Ham Radio/Ham Radio CD-ROM (Emerald Software) (1995).ISO/news/inham89/1026

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INFO-HAMS Digest            Fri, 15 Dec 89       Volume 89 : Issue 1026

Today's Topics:
                Builder's Success - HF Sweep Tube Amp
                              CoCo WEFAX
                            Kenwood TS140
             Modifiying radios for out of band operation
                     rec.radio.shortwave "invite"
                             RST (2 msgs)
----------------------------------------------------------------------

Date: 14 Dec 89 23:14:41 GMT
From: hpfcso!hpfcdc![e-mail]  (Perry Scott)
Subject: Builder's Success - HF Sweep Tube Amp
Message-ID: <[e-mail]>

I've been pestering the net for the past few months about a Rube Goldberg
HF linear amp I've been building from a buncha 6LQ6s.  I finally got it
working well enough to report the results.

Much of this will be familiar to the OFs, but many of us younger OFs
weren't around during the sweep tube period in the 60s and 70s.  I had
quite a bit of trouble finding information on them, and had to rely on
friend's old QSTs, ca 1969-1970.

Sweep tubes are interesting beasties to work with.  They have a relatively
high plate capacitance, low plate voltage (I used 800 V), dissipate 30W
continuously, or 300W for 10 seconds.  For this reason, they make good
SSB amplifiers.  Another advantage is that you can usually find someone
trying to get rid of these dinosaurs - I got some for $4.95.

I found the DeMaw articles (QST 1969, 1970), and used his biasing
arrangement to balance the currents in six sweep tubes.  I used a bias
voltage of -20V, and then used 10K pots to set the individual grid
voltages to somewhere around 14 volts.  The grids (control, screen, and
suppressor) were RF grounded through a .01uF disc ceramic.

The input circuit was merely capacitively coupled to the cathode.  I
put in a 1 ohm resistor and RF choke in the cathode circuit to meter
the plate current.  I may add a real tuned input circuit in the future,
but my old Kenwood TS520 is able to resonate the input circuit, so it
is not a priority.

The output circuit was a conventional pi, with Rp = 450 ohms.  This was
determined with the standard equation - Rp = Vp / (Ip * K) - right out
of the ARRL Handbook.  At this low Rp value (>2K is the norm), the
tune and load variable capacitors become quite large, adding to the cost.

I made the mistake of using a disc ceramic in parallel with C-tune for
the 80 meter band, and promptly burned two of them (let the smoke out in
electronics parlance).  The small disc ceramics cannot handle the
current.  I've given up on 80 meters until I can find a doorknob-type
capacitor.  I used commonly available silver-mica in parallel with
C-load, which seem to be tolerating the current so far.  I have gotten
40 and 20 meters to work, while 10 and 15 are elusive, probably due to
the high plate capacitance of the six tubes in parallel.

I'm running the amplifier slightly into the class C region, and am
getting 60-65% efficiency out of it.  The loaded tank Q is around 12,
and total output power is over 400 watts (my RF meter scale only goes up
to 300 :-) with about 80 watts drive.  So far, most of my testing has
been limited to a dummy load, since I am unsure how to measure harmonic
power and how the FCC expects us poor hams to comply with their 40dB
(is that right ?) harmonics floor.


Next on the agenda is a trio of 4CX250Bs.  I've found a cheap (free)
source of used tubes that still have some life in them.  We'll see if I
can hit the 1500W legal limit with those.  After balancing 6 sweep
tubes, a trio of real transmitting tubes should be a piece of cake.

Thanks to the Net for all the help.  It's always nice to know we still
have the capability to build useful equipment out of baling wire and
bubble gum.

