QRZ! Ham Radio 5/QRZ Ham Radio Callsign Database - Volume 5.iso/digests/homebrew/940269.txt

Internet Message Format | 1994-11-13 | 22KB

Date: Sat, 10 Sep 94 04:30:29 PDT
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
Errors-To: [e-mail]
Reply-To: [e-mail]
Precedence: Bulk
Subject: Ham-Homebrew Digest V94 #269
To: Ham-Homebrew


Ham-Homebrew Digest         Sat, 10 Sep 94       Volume 94 : Issue  269

Today's Topics:
                           100MHz TTL Clock
           AG6K and this month's Tech Correspondence in QST
                           EME amp (3 msgs)
                 H.P. Digital Panbel Meters (2 msgs)
                      Heeeeeeeeeeeelp! (3 msgs)
                    ICOM 22S mod (repeater switch)
                Mitrek 800 Mhz Service Manual/ Info ??
                       need 100 MHz TTL clock
                   SETIQuest Magazine - Exobiology
                    unusual modulation techniques
                             xtal filters

Send Replies or notes for publication to: <[e-mail]>
Send subscription requests to: <[e-mail]>
Problems you can't solve otherwise to [e-mail].

Archives of past issues of the Ham-Homebrew Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew".

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: Fri, 09 Sep 1994 13:01:30 -0400
From: ihnp4.ucsd.edu!agate!howland.reston.ans.net!sol.ctr.columbia.edu!news.msfc.nasa.gov!niven.ksc.nasa.gov!algol.ksc.nasa.gov!k4dii.ksc.nasa.gov![e-mail]
Subject: 100MHz TTL Clock
To: [e-mail]

In article <[e-mail]>, [e-mail] (Muenzler,
Kevin) wrote:
> If you just need a 100MHz pulse rate, you can use any of the
> 74Fxx or 74ALSxx series chips.  They should have no problem
> running at 100MHz.  All you would need is the 100 MHz
> crystal.

Kevin-

A 100 MHz crystal is most likely used in a fifth or seventh overtone
mode.  How do you ensure that the crystal oscillates at the correct
overtone, instead of the fundamental or an "easier" overtone?

73, Fred, K4DII

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

Date: Thu, 8 Sep 94 19:37:18 GMT
From: dog.ee.lbl.gov!agate!howland.reston.ans.net!gatech!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!news.kei.com!ub!galileo.cc.rochester.edu![e-mail]
Subject: AG6K and this month's Tech Correspondence in QST
To: [e-mail]

I was leafing through this month's QST magazine.  The technical
correspondence column made some very interesting reading.

I had previously read the articles on VHF/UHF parasitics in HF amps,
design of HF amps, design of balanced tuner and so on by Rich Measures in QST.
His articles on these topics have also appeared in the now defunct Ham Radio
Magazine.  This month's Tech Correspondence column is devoted to a critical
examination of Rich's theories.  It has comments by an engineer from
Eimac, an engineer who designs amps for ameritron and others.  To put
it mildly, it disagrees with Rich Measures.

What did you think?

On many points, it is clear that the critics are right.  For instance,
consider the anode parasitic supressor.  The common form of it is a
resistor with a coil wound around it.  One of Rich's ideas is
to make the coil out of nichrome wire (has some resistance) to
prevent V/UHF parasitics.  He sells this in kit form.  But as the critics
point out, At VHF/UHF the coil has high impedance and it is the resistor
that is a part of the anode circuit, lowering its Q at those frequencies.

The critics also disagreed about removing electronic drive control, alc,
using improper protection in the HV section, using resistor in grid-ground
circuit to introduce negative feedback to reduce gain and most seriously,
about using MOVs in the HV circuit.

While I tend to agree with the critics generally, several of them
said that UHF/VHF parasitics are not a problem in most commercial
amateur amps.  My tiny experience in these things seems to be otherwise.
I have seen amps with some of the symptoms that Rich Measures described.

What has your experience been?

Another curious point:  If the article was so off the mark, what does
it say about QST's editorial process.  It is bad that it hapened
but good that they own up to it? or what?  In QST's defense,
even the best of scientific journals have this problem.

