Subject: Time: 10:10 AM
To: <towertalk@contesting.com>
OFFICE MEMO Which cable to use?? Date: 5/29/98
hello to all,
i have just subscribed to towertalk and i am hoping to draw
on everyones experience with a new tower installation of
my own...i am putting up a 48ft self support tower...on top
will go a TH7 tribander...i wish to run one feedline from
shack to a RCS-4 antenna relay box...at top i will string wire
antennas to cover 40,80,160...so will make up jumpers to go
from RCS-4 up to these antennas...total length of feedline
from shack (just outside the wall-jumper required to go inside)
to bottom of relay box is abt 160-170ft.
i also want to put up an omni directional VHF antenna (for cluster
connect/bbs etc) on a side arm up abt 45ft. cable run to be abt
same length as HF run....now the questions....
1. What cable should i be looking at for both the HF and VHF feedlines
based on the lengths?? Can i use 75 ohm CATV in both cases?
2. If u use 75 ohm cable, will i need transformers of any type to match
the 75 to 50 ohm loads??
3. Should the jumpers at both ends of the runs also be 75 ohm (assuming
75 ohm CATV is used) or can i get away with rg213 jumpers??
4. Does anyone have the attenuation specs for 75 ohm CATV for various
frequencies??
5. Has anyone ever mounted/used an R7 vertical above a TH7?? not sure
what to expect or whether the cost vs use ( for 40m use ) is justified?
Any help on the above would be greatly appreciated...73 Ted VE3SS
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