Fw: [Ham-Antennas] Very Good Site for Knowledge ..

[David Tanks]

Good info on End-Fed Half-Wave antennas and End-Fed Off-Center

antennas.

David AD4TJ

----- Forwarded Message -----

From: KX8K <donh...@roadrunner.com>

To: "ma...@ham-antennas.groups.io" <ma...@ham-antennas.groups.io>

Sent: Saturday, November 1, 2025 at 11:27:04 AM EDT

Subject: Re: [Ham-Antennas] Very Good Site for Knowledge ..

On Fri, 31 Oct 2025 16:47:18 +0000, "W0LEV via groups.io"

<davearea51a=gmai...@groups.io> wrote:

>But I've been bashed and flamed

>for many of my comments.  Here it all is from another excellent source.

As many have said, they can work OK under certain conditions. But in many cases,

people wonder why the EFHW/EFLW doesn't work as well as many claim it does.

I found this to be interesting. It's taken from this part of that website:

https://shop.rf.guru/pages/end-fed-antennas-explained

"Key nuance: standard 49:1 EFHWs are unstable on lower bands due to soil and

height variations. However, in purpose-built Inverted-L designs with higher

ratio transformers (68:1–70:1), stability improves dramatically—showing that

transformer design and geometry matter as much as the wire itself."

It also covers the EFOC (end-fed off-center) antenna, which is more manageable

than the above. It's worth a quick read of that page. This particular part

explains why the EFHW as a multi-band antenna may not be the Holy Grail of

antennas:

=========================================

Why We Do Not Like the “Wideband EFHW”

Some commercial EFHWs are marketed as “wideband” solutions, claiming low SWR

across HF without a tuner. In reality:

The flat SWR curve often comes from lossy ferrites or resistive elements inside

the transformer. This “absorbs” mismatch rather than transferring power to the

antenna.Efficiency can be dramatically reduced—sometimes more than half the RF

power is lost as heat.

=========================================

So a good SWR, as stated in this group many times, does not mean that the

antenna is efficient. A dummy load is probably the most inefficient antenna

possible, yet it offers a 1:1 SWR.

I used an end fed multiband antenna for a few years and had a decent enough

ground system, and it did OK, but I matched it directly with a tuner, no voltage

transformer or balun.

Donald KX8K

----------------------------------------------------

Some ham radio groups you may be interested in:

https://groups.io/g/ICOM  https://groups.io/g/Ham-Antennas

https://groups.io/g/HamRadioHelp    https://groups.io/g/Baofeng

https://groups.io/g/CHIRP  https://rf-amplifiers.groups.io/g/main

[David Gordon]

Interesting read. I use two EFHW antennas. One is a 40-10m and the other is an 80-10m; in an L configuration using the 49:1 unun, two ferrites each. Low swr on most bands, < 1.3:1 or better. On 75m, low swr from 3800 to 4000 kHz, but need to use my tuner from 3525 to 3800 kHz. No coil heating because I’m usually running less than 300 watts. Height for both are 20 feet. The 49:1 coils are hand wound, not store-bought. My 80-10m is N-S, and the 40-10m is E-W. 

The N-S gives me a nice side lobe into Europe on 15 and 10m, whereas the E-W gives good coverage stateside and to AK on 20m. 

Side note: my EFLW uses a 9:1 and 145.5’ of wire, gives good results on 17m, low swr. 

CP's are my coax shields, 80' to my CMC's before entering the house. No RF in shack. 

David, Kb4lci 

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---

From: 'David Tanks' via Valley Hams <valle...@googlegroups.com>
Sent: Saturday, November 1, 2025 11:39:52 AM
To: valleyhams <valle...@googlegroups.com>
Subject: [Valley Hams] Fw: [Ham-Antennas] Very Good Site for Knowledge ..

 

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