QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/homebrew/940014.txt

Internet Message Format | 1994-11-13 | 15KB

Date: Sun, 30 Jan 94 04:30:27 PST
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Homebrew Digest V94 #14
To: Ham-Homebrew


Ham-Homebrew Digest         Sun, 30 Jan 94       Volume 94 : Issue   14

Today's Topics:
                 Antenna Tuner Project Advice Needed
                          Crazy VFO (2 msgs)
                       HF circuit advice needed
                  High Voltage Power Supply (2 msgs)
                  Tuner modules (Have you seen any?)
              Using ICOM filters in SONY ICF-2010/2001D?
                          XTAL source needed

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Archives of past issues of the Ham-Homebrew Digest are available
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We trust that readers are intelligent enough to realize that all text
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policies or positions of any party.  Your mileage may vary.  So there.
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Date: Fri, 28 Jan 1994 13:43:16 GMT
From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!usenet.ins.cwru.edu!gatech!wa4mei.ping.com!ke4zv![e-mail]
Subject: Antenna Tuner Project Advice Needed
To: [e-mail]

In article <2i8muq$[e-mail]> mb@xmb (0000-Admin(0000)) writes:
>Richard Measures, AG6K, wrote an article in the Feb. 1990 QST about a
>balanced antenna tuner, made for just such an antenna system as you
>describe.  The balun is at the input of the tuner (i.e., between the
>transmitter and the tuner).  The tuner itself consists of two roller
>inductors for the series reactances and a variable capacitor for the
>shunt reactance.
>
>         +----+
>         |    v L1
>         +-((((((--+-------
>         |         |/
>---     -+       -----
>   balun         ----- C1   --> to ladder line
>---     -+        /|
>         |         |
>         +-((((((--+-------
>         |   ^ L2
>         +---+
>
>The roller inductors are mechanically ganged by a belt and pulleys on
>the inductor shafts.  The idea of a balanced tuner feeding a balanced
>transmission line to a balanced antenna is appealing...

Yes it is, but be careful of C1. It has to float hot and most variable
capacitors have one side attached to the frame making it hard to maintain
balance. You can mount it on a sheet of plexiglass, and don't forget
an insulated tuning shaft. A capacitor that has both sets of plates
insulated from the capacitor frame is best, but they're harder to find.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 28 Jan 1994 08:13:01 GMT
From: usc!howland.reston.ans.net!cs.utexas.edu!swrinde!sgiblab!sgigate.sgi.com!olivea!flash![e-mail]
Subject: Crazy VFO
To: [e-mail]

I cannot exlplain this to myself :

I build a VFO that is very similar to the VFO of the
"Optimized QRP Transceiver" from Roy W. Lewallen
W7EL , the only difference is that it
is not for the same frequency because I have to use it in a
etherodyne transceiver born for fixed cristal oscillatorA
operations.

The Vfo was performing good , after warming up for 20 minutes
it was moving in a range of max 20  Hz.
The frequency from power-on increase of 90-100 Hz.

The operating frequencies are from 8050 to 8190 more or less.
Output 1.5 Volts pp over a 50 ohm load.
Now the problem is  that if I put the vfo inside its metal box
to make it usable and connecting the box itself to the ground of the
vfo (as it should be )  etc etc ...
In a few words  putting it in its
final state then it starts to become instable increasing or decreasing
its frequency of more than 800 or more Hz and trying to drift also after
more than 1 hour from power-up.

The last info I used a copper board like one for pcb scraching out copper
for making the needed wiring leaving a lot of copper for the ground connections

I hope to have done a good desriptions of the item.

Also I took out from the box the VFO and it returned to original good
performance.

IT IS DRIVING ME CRAZY !!!!!!

Roberto

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

Date: 28 Jan 1994 15:17:24 GMT
From: news.cstar.andersen.com!news.acns.nwu.edu!casbah.acns.nwu.edu![e-mail]
Subject: Crazy VFO
To: [e-mail]

In article <2iahed$[e-mail]>,
Roberto Valfredini <[e-mail]> wrote:
>
>I cannot exlplain this to myself :
>
>I build a VFO that is very similar to the VFO of the
>"Optimized QRP Transceiver" from Roy W. Lewallen
>W7EL , the only difference is that it
>is not for the same frequency because I have to use it in a
>etherodyne transceiver born for fixed cristal oscillatorA
>operations.
>
>The Vfo was performing good , after warming up for 20 minutes
>it was moving in a range of max 20  Hz.
>The frequency from power-on increase of 90-100 Hz.
>
>The operating frequencies are from 8050 to 8190 more or less.
>Output 1.5 Volts pp over a 50 ohm load.

