Paul

I didn’t follow whether you are using this loop for transmit and receive. The answer to use tube indicates that you are using it for both. Do be aware that improving ie reducing losses also makes the bandwidth more narrow and “twitchy” to tune.  If this is untuned then you are not using it for transmit.
For the same size loop I doubt you will detect “much” difference on receive  using tube because of the high performance of the amplifier.

David G3UNA 

On 29 March 2022 at 09:49 "paul newland via groups.io" <p.newland=btinternet.com@groups.io> wrote:

Chris Moulding

Mar 28    #826
Hi Paul,

Using the copper tube would reduce the inductance of the loop which will allow more RF current to flow giving stronger signals.


Thanks for your reply Chris
And I certainly appreciate you taking the time.
Just the one additional thing is the query whether the ++ would be better than the + down low?
And I won't trouble you further.
Best wishes
Paul

Hi Simon

Your practical experience re tube v wire is invaluable; I note you say your copper loop is larger than the wire loop under consideration.   Looking at your pics it is evident that you are in an rf noisy hell hole.   I have to congratulate you on your application. 

David G3UNA

On 29 March 2022 at 11:50 Simon <ohhellnotagain@...> wrote:


Hi Paul

Wondering about your location rf noise wise..
I ask as if in a quiet ( say rural) area then playing with different loops will make a difference that you can notice.
If in a urban silly rf noise area then maybe not..( ie you just won’t notice the difference due to the man made noise.)

Here, my favourite loop antenna for say the laa is a crossed parallel loop made of copper, each loop no more than 1m square( smaller works too.) this has the advantage of a real low inductance and large capture atea..but is tricky to make.

But from a tried that, done that perspective a 1m dia single copper loop will work better than a similar loop of wire.and you will notice the difference even in a semi rf noise pollution area.

Below hopefully are pics of crossed parallel loops at use here in London.

The one that looks like a turnstile is switchable in directions. Each loop is about 75cm across, the other is about 82cm across each loop.



Of course then there is Chris designed cardioid loops..but you need to mod the laa of buy one specific from chris for them. ( but worth it.) see Ccw website for info.

Hope some of above helps. My location in esst london. Sometimes rf noise stupid, sometimes not so bad..but always useable with the many loops i have ( atleast 1 will be quiet depending upon direction of incoming local noise.)

Below is a pic of the 160m cardiod loop, switchable in 2 directions. Works very well to remove European qrm ( when facing NA) even down to Lw etc. It is 2m square.

All above loops will work very well with Ccw rx preamps.



Simon g0zen

With the current version of the LAA++ we specify it as working down to 50 kHz.

This is tested using the 2.5 m length of wire we now supply with the LAA++.

That wire length is resonant as a full wave loop around 125 MHz so it makes a great VHF airband antenna when used with the LAA++.

Part of the test routine with each LAA++ is an on-air test with the time signals on 60 and 77.5 kHz among the list of signals checked.

If a larger loop say 2 or 3m in circumference or a thicker tube is used then the amplifier will work down to around 15 kHz.

Regards,

Chris