Honey, where is the salt shaker?  I received this month's QST.  :)

Rajiv
aa9ch/2

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

Date: Thu, 8 Sep 1994 20:32:11 GMT
From: agate!howland.reston.ans.net!europa.eng.gtefsd.com!newsxfer.itd.umich.edu!isclient.merit.edu!msuinfo!netnews.upenn.edu!news.drexel.edu!news.ge.com!knight.vf.ge.com!nadir![e-mail]
Subject: EME amp
To: [e-mail]

I've heard that Russian tubes are available. Does anyone have info (costs, types, where) in the US?

73, Harry, W3IIT

[e-mail]

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

Date: Thu, 8 Sep 1994 20:31:38 GMT
From: agate!howland.reston.ans.net!europa.eng.gtefsd.com!newsxfer.itd.umich.edu!isclient.merit.edu!msuinfo!netnews.upenn.edu!news.drexel.edu!news.ge.com!knight.vf.ge.com!nadir![e-mail]
Subject: EME amp
To: [e-mail]

I've heard that Russian tubes are available. Does anyone have info (costs, types, where) in the US?

73, Harry, W3IIT

[e-mail]

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

Date: 9 Sep 94 09:46:59 CDT
From: timbuk.cray.com!ned.cray.com![e-mail]
Subject: EME amp
To: [e-mail]

In article <[e-mail]>, [e-mail] (Bryan LaPlante) writes:
> What are people using for power amplification on EME?  I'm looking at 2m or
> 432, and trying to keep the costs down somewhat.  How much power are you using,
> and what is your amp... homebuilt, surplus, used....?

If you are going to use a reasonably sized antenna system, then a very
economical amp would be a pair of 4CX250s.  These tubes are very common on
the surplus market, and usually at reasonable prices ($25-40, maybe less).
The sockets for these tubes are also fairly inexpensive.  There have been
numerous articles written on amps for both 2m & 432 that use a pair of
these tubes.  10 watts of drive should get you about 600 - 800 watts output.
The disadvantage of using tetrodes is the fact that you have to provide an
additional power supply for the screen.

I have been running 2m EME for about a year.  I'm running a pair of 4CX300A's
which deleivers about 800 watts output.  It is a hamebrew amp that I bought
at a hamfest.  These tubes work fine on 2m, but they are a lot harder to find
than the '250s, and generally the sockets are more expensive (the tubes have
a bayonet style base rather than pins, so they require special sockets).

My antenna system is 4 x 10 element yagis (K5GL design).  It's actually a
fairly small system for EME, but it works reasonably well.  I have made 11 QSOs
with it, including several other 4 yagi stations, plus I've heard quite a few
stations that I didn't complete QSOs with.  I have, at times, been able to
hear my own echos with it as well.

Charlie Betz
N0AKC

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

Date: 9 Sep 1994 11:33:03 -0400
From: ihnp4.ucsd.edu!pacbell.com!sgiblab!swrinde!gatech!swiss.ans.net!newstf01.cr1.aol.com!search01.news.aol.com![e-mail]
Subject: H.P. Digital Panbel Meters
To: [e-mail]

Can anyone help me with documentation for H.P. Model 3431A Digital Panel
meters? I have acquired two of them that I want to use in my 4-1000A
Amplifier Project but I don't have pinout numbers or any other info. They
are AC operated and look to be 3 1/2 digits. Anyone help on this one?

73 from Russ WA6CWV, Boise

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

Date: 9 Sep 1994 18:21:01 -0400
From: newstf01.cr1.aol.com!search01.news.aol.com![e-mail]
Subject: H.P. Digital Panbel Meters
To: [e-mail]

Thanks for the responses to this inquiry. I have what I need !!!
Russ Ellsworth WA6CWV

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

Date: Thu, 8 Sep 1994 17:25:00 +0000
From: ucsnews!newshub.sdsu.edu!nic-nac.CSU.net!charnel.ecst.csuchico.edu!yeshua.marcam.com!insosf1.infonet.net!news.i-link.com!news.sprintlink.net!demon!microvst.demon.co.uk!tgold@@ihnp4.ucsd.edu
Subject: Heeeeeeeeeeeelp!
To: [e-mail]

In article <34kebn$[e-mail]>
           [e-mail] "Michel Soldevila - LENR" writes:

>
> Hi everybody
>
> My coax relays are 26 volts models. A long time ago, I saw a circuit able to
>  trigger
> such relays from a 12 volt source. The only thing I remember is that it was a
>  kind
> of voltage doubler who supply the relay with 2x12 volt during a short time, and
>  then
> supply it with 12v.
>
> Does anybody knows this circuit ?
>
> Thanks a lot
>
> 73 de F1GOC K
>
The trick is to use both your 12v supply plus 12v from a capacitor to
push the relay over and then hope that 12v is sufficient to hold it
over. No guarantee that only 12v will apply enough contact pressure!

