[TowerTalk] BigIR question

[Grant Saviers]

Mike,

Note there are 3 coil versions for the 80m BigIR with different power 
ratings.  So which one is being discussed?
http://www.steppir.com/wp-content/uploads/2011/10/80m-Coil-Kit-Assembly.pdf

Please consider the crankIR manual as it specifies 1500 w PEP and offers 
the option of a high power balun.
http://www.steppir.com/wp-content/uploads/2016/11/CrankIR-v2-Manual_Rev-2.1b.pdf

Grant KZ1W

On 12/8/2017 9:08 AM, W0MU Mike Fatchett wrote:
> I am a mod on the SteppIR yahoo group and I have never heard of this 
> before.  We have many many BigIR users and if this was the case it 
> would be a big issue.  It does sound like there is a problem with this 
> particular setup.
>
> Has SteppIR been contacted about it?  If not it is hard to fix 
> problems they don't know about.
>
> W0MU
>
>
> On 12/7/2017 10:42 AM, john at kk9a.com wrote:
>> If that is really what is occuring and if Doug is only using 1500 
>> watt CW
>> there is a design flaw.  This can be easily remedied as you suggested 
>> and
>> it would be worth trying, even if the SteppIR is not his primary 
>> antenna.
>>
>> John KK9A
>>
>>
>> Sent via the Samsung Galaxy 7 edge, an AT&T 4G LTE smartphone.
>>
>> On Thu, Dec 7, 2017 at 11:56 AM, Grant Saviers <grants2 at pacbell.net> 
>> wrote:
>>
>>> 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 at sbcglobal.net> Date: 07/12/2017  00:58 (GMT+00:00) To: 'Doug
>>>> Turnbull' <turnbull at net1.ie>, john at kk9a.com, towertalk at contesting.com
>>>> Subject: RE: [TowerTalk] BigIR question
>>>> What is your SWR on 80?
>>>>
>>>> Keith NM5G
>>>>
>>>> -----Original Message-----
>>>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
>>>> Doug
>>>> Turnbull
>>>> Sent: Wednesday, December 6, 2017 9:56 AM
>>>> To: john at kk9a.com; towertalk at 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 at contesting.com] On Behalf Of
>>>> john at kk9a.com
>>>> Sent: 06 December 2017 12:23
>>>> To: towertalk at 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 at gmail.com>
>>>> Subject:        Re: [TowerTalk] BigIR question
>>>> From:   Ed Richardson <ed_richardson at 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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>>>
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