QRZ! Ham Radio 3/QRZ Ham Radio Callsign Database - Volume 3.iso/digests/homebrew/930143.txt

Internet Message Format | 1994-06-04 | 18KB

Date: Sat, 25 Dec 93 04:30:21 PST
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Homebrew Digest V93 #143
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Ham-Homebrew Digest         Sat, 25 Dec 93       Volume 93 : Issue  143

Today's Topics:
                - - television disruptor - - (2 msgs)
             funny reception on my amp (?)  ....curious.
                         Heathkit DX-60B Mod?
                       Mini-Circuits MAR-6 amp

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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: Wed, 22 Dec 93 22:20:30 EST
From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!news.intercon.com!psinntp!newstand.syr.edu!rodan.syr.edu![e-mail]
Subject: - - television disruptor - -
To: [e-mail]

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (Looking for Sancho)
> writes:
>>   The intended use of this device is to be put with a timer
>>  against the wall where my new neighbor has his television set.
>>  He comes home around midnight and keeps his television
>>  loud until 3 am almost every day. I wonder about the legality
>>  of my idea, therefore I would like something with regulated
>>  signal strength since I would not like to affect other neighbors.
>
>Deliberately causing interference is definitely illegal under FCC regs, and
>may also constitute harrassment, etc., under local laws.
>
>Have you tried talking to your neighbor?  And/or to your apartment manager?
>The clown doesn't necessarily have to be convinced to turn it off; simply
>moving the set to a non-adjoining wall will make a vast improvement.  A request
>phrased as "I can't sleep at night any more" might work better than just "it's
>too loud".
>
>There ARE things you could do, especially if the set is really shoved up
>against a common wall with your apt., but if you know that little about
>electronics your chances of building anything and getting it working are slim
>to none.  There are RF generators available with the appropriate frequency
>range, but their output is low (they're intended for direct connection to a
>device being tested) and they won't have much effect if the guy is watching
>cable or playing a tape on the VCR.
>
>If the set is remote-controlled, you could always get a universal remote and
>try to turn the set off from outside his window. :-)
>
> --- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
>Internet:  [e-mail] (JH645)  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055


Information Unlimited  800-221-1705  TV & FM Joker/Jammer #EJK1KM Easy to
   Assemble Electronic Module Kit    $19.50 + $5.25 P&H

C&S Sales 800-292-7711  TV/FM Oscillator (Ch 2 -13) $6.50 + $3.00 P&H
 ($10.00 min order)

Ocean State Electronics 800-866-6626  TV/FM Oscillator (Ch 2-13)  #K-29
  $5.30 + $4.50 P&H ($10.00 min order)

Gratuitous Advice:  You risk a fine from a government agency, you risk
getting kicked out of your apartment, if you are a student you risk
expulsion. Oh yeah, your neighbor might kick the shit out of you. 'Nuff said.

Instead of a timer you might want to hook up a noise level sensor. When
the volume increases above a certain level his TV gets jinked. He'll
more likely think he has a bad TV. If you are too consistent (timer) then
you'll be tracked down sooner.  Also hide the silly thing when you are
not home. (landlords have been known to snoop).

Hope you can resolve this without going to extremes.  Good luck.

)

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

Date: Thu, 23 Dec 1993 17:10:49 GMT
From: valinor.mythical.com!n5ial![e-mail]
Subject: - - television disruptor - -
To: [e-mail]

In article <[e-mail]> [e-mail]
(Jerry Dallal) writes:

>I would agrue against the disruptor as being ineffective.  He'll just try to
>get the tv fixed, will probably succeed, and he'll be mighty upset if
>he ever figures out what was going on.  *Don't* do this if he hasn't already
>proven unreasonable.  It'll be easy to work with him if you keep it on a
>friendly basis.  Difficult if you become enemies.

I'll go along with that.....  If I were having problems with a neighbor,
for example, if my HF rig were getting into their TV or something, I'd be
more than happy to help correct the problem as long as they were civilized
about it.  If, on the other hand, they came over demanding that I simply
stop transmitting, period, or if they sabotaged my antenna (that assumes
they could find it first), I'd just be more likely to keep right on
operating (and if needed, help any other neighbors with filters, etc.).

Or, to relate this more to the current (non-amateur-radio) thread, if a
neighbor thought my stereo was turned up too loud, if they simply asked
me to turn it down, I'd gladly do so.  If they went straight to the
apartment management (or worse, the police), I'd simply ask the management
to let the neighbor know that if they'll just politely ask (IMHO, that
implies asking me directly), I'd be more than happy to turn it down, but
that so far, nobody had even asked.

I don't think I'm the exception to the rule here....  If you ask nicely,
you'd be surprised at how good the results will usually be.  If you start
off by being rude/nasty about it, you'll also be surprised at the results,
except they'll probably be just the opposite of what you were hoping for.

That reminds me of people who just bang on the walls...my reaction is to
wonder why they keep banging on the walls, and to turn the stereo up so
I can hear it clearly over the noise.  :-)

Fortunately, in my case, none of this has been a problem for years.

