6m Delta Loop Tuning

Tuning the 6m Delta Loop is relatively easy. It is similar to tuning a dipole antenna. If your antenna is to high in frequency, then you lengthen the element. If your antenna is low in frequency, then you shorten the element.

The best way to tune is with a swr analyzer. I use an older MFJ-259B. I have seen several on amazon for relatively cheap and plan on trying one out. Once i get my hands on one, I will post the results. Even if you do not plan on building a lot of antennas, a swr analyzer is a valuable tool.

Advertisements

Lower the 6m Delta Loop so you can get to where the wire loop connects.

Advertisements

When cutting the loop during construction, 2 inches was added to the length of the loop to insure the frequency was lower than desired. This allows us to trim the antenna down instead of having to add wire during tuning. I like to trim small sections and then test again. Usually the max trimmed at a time is no more that 1/2 in. As you get closer to your target frequency trim less each time.

In my case, This antenna will be used for FT-8. The preset frequency for FT-8 6m is 50.313. This is where I want my best swr reading. I was able to get the swr down to between 1.3 – 1.4. This is acceptable for most transmitters.

Advertisements

Before attaching this antenna to my transmitter, I am going to experiment more with the matching. The measurements for the 75 ohm antenna where based off another person’s calculations. Since the velocity factor of cable varies depending on brand and model of the cable, This portion will be recalculated. Once this is done there will be future testing and results will be posted.

Advertisements

If you decide to build this antenna with the existing matching design. Make sure to waterproof your connections on the matching section. First use a high quality rubberized splicing tape and then wrap with high quality electrical tape. Some times, I will even put a nice thick layer of liquid tape over that. 3M has a nice selection of good tapes for waterproofing.

6m Delta Loop Rebuilt with Different Matching Section

Links

https://km4nmp.com/2020/03/28/improving-the-6m-delta-loop/

https://km4nmp.com/2019/06/22/6m-delta-loop/

https://cqhq.wordpress.com/2009/06/02/50mhz-6-metre-delta-loop/

http://www.ws6x.com/ant_calc.htm

https://km4nmp.com/2019/05/05/2m-1-4-wave-ground-plane-antenna-review/

https://km4nmp.com/2019/05/04/2m-1-4-wave-ground-plane-antenna/

Welcome to the Lab

Advertisements

Latest Posts

Home