QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940197.txt

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

Date: Thu, 23 Jun 94 04:30:17 PDT
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Ant Digest V94 #197
To: Ham-Ant


Ham-Ant Digest              Thu, 23 Jun 94       Volume 94 : Issue  197

Today's Topics:
                            Copper Cactus
                          HF Mobile Antennas
                     MFJ-16010 ant tuner manual?
                 Need low profile NMO trunk lip mount
             Super Sensitive FSM Circuit Wanted (3 msgs)
                       WANTED: MANPACK Antenna

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Archives of past issues of the Ham-Ant 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: 22 Jun 1994 22:24:56 GMT
From: ihnp4.ucsd.edu!munnari.oz.au!yoyo.aarnet.edu.au!news.adelaide.edu.au![e-mail]
Subject: Copper Cactus
To: [e-mail]

Has anyone built the copper cactus (2m/{70cm}) Jpole from 73 a few years
back ? its the design using hard drawn plumbers copper tube (12mm/.5inch)
with an elbow and tee.

Problem seems to be that tubing goes soft after silver soldering the joints,
and it all tends to go a little mobile :-)

has anyone experimented with using larger tube, or any other ideas ?

the antenna took me 1/2 hour to build, and worked great after little tuning,
so I can recommend it from that perspective, just that its all a bit soft
to stop bending near the solder joints (in the tube not the joint)

replies via email pls ..

73 .. Rob
--
rob mayfield senior technical analyst, australian submarine corporation p/l
vk5xxx / vk5zeu    (postal) po box 73, oaklands park, south australia, 5046
i-net  [e-mail]   or   [e-mail]
packet radio vk5xxx@vk5xxx.#adl.#sa.aus.oc   wire [phone]w +618< ask >h

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Date: 22 Jun 1994 11:35:06 GMT
From: ihnp4.ucsd.edu!agate!spool.mu.edu!torn!nott!ehd.hwc.ca!hpb.hwc.ca![e-mail]
Subject: HF Mobile Antennas
To: [e-mail]

I have recently purchased a Kenwood TS-50S for use as my HF rig.  I will
be using it mainly in my apartment but would also like to put it in my
4Runner to do some HF mobiling.  Problem is, I have never used an HF rig
mobile and am unfamiliar with the current crop of HF mobile antennas.  I
would appreciate any info that you might have or experiences (good or
bad) with specific antennas.
Please EMAIL me directly (see address below) or send a packet message to
me at VA3GE@VE3KYT.#EON.ON.CAN.NA

    '73 de Stephen, VA3GE
___________________________________________________________

STEPHEN BJARNASON
AIR QUALITY - HEALTH EFFECTS RESEARCH SECTION
RM. 337, BLDG. 8
TUNNEY'S PASTURE
OTTAWA, ON  K1A0L2

INTERNET: [e-mail]
____________________________________________________________

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Date: Wed, 22 Jun 1994 16:26:11 GMT
From: ihnp4.ucsd.edu!library.ucla.edu!csulb.edu!csus.edu!netcom.com![e-mail]
Subject: MFJ-16010 ant tuner manual?
To: [e-mail]

Greetings!   I just aquired an MFJ-16010 (very) small antenna tuner
made by MFJ from a friend.  I was told that the tuner works only with
balanced antennas (eg - gotta use a balun with a dipole, etc).
The unit comes with SO-239 connectors.
However, according to the AES catalog, this little item is supposed to
be a "random wire tuner".  hmmmmmmmmmm

Since I did not receive a copy of the manual, I'm wondering if some
kind soul could enlighten me on the use/operation of this little gem?
Perhaps even a copy (I'll pay of course) of the documentation - tho
that is not an immediate necessity.

I'm hoping to use this with a small QRP rig I have.

Cheers & 73 de,
Sandy WA6BXH/7J1ABV
[e-mail]


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

Date: 22 Jun 1994 18:39:47 GMT
From: ihnp4.ucsd.edu!sdd.hp.com!hp-pcd!hp-cv!reuter.cse.ogi.edu!ese.ogi.edu![e-mail]
Subject: Need low profile NMO trunk lip mount
To: [e-mail]

I am looking for a low profile NMO trunk lip mount to use with
a Larson NMOQ-special 1/4 wave antenna.  The Larson mount is
sizeable and really overkill for a 1/4 wave.  I am looking
for something smaller and in black (black antenna).

