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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