I just ordered a HF 3.6-50MHz Wideband Multi Tuneable Mobile Antenna 80m-6m Portable HAM from Indonesia. I'll report after I try it out. I tried building one and had reasonable results but figured that the professionals can do better? Let's hope.
I just picked up the Alpha ProMaster https://alphaantenna.com/category/community-and-support/reviews/base-hf-promaster-antenna/ So far I would say it works very well on 20 and above, fair on 40, not so good on 60 and 80. I will probably just stick with my Icom AH-3 and random wire for now.
Quite a few of us are using Scorpions screwdrivers on fold up mounts attached to the ladder. Fully deployed easily in a few minutes and tunes everywhere without a tuner/ you can also run high power. Bottom line they work very. efficiently. K6UDA Bob has done some videos on them in the past just Google it.
[QUOTE = "W8GV, post: 5748668, member: 961888"] Ищу хорошую вертикальную антенну для ВЧ. Моя жена и я в настоящее время живем полный рабочий день в доме на колесах, поэтому его будет довольно легко снять и снять. В Мичигане была ветчина или компания, которая производила что-то подобное, но не могла придумать название. Полагаю, это часть процесса старения. 73 W8GV [/ QUOTE] Вот самый надежный вариант!
Yesterday I put it up outside on a tripod about 4 feet off the ground. I followed the instructions and first set the coil length and then the whip length. Adjusting both I tuned it to 7.250 MHz using the NanoVNA. It took maybe one or two minutes. The band is extremely narrow which is good for noise but doesn't provide flexibility. The lowest SWR was about 3. However, with a short counterpoise it was below 2. The company says that a counterpoise is not required. Well, if you use an ATU maybe not, but then you lose some power in the ATU (and it is an extra weight in your backpack). Next I connected my YouKits TJ5A (20 W max output) and no ATU. Despite the poor propagation I made contact in Kentucky (43) and Massachusetts (57). This antenna is perfect for backpacking expeditions. It comes apart in lengths under two feet.
FWIW: Antenna efficiency and SWR are not directly related. A good 50 ohm resistor can have a perfect 1:1 SWR and radiate nothing. You can reduce SWR at the rig by using a log lossy feedline. You'll get lower SWR, but also lower efficiency. SWR is important for two things, the rig's ability to drive the load at full power, and how it affects losses in feedlines. Properly lowering SWR is definitely not a bad thing, but may not directly effect the efficiency of an antenna.
