TopBand: z measurements

[K3BU@aol.com]

In a message dated 98-08-06 00:01:07 EDT, W7LR writes:

<< 
 I believe that this is a topband topic.  I'd like to make impedance
 measurements on verticals to be used in an array.  No luck with MFJ AEA
instruments due to overload from bc stations.  >>


I used the following method to measure impedance of antenna: 
(might be crude, and won't tell you reactances)

I fired up transmitter at low power through the SWR bridge and antenna tuner
on desired frequency into the antenna. Tune the tuner for 1:1 SWR. Disconnect
the antenna and replace it with suitable (to handle TX power) resistor bank or
potentiometer (noninductive) and set the resistance to achieve 1:1 reading
again.
Take ohmmeter and measure resistance, this gives you equivalent impedance of
antenna under question.
Used this method to find out impedance of beverages and rhombics in days
before antenna analyzers. Hope it helps.

73 Yuri, K3BU, VE3BMV

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