Perry Scott
KF0CA

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

Date: 16 Dec 89 01:50:38 GMT
From: unsvax!arrakis.nevada.edu![e-mail]  (Mike Storke N7MSD)
Subject: CoCo WEFAX
Message-ID: <[e-mail]>

  Ok, since so many people are having mail bounce problems, and even though I
don't want to waste net bandwidth, I'm going to post the UNENCODED program to
this news and also to REC.RADIO.SHORTWAVE.  As I am leaving for home tomorrow,
and will not return until mid-January, I think this is necessary.
  The file will be in unencoded ascii code.  All you have to do is remove
headers and the like.  I will post it later tonight.
  I'm sorry for any inconvenience this will cause to the network, but it is
necessary.  The WEFAX program is NOT long, and will only consume as much room
as a typically long message (or a couple of the messages from these stupid
threads we're seeing).  73's, Mike, N7MSD (Sig file will be in program message)

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

Date: 16 Dec 89 00:43:40 GMT
From: rochester!rit!ultb![e-mail]  (C.E. Piggott)
Subject: Kenwood TS140
Message-ID: <[e-mail]>

>I am considering purchasing a Kenwood TS140.  I would like to receive
>opinions of the rig from people who have them.  TU es 73's

I like the 440 more.  The $500 difference for a TS440S (with the built
in antenna tuner) is worth it, if only for direct frequency entry
keypad and SWR meter.  The only thing that I wish they BOTH had is
a built-in electronic keying unit.  I like a station with as few
separates as possible, for when I want to go portable, and it'd
be nice to just be able to plug in a decent set of paddles, with
the electronic keyer part built inside.  (It's not even listed as
an option in the TS440S or TS140S ads, and there's no controls for
it on the panel).

The ICOM IC-745 has this as an optional internal add-on board.  The
745 is a great rig, except no QSK (only semi-breakin) and it's 100 watts
(Kenwoods are 200w), and a TS-140 looks like a better deal than an
IC-735 (ours is a 745, no longer made).

Don't forget about the Yaesu 747, it looks pretty neat for the price,
except that the panel layout is not as high-tech and pretty as it
could be.


De Chris, N2JGW
R.I.T. Amateur Radio Club
[e-mail]

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

Date: 12 Dec 89 23:16:27 GMT
From: zaphod.mps.ohio-state.edu!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!peregrine!ccicpg!cci632!rit!ultb![e-mail]  (C.E. Piggott)
Subject: Modifiying radios for out of band operation
Message-ID: <[e-mail]>

In article <[e-mail]> [e-mail] (anmar mirza) writes:

>Also, where is it a LAW that I cannot transmit out of bands on my radio?

I disagree with you, and feel that the type-certifications are important.
Even if I look at it from strictly a ham-radio point of view, to tell you
the truth I have some serious reservations about the number of EMT's etc.
who are out there with IC-02AT's and the like who are *NOT* hams.

>Last I looked, it was merely a regulation through the FCC, not a LAW.

But you bring up an interesting question: part 97 doesn't make any
mention of penalties for infractions, except with regard to loss of
your license for failure to answer an official notice of violation.
Is this stuff, in fact, written somewhere?  And for that matter,
if it's 'law', do normal constitutional rights apply, or do we waive
them when we sign the 610 form?  (Like Driver's licenses)
(Can we ask for a jury trial? :-) )

>I also seem to remember something about certain regulations that are
>suspended during emergencies, I highly doubt that I would get cited
>for using my radio in good faith out of band during an emergency,

I think that's quite a stretch.  Even during emergencies, normal rules
are only waived when other communications links fail.  For the same
reason, if your car breaks down in front of a telephone booth,what
do you think would be the appropriate LEGAL response, to use the
autopatch, or to get out of the car and use the payphone?  The
answer is quite clear; if the FCC thought that emergency services
were an exception because they respond to emergencies, I think that
they wouldn't be required to be type-certified in the first place.

(Is anybodys still reading?)

