Topband: Fw: Re: : antenna question ...this is not going todieqiuite yet....................

[ZR]

And one should never rely on a single source of information unless it has 
been well vetted. That is something that wont happen on Antennex but there 
are enough qualified people on Eham and here to seperate truth and fiction.

Carl
KM1H


----- Original Message ----- 
From: "Bill Aycock" <billaycock at centurytel.net>
To: <topband at contesting.com>; "mike l dormann" <w7dra at juno.com>
Sent: Monday, December 10, 2012 9:50 PM
Subject: Re: Topband: Fw: Re: : antenna question ...this is not going 
todieqiuite yet....................


> Mike--
> Often, quoting eHam is repeating  nonsense. Sorry, but it is so, and this 
> is a good example. Any Ham that relies on published Velocity factor data, 
> without verification,  gets errors, and (frequently) blames it on 
> something else.
> Start over; read some texts or handbooks; Think; read stuff from people 
> like W8JI (and people he disagrees with).
> Reading eHam is like reading Antennex; There may be something good there, 
> but how can you tell? It's not checked by anyone qualified.
> Bill--W4BSG
>
> -----Original Message----- 
> From: mike l dormann
> Sent: Monday, December 10, 2012 2:46 PM
> To: topband at contesting.com
> Subject: Topband: Fw: Re: : antenna question ...this is not going to 
> dieqiuite yet....................
>
>
> if I may quote eHam.....
> Dale Hunt:
> The velocity of typical cheap TV twinlead is usually in the range of
> 0.8 to 0.85 (and can vary along a single role.)  This is important if
> you are creating a quarter wave matching stub, but not for the
> overall length of a folded dipole antenna.  Use the standard single-
> wire dipole formulas and it should work fine.
>
> One variation I have seen is to connect a short jumper wire across
> the twinlead a short distance in from each end of the folded dipole.
> The idea is that, while the overall antenna length is not corrected
> for the velocity factor, each half of the antenna is effectively a
> quarter-wave stub which does need the correction.  The shorting
> bar is put on each side about 85% of the way out from the center.
> This may improve the SWR somewhat in a 300 ohm system, but
> if you are using a tuner to match 50 ohms to 300 ohms, then you
> won't seem any noticable improvement.  (The tuner setting will
> compensate for any slight mismatch due to the velocity factor.)
>
> I guess if one was to use a balan of some sort to have the end to the
> transmitter be 50 ohms, this could of of some importance
>
> mike w7dra
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