QRZ! Ham Radio 5/QRZ Ham Radio Callsign Database - Volume 5.iso/digests/homebrew/940142.txt

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

Date: Fri, 27 May 94 04:30:25 PDT
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Homebrew Digest V94 #142
To: Ham-Homebrew


Ham-Homebrew Digest         Fri, 27 May 94       Volume 94 : Issue  142

Today's Topics:
               Converting an old HT-220 to 2M (2 msgs)
                 Help needed for external 22AT power
        How can I reduce RFI from flourescent lights? (2 msgs)
                    pcb laser printer iron method
                         SSB Filters (2 msgs)
                      Transmitting Tube Cooling

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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: 26 May 1994 13:21:04 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!spool.mu.edu!bloom-beacon.mit.edu!senator-bedfellow.mit.edu!space.mit.edu![e-mail]
Subject: Converting an old HT-220 to 2M
To: [e-mail]

By the way, I have 5 Motolora HT-220 for sale. I would like $35/ea or 150/all.


For more info, e-mail to [e-mail].


thanks,

-------------------------------------
Christopher S. Pak
Massachusetts Institute of Technology
Center for Space Research
37-487
77 Massachusetts Ave.
Cambridge, MA 02139
Phone: [phone]
Fax: [phone]
E-mail: [e-mail]

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

Date: Thu, 26 May 1994 18:20:17 GMT
From: pa.dec.com!crl.dec.com!nntpd.lkg.dec.com!ryn.mro.dec.com!est.enet.dec.com![e-mail]
Subject: Converting an old HT-220 to 2M
To: [e-mail]

In article <[e-mail]>, [e-mail] (Oracle News Poster) writes...
>        I have a Motorola Ht-220 Type CC3540 Serial # L06K2D Model H33FFN1100E.
>It transmits and Receives on 163.5375 MHz. It has a 15 Volt NiCad. It is
>                xmit: 18170.8

The transmitter in these uses freq. triplers to get up from the xtal freq. to
TX freq. 18170.8 x 3 x 3 = 163537.2. Mine is a 462 MHz unit that has one more
tripler to get up there.

>                rcv:  48912.50

Let's see... receive xtal = (Tx freq - IF freq) / n; where n = 3,9,27 etc.
Using n=3 we get an IF of 16.8 MHz, which sounds reasonable. International
Crystal Mfg. has crystals for these radios - call them at 405 236 3741 and tell
them what you have. You may need model number and "chassis number" which is a
number like NUE6001BA that you can find inside the battery compartment. The
xtals are a bit pricey - $15 to $25 each, but what the heck, I only paid $10
for the radio at a flea. You will need to re-tune the tuned circuits in the
radio, and for this you will need the Motorola manual... try Motorola or a
local service shop for that. I copied the 450-488 MHz radio manual that another
ham here had around. Make sure whoever knows you are re-tuning to a ham
band, or else they'll want to know your commercial license #!

By the way, I have a line on cheaper crystals from a different source, still
waiting for someone to get back to me on that.

>There is also a "PL Reed" that I will probably need.

This is pre-microprocessor coded squelch technology. A tiny mechanical reed
functions similar to a quartz crystal, except at audio freqs. If you're going
to use the HT to get into a repeater with PL tone access you need it, otherwise
you don't, like for simplex. Mine came with one, but you could always add one
of those tiny PL decode/encode boards from the back of QST.

>        Last (and least?) I need a charger for the Ni-CAD.

Yah, these radios typically are placed in a "drop-in charger" which does the
job. I'm not sure how I'm going to handle this myself... The battery that came
in mine was good, though, and charged up to 15V no problem. Pick up a spare at
a flea, as Moto wants something like $75 for them.

