[TowerTalk] 80 Meter yagi question

[Richard Thorne]

Hi John,

The preset's are built into the MFJ-1924 mobile antenna controller.

So if I know I'm going to qsy more than 20 khz in either direction I'll 
have to push one of the memory buttons on the 1924.

Jim at TuneMatic was gracious enough to let me borrow one of his mobile 
antenna controllers.  My goal was to interface one of his unit's to my 
Flex 6700 so the tuner would follow the vfo and automatically adjust the 
antenna.  It has a feature to break the PTT line so the amp would be off 
line while the coil adjusted.

Unfortunately I could not get the tuner and the TuneMatic to play well 
together.

I may investigate this again in the future.

Hopefully I'll never find out if the Tornado Tuner will survive a 
lighting hit.  The tower has been up since July 2015 and no hit's yet 
(knock on wood).

Rich - N5ZC





On 10/9/2017 6:15 AM, john at kk9a.com wrote:
> Nice antenna Rich! At one time I had a homebrew 90++ foot dipole that
> covered the portion of the phone band that I used but on CW the SWR was
> pretty high. Are there presets for the tornado coils or do you have to
> tune it every time you QSY?
>
> OptiBeam and Force12(sk) use relay controlled coils at the center for
> changing resonance.
>
> I wonder how either of these methods hold up to lightning strikes!
>
> John KK9A
>
>
>
> To:	towertalk at contesting.com
> Subject:	Re: [TowerTalk] 80 Meter yagi question
> From:	Richard Thorne <rthorne at rthorne.net>
> Date:	Sun, 8 Oct 2017 18:58:42 -0500
>
> I can recommend the 80m JK801 rotatable dipole.
>
> I have one at 138' and so far so good.  It's only been up since July so
> I'm looking forward to the fall/winter DX season.  The antenna does not
> use coils, it uses T-hats towards the ends.  There isn't much droop to
> it(note there is no truss cable) and it has handled the winds here in
> Amarillo nicely.
>
> There's a picture of my JK stack on my qrz page.  The dipole is at the top
> followed by a Mid-Tri Tribander, JK3040SR 40/30 yagi, another Mid-Tri and
> finally a F12 WARC 2/2 at about 55' to cover 12/17.  I'll probably add
> another Mid-Tri when 10 meters is more active.
>
> The only interaction I've had is on 20m, I had to move the JK801 parallel
> with the other booms to fix the 20m swr issue.  At the time of
> installation the tornado tuner was not active.  I'm going to climb the
> tower and have a buddy monitor the 20m swr while I move the JK801 parallel
> with the elements.
>
> Each half of the JK801 is 27' long and with the T-Hat it probably acts as
> a half wave on 20m.  I'm hoping with the tornado tuner on line,  that the
> 20m portion of the upper Mid-Tri won't be affected. I'd like to get this
> resolved from an SO2R stand point.  More than likely propagation will be
> coming from the same direction on both 40 and 80 which requires both
> antennas to be pointed in the same direction vs a 90 degree offset.
>
> I've worked lots of DX on FT8 with it along with some phone and cw.
>
> I can cover the entire 80m band from below 3.5 mhz to above 4.0 mhz via
> the tornado tuner and the mfj-1924 controller.
>
> I have the following swr bandwidth as follows:
>      - 1.5:1 40 khz
>      - 1.75:1 60 khz
>      - 2.0:1  80 khz
>
> I use 5 of the MFJ memories to cover cw and 5 for SSB then fine tune if
> needed with the up and down buttons.  I may change that to 4 on CW and 6
> on SSB.
>
> Rich - N5ZC
>
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