I built mine for the 20m band and it puts out about 2vpp into a 50
ohm load. (after the buffer).  An unrelated comment: did you
pick up the new buffer from the feedback column in Nov 1980 QST?

>Now the problem is  that if I put the vfo inside its metal box
>to make it usable and connecting the box itself to the ground of the
>vfo (as it should be )  etc etc ...
>In a few words  putting it in its
>final state then it starts to become instable increasing or decreasing
>its frequency of more than 800 or more Hz and trying to drift also after
>more than 1 hour from power-up.
>
>The last info I used a copper board like one for pcb scraching out copper
>for making the needed wiring leaving a lot of copper for the ground connections
>
>I hope to have done a good desriptions of the item.
>
>Also I took out from the box the VFO and it returned to original good
>performance.
>
>IT IS DRIVING ME CRAZY !!!!!!

It would drive me crazy too. ;(

I think that there may be two things going on:
  1.  a long term problem such as heating that is contributing to
      drift after an hour and
  2.  a short term problem that may be related to improper grounding/ground
      loops or not stiff enough connection between vfo and box.  This could
      lead to:
        - abrupt changes in parasitic capacitance and tuned frequency as
          components move about - not so micro micrphonics
        - parasitics induced because of inductance from ground loops and
          parasitic capacitance.  This may also explain the increased long
          term drift as the components get warmer.


Rajiv
aa9ch
[e-mail]

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

Date: 26 Jan 1994 21:35 EST
From: vtserf.cc.vt.edu!solaris.cc.vt.edu!vtcc1.cc.vt.edu![e-mail]
Subject: HF circuit advice needed
To: [e-mail]

Hi,

I need advice on building an induction heater of about 1 - 2 kW for
outgassing electrodes and vacuum tubes. I was considering modifing
a transmitter for this purpose. The frequency should be around
1 - 1 MHz. If someone already has something suitable I would be interested
in a possible trade, purchace, etc.

P.S.  If you have an expensive power tube which needs repair I may be able
to rebuild it for you.
                -thanks!
                    David   "[e-mail]"
                        or 717-993-3596

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

Date: Thu, 27 Jan 1994 15:19:22 GMT
From: spool.mu.edu!howland.reston.ans.net!EU.net!Germany.EU.net!netmbx.de!zrz.TU-Berlin.DE!zib-berlin.de!uni-paderborn.de!urmel.informatik.rwth-aachen.de![e-mail]
Subject: High Voltage Power Supply
To: [e-mail]

Hi OM`s

I need a high voltage power supply for a tube PA.
But I can`t find the right schematic and part list.
The tube runs with a current of 7000V and 2Amp.
I hope you can help me.
Thank's Martin

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

Date: Thu, 27 Jan 1994 16:36:16 GMT
From: sdd.hp.com!hpscit.sc.hp.com!cupnews0.cup.hp.com![e-mail]
Subject: High Voltage Power Supply
To: [e-mail]

Martin Stille ([e-mail]) wrote:
: Hi OM`s

: I need a high voltage power supply for a tube PA.
: But I can`t find the right schematic and part list.
: The tube runs with a current of 7000V and 2Amp.
: I hope you can help me.
: Thank's Martin

hmmm, 7kv x 2 amp, about 14kw on the plate....thats one healthy afterburner.
You should be worried about the coax feed also.

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

Date: 28 Jan 94 04:33:45 GMT
From: usc!howland.reston.ans.net!agate!apple.com!amd!amdahl!JUTS!p1svp10![e-mail]
Subject: Tuner modules (Have you seen any?)
To: [e-mail]

I've been trying to get a hold of a few Mitsumi CATV 17, 18, or the new
19 tuner modules.  If you have seen any of these laying around in fair
supply please respond.  Thanks....

--

--------------------------------------------------------------------------
 Dave Sharpe Sunnyvale Ca. [e-mail]
--------------------------------------------------------------------------

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

Date: Thu, 27 Jan 1994 17:43:20 GMT
From: nntp.ucsb.edu!library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!newsserver.jvnc.net!raffles.technet.sg!ntuix!ntuvax.ntu.ac.sg![e-mail]
Subject: Using ICOM filters in SONY ICF-2010/2001D?
To: [e-mail]

Hi,

    Does anyone know if I can use the SSB filters for ICOM or for
Kenwood in other radios or in my own IF strip? I am thinking of use
for SSB/RTTY/CW. The reason I ask is because the Kiwa filters I want
are not available locally but the ICOM filters are. Does anyone who
have access to both know?