Chris N2JGW
[e-mail] (pls. include a return path)

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

Date: 15 Dec 89 09:27:27 GMT
From: philmtl!philabs!ttidca![e-mail]  ( Avatar)
Subject: rec.radio.shortwave "invite"
Message-ID: <[e-mail]>

In article <[e-mail]> [e-mail] (Steve Dowman) writes:
+In article <[e-mail]>, [e-mail] ( Avatar) writes...
+  (mindless drivel on swl'ers being dweebs and anti-Ham)
+
+   Hey Avatar, how are we gonna kiss your ass if you keep talking through
+   it?  Sheesh, who are you anyway, The Incredible Iron Ham Man?  Your
+   attitude is amusing.  This Ham is cooked!

 Mr. Dowman,

   Your choice of language and the tone of your posting simply  proves  my
point about this issue.  I doubt that you understand the significance of the
conflict on .shortwave: The chap who lost the round, claims to be an officer
for the American SWL clubs or some suchlike. Now wouldn't you think that a
person so involved would have a better background on radio law and history?!!

   His ignorance about such matters is compounded by the fact that he seems
unable to admit, in public, that he is in error regarding the facts. Does
this extend to you as well? I never called YOU a dweeb...be a little more
careful what you sling, eh? ;-)
--
-Avatar-> (aka: Erik K. Sorgatz) KB6LUY           +-------------------------+
Citicorp(+)TTI                          *----------> panic trap; type = N+1 *
3100 Ocean Park Blvd. Santa Monica, CA  90405     +-------------------------+
{csun,philabs,psivax,pyramid,quad1,rdlvax,retix}!ttidca!sorgatz **

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

Date: 13 Dec 89 22:53:08 GMT
From: zaphod.mps.ohio-state.edu!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!peregrine!ccicpg!cci632!rit!ultb![e-mail]  (C.E. Piggott)
Subject: RST
Message-ID: <[e-mail]>

In article <[e-mail]> [e-mail] (Gary B. Fariss) writes:

>N3xxx:  "KH6xxx 59 Pennsylvania."
>KH6xxx: "You're 59 Hawaii. QSL?"
>N3xxx:  "QSL. Thanks for Hawaii!  How's my signal out there?"

>   :-)

Our first contact during the conest was given a (quite honest) 55
signal report.  After two more QSO's we caught on that everyone was
giving out 59's, hearing something like this:

"You are 59 colorado 59 colorado"
"Thank you, you are 59 new york, 59 new york, please repeat your call
    prefix, we couldn't make it out, you're very weak, VERY weak!"

The awful part is that, for the remaining 35 hours 45 minutes of
operating, we were feeling guilty about giving the guy the 55!


Did any other university clubs out there participate in the conest?
We finaled 23 states and 32 dxcc countries, total about 29,000 pts.

--
Chris, N2JGW
R.I.T. Amateur Radio Club, K2GXT

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

Date: 16 Dec 89 01:05:02 GMT
From: rochester!rit!ultb![e-mail]  (C.E. Piggott)
Subject: RST
Message-ID: <[e-mail]>

In article <[e-mail]> [e-mail] (Scott Ellington) writes:

>Speaking of call signs, shouldn't stations be required to give their own
>call at least once per contact?

YEAH!!!!!!!!!!!!!!!!!!!!!!!

BOY is it AGGRAVATING to listen to some bonehead call "QRZ?" and then
repeat the calling station's callsign, say "THANK YOU FOR xyz, QRZ?"
and give his own callsign every 10 minutes or so!!!

(1) It's not fair to me, as a contest participant, to have to wait
    for you to give your callsign sometime in the next 8 or 9
    minutes.  I spend this time waiting to hear who you are,
    when I could be out contesting.  You would *THINK* that the
    big guns who are calling CQ on some freq. would show a
    little more courtesy in this respect.

(2) The law states at least every ten minutes during and at the end
    of EACH COMMUNICATION.  This means when you're DONE talking
    to ME, you give your callsign, *NOT* in 10 or 15 exchanges,
    after EVERY ONE.  I don't think that there's any room
    here for interpretation.


This is the way *I* operated, and it didn't hurt at all.


                    Chris, N2JGW

[e-mail]

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End of INFO-HAMS Digest V89 Issue #1026
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