Any ideas?

Thanks,
D. Reeves, N6XHW



--
|B. Douglas Reeves    Dept. Env. Sci.& Eng.     Oregon Graduate Institute|
|N6XHW on 146.900 in PDX              [e-mail] everywhere else|
|"... life itself represents a nonequilibrium condition." - J. F. Pankow |

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

Date: Tue, 21 Jun 1994 18:09:26 GMT
From: psinntp!relay1!unislc![e-mail]
Subject: Super Sensitive FSM Circuit Wanted
To: [e-mail]

Cecil A. Moore -FT-~ ([e-mail]) wrote:
: Hi Frank, I have a very sensitive field strength meter in my truck that
: works from miles away. It's called an ICOM-725.  :-)

Do you know the difference between NEAR field and FAR field?
I assume what the person is looking for is a NEAR field meter.
You can find a transmitter with a receiver (FAR field meter),
but it is easier to find hidden bugs, etc., with a NEAR field
meter.

--
     |                                  |
     |   Clyamseuq marhs!               |    Frank PoWell
    / \    El es ual wilojskysecot.     |    [e-mail]
                                        |

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

Date: Tue, 21 Jun 1994 18:13:19 GMT
From: psinntp!relay1!unislc![e-mail]
Subject: Super Sensitive FSM Circuit Wanted
To: [e-mail]

Tom Bruhns ([e-mail]) wrote:

: I built a FSM with about 2 nanowatt sensitivity, with a logarithmic panel
: meter readout.  Thought about putting an amp in front of it.  BTW, 2
: nanowatts is about .3 millivolts at 50 ohms. The difficulty I have, though,
: is that in a fox hunt, I can seldom use the full sensitivity, because it's
: not selective enough:  far too often there are other transmitters in the
: area that mess things up.

: As Cecil Moore mentioned, a receiver can be a very sensitive FSM; the usual
: difficulties are to get one well enough shileded that you can put attenuation
: on the front end and have it meaningful, and to get a decent readout device
: with enough resolution and appropriate response times.

I know the problem.  The FSM I use is good from DC to
about 2.5Ghz.  I have not had a problem yet, as it has
a removable antenna, and when I get a full scale reading,
I just remove the antenna.  Works everytime, so far.
               Frank
--
                                      |
  /\_/\    I never met a cat          |    Frank PoWell
 ( o.o )   I didn't like!             |    [e-mail]
  > - <        N7KSK  __,,,^..^,,,__  |

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Date: 22 Jun 1994 15:48:27 GMT
From: ihnp4.ucsd.edu!swrinde!gatech!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!news.kei.com!ssd.intel.com!chnews![e-mail]
Subject: Super Sensitive FSM Circuit Wanted
To: [e-mail]

Frank Powell ([e-mail]) wrote:

: Do you know the difference between NEAR field and FAR field?

Do you know what it means when one includes the ASCII characters:

3Ah 2Dh 29h  ?   :-)

73, KG7BK, OOTC, [e-mail]

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

Date: 20 Jun 1994 17:20:12 GMT
From: ihnp4.ucsd.edu!news.cerf.net!hacgate2.hac.com!hc89042.es.hac.com![e-mail]
Subject: WANTED: MANPACK Antenna
To: [e-mail]

I'm trying to locate a government surplus outlet that sells the antenna for
the
Hughes MANPACK transceiver.  The part label reads as follows:

     ANTENNA
     AS-1887A/PRC-74
     HUGHES AIRCRAFT CO
     P/N 1550159-100 US

Please respond via e-mail.  Thanks in advance.
--
Don Putnick     [e-mail]

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

Date: Wed, 22 Jun 1994 11:08:16
From: ncrgw2.ncr.com!ncrhub2!jupiter.WichitaKS.NCR.COM!WichitaKS.NCR.COM![e-mail]
To: [e-mail]

References <[e-mail]>, <2u7i5v$[e-mail]>, <[e-mail]>
Subject : Re: Diamond ant. water problem


>>>Ken Thompson ([e-mail]) wrote:
>>>: Has anyone else had repeated moisture problems inside Diamond's base
>antennae?
>>>The North Coast Amateur Radio Club in Cleveland has thrown away a number
>>>of Diamond antennas due to interior corrosion.  Diamond uses a small steel
>>>crimp between sections of their antenna components.  Open cell foam keeps the
>>
>>The stock Diamond weatherproofing definately isn't enough.  I use
>>Scotch Super88 and Scotchkote to seal them up.  Also seal up the tip -
>>I've had one antenna where the metal cap actually blew away in the wind...

