QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940087.txt

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

Date: Fri,  1 Apr 94 04:30:10 PST
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Ant Digest V94 #87
To: Ham-Ant


Ham-Ant Digest              Fri,  1 Apr 94       Volume 94 : Issue   87

Today's Topics:
                          AEA Hotrod trouble
                       AEA Hot Rot whip for HT
                CB Mag mount for 10M mobile? (3 msgs)
            Circular Polarization in Mobile Communication
                    Cushcraft R7 Vertical (2 msgs)
                           super antenna, ?

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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: 31 Mar 94 15:09:51 GMT
From: [e-mail]
Subject: AEA Hotrod trouble
To: [e-mail]

Jerry Writes:

>I recently purchased an AEA HotRod 1/2 wave whip antenna from Kevin Jensen
>N1KCG from rec.radio.swap.  He used it in his htx202 and said it was
>working.
>
>However, when I got the antenna and connected it to my antenna, I did not
>get better coverage with the hotrod compared to the htx202 rubber duck
>antenna.
>In fact it was worse, what I can reach with the rubber duck antenna,
>the hotrod antenna cannot.
>
stuff deleted...
>
>jerry
>N3RKD

The 1987 "Hints and Kinks" compendium had an interesting short piece about
the relative performance of the "Hot Rod".  The author had a kenwood HT and
did some comparison tests among the "Hot Rod", two homemade 1/4 wave whips
(for 2 meters), and the HT rubber duck WITH AND WITHOUT a 1/4 wave (19.5
in.) piece of wire alligator-clipped to the base (i.e. shield) of the HT's
bnc connector.  He transmitted to another operator who recorded s meter
readings for the various combinations.  these went something like this,
although I may not have the numbers exactly right:

                Without 1/4 wv. radial          With radial

Rubber duck     6                               8.5
Homemd whip     8                               9.5-10
Hotrod          9.5-10                          9.5-10

The author also stated that he lived in Seattle and was easily able to work
a repeater 70 miles away in Vancover using either the duck-radial, or
whip-radial combination.  So, it's possible that your "Hot rod" is
defective.  I'm looking forward to trying this out with my own HTX-202.
I'll post results.

'73
Mark KA3LFG

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

Date: 30 Mar 1994 17:59:51 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!vixen.cso.uiuc.edu!ux1.cso.uiuc.edu![e-mail]
Subject: AEA Hot Rot whip for HT
To: [e-mail]

It sounds like a bad antenna.  I use the Hot Rod when I need better coverage
and it works much better than any other whip or duckie on my radio.  I am
really pleased with the Hot Rod.  The SWR does go to a fairly low value in
the 2 Meter Band - I don't remember what it was, however.

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

Date: Wed, 30 Mar 94 15:52:43 GMT
From: dog.ee.lbl.gov!agate!howland.reston.ans.net!torn!utnut!utcsri!newsflash.concordia.ca!canopus.cc.umanitoba.ca!tribune.usask.ca!kakwa.ucs.ualberta.ca!quartz.ucs.ualberta.ca!@@ihnp4.ucsd.edu
Subject: CB Mag mount for 10M mobile?
To: [e-mail]

[e-mail] (Bill Turner) writes:

>I haven't seen that particular antenna, but the component most likely to
>restrict the power handling capability of a mobile antenna is the
>insulation of the loading coil.  At the 100 watt level several thousand
>volts can be generated across the coil.  This can cause arcing and also
>can cause heating if the coil is wound on a lossy form.

Hardly, considering the impedance of the shortened antenna is low (4-8
ohms), the killer is the current. The voltage across the coil is
in the order of about 300V (Even the standard lacquer has a 600V breakdown)
feeding a 1/8 wavelength shortened antenna at 100W, the current is 12 Amperes
or so, usually passing through a #26 wire ...

>Survey after survey has shown that antenna holes do not affect a car's
>resale value.

It affects how fast the car can sell ... One can always find a buyer at
almost any price ... ;-/

Ciao, 73 de VE6MGS/Mark -sk-

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

Date: Wed, 30 Mar 1994 22:24:24 GMT
From: amd!amdint.amd.com!dvorak.amd.com!positron![e-mail]
Subject: CB Mag mount for 10M mobile?
To: [e-mail]

(Chris Moore) writes:
> It occured to me that I should be able to get
> a CB mag mount antenna and trim it a bit to use it on 10M.
>
> Chris Moore

If you can find a CB antenna where you can get into the coil housing
without destroying it, you'll get a wider bandwidth if you shorten the
coil rather than the whip part.

For tuning the whip, substitue a length of copper wire for the whip.
Tune the copper wire and then cut the whip to match.  Copper cuts much
easier than spring steel.

   Brian McMinn   N5PSS   [e-mail]

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

Date: 31 Mar 94 07:07:54 GMT
From: agate!howland.reston.ans.net!darwin.sura.net!udel!news.sprintlink.net!connected.com!beauty!rwing!eskimo![e-mail]
Subject: CB Mag mount for 10M mobile?
To: [e-mail]

<[e-mail]>
Distribution: na
Organization: Eskimo North (206) For-Ever

In article <[e-mail]>,
Mark G. Salyzyn <[e-mail]> wrote:
>[e-mail] (Bill Turner) writes:
>
>>I haven't seen that particular antenna, but the component most likely
to
>>restrict the power handling capability of a mobile antenna is the
>>insulation of the loading coil.  At the 100 watt level several
thousand
>>volts can be generated across the coil.  This can cause arcing and
also
>>can cause heating if the coil is wound on a lossy form.
>
>Hardly, considering the impedance of the shortened antenna is low (4-8
>ohms), the killer is the current. The voltage across the coil is
>in the order of about 300V (Even the standard lacquer has a 600V
breakdown)
>feeding a 1/8 wavelength shortened antenna at 100W, the current is 12
Amperes
>or so, usually passing through a #26 wire ...
>
>>Survey after survey has shown that antenna holes do not affect a car's
>>resale value.
>
>It affects how fast the car can sell ... One can always find a buyer at
>almost any price ... ;-/
>
>Ciao, 73 de VE6MGS/Mark -sk-