You will need a 12v DPDT relay and a 330-470 mFd @ 25 volt capacitor. Also
put rectifier diodes across both your 26v and the added 12v relays to kill the
spikes plus one more to feed the capacitor.

I would guess that you can figure it out. Regret I can't draw a schematic
on a keyboard.

By the way you can get a very neat complete kit of parts and PC board from
Down East Microwave in Maine, tel [phone] fax [phone]. Costs $10
for their model DEM RVD-1.
--
Anthony R. Gold, G3SKR and AA2PM

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

Date: Thu, 8 Sep 1994 17:15:08 GMT
From: agate!howland.reston.ans.net!europa.eng.gtefsd.com!newsxfer.itd.umich.edu!news1.oakland.edu!rcsuna.gmr.com!kocrsv01![e-mail]
Subject: Heeeeeeeeeeeelp!
To: [e-mail]

In article <[e-mail]>, [e-mail] (Jim Buchanan) writes:
>
> In article <34kebn$[e-mail]>, [e-mail] (Michel Soldevila - LENR) writes:
>
> --
> Jim Buchanan                    N9SDV
> [e-mail]  "Catch 22"
> [e-mail]
> '73 BMW R75/5                   "Frau Bluecher"
> --
> Jim Buchanan
> [e-mail]  "Catch 22"
> [e-mail]
> '73 BMW R75/5                   "Frau Bluecher"

Wow, I've never (to my knowledge...) double sig'd before! Good work Jim!
--
Jim Buchanan
[e-mail]  "Catch 22"
[e-mail]
'73 BMW R75/5                   "Frau Bluecher"

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

Date: Thu, 8 Sep 1994 17:09:22 GMT
From: agate!howland.reston.ans.net!gatech!newsxfer.itd.umich.edu!news1.oakland.edu!rcsuna.gmr.com!kocrsv01![e-mail]
Subject: Heeeeeeeeeeeelp!
To: [e-mail]

In article <34kebn$[e-mail]>, [e-mail] (Michel Soldevila - LENR) writes:
>
> Hi everybody
>
> My coax relays are 26 volts models. A long time ago, I saw a circuit able to trigger
> such relays from a 12 volt source. The only thing I remember is that it was a kind
> of voltage doubler who supply the relay with 2x12 volt during a short time, and then
> supply it with 12v.
>
> Does anybody knows this circuit ?
>
> Thanks a lot
>
> 73 de F1GOC K

I remember seeing that too. I don't remember the exact circuit, but here is
my best guess.



+12 V    -----------.----------
                    |          |
                Q1  |          \
            R1    |/           / R3
signal in --/\/-.-|            \
                | |\     D1    |
                \   >-.--->|---.
            R2  /     |        |
                \     .---||---.---
                |     |  C1 +  |   |
                |     \        |   >||
                |     /R4      V   >||
                |     \     D2 -   >|| K1
                |     |        |   |
ground    ------.-----.--------.---

C1 charges through R3 and and R4 when Q1 is off. When Q1 is switched on, it
applies 12V to the low side of C1. The voltage on C1 adds to this 12V and
you get 24V across the relay. D1 allows 12 (well, 12 - 0.6) volts to be
applied to K1 after C1 has discharged. D2 shunts any inductive kickback back
into the coil. If K1 must open rapidly, you might want to substitute an RC
snubber circuit.

I have not tried this circuit, but it looks likely. Does anyone remember
the original circuit? Is it simpler than this?

