message-ID: <[email-masked]>

Hey no fair! You are getting out a watt more than me!
Mine was about T5 using the power supply the previous owner had 
concocted. So I added about 80 uF at 450V across the B+ and it came 
right in to a clean T9 note (best I can tell)
It was like a buzz saw before, he he!
But I think yours is a one-tuber. I use a 6AG7 osc feeding the 6L6 
and it seems easier to tame.
********************************************************
*** 73 from Radio AF4K / G3XLQ in Gaithersburg, MD USA *
**  E-mail to:  [email-masked]                         *
*** See the great ham radio resources at:              *
**  http://www.mnsinc.com/bry/                         *
********************************************************

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

Date: Sat, 30 Nov 1996 18:34:00 -0600
From: [email-masked]
To: [email-masked]
Subject: Bare Essentials+6T9
Message-ID: <[email-masked]>

In reply to a couple of Questions--here's what I've got
1st- The Bare Essentials is just what its called. It was originally
published in "Electronics Illistrated" in the 60's. It's a one tube rock
bound xmtr using a 5OC5 and no power xfmr. The schematics were
republished in CQ Oct 1994. The directions tell how to put it on 40 or
80. It could easily be moved to 30.
2nd- The 6T9 schematic in "Understanding Amateur Radio" is missing pin 6
connection- it goes to ground.
I've got most of the parts either in hand or on order and I also got
some FT243 xtals to try to grind HA HA.
73's Larry AA0DM
St.Louis
[email-masked]

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

Date: Sat, 30 Nov 1996 16:59:29 -0800
From: [email-masked] (michael silva)
To: [email-masked]
Subject: Re: Bad tubes :-(
Message-ID: <[email-masked]>

>I recently got hold of some old tubes and finally got a chance to look 
>them over carefully.  Many have been damged (loose parts inside) from 
>rough handling over the years.

Sometimes those loose parts may not be a problem.  Occasionally I've 
seen small flakes from the mica spacers floating inside a tube -- these 
shouldn't be a problem as long as they don't get between cathode and 
plate and screw up the electron flow.  I've also seen cases where the 
insulation on a "crossing" wire in the base has crumbled and floats 
around under the press.  I imagine this insulation is mostly important 
for keeping the wires apart during assembly, and once the tube is 
assembled the insulation has served it's purpose (at least on 
lower-voltage tubes).  Of course, I'm just opining here.

73,
Mike, KK6GM

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

Date: 	Sat, 30 Nov 1996 17:04:59 -1000
From: Jeffrey Herman <[email-masked]>
To: [email-masked], [email-masked]
Subject: Looking for ...
Message-ID: <96Nov30.170504hwt.188175(9)@uhunix3.its.Hawaii.Edu>

Just found this little request - note the email address to respond to:

----------------------------------------------------------------------
Young ham without Newsgroup access would like:
A tube,  6GH8A and
A straight key, of European style.  Long, narrow, and heavy base.
Please forward reply to  Peter,    [email-masked]
----------------------------------------------------------------------

Jeff KH2PZ

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

Date: Sat, 30 Nov 1996 23:31:28 -0600
From: [email-masked]
To: [email-masked]
Subject: new email address
Message-ID: <[email-masked]>

Hello everyone!! just wanted to let you know I'm changing my Email
address: OLD [email-masked]  NEW [email-masked]

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

Date: Sun, 1 Dec 1996 00:23:27 -0800 (PST)
From: Dave <[email-masked]>
To: [email-masked]
Subject: Just got a receiver chassis - What to do?
Message-ID: <[email-masked]>

Hi again!

I just got a neat little DuKane AM/FM receiver chassis of the
type that would have been used in an old intercom system for
distribution of tuner audio.  Hasn't been used too much.

The only problem was that all of the tubes were pulled and
just left with it.  After an hour of making some really
interesting internal arcs, I got them all back where they
should be.  Powered it up and it seems to work pretty darn
well, both on AM and FM.  I peaked the IF and RF coils and
it is about as hot as such a receiver could be.  It's open
chassis, steel, with only an audio preamp stage.  There is
also an auxilliary input for a phono cartridge.

My idea?  Would this be worthwhile to use as a tuneable IF
for a receiver project?  I would build a 455kc BFO first,
then add an 80meter converter, then add converters to that
to achieve the band coverage I want.  There is a big slide
rule dial that is already geared down, and I would add 
more gearing in the form of a vernier.  The main dial would
be bandspread, with a separate band set on each converter
to select the band segment of interest.

Does this sound worthwhile?  Will I have terrible BCB
interference (I'm in a metropolitan area)?  What are the
pitfalls?

I've always wanted to build a station receiver to call
homebrew, and it seems that this would be a very good start
in the IF department.  I'd be starting with a known good
IF and build from there.

Ideas?  Good, bad, and indifferent are all equally welcome.

73's

Dave WB7AWK
[email-masked]
[email-masked]

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End of GLOWBUGS Digest 369
**************************