Screwdriver auto controllers - thoughts?

Discussion in 'Mobile Radio Systems' started by KC8QVO, Feb 24, 2019.

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  1. W9CLL

    W9CLL Ham Member QRZ Page

    I had the original Turbo Tuner and it was a piece of crap and they went out of business, TennaTronix picked it up and hopefully fixed all the problems.
  2. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    I could postulate on this subject, and fill a page or two. However...

    NONE (!) of the current, screwdriver antenna controllers properly detect two issues: Stall current and SWR. Everyone detects stall current by measuring the voltage drop across a resistor. That is the correct (simplest, really) way to do it. The question is, WHEN they measure it. We need to understand, that weather conditions often dictate the stall and running current. As a result, most controllers develop issues during cold weather, especially so if snow and ice are present. The question remains, when do you detect stall current? That is almost a trade secret! Remembering that the stall and run current are dynamic in nature, the answer is just after the motor starts to turn as detected by the reed switch. If you do it correctly, there will be no weather-related issues.

    Ah! SWR! Almost no one correctly adjusts the SWR of their screwdriver antenna. The preferred method is to use a shunt coil, but only if the antenna is mounted correctly (with lots of metal mass under it). Done correctly (both mounting and shunt coil adjustment), the SWR will always be under 1.6:1 across the 80 through 10 meters. That level of SWR can easily be detected, IF the detection methodology is correct. Of the four, currently popular, screwdriver controllers, only one does it correctly. In other words, measuring only the V-SWR (simple SWR bridge circuitry) isn't accurate enough.

    The only screwdriver controller which did these things correctly, was BetterRF. Alas, they are out of business, and we are all diminished.
    NH7RO likes this.

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