Topband: Short Verticals

[Clive GM3POI]

Eznec is your friend Dave. Having used a previously short Vertical  51ft  for 20+ years, the top loading is not your problem. Because the feed Z is low you will require longer radials. Mine are typically 0.4 wavelengths. 
I will stand corrected but the formula is E (efficiency) = Feed Z/ Feed Z plus loss  (the loss being mainly ground loss)
So typically with a short vertical we could have 12/ 12+ plus loss which could be any amount dependent on your radial system.
The only way to deal with this is either by a vast radial system or a taller vertical.  In the end it's all a numbers game.
73 Clive GM3POI (306 current confirmed)

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of David Cole via Topband
Sent: 13 June 2017 21:08
To: topband at contesting.com
Subject: Topband: Short Verticals

Hi all - 
Assuming a standard 1/4 wave vertical is 36 ohms - is there any formula that will calculate the Z if the vertical is short and brought to resonance by top loading wires - I understand the Z will be less - but how much by ? I am trying to use the formula on ON4UN disc to calculate the approx LC ratios for a Lahlum-Lewallen phasing system.
Thanks Dave g3rcq 
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