    I am looking to put the ICOM narrow filters (2.4 kHz) into my
SONY ICF-2010/2001D. Does anyone have any comments about doing this?

73 de 9V Daniel

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

Date: 27 Jan 1994 17:06:49 GMT
From: sdd.hp.com!hpscit.sc.hp.com![e-mail]
Subject: XTAL source needed
To: [e-mail]

>In article <[e-mail]> [e-mail] (Patrick Tatro) writes:
>>Im looking for a vendor willing to supply crystals in the 1 or 2 quantity
>>basis. Most vendors have minimum quantities that far exceed my needs. I am
>>also not sure if I can locate crystals at 16.660Mhz and 16.600Mhz. Im trying
>>to convert an FM pocket tranciever into a cordless phone unit. Any help will
>>be greatly appreciated.

Also, Hy-Q Intl. in Erlanger, Kentucky.  They don't mind selling
small quantities and can give 2 day delivery if necessary.

Rick Karlquist
[e-mail]

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

Date: 27 Jan 1994 15:49:08 GMT
From: sdd.hp.com!vixen.cso.uiuc.edu!howland.reston.ans.net!sol.ctr.columbia.edu!news.columbia.edu!namaste.cc.columbia.edu![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <2i6sje$[e-mail]>edu
Subject : Re: IBM-PC Shareware for PCB Photo work


I've pretty much settled on CIRCAD from Holophase in Fl.
(thanks Al)
I did not find it on an FTP site but first found it on Online America
which had a very old version.
I called Holophase up and then later downloaded it directly from their
very small, but 14,400 BBS.
They offer a very attractive discount to Hams also for the full registered
version. The demo i have is limited in number of parts etc.. but quite
functional.

Mike Cecere
Applied Physics Department
Columbia Univeristy

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

Date: Thu, 27 Jan 1994 17:36:26 GMT
From: sdd.hp.com!cs.utexas.edu!howland.reston.ans.net!newsserver.jvnc.net!raffles.technet.sg!ntuix!ntuvax.ntu.ac.sg![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <2i68cr$[e-mail]>tuvax.n
Subject : Re: Antenna pre-amp design. Help!

In article <2i68cr$[e-mail]>, [e-mail] (Scott Dorsey) writes:
> In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>
>>In looking through my collection of ARRL Handbooks, I don't find a
>>HF preamp until I go back to the 1962 edition. They have one using
>>a 6AK5 pentode. This should give you an idea of the apparent lack
>>of need for such circuits with more modern equipment.
>
    Gary is probably right but then if you look in the MFJ catalog I
am sure you will find one or two active antennas, which are quite expensive
when you consider the number of components involved. Thus in case of the
lack of a good antenna, active antennas/pre-amps still help.

> Actually, I recommend this circuit... I built it when I was a kid and
> hung it on the front of a modified Philco table radio and it worked very
> nicely to the point where the rotten selectivity of the radio was a problem.
> The manufacturer probably never expected anyone to tear windings off the
> AM loopstick to move it to 80M.
> --scott

    However, a valved pre-amp was not quite what I had in mind :) I was
thinking more along the lines of the dual-gated mosfets or bi-polar types
for broadband amplification as well as for narrow band. :)

> --
> "C'est un Nagra.  C'est suisse, et tres, tres precis."

73 de 9V Daniel

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

Date: 26 Jan 1994 22:58:54 GMT
From: news.ingr.com!b11!cmack.b11.ingr.com![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>1.ingr
Subject : Re: IBM-PC Shareware for PCB Photo work


(From a posting in sci.electronics from Christopher Webster ([e-mail])
Tue, 1 Jun 1993 20:33:12 EDT)

> Several freeware schematic/PCB CAD programs are available via anonymous ftp
> from rigel.acs.oakland.edu (141.210.10.117).  These are contained in the
> "pub/msdos/cad" directory; read "00-index.txt" first to see what's
> offered.

I've used this S/W also; it is excellent.  The documentation leaves something
to be desired; nowhere is it stated that you can mirror text (strings) by
selecting text for moving, then typing an 'x'.  Small complaint for something
that's free; I've used it for several boards already.

                        -Dan Kerl
                        [e-mail]

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End of Ham-Homebrew Digest V94 #14
******************************