End fed half-wave antenna question

[KC1LML]

I know I could just try this and see what happens but thought I would get some advice. I currently have a 40 meter (66' 10") end fed half-wave between 2 trees in my back yard. It's easy enough to lower it down to work on it. I'm wondering if it is feasible to cut the wire at 33' 5" for 20 meters and install an insulator at the cut. The unused 33' 5" piece of wire would not be connected to anything except the insulator and my nylon rope at the far end.

Would the unused wire affect the 20 meter piece in use? And would I be able to simply lower the antenna and jumper across the insulator to get back to 40 meters?

 

[AK9R]

It should work OK.

Some portable operators use "linked dipoles" which are built as you describe. Band changes are a little inconvenient, but having a real dipole is sometimes an advantage.

Linked Dipoles

www.sotabeams.co.uk

 

[KC1LML]

I called Radiowavz, which I should have done to start with. At least I didn't cut the wire yet. This is their EFH 40. The tech support guy says the balun is made in such a way this particular one will only work on 40 meters.

 

[prcguy]

If you use a broad band 49:1 or 64:1 transformer like most EFHWs it will work all harmonics like 20, 15 and 10m.

 

[KC1LML]

Eventually I'd like to figure out a way to put up a 40m dipole. Up to now I've been using my end-fed antenna just for receiving MW & SW. Like most everybody, I have backyard issues. In my case, tall pine trees at opposite ends of the yard with nothing in between. So, I have 20' of rope at the balun end of the 67' EFH antenna and 40' of rope at the far end. I imagine I would have quite a bit of sag on a dipole's center feed to the house.

 

[popnokick]

What are you hoping to gain with a dipole? Your EFHW is quite efficient... and multi-band (unlike a dipole). And as you've noted, you'll need to add a longer run of sagging coax pulling down the wires between the trees (vs feeding the end of the EFHW).

 

[KC1LML]

Well, that's a good question. I've been doing VHF/UHF for a couple of years but am new to HF. From what I have found online, there seems to be quite a bit of controversy about EFH antennas. So. I was thinking a dipole was a better way to go. I can't put up much of a tower antenna, because I am only a few blocks from town center.

 

[prcguy]

A resonant end fed half wave is a great antenna and you can't tell the difference between one and a 1/2 wave dipole at the same location. If the transformer in your Radiowavz version is 40m only you can build a 49:1 or 64:1 transformer very cheap and have 40, 20, 15 and 10m working on the same piece of wire. A 100w version of the transformer might cost $10 to build including the box and connector and a 400w version would be about $20.

 

[AK9R]

From what I have found online, there seems to be quite a bit of controversy about EFH antennas.

As I'm sure you know, on the Internet, everyone is an expert.

What is the nature of this controversy? Is it coming from people who have actually tried EFHW antennas? Is it coming from people who have tried EFHW antennas, but didn't install them correctly? Is it coming from people who have tried EFHW antennas, but found that their heightened expectations didn't quite match reality?