Topband: RG11 75ohm and 4 square 80m

[Stein Roar Brobakken]

Hi Guys

I been searching around the internet now for a while, I am about to build a
80m 4 square and and to cut coax for it. I am going to use black RG11 coax.

I have a MFJ 259B to measure velocity factor with
. It's about 10 years
since I did previous time, and now I thinking about to build a 80m 4 square.

So I have a few question for you.
1.	Is it any difference measure 75 or 50 ohm ? I meant it should be X=1
if you used it on 75 ohm instead of X=0 on 50 ? this is on a ¼ wl 75 ohm
2.	I have a RG-11 75ohm coax I plan to use, but I am not sure of the VF
all my friends says is should be VF 0.66 ?

To use the MFj 259 B ...
What I believe I did previous time I was making cables for a 40m 4 square I
did

1.	to cut the coax on 14,5 meter
2.	Solder one connector in the end 
3.	connected it to the MFJ 259.
4.	Measure on 3675 
5.	Cut until X=1 

I meant I saw a footnote into the old manual about "this" way of measure 75
ohm instead of 50 ohm
 but I cannot find any reference in any topic on the
net.. I tried to email W8JI, but reply.

The Comtek ACB-4 80m says it need  a ¼ wl 75 ohm coax as I remember. But I
saw here in MFJ 259B manual you can measure 1/4, 3/4,1-1/4, etc.
So does the 4 Square accept if I use ½ wl of 75 ohm to each vertical ? what
will happen?
 
If I cut one ¼ wl on 3,675 khz is 20,40 meter x 0,66 VF = 13,47 m + 5 %
extra for tuning ? = 14,14 m. it will be too short for get across between
two verticals.

I am worried about the length of this coax since I plan to have the feeding
point of each vertical @ 2.5-3 m above the ground.
I found out that my if I have a 20.5 m x 20.5 m square and the it will be
29,05m across
 so then the coax of 13,47-14,14m is not long enough
 
29,05 / 2 = 14,525 m
. so the coax will be to short anyway
. 
What is normal to do in a ¼ wl 4 square ?  the  coax can't be run as  a
string in the air, I wanna have it smooth into the ground....

if I double the length ? it will be about 26,8 +/. Meter. 
Will the coax work ok? if I plan to have the feeding point on 2,5-3m above
the ground on 2 x 2”x6” wooden poles on each vertical.


Can anyone tell me How wide is a 80m 4 square in frequency ? 


73s Rag LA6FJA
LN5O in contest also:K3RAG SO5RAG