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I was born 1953 Got my licence 1973




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Remote adjustment of 80m operating frequency on my Butternut HF9V
Butternut HF6V SWR readings



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SDRPlay with GPSDO with 24MHz to SDRPlay and 10MHz to K3 

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Remote adjustment of 80m operating frequency on my Butternut HF9V

The installation on the roof. The green brackets I found in a store that sells
hydraulic hoses. In order not to affect the antenna I placed the motor under

the feed point and I am using a glassfiber tube to move operations to 80m's coil.
I mounted a support between the lever and the coil, the green clamp on the
glassfiber tube allows it to move freely. Then the tube is stable and the coil is
held in place
during movement.


The achieved frequency coverage. Since I have not thought about running CW on 80m but RTTY I
the ratio of the lever this setting.
One side effect was that I can change frequency on 40M between 7088-7148 MHz.
On the other bands I have not noticed any impact.


The new flexible connection of the coil to the antenna tube. I used the metal braid
normally used in cars. The lower part of 80m's coil is secured to the glass tube
and is connected flexibly to the old terminal tab. By moving the position of the
fiberglass tube so I can set the upper frequency. On the lower part is also visible support.


Lever. When the actuator movement was not enough for the frequency
coverage I wanted so I mounted a lever that changed the movement by
moving the
roll center. 126mm/84mm= factor 1,5. I also made extra holes

for the tuning but the calculations did exactly, so they need never be used.

Installation of the motor below the feedpoint and movement
thru the fiberglass tube.

For details see http://www.mit.se/pdf/MLD3.pdf






In the radioroom, I chose to use a control card from Electrokit with PWM "pulse width modulation",
which provides adjustable speed. See http://www.electrokit.se/download/k166.pdf for more data
on the control board. It also has a bipolar function. I can then by turning the potentiometer to the
pull-80m coil bottom down, expand the coil, reducing the inductance, ie. increase the
resonance frequency. Depending on how far I turn so it goes faster and faster. To the left is
the reverse action. On the control box I put a momentary push button that connects 24V to the
control board. This makes it easier to quickly stop when I got the lowest SWR. I have no indication
other than to keep an eye on the SWR meter, but it works well.
I also built a separate 24V power supply, not in photo, which through a relay switches on
I turn on the rig.

I fed motor voltage via two bias-T, ie. DC via coax then I have no control cable wired to the roof.


Bias-T, DC thru coax



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Butternut HF9V SWR readings








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8135701 Last modified: 2017-06-03 19:43:06, 20645 bytes

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