Topband: Two Wire Beverage Query...

[Ford Peterson]

Tom wrote:

> Hi Ford,
> 
> It seems to me that I've seen some discussion about running
> a wire on the ground along the length of a beverage to
> connect the grounds between the feedpoint and the
> termination.  Is this true?>>>
> 
> I can't think of a single logical reason in the world to do
> that. IMO, it is a very poor suggestion.

Well, it comes with some merit at this link...

http://exax.net/

Several of the diagrams describe a ground return line between the ends.

...SNIP...

> 
> For a look at measured ground resistances, check out
> http://www.w8ji.com/ground_resistance_measurements.htm
> 
> When your antenna surge resistance is 600 ohms, a 50 ohm
> ground termination resistance doesn't look so bad.
> 
> When the surge impedance is 300 ohms, 50 ohms looks twice as
> bad.

...SNIP...

> 73 Tom


Several respondants to the query indicate that would be a good idea to run the extra wire and others agree with Tom.  Geez guys, I'm not an engineer.  I'm an accountant.  It appears that there is some confusion as to the best approach to Mr. Beverage's work.  I'm not trying to start WWIII in some debate, I'm trying to build a better beverage...

Tom,

I studied your 'ground measurements' page with great interest.  I wish you had described your test setup a bit better.  I guess I'm a bit confused as to how you measured the impedances reported in the table.  

Also, re: 'surge impedance.'  How does one measure this?  I was effectively able to measure the characteristic impedance of the two wires to be in the 680 ohm area.  The data I collected is very solid using a sweep of 1 to 8 MHz.  And a sweep of a single wire over ground came in at about 450-470 ohms with the data not nearly as convincing in the same sweep.  But how do you measure to see whether the surge impedance is 300 or 600 ohms?

Ford-N0FP
ford at cmgate.com