In article a5O8e.8716$c93.3154@trnddc08,
"Dale Parfitt" wrote:

"David" wrote in message
...
Make Folded Dipoles and use a CATV balun backwards at the feedpoint.
Then you can use plain old RG-6 and F-Splitters. Not only is this
incredibly cheap, the entire antenna system is at DC ground*.
Caution, do not use Baluns with little capacitor inside.

*Use an F Grounding Block where the coax enters the house. And a
drip loop.

http://members.shaw.ca/weskyscan/ima...ldedDipole.gif

There is a potential problem here in that many, many baluns and splitters
intended for CATV have very poor performance at HF- i.e. balance is poor,
insertion loss can be well above theV/U values. For the splitters, port to
port isolation can be very poor, loss higher than may be acceptable.
Finally, I have yet to see a CATV Balun that is acceptable for out door use.
I wouldn't count on the system being at DC potential either- there are
several methods for creating a 4:1 balun- and seeing as how the wire used in
these baluns is smaller than #36 gauge- it wouldn't take much to fry it
anyway.
Wouldn't it be much simpler to build a classic dipole from single conductor
wire, place several clamp on #43 cores at the dipole to feedline transition
and forget about the CATV stuff and fragile twinlead??

I have checked the insertion loss on some and found them not very good
with high loss 10MHz and down. The units with bigger cores generally
seemed to be better. I have some that are good down to 1 or 2 MHz. The
smaller higher permanence cores perform poorly below 10MHz.

--
Telamon
Ventura, California

"David" wrote in message
...
On Mon, 18 Apr 2005 16:36:24 GMT, "Dale Parfitt"
I seem to recall that the wider bandwidth of the folded dipole
configuration
is attributable to the effective larger diameter conductor- probably
easily
offset by using a larger wire diameter in a classic wire dipole.

Dale W4OP
The dipole wire would have to be a half-inch in diameter for plain old
TV Twinlead. A T2FD is an example of a widebanded folded dipole.

I did the modeling David, and your 1/2" value is pretty darned close to the
mark- about a 6% increase in BW which is not trivial.

Dale W4OP

On Tue, 19 Apr 2005 16:28:16 GMT, "Dale Parfitt"
wrote:


"David" wrote in message
.. .
On Mon, 18 Apr 2005 16:36:24 GMT, "Dale Parfitt"
I seem to recall that the wider bandwidth of the folded dipole
configuration
is attributable to the effective larger diameter conductor- probably
easily
offset by using a larger wire diameter in a classic wire dipole.

Dale W4OP
The dipole wire would have to be a half-inch in diameter for plain old
TV Twinlead. A T2FD is an example of a widebanded folded dipole.

I did the modeling David, and your 1/2" value is pretty darned close to the
mark- about a 6% increase in BW which is not trivial.

Dale W4OP

I read it in an old QST or the ARRL Antenna book, decades ago.