On 2015-04-27 1:02 PM, TexasRF--- via TowerTalk wrote:
So, is there ANY solution to providing a feedline choke for an OCF
dipole used with high power?
Gerald, they typical solution is to cascade a 4:1 current balun *and*
a high choking impedance common mode choke. The problem is maintaining
the high impedance across the entire operating range of the antenna.
By the time one has the 4:1 current balun (two cores) plus a pair of
high impedance chokes in series (one for 20-10, the other for 80-30)
that is a substantial amount of bulk *and weight* at the feedpoint.
It is somewhat practical for low power (< 250W) installations but gets
difficult for "legal limit" applications.
73,
... Joe, W4TV
On 2015-04-27 1:02 PM, TexasRF--- via TowerTalk wrote:
In a message dated 4/27/2015 11:41:23 A.M. Central Daylight Time,
jim@audiosystemsgroup.com writes:
On Mon,4/27/2015 6:50 AM, Alex Malyava wrote:
What would be the bestest design for choke or balun to be used with
dipole
or OCF dipole?
Like what type of core, number of turns or number of beads?
k9yc.com/RFI-Ham.pdf
See the Choke Cookbook and text that precedes it.
An off-center fed antenna is inherently poorly balanced, so it puts a
high common mode current on the feedline, which in turn places a high
common mode voltage across any choke. It is well known that even very
good common mode chokes are likely to fry (fail destructively) when used
with even moderate power levels. You MIGHT get away with it at 100W, but
at some higher power level it WILL break.
73, Jim K9YC
So, is there ANY solution to providing a feedline choke for an OCF dipole
used with high power?
73,
Gerald K5GW
_______________________________________________
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|