Later,
   --jim

--
#include <std_disclaimer.h>                                  73 DE N5IAL (/4)
-------------------------< Running Linux 0.99 PL10 >--------------------------
Internet: [e-mail]  |  [e-mail]     ICBM: 30.23N 86.32W
Amateur Radio:  (packet station temporarily offline)       AMTOR SELCAL: NIAL
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E-mail me for information about KAMterm (host mode for Kantronics TNCs).

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

Date: Thu, 23 Dec 93 02:18:50 GMT
From: library.ucla.edu!agate!howland.reston.ans.net!newsserver.jvnc.net!a3bee2.radnet.com!cyphyn![e-mail]
Subject: funny reception on my amp (?)  ....curious.
To: [e-mail]

  antonio gatta ([e-mail]) wrote:
: the other night i put together a small amp to drive a small pm
: speaker that i wanted to use on my sw xtal radio (instead of headphones).

: it picked up a station!  (the amp was not hooked to the radio).  I was

: no coil, nothing.  any ideas?  (just curious).
:
The amplifier was acting as if it was a diode-radio...or cats-whisker radio
which will pick up ANY station that is strong enough to override the
others....if you had listened close, you would have heard several stations
in the background.

When the antenna wire touched, it must have hit the audio input, and the
amplifier's input acting like a diode, rectifys (detects) the signal.
The rest of the amplifier, amplifys it.

You probably could repeat that and so hear those other stations .

By the way...how you discovered that, is how Alexander Bell got his
telephone to work.   (zzzt!  oops! )





--
Randy KA1UNW              If you get a shock while
                         servicing  your  equipment,         "Works for me!"
randy@192.153.4.200             DON'T  JUMP!                     -Peter Keyes
                     You might break an expensive tube!

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

Date: Fri, 24 Dec 1993 16:47:43 GMT
From: nevada.edu!news.unomaha.edu!cwis.unomaha.edu![e-mail]
Subject: Heathkit DX-60B Mod?
To: [e-mail]

Just to let you know, I do have a HG-10B.

later

73 de N0YBC Michael
--
| Michael Fortner   N0YBC              |  "What do you want for Christmas,    |
| [e-mail]             |   Crow?"                             |
| N0YBC @ WB0BLR.#SWIA.IA.USA.NA       |  "I want to decide who lives and who |
|                                      |   dies!"        - MST3K              |

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

Date: Wed, 22 Dec 1993 23:47:11 GMT
From: rit!isc-newsserver!ultb![e-mail]
Subject: Mini-Circuits MAR-6 amp
To: [e-mail]

In article <2f8h82$[e-mail]> [e-mail] (Donald J. Miller) writes:
>
>Yep.  Amps like these that are already matched for 50 ohms are actually
>somewhat undesirable for pre-amp use because unless you transform up to a
>higher impedance in your input circuitry before you transform back down,
>the pre-amp will be very broadband.  Strong signals in the FM, AM, HF,
>you name it band could create real havoc for you.  The only real
>selectivity you will have to protect you from intermod will be the
>antenna itself.
>
>Your situation will determine if you can use one of these.  If you are
>not in an urban area  -- maybe no problem.  I would lean towards a FET
>device with a higher Q input matching network.
>
>73's    Don Miller  KM4AS    [e-mail]
>
Thanks for all the replies.  For 2-meter use, would a bandpass filter
on the input suffice?  I was thinking of picking a generic one from the
ARRL Handbook, and adjusting the values for 146 mhz.

73...Jim
N2VNO
lowpass filter

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

Date: 23 Dec 1993 01:06:50 GMT
From: koriel!newscast.West.Sun.COM!abyss.West.Sun.COM!sunspot![e-mail]
To: [e-mail]

References <[e-mail]>, <2f8h82$[e-mail]>, <[e-mail]>
Subject : Re: Mini-Circuits MAR-6 amp

In article <[e-mail]> [e-mail] (J.D. Cronin) writes:
>In article <2f8h82$[e-mail]> [e-mail] (Donald J. Miller) writes:
>>
>>Yep.  Amps like these that are already matched for 50 ohms are actually
>>somewhat undesirable for pre-amp use because unless you transform up to a
>>higher impedance in your input circuitry before you transform back down,
>>the pre-amp will be very broadband.  Strong signals in the FM, AM, HF,
>>you name it band could create real havoc for you.  The only real
>>selectivity you will have to protect you from intermod will be the
>>antenna itself.
>>
>>Your situation will determine if you can use one of these.  If you are
>>not in an urban area  -- maybe no problem.  I would lean towards a FET
>>device with a higher Q input matching network.
>>
>>73's    Don Miller  KM4AS    [e-mail]
>>
>Thanks for all the replies.  For 2-meter use, would a bandpass filter
>on the input suffice?  I was thinking of picking a generic one from the
>ARRL Handbook, and adjusting the values for 146 mhz.


Take a step back....

An ideal pre-amplifier will provide a stable gain, contribute no noise,
and handle infinitely large signals.  You can't buy such an amplifier,
not even from HP/Avantek.

In the real world, you'll pick an amplifier that gives you a good combination
of gain, noise and strong-signal handling capabilities.