--
Jim Buchanan                    N9SDV
[e-mail]  "Catch 22"
[e-mail]
'73 BMW R75/5                   "Frau Bluecher"
--
Jim Buchanan
[e-mail]  "Catch 22"
[e-mail]
'73 BMW R75/5                   "Frau Bluecher"

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

Date: Fri, 09 Sep 1994 12:57:30 -0400
From: ihnp4.ucsd.edu!agate!howland.reston.ans.net!sol.ctr.columbia.edu!news.msfc.nasa.gov!niven.ksc.nasa.gov!algol.ksc.nasa.gov!k4dii.ksc.nasa.gov![e-mail]
Subject: ICOM 22S mod (repeater switch)
To: [e-mail]

In article <[e-mail]>,
[e-mail] (Ken M. Edwards) wrote:
> A friend of mine (without internet access) has a ICOM 22s that has
> been mod'ed so that all the repeater pairs btwn 146 - 148 on the
> front panel instead of the '1', '2', '3', etc. where the diode matrix
>         determined the Tx and Rx freq.s and included simplex.  The
> problem is, now that the mod had been made, the simplex freq.s are
> no longer avail., but a four row diode matrix is avail.


Ken-

If that is the same mod as I have, each switch postion is actually for the
lower frequency of the repeater pair.  When the left-hand toggle switch is
in one postion,  the radio transmits and receives on the same frequency.
When in the other position, it transmits and receives 600 KHz apart.  The
right-hand toggle switch determines whether the transmit frequency is
offset plus 600, or the receive frequency is offset plus 600.

Included among those repeater frequencies, are the simplex frequencies as
well.  As I recall, the switch has MANY postions, and covers from 146.01
to 147.57, in 30 KHz steps.  There was an ultra-miniature toggle switch
that could be added, that would change the main switch range by 15 KHz, so
that all channels could be accessed.  A second ultra-miniature toggle
switch could be added to make BOTH transmit and receive frequencies be
offset plus 600 from the switch setting.

As you suggested, I believe there were one or two "blank" switch postions
that might be used for diode-programmed frequencies.

73, Fred, K4DII

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

Date: 9 Sep 1994 13:58:41 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!library.ucla.edu!csulb.edu!nic-nac.CSU.net!charnel.ecst.csuchico.edu!olivea!koriel!newsworthy.West.Sun.COM!abyss.West.Sun.COM![e-mail]
Subject: Mitrek 800 Mhz Service Manual/ Info ??
To: [e-mail]

In article [e-mail],  [e-mail] (Ken M. Edwards) writes:
>I have aquired an 800 Mhz Mitrek rig, and wandered  if there is a
>service manual or info avail. on this unit.  Also, is it even remotely
>possible to tune this rig in the 33 cm band ?
>
>Thanks..

Try calling Motorola National Parts at [phone] for manual.  A radio
as recent as the Mitrek should be no problem for a manual.

---
 * Dana H. Myers KK6JQ, DoD#: j    | Views expressed here are    *
 * [phone]         | mine and do not necessarily    *
 * [e-mail]    | reflect those of my employer    *
 * "Sir, over there.... is that a man?"                         *

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

Date: Thu, 08 Sep 94 15:40:22 GMT
From: ihnp4.ucsd.edu!pacbell.com!amdahl!netcomsv!netcomsv!skyld![e-mail]
Subject: need 100 MHz TTL clock
To: [e-mail]

In article <34l4ru$[e-mail]> [e-mail] writes:

  > Can anyone tell where I can get a 100 MHz TTL clock (i.e. in
  > quantities of 1/2).

  Wouldn't that be a 50 MHz clock then?


 Amateur: WA6FWI@WA6FWI.#SOCA.CA.USA.NOAM | "You have a flair for adding
Internet: [e-mail]        |  a fanciful dimension to any
 US Mail: PO Box 4425 Carson, CA 90749    |  story."
   Phone: [phone]                |           Peking Noodle Co.

Hate "Green Card Lottery"? Want to help curb ignorant crossposting on Usenet?
E-mail [e-mail] for more information, or read news.groups.

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

Date: 8 SEP 94 18:06:47 EST
From: pa.dec.com!nntpd.lkg.dec.com!mtwain.enet.dec.com![e-mail]
Subject: SETIQuest Magazine - Exobiology
To: [e-mail]

        SETIQuest is a new quarterly print/electronic mail (E-mail)
    periodical containing news, technical information, and tutorials
    devoted to bioastronomy and its subset, SETI (Search for
    Extraterrestrial Intelligence).

