Topband: LZ2CJ verticals

[Valeri Stefanov]

Hi fellow topbanders,

I have been lucky enough to obtain at very reasonable price a 15m high 
telescopic military mast. I am going to add another 6m at the top to 
make it 21m high.
I plan to use this 21m high mast as a support for a wire ( 10mm dia) 
made short vertical for 160m.  This one will be a second vertical I will
ad to the first one I already errected in October 2000.(see LZ2FV 
claimed result in CQWW CW 2000)
I would like to make the same system I used 17years ago at my previous 
contest QTH.  This time two verticals will not be identical and I would 
like to learn from antenna experts if it significant for the performance 
of the system or not?
I'll have: a. 20m high vertical ( 100 mm dia) base loaded and b. 20m 
apart I'll place the second one made of 10mm wire.  I will use identical 
base loading coils. Radial system will be equal for two verticals.  I  
intend to feed them like I did in the past -connecting each vertical to 
a 75 oms coax. Both pieces of coax this time will be 1/4 wave lenght on 
160m and I will connect the central conductors together and shields 
together aiming to achieve acceptable resistance value.  I will use 50oms 
RG213 coax from this point to the radio. Suppose with this feeding SWR 
to be around 1.5 and I'll use the tuner to make it 1:1.  Thus I plan to 
have a system which will radiate omnidirectionally and will have app. 
2.7db gain over a single vertical of a same kind.

Am I right in my assumptions?  Any comments.
(I used the same system 17 years ago, but 75 oms equal lenght coax 
pieces were going directly to the rig, without a piece of 50 oms coax in 
between and system exibited 1.2 :1 SWR over the entire 1800 - 1900 khz 
portion( 1:1 on 1845).  Both verticals were 20m high, 100mm diameter and 
spaced 12m each from the other and each had 16 20m long radials.

Thanks in advance and see you all this comming weekend in CQWW CW test

( We'll be M/S as  LZ8T / ops LZ2FV,LZ2HM,LZ1UQ,LZ2CJ - FT990-IC735 and 
ACOM 2000A)

de Wally LZ2CJ / LZ8T



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