29.5 ft EFRW for QRP

[Brian - K3ES]

being able to "load" or "tune" if you prefer does not mean efficient radiation a dummy load will "tune" just fine

Hi Andrew,

I will make no claim about this being optimized as an antenna. It is not. I do find it excellent for field use: it deploys easily, it takes up little space, and it is very stealthy. It also proves its worth as an antenna based on contacts made, and here is one example:

I had a few hours for radio on Sunday, March 2, 2025, so... From POTA entity US-8725, located at grid FN01jk, I made 109 contacts over a 4 hour period with the 29.5 ft EFRW described above. This included contacts on each of the following HF bands: 40m, 30m, 20m, 17m, 15m, 12m, and 10m. While most contacts were US and Canada, I also made DX contacts in France, Italy, Belgium, England, and Japan. I was running CW mode at 5 watts, with the radiator nearly vertical.

The bands were amazing that day. I have no doubts that I could have made more contacts with an optimized antenna or with higher power. Just the same, this particular 29.5 ft EFRW has earned a place in my field radio kit.

Best 73 de Brian - K3ES

[AA5ET]

https://k7mem.com/Ant_End_Fed.html#Not_Random_Multi

Andrew do you actually have experience with a 29 ft end fed antenna? I do, and it works pretty well on 40-10 with a 9:1 transformer.

[Andrew (grayhat)]

https://k7mem.com/Ant_End_Fed.html#Not_Random_Multi

Andrew do you actually have experience with a 29 ft end fed antenna? I do, and it works pretty well on 40-10 with a 9:1 transformer.

no, didn't try it; but the fact that it's shorter than 1/4 wave on 40 raises some doubt about its radiation efficiency down there and given that when it comes to QRP we want to efficiently radiate the little power we use...

[AA5ET]

https://k7mem.com/Ant_End_Fed.html#Not_Random_Multi

Andrew do you actually have experience with a 29 ft end fed antenna? I do, and it works pretty well on 40-10 with a 9:1 transformer.

no, didn't try it; but the fact that it's shorter than 1/4 wave on 40 raises some doubt about its radiation efficiency down there and given that when it comes to QRP we want to efficiently radiate the little power we use...

Not much shorter than 1/4-wavelength on 40, longer on all the higher bands.

It certainly won't be as good as a yagi at 70 ft, but it is good enough for something that can be thrown into a tree or attached to a fiberglass pole in just a couple of minutes. I've used them with good success. Often on 40 band conditions are much more important than a few dB difference in antennas.

[Andrew (grayhat)]

Andrew do you actually have experience with a 29 ft end fed antenna? I do, and it works pretty well on 40-10 with a 9:1 transformer.

no, didn't try it; but the fact that it's shorter than 1/4 wave on 40 raises some doubt about its radiation efficiency down there and given that when it comes to QRP we want to efficiently radiate the little power we use...

Not much shorter than 1/4-wavelength on 40, longer on all the higher bands.

It certainly won't be as good as a yagi at 70 ft, but it is good enough for something that can be thrown into a tree or attached to a fiberglass pole in just a couple of minutes. I've used them with good success. Often on 40 band conditions are much more important than a few dB difference in antennas.

less than 9m is quite shorter than 1/4 wave on 40m but it will be ok starting from 30m

[Andrew (grayhat)]

wanna try a "no tuner" antenna ?

here is the idea;

pick a dummy load and some lenght of coax cable

at one end of the coax place a connector going to the dummy load, that will be the "far end" of the antenna (the "top" if laid as a vertical, at the other end of the coax place a box hosting a connector the latter will be "reversed' that is braid and center conductor will be swapped, such connector will then plug to the coax going to the RTX (add a choke to that coax)

the lenght of coax making the antenna isn't critical, it can be laid out as the dituation allows; horizontal, sloping, vrrtical, inverted vee

the dummy load will terminate the coax giving low SWR, the braid of the "reversed coax" will be our antenna radiator (hence the need for a choke on the coax used as feedline)

don't expect high performances from such antenna, it will just work w/o an ATU and despite the deployment conditions