>                Doug N8TUT

Good luck with the mods! I'll be doing mine as soon as I find out about those
cheap xtals! Makes an interesting project...
-Tom R.   N1OOQ   [e-mail]

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

Date: Thu, 26 May 1994 21:52:42 GMT
From: ihnp4.ucsd.edu!library.ucla.edu!europa.eng.gtefsd.com!newsxfer.itd.umich.edu!nntp.cs.ubc.ca!unixg.ubc.ca!quartz.ucs.ualberta.ca!tribune.usask.ca!sue![e-mail]
Subject: Help needed for external 22AT power
To: [e-mail]

My Kenwood 22AT has only one external power input jack located on
the side of the radio.  Kenwood supplies a 12.5V 70ma adapter to
use with the unit.  The adapter charges the battery but does not
have enough current to transmit with.  I am planning on building
a simple 12V 3A power supply to used with the radio.  My concern is
that I will be over charging the internal 6Volt 600ma battery.
Should I be removing the battery when using an external high current
power supply?  Kenwood does not show a external AC power supply as
an option for this radio, but they do have a car adapter- which
could cause overcharging of the battery.  Kenwood recommends a max
of 15 hours using the 12.5V 70ma charger.

Any suggestions?

Thanks in Advance.

Mike Murray
[e-mail]
VE5EF

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

Date: Thu, 26 May 1994 07:50:20 -0800
From: nwnexus!pt.olympus.net!ptpm004.olympus.net![e-mail]
Subject: How can I reduce RFI from flourescent lights?
To: [e-mail]

I have a beach cabin with solar panels & batteries for
power.  I use 12VDC flourescent lights in each room
(made by REC Industries) with electronic ballasts.
When the lights are turned on I get all kinds of squeals
in the AM & SW bands.  The 12 V negative line common to
 the solar panels & battery is grounded with a 10 foot
ground rod (but driven into dry sand).

Any ideas how to quiet these lights?  Now I have to
turn them off to use the radio.

Also does anybody have experience with the small 12VDC
to 120 VAC inverters (100W-200W)?  Do they generate RFI also?

Thanks & 73
(these ham newsgroups are great, full of the latest info.)

--
[e-mail] (Phil Keys)      KB7WXQ
Software Consultant - specializing in software safety & SQA
Port Hadlock, WA 98339    [phone]
West of Puget Sound.....South of British Columbia.... 122 44.0W  48 02.0N
_____________________________________________________________

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

Date: Thu, 26 May 1994 16:58:42 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!gatech!newsfeed.pitt.edu!gvls1![e-mail]
Subject: How can I reduce RFI from flourescent lights?
To: [e-mail]

In article <[e-mail]> [e-mail] (Phil Keys) writes:
>I have a beach cabin with solar panels & batteries for
>power.  I use 12VDC flourescent lights in each room
>(made by REC Industries) with electronic ballasts.
>When the lights are turned on I get all kinds of squeals
>in the AM & SW bands.  The 12 V negative line common to
> the solar panels & battery is grounded with a 10 foot
>ground rod (but driven into dry sand).
>
>Any ideas how to quiet these lights?  Now I have to
>turn them off to use the radio.

That's why you need those tube radios that "glow in the dark"  ;-)

[sorry I couldn't resist]

=================================================================
Pete Rossi - WA3NNA                  [e-mail]

Unisys Corporation - Government Systems Group
Valley Forge Engineering Center - Paoli, Pennsylvania
=================================================================

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

Date: 26 May 1994 13:09:13 GMT
From: ihnp4.ucsd.edu!swrinde!pipex!bnr.co.uk!bnrgate!bmerha64.bnr.ca!bnr![e-mail]
Subject: pcb laser printer iron method
To: [e-mail]

I am very interest in what you have to say about using the direct
iron on method from a laser printer.


Bill Kirkland

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

Date: Thu, 26 May 1994 12:06:13 GMT
From: ihnp4.ucsd.edu!usc!elroy.jpl.nasa.gov!ncar!csn!col.hp.com!news.dtc.hp.com!hplextra!hplb!hpwin055.uksr!hpqmoea![e-mail]
Subject: SSB Filters
To: [e-mail]

   I know of one world-class crystal filter manufacturer based in
France,  C.E.P.E.   part of Thomson-CSF.  I've got one in front of me
now, but no address.