A GaAsFET can be quite nearly the optimum combination, but a grounded gate
JFET (like the J310) at 2m is 98% of what a GaAsFET is if you use the right
circuit.

What *I* would suggest is either the Hamtronics GaAsFET pre-amp (<$30 for a
kit, very nice) or the helical resonator pre-amplifier (around $50, I recall).
The GaAsFET makes sense if you already have a good receiver that is simply
not hot enough (i.e. Motorola Micor, GE Mastr Executive II or Custom MVP, etc.).
The helical pre-amp makes sense if you have a common amateur grade radio,
like an HT, etc.  In either case, you need to arrange to insert the amplifier
between the receiver and T/R switch or provide an external T/R switch.

Try glancing at the ARRL "Handbook" for further info and pointers.

Dana
--
 * Dana H. Myers KK6JQ, DoD 466 | Views expressed here are *
 * [phone]   | mine and do not necessarily *
 * [e-mail] | reflect those of my employer *
 * This Extra supports the abolition of the 13 and 20 WPM tests *

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

Date: Fri, 24 Dec 1993 03:58:06 GMT
From: yuma![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>
Subject : Re: Mini-Circuits MAR-6 amp/Filtering the input.

In article <[e-mail]> [e-mail] (Bruce Toback) writes:
>In article <[e-mail]> [e-mail] (Galen Watts) writes:
>>In article <[e-mail]> [e-mail] (J.D. Cronin) writes:
>>>Thanks for all the replies.  For 2-meter use, would a bandpass filter
>>>on the input suffice?  I was thinking of picking a generic one from the
>>Look at the Toko Helical Resonator filters in the Digi-Key catalog.  Toko
>>also has some that won't require retuning, but their catalog is at my office
>>and I'm on vacation.
>>Galen, KF0YJ, DN70
>Good idea, Galen! The Toko TK3506 has a center frequency of 145mHz with
>a bandwidth of 2.8mHz. It's available from Digi-Key for $23.53 for one,
>or $117.67 for ten.
>By the way, their catalog is free and is well worth having. The phone
>number is 1-800-344-4539 (800 DigiKey).
>-- Bruce Toback

There's another Toko that works at 145MHz but only has 3dB of loss.  I think
the TK3506 loses around 8dB.  I also noticed a few that worked up around
430, 440 MHz.  Hmmmmmmm....
Galen, KF0YJ

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

Date: Thu, 23 Dec 1993 20:27:40 GMT
From: mdisea!mothost!schbbs![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <2fa416$[e-mail]>
Subject : Re: Heathkit DX-60B Mod?

In article <2fa416$[e-mail]>, [e-mail] (Ted Zateslo) says:
>
>In article <[e-mail]> [e-mail] (Michael Fortner) writes:
>>I do not think it is worthless to try to convert this piece of equipment.
>>Many newer hams (myself included) can not afford the outragous prices of
>>new and "newer" used equipment.  However, we can afford and often enjoy
>>modifying what we can afford.  It is much better to take a piece of working
>>electronics and keep it useful than have it take up space in a landfill.
>
>I think the point was that this _particular_ modification (making
>a DX-60 do SSB) was just plain impracticable.  The "SSB adaptors"
>made in the late 50s and early 60s cost quite a bit more than
>a basic transmitter like the DX-60.  They were also mostly
>phasing-type units, which made them very tricky to set up.
>The DX-60 doesn't have a built-in VFO, and the one most often
>used with it isn't really stable enough for a good SSB signal.
>If you were to try to modify a DX-60 itelf for SSB, you'd have
>little left but the final stage, and you'd have pretty much
>destroyed a nice little CW transmitter.
>
>There are lots of old SSB transmitters and transceivers on the used
>market, some at very reasonable prices.  It's a better investment to
>buy an old TR-3 or Swan and fix or modify it than to make a DX-60
>into something entirely different than it is.
>
>That said, I sure hope nobody is throwing DX-60s (or any other
>vintage ham gear) into landfills!
>
>Ted Zateslo, W1XO
>[e-mail]
>
I already followed up on this under rec.radio.amateur.equipment, but here
are a couple of more thoughts relating to the above.  First, if you can even
find one, the Heath SB-10 sideband adapter should cost you around $25
tops.  What was said about the VFO (by the way do you have the HG-10?)
may be true, but I believe it may actually be marginally stable enough.  I
had one and am kind of picky about that sort of thing and still do not remember
having much if any drift problem.  However, on 10 meters it might be
questionable.  If you run across an SB-10 with the Apache transmitter you
should be able to get that for $75 tops, and its all designed to work together.
It would be kind of tough to figure out without the manuals though.

It will work on 10 M, stable VFO, and great audio, but total weight is around
120 pounds.  I know.  I owned and used one for many years and a lot of that
time was spent on 10 meters.  On the other hand for abound $150 you can
buy an SB100, 101 or 102, and for around $200 some of the earlier solid
state rigs are available.  You pays your money and takes your choice.

Merry Christmas.

Curtis, WB6PUS

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End of Ham-Homebrew Digest V93 #143
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