Or do like I did after burning up several of the M2 Yagi baluns (really just
small ferrite binocular chokes)... replace them with coax air core chokes.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Grant
Saviers
Sent: Thursday, December 07, 2017 16:57
To: turnbull; Keith Dutson; john@kk9a.com; towertalk@contesting.com
Subject: Re: [TowerTalk] BigIR question
On 80 and 160 a matching ferrite transformer such as used in the CrankIR is
subject to heating with QRO rtty. The solution is a larger core - larger
diameter core or a stack or lower power on these lower frequencies.
Grant KZ1W
On 12/7/2017 0:06 AM, turnbull wrote:
> Starts at about 1.2 and heads for 2 to 1. The BE is maybe 20 kHz. This
is a Hi Q device when using the loading coil. 73 Doug EI2CN
>
>
> Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: Keith Dutson
> <kdutson@sbcglobal.net> Date: 07/12/2017 00:58 (GMT+00:00) To: 'Doug
Turnbull' <turnbull@net1.ie>, john@kk9a.com, towertalk@contesting.com
Subject: RE: [TowerTalk] BigIR question What is your SWR on 80?
>
> Keith NM5G
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Doug Turnbull
> Sent: Wednesday, December 6, 2017 9:56 AM
> To: john@kk9a.com; towertalk@contesting.com
> Subject: Re: [TowerTalk] BigIR question
>
> Dear OMs and YLs,
> I have a BigIR mounted on an extensive radial field and also with
the
> 80/60M loading coil. In contests, I am allowed to run 1500W - I find
that
> on 80M the antenna does not stay in tune while transmitting for a while
and
> assume this is to do with heating but am not sure. Normally I would not
> operate with more than 500 W for a contest on 80M then there is no
problem.
> On 40M to 10M there is no such problem.
>
> This is not my prime antenna but is a useful fallback. It is an
> excellent vertical.
>
> 73 Doug EI2CN
>
> PS Only in contests are we allowed this higher power level.
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> john@kk9a.com
> Sent: 06 December 2017 12:23
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] BigIR question
>
> This is a much better antenna than the fixed height 43' vertical that
> is so popular.
>
> John KK9A
>
>
> To: Frank VO1HP <invl160@gmail.com>
> Subject: Re: [TowerTalk] BigIR question
> From: Ed Richardson <ed_richardson@shaw.ca>
> Date: Tue, 5 Dec 2017 19:44:07 -1000
>
> Jim. The bigIR can be tuned to a quarter wave on all frequencies from
> 7 to
> 54 MHZ. On frequencies from 21-54 MHz you can select a 3/4 wavelength
mode.
>
> I have used this antenna with raised radials, tuned stub radials and a
> ground mounted radial field. Works well in all cases. It is still a
> quarter wave vertical.
> No magic
>
> Ed. Ve4ear
>
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