The endfed antenna has become one of the most popular choices among amateur radio operators in recent years. Its ability to cover multiple bands and its easy installation often make it the first antenna many radio amateurs put up. But there is one major drawback: the endfed antenna is highly sensitive to man-made noise (QRM).
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Why Endfed Antennas Pick Up So Much Noise
The endfed is especially attractive in places where space is limited. Unfortunately, that often means installing it in urban or suburban environments, where electrical devices generate plenty of interference. Because of its electrical characteristics, the endfed antenna readily picks up this noise, which can ruin your operating experience. You may hear loud static while weaker signals disappear completely.
Being Heard, But Not Hearing Back
One of the biggest frustrations is when the other station hears you clearly, but you can’t copy their signal because it’s buried in noise. Moving the antenna away from noise sources sounds like a logical solution, but in practice it’s often impossible. Not only is space limited, interference usually comes from multiple directions at once.
Is the Endfed a Bad Antenna?
On forums and social media, some hams dismiss the endfed as a “bad” antenna and suggest switching to a deltaloop or another design that’s less sensitive to QRM. The truth is: while the endfed is not the best choice for reception in noisy locations, it is an excellent antenna for transmitting. If you want reliable QSOs, an endfed can do a great job—provided you support it with a better solution for receiving.
The Magnetic Loop as a Receiving Antenna
Most radio amateurs agree that the magnetic loop antenna is one of the best solutions for receiving in high-QRM areas. With diameters up to about 1 meter (3 ft), these active receiving loops are small, effective, and easy to add alongside your transmitting antenna. This leads to a powerful setup: transmit with the endfed, receive with the magnetic loop.
Using the Loop to Null Out Noise
One of the best features of a magnetic loop is its sharp null. In certain directions, reception drops dramatically. When you put the loop on a simple rotator, you can turn the null toward a noise source. This allows you to significantly reduce interference while still receiving the desired station clearly.
Switching Automatically Between Antennas
Many modern transceivers include a dedicated input for a receive antenna. If your rig doesn’t, there are hardware solutions that handle automatic switching between transmit and receive antennas. So called T/R-switch or TRX-switch.
- MFJ once offered the MFJ-1708B, but it’s no longer in production.
- The TRS-450 switch from SV1AFN has also been discontinued.
- Fortunately, QRO.cz (hamparts.shop) now offers a similar option: QRO.cz RX Antenna Switch.
- W6LVP offers a complete receive loop with T/R-switch.
No doubt more products will appear to fill this need.
Loops in All Shapes and Sizes
So which magnetic loop should you use? There are many options, each with different strengths depending on the frequency range.
- Some commercial models come with switchable loops for different bands.
- The popular MLA-30+ from China is a budget-friendly option with decent performance.
- I personally use the Wellgood Loop v4 from M1GEO. It’s a loop amplifier with bias tee power injection, delivered as a PCB. You’ll need to mount it in a housing and build your own loop from metal tubing or wire.
Good News for Endfed Users
If you own an endfed antenna and struggle with QRM, there’s no need to give up. By combining your endfed with a magnetic loop receiving antenna, you can enjoy the best of both worlds:
- Strong transmission with the endfed.
- Noise-resistant reception with the loop.
In short: the endfed is far from a “bad” antenna—it just needs the right partner.