Topband: THE ITINERANT 160 METER ANTENNA PROJECT

[Joe Subich, W4TV]

> Note that Bill was obtaining his results from the K6STI antenna
> modeling software he was using. I am not familiar with that program's
> capabilities or accuracy and it is clear from the article he believed
> the results he obtained from it.

Bill simply did not understand the difference between antenna feed
impedance and radiation resistance.  A folded dipole or folded unipole
is no different than a conventional radiator with an N:1 UN-UN or
balun between the feedline and antenna terminals.  The matching device
(balun, un-un, L-network, pi-network, "hairpin", beta match, etc.)
transforms the sum of the radiation resistance *and* loss resistance
equally.

> But Bill's contributions to amateur radio were vast and valuable and
> greatly overshadow this one slip-up.

This is far from Bill's only "slip-up" - his bully-like advocacy of
floating grids in grounded grid amplifiers is another case of non-
science.


73,

    ... Joe, W4TV


On 8/3/2012 11:23 AM, Thomas wrote:
> See, "Ham Radio Techniques - 160-Meter Antenna Problems and
> Solutions," Ham Radio magazine,  Pg. 49, March 1990. A 3-wire version
> is also proposed to increase the radiation resistance by 9x. In the
> single and multi-wire folded versions the ground loss resistance
> remained constant. Note that Bill was obtaining his results from the
> K6STI antenna modeling software he was using. I am not familiar with
> that program's capabilities or accuracy and it is clear from the
> article he believed the results he obtained from it. It was the early
> days of NEC programs for PCs and many of us were just learning how to
> use and apply the antenna simulation programs.
>
> It is impossible to know the basis for his errors in this case. But
> Bill's contributions to amateur radio were vast and valuable and
> greatly overshadow this one slip-up.
>
> '73, Thomas - ac7a (Tucson)
>
>
> ---- "Wes Attaway (N5WA)" <wesattaway at bellsouth.net> wrote:
>> Yes, he did.  I remember the article from a long time ago.  The
>> theme of the article was how you could improve efficiency by
>> folding the element.  It raised the feed impedance and therefore
>> reduced losses.  I do not have the article at hand but I do
>> remember it.  If it was a QST article then it will be in their
>> online archives.
>>
>>
>> ----------------- Wes Attaway (N5WA) ------------------- 1138
>> Waters Edge Circle, Shreveport, LA 71106 318-797-4972 (Office) -
>> 318-393-3289 (Cell) Computer Consulting and Forensics
>> -------------- EnCase Certified Examiner ---------------
>>
>>
>> -----Original Message----- From: topband-bounces at contesting.com
>> [mailto:topband-bounces at contesting.com] On Behalf Of ZR Sent:
>> Thursday, August 02, 2012 5:58 PM To: Tom W8JI;
>> topband at contesting.com Subject: Re: Topband: THE ITINERANT 160
>> METER ANTENNA PROJECT
>>
>>
>> ----- Original Message ----- From: "Tom W8JI" <w8ji at w8ji.com> To:
>> <topband at contesting.com> Sent: Thursday, August 02, 2012 6:21 PM
>> Subject: Re: Topband: THE ITINERANT 160 METER ANTENNA PROJECT
>>
>>
>>>> (1) 130 feet of 300 ohms twin lead with the far one end shorted
>>>> and pulled up over a coconut by a local climber $5 US max and
>>>> connected to a small nylon line for adjustment in an inverted
>>>> or sloping fashion back to my hotel room on the beach. (without
>>>> the local climber  bring along a slingshot fishing line
>>>> launcher.) If the hotel wasn't right on the beach or had any 70
>>>> foot palms I just drove to another one that did. Masting
>>>> anything up beyond 50 feet by yourself just forget it.  Palm
>>>> trees are great substitutes.  I think this antenna was describe
>>>> for 160 in Bill Orr's (W6SAI) firsts handbooks.
>>>
>>>
>>> Just be aware Orr had a consistent mistake in his articles on
>>> folded antennas. He claimed folding reduced ground losses by
>>> significant amounts.
>>>
>>> I'm not sure where that idea started, but using a folded element
>>> does not change ground loss one bit.
>>>
>>> 73 Tom
>>
>>
>> Did he actually claim that or that the effect of the ground loss
>> was reduced? I dont have a reference handy.
>>
>> Carl KM1H
>>
>>
>>
>> _______________________________________________
>>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>>
>>>
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>>
>> _______________________________________________ UR RST IS ... ...
>> ..9 QSB QSB - hw? BK
>>
>> _______________________________________________ UR RST IS ... ...
>> ..9 QSB QSB - hw? BK
> _______________________________________________ UR RST IS ... ... ..9
> QSB QSB - hw? BK
>