[Antennas] To anyoine made T2FD antennas

Mon, 4 Nov 2002 22:30:48 +0200

Dear frinds of the list 
Please reply directly to me!!
I tried the previous week to make one T2FD of 20m + 60 cm sizes using 5 
mm thick PVC as main spreader for the terminator resistor ( 3 x 330 Ohms 
in parallel) and collector (a TV air-core balun for the moment ) but with 
expanded PVC for all other spreaders. The result was that these expanded 
PVD spreaders were very easily broken on handicraft so that I will delay a bit 
the installation of the T2FD , in order to find first some batter materials for 
this work. Possibly plastic tubing used for sub-floor heating which I know is 
very strong, as well as strng PVC sheet for the main spreader. 
Just a little about the current situation: 

My RX point is on the top of a mountain , with very strong winds up to 10 B . It 
is a two store house and the maximum length I can install a T2FD antenna is 
about 25m . ( by calculation) 
For the moment I use one 16m simple wire on 4 m height and one 2 m 
height , 2 x 14 m dipole. 

I try now to install two new antennas , the above mentioned T2FD , as 
well as a new inverted dipole of ca 2 x 17+6 m (dual band) . Both will be 
supported on the highest point of the house whre a previous TV antenna 
installation occurred. 

Here I give you some questions about the making of the antenna and 
something more general . Please reply to each question separately.

1. Do you think that using SWG#12 will have any better gain over #14 ? 
Using #12 however was relatively difficult to handle but I think that #14 
could be much easier. But still I think since the wires are already cut to 
length, minus a few cm , it is better to be reused . THe one pole is about 
3-4 cm shorter than the other pole 

2. About nylon cord. Do you think that if I replace nylon with normal wire 
can affect the reception ( negatively or positively) ?Do you know if grass 
cutting nylon cords are OK for this?

 3. Do you think that aircore balun for VHF can be used OK? I have some 
printed circuit baloons available 
4. Will there be any problems using a 75 Ohm TV cable instead of 50 , 
with the use of the VHF balun? I have too many spare cables, suitable 
also for satellite TV ) 
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