I've got an LAA++ arriving next week and have ~8 metres of URM67 coax to make a loop with. 

Should I just make a 1 meter diameter loop or is there a configuration that will allow me to use all of it?

I've tried probably all the loop configurations that could be used with the LAA++.

The best one is the simple 1m diameter loop. This gives the lowest inductance and will cover the HF bands up to 30 MHz.

If you want to use the LAA++ with the loop to monitor VHF airband then you can reduce the circumference of the loop to 2.5m so that it is a full wave loop at 125 MHz. This will still work well at HF.

If you want to use the extra coax try making a double loop similar to the military HF loops. That consists of two identical 1m diameter loops about 100mm (4 inches) apart connected together at the ends to connect to the amplifier terminals. This will reduce the inductance of the loop allowing more RF current to flow and will give a similar result to using copper pipe without the extra expense or plumbing skills needed.

Regards,

Chris

Cheers Chris.

On Sun, Sep 18, 2022 at 06:49 PM, Chris Moulding wrote:

The best one is the simple 1m diameter loop. This gives the lowest inductance and will cover the HF bands up to 30 MHz.

I agree with Chris, screened and Moebius loops simply aren't worth the effort, and rarely provide any of the advantages that are claimed of them.

https://www.g8jnj.net/moebius-loop-antenna

Notes regarding broadband loop inductance.

https://www.g8jnj.net/loop-inductance

If you are connecting loops in parallel, there seems to be an optimum value of spacing, which is somewhere around 1 loop radius.





Regards,

Martin