Re: 10m tuneup - total disaster and embarrassing lesson learned

Paul Butzi (W7PFB)

The problem with two tuners is that they’re solving for a tuning solution at the same time, at varying speeds and by adjusting impedances in different ways.

In essence, each tuner is expecting a static target but the other tuner presents a moving target.  Chaos ensues.

BTW I would not call this a disaster at all, let alone a total disaster.

Total disaster is when you run into this problem for the first time right after the world goes wahoonie shaped and the lives of your family are depending on things working.

I think the correct term for this is “problem discovered and corrected during training”, which is sort of what training (and drills) are all about.

-p W7PFB
73, Don’t forget to smile and have fun!

On Jul 17, 2020, at 1:07 PM, Paul Zoba <pezoba@...> wrote:

Hmm, I don’t understand why they don’t work together? And doesn’t this happen anytime you’re on HF then? I have the LDG IT-100 tuner paired with my 7300. It tunes when I press the Tune button on the radio.

I don’t know why you’d consider this embarrassing as I don’t think it should happen at all. Seems like something isn’t working right.  Embarrassing is when I tried to call in using 70cm on a 2m beam antenna. Doh! 🤦🏼

On Jul 17, 2020, at 12:00 PM, Howard E. Mahran / WA1HEM <wa1hem@...> wrote:

If my life depended on getting on 10m yesterday to report my location during a disaster - I'd be dead today. My 10m antenna is not the best to begin with. It's a 6-40m dipole. I get better luck with 10m sticks but I didn't have them set up. So for the tuneup, it was either the dipole or nothing.  Just before the tuneup, I tuned my rigs SWR to less than 1.4.

Ok so we start the tuneup and I was dead in the water.. couldn't get a message out also had lots of noise.  My SWR started to swing wildly, causing my power to swing wildly from 100w to 0. Repeated attempts to retune failed. No one could hear me and when they did it was brief and wonky.  I thought maybe my dipole crashed but a test with a meter showed a very tuneable 2.3 SWR on 29.52mhz. What the heck was going on?

After pulling my hair out it turned out to be something so silly I'm actually a little embarrassed to mention it... but I'll swallow my pride in the hopes that my stupidity will potentially prevent someone else from the same frustrating debacle. I have an LDG 100 antenna tuner. Its two parts - the tuner is remote (out near the antenna) with a small control unit that sits indoors. I have mine on a shelf below my rig. It comes on automatically when I turn on the power supply. It's a very unassuming little guy. I totally forgot about it, as its so little and unobtrusive. What the LDG does is automatically try to tune the antenna- no input needed. So... you can see the problem... In combination with my 7300, which was also set to TUNE - I had the SWR equivalent of dueling banjos! They just fought with each other, swinging the SWR wildly and eventually shutting down the 7300's Tx power to save the finals (thank goodness for that protection!). Lesson learned. I finally shut off the LDG and just used the 7300's tuner. I think all was finally stable at the point... unfortunately... the exercise was long over.... ahhh... the lessons we learn...

Howard E. Mahran
(425) 864 - 5104

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