        SETIQuest is published for professionals, serious amateur
    astronomers, and individuals curious about this fascinating field of
    observation.  SETIQuest fills the need for a specialized astronomical
    publication devoted exclusively to the on-going search for evidence
    of life in the Universe.  Such evidence could be intentional or
    inadvertent signals of other civilizations.  Such evidence could be
    found in spectral signatures of biological activity on extrasolar
    planets or in the interstellar medium.

        SETIQuest is written and edited for the scientifically literate
    individual taking part in the progress of our technological
    civilization, with articles by amateur and professional scientists.
    SETIQuest includes information about hands-on observational programs
    that can be carried out by individuals and groups of amateur
    astronomers at radio and optical wavelengths.

        SETIQuest is filled with articles covering topics such as:

        * Tutorials about bioastronomy and SETI
        * Microwave or optical SETI as practiced by amateurs
        * "Do-it-yourself" participation in bioastronomy and SETI activities
        * Book reviews
        * Regular commentary on issues relevant to SETI and bioastronomy:

        SETI and the political milieu

        Philosophical issues regarding the prospects of success and
    failure in the search

        SETI as a parable of science versus pseudo science

        Publications Watch:  Summaries of recent scientific/general
    publications relevant to SETI

        For your FREE issue of SETIQuest (Volume 1, Number 1), send us
    your postal address by fax, E-mail, or conventional mail to:

        SETIQuest Inquiries, Department EX
        Helmers Publishing
        174 Concord Street
        Peterborough, NH  03458-0874
        Telephone: [phone]  FAX [phone]
        Internet E-mail: [e-mail]

    --------------------------------=|=---------------------------------------
    Carl Helmers,  President & Editorial Director,  Helmers Publishing, Inc.
       --< Publishers of Sensors, ID Systems and SETIQuest magazines >--
                 (what else do you do after starting BYTE?)
    INTERNET:  [e-mail]
    SNAILMAIL: 174 Concord Street, Peterborough, NH 03458
    PHONE:     [phone]            -=-  FAX: [phone]

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

Date: Thu, 8 Sep 94 19:57:25 -0500
From: news.delphi.com![e-mail]
Subject: unusual modulation techniques
To: [e-mail]

 A while back I asked about putting 4 distinct voices on a carrier using
both sidebands and both quadrature phases. I was told that it's not possible
to use both techniques at the same time. I wonder what you'd get, then , if
you suppressed one sideband of a QAM signal. (?)
 Also, I've noticed that the sidebands of an FM signal seem to contain
harmonics of the tone being carried. I wonder if there is some way of
processing audio (such as distorting it) that will cause an AM transmitter to
transmit FM. I want to know if I can transmit FM with a non-variabkle
oscillator producing the carrier. (?) Is this possible?

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

Date: 9 Sep 1994 14:01:47 GMT
From: ihnp4.ucsd.edu!usc!nic-nac.CSU.net!charnel.ecst.csuchico.edu!olivea!koriel!newsworthy.West.Sun.COM!abyss.West.Sun.COM![e-mail]
Subject: xtal filters
To: [e-mail]

In article [e-mail],  [e-mail] (David Shalita) writes:
>I also need to build xtal filters for a NE-602 project and this method
>looks attractive. Need following filters:
>        10.7 mhz 55 khz bandwidth
>        10.7 mhz 15 khz bandwidth
>
>Can I use cheap Microprocessor xtals for this 10.7 mhz task?
>
>Can I make a xtal filter "as wide as" 55khz or 15khz with this technique?
>
>How can I determine input and output impedance requirements
>for the xtal filters produced by this method?

It isn't worth the trouble.  A&A parts is always at the TRW swap meet selling
30KHz and 15KHz xtal filters for maybe $7/ea.  You can probably do better
if you go to a distributor, but there's likely to be a minimum order.

The 55KHz wide filter may be a problem, but I bought a couple of 15KHz
filters from A&A last year.

---
 * Dana H. Myers KK6JQ, DoD#: j    | Views expressed here are    *
 * [phone]         | mine and do not necessarily    *
 * [e-mail]    | reflect those of my employer    *
 * "Sir, over there.... is that a man?"                         *

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

End of Ham-Homebrew Digest V94 #269
******************************