Wednesday, April 6, 2022

POTA (K-1889) with the Penntek TR-35 & Hardrock-50

Lightstand antenna in background
My recent POTA activations in Arizona and New Mexico brought home the realization that trees are not always available as antenna supports. My go-to antenna prior to those destinations has always been end-fed half wave antennas from either PAR or My-Antennas. Both are excellent performers on several bands.

There were trees a'plenty at today's location (K-1889, Lake Griffin State Park, Florida) but I wanted to test the effectiveness of my "treeless solution". It consists of:

Basically, it's just a way to mount a HamStick vertical without having a car nearby with which to affix a magnetic mount.

Non-antenna gear:

  • Penntek TR-35
  • Hardrock-50 amp with ATU
  • Bioenno 12V 12 AH LiFePO4 battery

I brought along my big, heavy Nye Viking paddles so as to do one-handed CW - small, lightweight

Click for lager, er larger
paddles must be held with the other hand, thereby mitigating their size and weight advantage with a big dose of Inconvenience. Been there, done that - don't care for it.

Although I had lower HamStick "resonators" for 4 bands (and one upper whip), I only ended up operating on 20 and 40 meters. Even with 4-band capability, this makes for a lightweight, small antenna that can be used anywhere, regardless of trees or terrain. The lightstand extends to 10 feet so that is where the feedpoint was.

The workhorse in all this - at least as far as flexibility of antenna mounting is concerned - is the vise grip. It can be attached to a tripod, grill, fence post, etc, etc. If you buy one, make sure that it offers two antenna connection points, each rotated 90 degrees apart from the other. Most do not. The benefit of the two 3/8-24 fittings is that the antenna can be attached vertically, regardless of the orientation of the vise grip.

I drilled a hole through my vise grip and attached an alligator clip. This is the attachment point for the ground radials.

Results were as I'd hoped and the TR-35/Hardrock-50 combo is as if they were made for each other. A 90-minute activation used 2.1AH of juice from my 12AH battery. I'll be ordering a 3AH version before the week is out. No need to keep dragging the Big Guy out for sub-100 watt activations unless I'm going to be out there more than two hours.

A brief word about the Hardrock-50: unlike most amps made for QRP rigs, the HR-50 does not require a KEY IN signal. For simple rigs like the TR-35 that don't have a PTT OUT, the HR-50 is placed into COR Mode which uses the incoming RF to key the amp.

In the "It ain't pretty, but it works" category is my closed-cell foam cover for the TR-35's front panel, secured in high-tech fashion with a rubber band.  I will re-do this, neatly. Someday. Someday.....

Rigged for depth charge:


Rigged for action:

I will be returning to this park soon. It's less than 20 miles from home and has great "antenna trees" for when I want them. And it will be serving as my antenna test range for some other ideas I have for portable ops.



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