[TowerTalk] G5RV vs 40M dipole

[Peter Voelpel]

The AT2K is a Transmatch (t-tuner) which gives you possibly higher losses
then the pi net of the linear.

You can simulate the losses of a Transmatch: 

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

73
Peter

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Russ
Dearmore via TowerTalk
Sent: Montag, 27. April 2015 20:48
To: Tom Osborne; towertalk at contesting.com
Subject: Re: [TowerTalk] G5RV vs 40M dipole

I use my external tuner (Palstar AT2K) at the output of my linear. Internal
tuners are fine but why make them work to the extreme?  
   My Heroes Wear Combat Boots!             


     On Monday, April 27, 2015 11:37 AM, Tom Osborne <w7why at frontier.com>
wrote:
   
 

 One thing I have noticed with the built-in tuner on my radio is that all 
it does is make the radio happy.

The radio shows a 1:1 SWR, but the meter past the radio still shows a 
high SWR, so if there is loss on the line, even though the radio is 
happy, the loss is still there.  I think the tuners just give us a false 
sense of security.  73
Tom W7WHY

On 4/26/2015 9:23 PM, Fuqua, Bill L wrote:
>    Not everyone knows that a tuner only protects the rig. That is the job
of a dummy load.
> In fact the tuner matches the impedance of the antenna system to the rig
and not only that,
> by doing so providing the antenna with a conjugate match, that is to say
the antenna's radiation
> resistance is matched and its reactance is also matched by the equal and
opposite reactance thus
> making the antenna system resonant. If the antenna has a radiation
resistance of 10 Ohms and
> a capacitive reactance of 100 Ohms the antenna tuner matches it with 10
Ohms real resistance and
> an inductive reactance of 100 Ohms thus providing  maximum energy
transfer. While at
> the same time it provides 50 Ohms resistive load for the transmitter.
>    Resonating the antenna system with a tuner is equivalent resonating the
antenna. The only difference
> is that there may be some additional losses within the tuner and
transmission line which are generally
> minimal at HF frequencies. Also, there is a reduction in bandwidth of the
antenna system.
>    Yes it does change the currents and voltages in the antenna. The G5RV
was an antenna developed back
> when we had tube transmitters with a PI network output that could
accommodate a broad range of
> impedances. It also was made to work on 5 bands.
>    Just about every AM broadcast antenna system has an antenna matching
network. It is a shame that
> they don't work.
> 73
> Bill wa4lav

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