Discone antenna for VHF low band and CB
 

How well do the Radio Shack and Diamond discones (with the low band verticle
element) work in the 30-50 Mhz range and CB band? I know they are rated for
25-1000 Mhz coverage.

Frank

On Sun, 30 Jan 2005 03:40:17 GMT, "Frank Bals"
wrote:
anything below 140mhz they suck
fair to poor at best as a antenna


How well do the Radio Shack and Diamond discones (with the low band verticle
element) work in the 30-50 Mhz range and CB band? I know they are rated for
25-1000 Mhz coverage.

Frank

Frank Bals schrieb:
How well do the Radio Shack and Diamond discones (with the low band verticle
element) work in the 30-50 Mhz range and CB band? I know they are rated for
25-1000 Mhz coverage.


I have a Diamond discone with two extended legs adjustablefor CB or
10mtr TX use. It does not work as good as a designated CB-antenna but is
DOES work with low SWR. For TX use you must be aware this antenna will
spread out a bunch of harmonics as well...
If you are in need of a specified frequency coverage below 140Mhz just
replace one or two cone elements with some 1/4 wave resonant elements
(shortened with coils) of that frequency.
If you want continous coverage down to 26Mhz you'll have to extend all
cone elements to full length of 10ft.

"Volker Tonn" wrote in message
...


Frank Bals schrieb:
How well do the Radio Shack and Diamond discones (with the low band
verticle
element) work in the 30-50 Mhz range and CB band? I know they are rated
for
25-1000 Mhz coverage.


I have a Diamond discone with two extended legs adjustablefor CB or
10mtr TX use. It does not work as good as a designated CB-antenna but is
DOES work with low SWR. For TX use you must be aware this antenna will
spread out a bunch of harmonics as well...
If you are in need of a specified frequency coverage below 140Mhz just
replace one or two cone elements with some 1/4 wave resonant elements
(shortened with coils) of that frequency.
If you want continous coverage down to 26Mhz you'll have to extend all
cone elements to full length of 10ft.

If the transmitter is within spec, the antenna will not "spread out
harmonics".

The popular discones stop functioning as a discone around 130 MHz. The
vertical section supplied with some operates as a 1/4 wave radiator and the
cone rods as a limited counterpoise- very narrow bandwidth
If you want to extend the range of the discone below 130 MHz, you need to
appropriatly lenghten not only the cone section, but also increase the size
of the disc- w/o doing this, you no longer have a discone antenna, and the
feedline will now become part of the antenna.

Dale W4OP

"Dale Parfitt" wrote in message news:d68Ld.7697

The popular discones stop functioning as a discone around 130 MHz. The
vertical section supplied with some operates as a 1/4 wave radiator and the
cone rods as a limited counterpoise- very narrow bandwidth
If you want to extend the range of the discone below 130 MHz, you need to
appropriatly lenghten not only the cone section, but also increase the size
of the disc- w/o doing this, you no longer have a discone antenna, and the
feedline will now become part of the antenna.

Dale W4OP
-----------------------------------------------------------------------------------

I have used my discone (one with the vertical whip) on 6 meters with
a 2 to 1 swr. Although it was very narrow banded there. If memory
serves me it was in the 52mhz area that it worked. Outside of that 52mhz
the swr curve was pretty much V shaped with the swr rising precipitously.
The effective bandwidth was somewhere between 500Kc to 1 Mhz.


Jeff

Kc? Gads you must be as old as me!
Terry