   The highest reptation filters in amateur circles are German
KVG   Kristall Verarbeitung Neckarbischofsheim GMBH
     Postfach 61 D-6924 Neckarbischofsheim
     Telefon [phone]



  John Birkett
     25 The Strait
       Lincoln
         LN2 1 JF
            England

       Tel  [phone]

   Often has surplus crystal filters in stock. I've bought a number of
marine quality 1.4 MHz IF usb, lsb, cw filters from him


  The best advice is to first find your filters, then use IF to suit.

  Recently a lot of 1.4 MHz IF filters of superb performance have
flooded onto the British market at very low surplus prices (I paid the
equivalent of 40 francs each, although the prices fluctuate) Filters
for AM RTTY and various CW bandwidths are also to be found as well as
proper separate USB and LSB ones.  I think of good government surplus
components as a sort of tax refund!

   Bon Chance!

    David

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

Date: Thu, 26 May 1994 11:26:38 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!howland.reston.ans.net!noc.near.net!usenet.elf.com!rpi!psinntp!arrl.org![e-mail]
Subject: SSB Filters
To: [e-mail]

Elendir F1RCS ([e-mail]) wrote:
:  I'm (still) planning to build a multimode multibander (VHF/UHF) rig.
: In the course of designing the SSB part, I am of course facing the
: problem of filtering the unwanted LSB.
:  I've talked on the air with several hams that seem pretty positive that
: it is no more possible to find SSB Xtal filters in France.
:  Does someone have any clue regarding a possible US source for these ?
: What I'd like to find out is a 10.7003 to 10.703 Xtal Filter, with at least
: 60 dB at 10.6997 MHz. But a 9 MHz look-alike filter (or any IF) would
: fit also.

10.7 MHz SSB filters are rather unusual.  However, I'm surprised that
amateur dealers don't sell useable filters.  In the USA, you can often
buy optional filters to put in your amateur transceiver to get a different
bandwidth than what the radio came with.

However, the trend is to *make* your own filter out of microprocessor
clock crystals.  For roughly $10 worth of crystals, you can make a
decent filter and have some crystals for the oscillator(s).  They
even sell 9 MHz crystals.

--
Zack Lau  KH6CP/1           2 way QRP WAS
                           8 States on 10 GHz
Internet: [e-mail]   10 grids on 2304 MHz

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

Date: 26 May 94 14:58:34 CST
From: ihnp4.ucsd.edu!swrinde!news.uh.edu!ccsvax.sfasu.edu!ccsvax.sfasu.edu![e-mail]
Subject: Transmitting Tube Cooling
To: [e-mail]

In article <[e-mail]>, [e-mail] (Elie Nasr) writes:
> I hesitate to post to this group anymore - I seem to get responses indicating
> that I should know all the answers since I have an extra class license. Anyway:

Gosh, that's daunting. I have an extra ticket, too, and I know almost none of
the answers.
>
> Anybody ever made any sort of measuring device for measuring the back pressure
> in a cooling system for a transmitting tube? I have seen references to things
> like so many cubic feet of air flow. Or .6 inches of backpressure. Or does
> everyone just make sure they are running a blower that is over-rated just to
> be safe? I'd prefer to do it right, since the bigger the blower, the more
> noise present in the shack. Unless I put the blower in a different room! If
> this is the sort of thing that interests others, you might post your comments
> here rather than direct to me.   Thanks....
>
> 73's Doug

I guess you could build some equipment to measure airflow or back pressure, but
actually I think that's usually done by the blower manufacturer and reported as
a design spec. In practice, what I've always done when building high power
amplifiers is to use blowers similar to those I see in others' similar
equipment. Not scientific, but it's usually worked.

And, yes, I've been in a few shacks in the old days where the final amp was in
a separate room to keep the noise down. Some of those folks invested a good bit
of effort in remote tuning gear, too.
>
>
> --
>                       ---------------------------
>                      |       Doug Snowden        |
>                      |           N4IJ            |
>                      | email: [e-mail] |
>                       ---------------------------
>

Cheers & 73!

Jim  K5YUT

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End of Ham-Homebrew Digest V94 #142
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