On 14 Nov 2022, at 16:58, Chris Moulding <chrism@...> wrote:

Hi David,

The problem with using a multi-turn loop with a magnetic loop antenna is that it increases the total inductance of the loop.

This reduces the current flow in the loop compared to a single turn loop when used with a LAA++.

When the LAA++ was released I was getting many questions about what loop to use and I think I probably tried all possible loop options from a ferrite rod (useless when untuned) to a 5m square loop (no improvement over a 1 turn 1 m diameter loop on medium wave or HF but excellent below 100 kHz). I found that the 2 turn loop gave no noticeable improvement. A true A/B test would probably show a small loss.

Have you asked him why he wants more signal pickup?

Using one on 20m in the UK he is unlikely to be limited by amplifier noise. I had a report from a customer who used a LAA++ deep in the Australian outback and out there the external noise was lower than the amplifier noise. After that report I did some work to find a better ferrite and toroid winding option so the latest LAA++ have less input transformer loss and better isolation of the loop to prevent the loop element acting as an electric field antenna.

I suspect that he's comparing the signal level seen on his transmit antenna with that of the loop.  The total signal measured with his transmit antenna will also include the extra unwanted noise. Using the loop the wanted signal level should be similar but the noise level will be reduced which will lower the total signal measurement.

As long as he is limited by the external noise floor don't worry about the signal levels. Tell him to turn the RF gain up if he wants so that he gives everyone S9!

Regards,

Chris

On 14 Nov 2022, at 18:24, davidg3una@... wrote:

Hi Chris

As I suspected.  We’ve compared it to a low dipole and whereas I am used to noisey conditions he still finds it a challenge even with the new s/n ratio. The rf gain is limited somewhat and mutes / squelches at half way, unlike other radios. More things to try, we’re not finished yet, including just turning up the volume but that has its own issues .  

Thanks for the detailed info

David G3UNA 

On 14 Nov 2022, at 16:58, Chris Moulding <chrism@...> wrote:

Hi David,

The problem with using a multi-turn loop with a magnetic loop antenna is that it increases the total inductance of the loop.

This reduces the current flow in the loop compared to a single turn loop when used with a LAA++.

When the LAA++ was released I was getting many questions about what loop to use and I think I probably tried all possible loop options from a ferrite rod (useless when untuned) to a 5m square loop (no improvement over a 1 turn 1 m diameter loop on medium wave or HF but excellent below 100 kHz). I found that the 2 turn loop gave no noticeable improvement. A true A/B test would probably show a small loss.

Have you asked him why he wants more signal pickup?

Using one on 20m in the UK he is unlikely to be limited by amplifier noise. I had a report from a customer who used a LAA++ deep in the Australian outback and out there the external noise was lower than the amplifier noise. After that report I did some work to find a better ferrite and toroid winding option so the latest LAA++ have less input transformer loss and better isolation of the loop to prevent the loop element acting as an electric field antenna.

I suspect that he's comparing the signal level seen on his transmit antenna with that of the loop.  The total signal measured with his transmit antenna will also include the extra unwanted noise. Using the loop the wanted signal level should be similar but the noise level will be reduced which will lower the total signal measurement.

As long as he is limited by the external noise floor don't worry about the signal levels. Tell him to turn the RF gain up if he wants so that he gives everyone S9!

Regards,

Chris