If you're running 100 watts into a short, base or center loaded antenna
and only getting 300 volts across the coil, you've got some large losses
somewhere.  The impedance looking into the base is low, as you say, but
the impedance at the top of the coil is far higher.  If there was only
300 volts, please explain how one is able to draw a most impressive arc
from the top of the coil?

W7LZP


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

Date: Wed, 30 Mar 1994 23:42:42 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!csc.ti.com!tilde.csc.ti.com!m2.dseg.ti.com!m2.rts.dseg.ti.com![e-mail]
Subject: Circular Polarization in Mobile Communication
To: [e-mail]

I am trying to find a citation for an article that discussed using
circular polarized antennas for mobile communication.  I believe the
article appeared in a German ham magazine in the 1980s.  Does anyone
remember the article (or similar articles)?

Thanks
Ed ([e-mail])

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

Date: 30 Mar 1994 15:20:11 -0500
From: swrinde!cs.utexas.edu!howland.reston.ans.net!newsserver.jvnc.net!news.cac.psu.edu!news.pop.psu.edu!ctc.com!birdie-blue.cis.pitt.edu!dsinc!netnews.upenn.edu!msuinfo!news.@@ihnp4.ucsd.edu
Subject: Cushcraft R7 Vertical
To: [e-mail]

 I am intertested in hearing from people who own or use the Cushcraft
R7 Vertical antenna.  I am seriously considering buying one, and I would
like to know what success, if any you have had  with this  antenna.

It is my understanding that the R7 is designed especially for those who don't
have room for a ground system, like in a condo or 2nd story apartment.

I DO have room for a ground system, so perhaps there is a different
vertical that would suit  me better.  I am interested in 80-10.

Again, I am mainly interested in hearing from owners  of verticals, not
avid readers of magazines. ( I have read  about most  of them!)

Thanks, and  73

Chris  -=- N8PBI

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

Date: 31 Mar 94 07:20:49 GMT
From: agate!dog.ee.lbl.gov!ihnp4.ucsd.edu!library.ucla.edu!csulb.edu!csus.edu!netcom.com!netcomsv!skyld![e-mail]
Subject: Cushcraft R7 Vertical
To: [e-mail]

In article <2ncmtr$[e-mail]> [e-mail] writes:

  >  I am intertested in hearing from people who own or use the Cushcraft
  > R7 Vertical antenna.  I am seriously considering buying one, and I would
  > like to know what success, if any you have had  with this  antenna.

  I have their AP-8, it is the one onebody knows about...

  > It is my understanding that the R7 is designed especially for those who don't
  > have room for a ground system, like in a condo or 2nd story apartment.
  >
  > I DO have room for a ground system, so perhaps there is a different
  > vertical that would suit  me better.  I am interested in 80-10.

  They claimed it didn't need radials either. But it assembled with the 10
  meter section (the one closest to the connector) 3 feet shorter than the
  chart before it would load correctly on all 8 bands. Once I got that
  straightened out it still didn't radiate very well. The power must have
  been going somewhere, but it sure wasn't going towards any radios I knew
  about.

  I bought their radial kit (APR-8 I think) and suddenly the antenna works
  just like you would expect from a vertical. Poorly, but still better than
  terrible. And yes, I had to add the 3 feet back to the bottom section.

  73 es GE from Jeff



 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.

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

Date: 31 Mar 94 02:37:09 GMT
From: dog.ee.lbl.gov!newshub.nosc.mil!news![e-mail]
Subject: super antenna, ?
To: [e-mail]

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

> my question is, can it work as the ad says?
> or if any one has an experience in using it out there,
> could you share it with me?
> thanks in advance.
>
> again, please reply to [e-mail]

Well yes and no is my answer.   It will not work to get satelites if it
is the typical plug-in-the-wall TV antenna, but it will work better
than rabbit ears.

These antennas use the wires in your home and to the pole to gather TV
signals and then pass them to the TV without passing the 60Hz AC power.
  They are not great antennas, but they are better than rabit ears if
your TV tuner is OK.

Best thing about these is their low price and easy installation.
Usually these cost less than $10, I've seen them for $5.00 in newspaper
ads.

Have fun.
Roger Keating - KD6EFQ
[e-mail]

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

Date: Thu, 31 Mar 1994 00:49:52 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!gatech!wa4mei!ke4zv![e-mail]
To: [e-mail]

References <2n77mn$[e-mail]>, <[e-mail]>, <[e-mail]>ⁿ
Reply-To : [e-mail] (Gary Coffman)
Subject : Re: CB Mag mount for 10M mobile?

In article <[e-mail]> Cecil Moore <[e-mail]> writes:
>Gary Coffman <[e-mail]> writes:
>
>>The best way to operate 10 meters with a converted CB antenna is to
>>start with a bumper mount 102 inch whip and shorten it about 10 inches.
>
>Hi Gary, that would result in 92 inches. For the novice portion (28.4 MHz)
>I think it needs to be a little longer than 92 inche s for resonance.

What? There's activity other than FM on 10 meters? I'm shocked! :-)

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 #87
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