Topband: Vertical SWR problem

[Dieter Voss]

Hallo Jim, hello together,

the problem with the V160 is, that the resistance over perfect ground is about
11.5 Ohms. The tuning unit uses - as far as I know - only a loading coil. 
By using this with a good ground system you will never get usable SWR. If you 
use a bad ground the SWR is OK, but you fire 3 quarters of your power to heat 
the earth.
2 Solutions:
* LC Network for matching (C to ground on the coax-side)
* 4:1 UNUN between loading coil and coax (option: elevated radials)

The V160 I took to TX9 was matched by a 4:1 UNUN and loading coil. As ground
2 elevated radials were used.

73s Dieter, DL3KDV

> I've just installed a Titanex V160S vertical (87') with a V160AS (160m
> only) tuning unit. Yesterday I connected 12 radials (130') each, adjusted
> the taps on the tuning unit coil with an MFJ SWR analyzer, and got the
> resonant point down to about 1850 khz. with tolerable SWR (less than
> 1.5:1) at 1805 khz. So, here's the problem: today I added another 16
> radials, and the resonant point moved up to 1900 khz. The SWR is now high
> enough at 1825 khz that the amp shuts down. I tried adjusting the taps on
> the coil in the tuning unit, but to no avail.

> Anyone have any suggestions as to how to get the resonant point to a lower
> point in the band? Thanks.

> 73, Jim   W1YY/7

> (sorry for the duplicate message)

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