QRZ! Ham Radio 5/QRZ Ham Radio Callsign Database - Volume 5.iso/digests/homebrew/940038.txt

Internet Message Format | 1994-11-13 | 12KB

Date: Tue, 22 Feb 94 04:30:43 PST
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Homebrew Digest V94 #38
To: Ham-Homebrew


Ham-Homebrew Digest         Tue, 22 Feb 94       Volume 94 : Issue   38

Today's Topics:
       Advice, please, re 12V Battery Supply in Shack (2 msgs)
                      homebrew SSB xtal filters
            Homemade balun, unknown toroid material. Help!
                         Laser jammer wanted
          Looking for Motorola VHF power transistor sources
                 Need mic wiring info for Icom W2A...
                              Subscribe?
                   What test equipment do you use?

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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
herein consists of personal comments and does not represent the official
policies or positions of any party.  Your mileage may vary.  So there.
----------------------------------------------------------------------

Date: Mon, 21 Feb 1994 04:19:20 GMT
From: netcomsv!netcomsv!bongo![e-mail]
Subject: Advice, please, re 12V Battery Supply in Shack
To: [e-mail]

In article <[e-mail]> [e-mail] writes:
>
    Battery stuff:
>The question is the best way to keep the battery adequately charged
>without over-charging it - I'm not sure merely connecting a DC power
>supply to the battery is a very good answer.
>
>Suggestions as to the best method to both power the equipment AND keep
>the battery from deteriorating would be appreciated.


    This whole subject was very well covered in a series of
articles in that evil cultist rag QST.

    See "Practical Battery-Back-Up Power fro Amateur Radio
Stations - Part 1, 2, 3." March, April, May 1990.

Brian Kantor posted a good writeup on lead acid batteries on 28 May
1992. I have a copy and will mail it to the original poster or anyone
else who wants a copy.



--
Julian Macassey, N6ARE  [e-mail] Voice: [phone]
Paper Mail: Apt 225, 975 Hancock Ave, West Hollywood, California 90069-4074

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Date: Sun, 20 Feb 94 16:51:26 PST
From: nntp.cs.ubc.ca!mala.bc.ca!oneb!ham![e-mail]
Subject: Advice, please, re 12V Battery Supply in Shack
To: [e-mail]

I'm planning to resurrect my ham shack this spring (other projects and
illness have delayed it ).

I have a number of items in the shack I want to power off a 12 V battery
- including a VHF 10 W radio, a UHF 10 W radio, a small 12 V TV, a packet
TNC and a desk lamp.

A separate 12 V battery will supply power to a TS-820S as backup for
power failure, which happens fairly often around here. (Using the same
battery for both purposes is out, as the 820 DC power supply puts a heavy
ripple on the battery when in use).

The question is the best way to keep the battery adequately charged
without over-charging it - I'm not sure merely connecting a DC power
supply to the battery is a very good answer.

Suggestions as to the best method to both power the equipment AND keep
the battery from deteriorating would be appreciated.

Tnx, Bob, VE7EMD

Robert Smits                    There is *no* idiotproof filter.
VE7EMD                          Idiots are proof against anything!
Ladysmith B.C.                       - Richard Chycoski, VE7CVS
e-mail: [e-mail]

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Date: Wed, 16 Feb 1994 10:45:44 GMT
From: agate!howland.reston.ans.net!EU.net!uknet!dcl-cs![e-mail]
Subject: homebrew SSB xtal filters
To: [e-mail]

If you are considering building an SSB xtal filter it's well worth looking
at the article by W7ZOI on Cohn xtal filters. It appears in 'QRP Classics',
and is a reprint from QST. Although I've only built CW filters based on this
approach, SSB filters can easily be realised also, and I would think that
a filter with 3 or 4 xtals would satisfy your requirement. It probably
doesn't matter too much on the make, as long as all the crystals are quite
well matched in frequency ( to within 10 percent of the filter passband is a
good rule).

73
Simon G0GWA.

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Date: Mon, 21 Feb 1994 06:00:02 GMT
From: wintermute.fullerton.edu!ihnp4.ucsd.edu!sdd.hp.com!caen!math.ohio-state.edu!magnus.acs.ohio-state.edu!csn!col.hp.com!srgenprp![e-mail]
Subject: Homemade balun, unknown toroid material. Help!
To: [e-mail]

[e-mail] ([e-mail]) wrote:

: I just made a 1:1 current balun for use at the feed point of my
: 20 meter dipole fed from a RG-58. The problem us is that the toroid
: I used was unmarked so I do not know the actual effect of the "balun".
: Is there a way to test the balun? Or should I eliminate it
: altogether. What kind of effect will the balun (with ot without)
: have on my transmission and reception?

I assume you made the balun by wrapping your coax a number of times
through the toroid core.  You would get some balun action even if the
core had no magnetic properties whatever.  In fact, some people
habitually make "air baluns" by simply winding several turns of coax
in a loop.  I wouldn't worry too much about it -- it can't hurt and
it probably is giving you at least some balun action.

AL N1AL

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Date: Mon, 21 Feb 1994 02:31:15 GMT
From: netcomsv!netcom.com![e-mail]
Subject: Laser jammer wanted
To: [e-mail]

[e-mail] (John, Dawn V) writes:
>Does anyone have any information regarding the building of speed-detector jamm-
>ers ? If so please post or send me message by email.
>Later,
>Dvj

      This belongs in alt.rec.speeding.