>Sealing the top is useful, but it's better to drill some weep holes
>at the bottom and let the antenna radome breathe than it is to try
>to seal the radome completely. This way moisture won't accumulate
>in the antenna. Unless you can *really* make the radome air tight,
>and pressurize it with dry nitrogen, it's better to let it breathe
>freely in order to prevent excess moisture accumulation inside the
>radome. A radome with a slight air leak will "pump" water inside
>due to atmospheric pressure variations, and trap it there after it
>condenses. Bad news.


I have sealed the joints with the shack's silicon tape ( the orange stuff )
with electrical tape over it.  I soldered all the internal joints that
were just crimped by them.  Also had it back to RF Parts (Diamond) where they
drilled weep holes and "replaced" some of the foam.  They put in huge chunks
of it however that I think blocked any moisture movement.  I have corrected
that. Will try sealing with silicon chalk this time.

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

Date: 22 Jun 1994 14:27:04 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!gatech!newsfeed.pitt.edu!dsinc!netnews.upenn.edu!eniac.seas.upenn.edu![e-mail]
To: [e-mail]

References <[e-mail]>, <2u7i5v$[e-mail]>, <[e-mail]>iac.seas
Subject : Re: Diamond ant. water problem

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>Sealing the top is useful, but it's better to drill some weep holes
>at the bottom and let the antenna radome breathe than it is to try
>to seal the radome completely. This way moisture won't accumulate
>in the antenna. Unless you can *really* make the radome air tight,
>and pressurize it with dry nitrogen, it's better to let it breathe
>freely in order to prevent excess moisture accumulation inside the
>radome. A radome with a slight air leak will "pump" water inside
>due to atmospheric pressure variations, and trap it there after it
>condenses. Bad news.

Aren't the holes at the bottom of the Diamonds (adjacent to the coax
connector) drain holes?  I have a couple of F718A's, X500HNA, X200A,
F12?? (1.2 GHz), and U2000A.  I thought they all had drain holes at the
bottom.  I'll take a look again the next time I take one down.  I
agree with what you're saying - I was just suggesting a way of improving
the waterproofing where the radome sections are joined.

                            --- Jeff
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 Jeff DePolo  WN3A              Twisted Pair: [phone]H  387-3059W
 [e-mail]    RF: 443.800+ MHz   442.400+ MHz   24.150 GHz
 Claim to Fame: I got the first speeding ticket on the information superhighway

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

Date: Wed, 22 Jun 1994 06:42:51 GMT
From: ihnp4.ucsd.edu!swrinde!gatech!kd4nc!ke4zv![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <2u7i5v$[e-mail]>
Reply-To : [e-mail] (Gary Coffman)
Subject : Re: Diamond ant. water problem

In article <2u7i5v$[e-mail]> [e-mail] (Jeff DePolo) writes:
>In article <[e-mail]> [e-mail] (Steve Wolf) writes:
>>Ken Thompson ([e-mail]) wrote:
>>: Has anyone else had repeated moisture problems inside Diamond's base antennae?
>>The North Coast Amateur Radio Club in Cleveland has thrown away a number
>>of Diamond antennas due to interior corrosion.  Diamond uses a small steel
>>crimp between sections of their antenna components.  Open cell foam keeps the
>
>The stock Diamond weatherproofing definately isn't enough.  I use
>Scotch Super88 and Scotchkote to seal them up.  Also seal up the tip -
>I've had one antenna where the metal cap actually blew away in the wind...

Sealing the top is useful, but it's better to drill some weep holes
at the bottom and let the antenna radome breathe than it is to try
to seal the radome completely. This way moisture won't accumulate
in the antenna. Unless you can *really* make the radome air tight,
and pressurize it with dry nitrogen, it's better to let it breathe
freely in order to prevent excess moisture accumulation inside the
radome. A radome with a slight air leak will "pump" water inside
due to atmospheric pressure variations, and trap it there after it
condenses. Bad news.

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     |                     |

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End of Ham-Ant Digest V94 #197
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