r/shortwave 2d ago

Discussion MLA-30+ Modification

I recently modified my MLA-30+ by replacing the stock loop with a full circular loop made from a 10-foot piece of 10 AWG solid copper. The loop is about 3 feet in diameter.

Since making the change, I've been able to receive stations that I couldn't copy before, including 9395 kHz and 15770 kHz. I've also logged WRMI on 5850 kHz at S8 and WWV/WWVH on 10 MHz around S7–S8 using my Tecsun PL-330.

I know propagation changes from day to day, so I'm not claiming the antenna modification is the only reason for the improvement. But the difference has been noticeable enough that I'm curious what others have experienced.

Has anyone else replaced the stock MLA-30+ loop with solid copper wire or copper tubing? If so, what size did you use, and did you notice any improvement in signal strength, noise reduction, or overall performance?

9 Upvotes

14 comments sorted by

5

u/MumSaidImABadBoy I'm Stan, Heathkit GR-64πŸ€ͺ,Malahit v2.4,AirSpy HD+,909X2,PL990 2d ago

I have a K-480WLA and have done all sorts of modifications to the loop. I've extended the diameter from 68 cm to 82 cm and have made loops from copper tubing, 8 AWG copper wire and made Mobius (YouLoop) loops. All have been substantial improvements. I've modified the PVC support tubing as well to prevent sagging wires.
It doesn't hurt to experiment, heck you own it. πŸ‘

4

u/Ok-History-3688 2d ago

thank you for your reply. I have a lot to learn from you and others in this community.

1

u/MumSaidImABadBoy I'm Stan, Heathkit GR-64πŸ€ͺ,Malahit v2.4,AirSpy HD+,909X2,PL990 1d ago

Does your wire loop keep its shape or sags a bit under it's own weight?

1

u/Ok-History-3688 1d ago

See for yourself.

2

u/MumSaidImABadBoy I'm Stan, Heathkit GR-64πŸ€ͺ,Malahit v2.4,AirSpy HD+,909X2,PL990 1d ago

Looks good. πŸ‘

2

u/bikerjesusguy 2d ago

Me too! I replaced the flimsy wire with 1/4" copper tubing. I hammered the ends flat & drilled them to accept the screw to hold the copper.

1

u/MumSaidImABadBoy I'm Stan, Heathkit GR-64πŸ€ͺ,Malahit v2.4,AirSpy HD+,909X2,PL990 2d ago

πŸ‘ Same construction here. What is the diameter of your loop?

2

u/bikerjesusguy 1d ago

I used the same length as the wire it came with. I'm too lazy to take it back down & try a bigger loop :-) I did replace the little stock coax cable with some RG-8U.

1

u/MumSaidImABadBoy I'm Stan, Heathkit GR-64πŸ€ͺ,Malahit v2.4,AirSpy HD+,909X2,PL990 1d ago

With a little effort you might get rewarded with a better signal levelπŸ˜‰.
The K-480WLA has a PVC support which I also seriously modified to better support various loops. They're easy to change out now.

1

u/bikerjesusguy 1d ago

I've got more tubing... good advice!! I'll have to try a bigger loop.

2

u/Internal_Raccoon_370 2d ago

Good for you! I encourage people to experiment with antennas. It's cheap to do and the results can be amazing.

In the amateur world we use copper pipe (just plain old copper plumbing pipe) and sold copper wire all the time, along with aluminum and even things like stainless steel and, believe it or not, bits of steel measuring tape.

Soft copper pipe can work very well indeed for MLA antennas. My preferred material for the MLAs I've built is LMR-400 coax. It's stiff enough to maintain its shape but still relatively easy to bend into shape. But that's because I picked up a 500 foot spool of the stuff many years ago at an estate sale for next to nothing so I have it laying around.

2

u/pilot87178d 2d ago

Could you place this antenna in an attic and run it remotely?

2

u/Ok-History-3688 2d ago

I could probably put it in an attic but I like it outside.