                        John Nagle

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Date: Mon, 21 Feb 1994 23:10:25 GMT
From: rit!isc-newsserver!ultb![e-mail]
Subject: Looking for Motorola VHF power transistor sources
To: [e-mail]

I'm looking for some Motorola VHF power transistors (MRF240/A and
others).  The only catalog I found them in is from a company that
is no longer in business.  Any suggestions?  I looked in the
mailorder list from ftp.cs.buffalo.edu, but nothing looked
promising.

73...Jim
N2VNO

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Date: Mon, 21 Feb 1994 08:05:28 GMT
From: wintermute.fullerton.edu!ihnp4.ucsd.edu!sdd.hp.com!cs.utexas.edu!howland.reston.ans.net!agate!library.ucla.edu!csulb.edu!csus.edu!netcom.com![e-mail]
Subject: Need mic wiring info for Icom W2A...
To: [e-mail]

Could someone provide a wiring diagram for the combination speaker/mic jack
on an Icom W2A HT? I don't see how they can fit a speaker, mic, and a PTT
switch into a 3 terminal jack unless some trickery closes PTT when the mic key
shorts the speaker line. Many thanks in advance.

--
Bruce James Robert Linley  ----  [e-mail]  ----  Amateur radio: KE6EQZ

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

Date: 21 Feb 94 00:22:50 GMT
From: [e-mail]
Subject: Subscribe?
To: [e-mail]

Found this list via a crosspost to [e-mail].  I'm interested!  As
this is the only address I have, could someone subscribe me or send me
subscription info?

Thanks

John K0JD



---
 * Freddie 1.2.5 * "Aaaaaahhhhhh.........Baaaaach!" -- Radar O'Reilly

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Date: Mon, 21 Feb 1994 13:08:19 GMT
From: elroy.jpl.nasa.gov!sdd.hp.com!hpscit.sc.hp.com!hplextra!hplb!hpwin052!hpqmoea![e-mail]
Subject: What test equipment do you use?
To: [e-mail]

Gary Coffman ([e-mail]) wrote:

: Use this *now* David. Take scope pictures of all your antennas while
: they're working. You can then pulse the line anytime you wonder if
: something has gone sour. If the traces don't match, it has. Otherwise
: you've saved yourself a trip up the tower.

: Gary


    A very, very sound suggestion, but I'm in one of those ALL external
antennae banned areas. My HF doublet is on a halliard, and the 2m thing
is in the attic. I can get at all of them in under 2 minutes. The guys
with the big rotating towers and the stacked monobanders *really* need a
TDR.

   Nice for checking cables, even if there is a corroded region away
from the ends, this thing will spot them and measure their location.

  Cheers
          David

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Date: Mon, 21 Feb 1994 14:41:00 GMT
From: agate!library.ucla.edu!news.mic.ucla.edu!unixg.ubc.ca!nntp.cs.ubc.ca!utcsri!newsflash.concordia.ca!pavo.concordia.ca![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>ash.co
Subject : Re: What test equipment do you use?

In article <[e-mail]>, [e-mail] (Gary Coffman) writes...
>In article <[e-mail]> [e-mail] (David Stockton) writes:
>>   TDR  (Time Domain Reflectometer)  Well, it was on this stall at a
>>rally, and the bloke wanted 35 pounds, it proved 100% working when I got
>>it home.  This device is best described as an in-cable radar set, used
>>to test transmission lines and connectors. It fires a pulse down the
>>line and plots a trace of reflection voltage versus time so you can
>>measure exactly how bad a mismatch is, and measure just how far down the
>>line it is. It's nice to know I've got one, should I ever need it, but I
>>must confess I've not (yet) used it in anger. The name alone frightens
>>people, they seem to always be sold at "for the parts" prices. If people
>>stick pins in your co-ax, then you NEED one of these...
>
>Use this *now* David. Take scope pictures of all your antennas while
>they're working. You can then pulse the line anytime you wonder if
>something has gone sour. If the traces don't match, it has. Otherwise
>you've saved yourself a trip up the tower.
>
Great idea. Anyone who wishes that they had such a piece of equipment can build
one for next to nothing. The ARRL handbook page 27-31 (year 199?) has a great
little circuit that works very well. One drawback is that for it too be useful
for the lengths of coax that amateurs usually use (i.e. around 50ft) then you
NEED a scope with a bandwidth of 50MHz or more.
Enjoy

-Mark Hillier        Internet: [e-mail]
            Amateur:  VE2HVW
            PACKET:   VE2HVW@VE2FKB
" I hear, I forget. I see, I remember. I do, I understand"

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

Date: 22 Feb 1994 09:29:08 GMT
From: agate!howland.reston.ans.net!wupost!bigfoot.wustl.edu![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>
Subject : Re: Laser jammer wanted

Dave Walster ([e-mail]) wrote:
: [e-mail] (John Nagle) writes:
: >      This belongs in alt.rec.speeding.

: Is the .rec. short for reckless?

: Dave.

maybe so, but what are the chances anybody *there* will know how to build
one?

jesse.

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End of Ham-Homebrew Digest V94 #38
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