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Ways to improve the reception of the LAA++?
Rob Q
I was wondering if you can please help me improve my loop antenna for receiving.
My loop, which is made of 14 guage wire is 4' about the ground and aiming SW/NE, nulls are NW/SE. The coax connecting the loop to the bias-t is 37' of RG6 Quad Shield with the F to BNC adapters. Then, I have a 1.5' run of RG213 with PL259 adapters with SO239 to BNC adapters which connects the bias-tee to the RSPdx.
Simon
Hi
Thats abit like how long is a bit of string question.
THERE IS NO perfect antenna..There definitely is no perfect antenna from dc to light..or lets say 100khz to 200mhz..
Any antenna that does cover a large spectrum is a compromise ..That includes any make of loop/ preamp/ discone/ long wire etc
..yes they work, but not as good as if was designed for say 1 frequency.
This is the reason why many serious dxers have many many different rx antennas..
However one can make your loop better all around AND at specific frequencies bands. But this depends upon your willingness to make them..
So what frequencies are of interest to you??
( making the loop from copper tubing will improve it, but there is a point of diminishing returns..ie you won’t notice the difference between 1inch and 2 inch tubing, but you would between thin wire and say 15mm copper tubing..
Also crossed parallel loops work well..etc..)
You could phase 2 loops to get better dx ( low angle) receiption, 2 loops, 2 preamps and a phasing network..THAT helps ALOT! But not easy to do, need space and not alot of point if living in noisy urban environment.
Below are 2 examples of very effective rx loops..both made by me and tried and tested.
Simon
Thats abit like how long is a bit of string question.
THERE IS NO perfect antenna..There definitely is no perfect antenna from dc to light..or lets say 100khz to 200mhz..
Any antenna that does cover a large spectrum is a compromise ..That includes any make of loop/ preamp/ discone/ long wire etc
..yes they work, but not as good as if was designed for say 1 frequency.
This is the reason why many serious dxers have many many different rx antennas..
However one can make your loop better all around AND at specific frequencies bands. But this depends upon your willingness to make them..
So what frequencies are of interest to you??
( making the loop from copper tubing will improve it, but there is a point of diminishing returns..ie you won’t notice the difference between 1inch and 2 inch tubing, but you would between thin wire and say 15mm copper tubing..
Also crossed parallel loops work well..etc..)
You could phase 2 loops to get better dx ( low angle) receiption, 2 loops, 2 preamps and a phasing network..THAT helps ALOT! But not easy to do, need space and not alot of point if living in noisy urban environment.
Below are 2 examples of very effective rx loops..both made by me and tried and tested.
Simon
Juan - EA5XQ
Great designs Simon
I am wondering whether you could share how did you build them. I am using a 1.2m diameter copper tube with LAA++ and it does a good job from 100Khz-30Mhz but I would like to test other configurations like yours.
--
Juan, EA5XQ #SWL : EA50276FD / EA5040SWL / EA5-311-AER
AirSpy Hf+ Discovery
LOOP 1.2 Cu LAA++ Amplifier / PA0RDT MiniWhip
GQRX/SDR++ for MacOS
I am wondering whether you could share how did you build them. I am using a 1.2m diameter copper tube with LAA++ and it does a good job from 100Khz-30Mhz but I would like to test other configurations like yours.
--
Juan, EA5XQ #SWL : EA50276FD / EA5040SWL / EA5-311-AER
AirSpy Hf+ Discovery
LOOP 1.2 Cu LAA++ Amplifier / PA0RDT MiniWhip
GQRX/SDR++ for MacOS
Simon
Hi Juan
Nothing new in the designs.
The 3 circular parallel loops are each 1m dia ( i used 1/2inch copper air con pipe) separated by about 15cm. Supports were pvc plastic pipe from local diy store ( as is support pole.)
All 3 at bottom were joined together by same copper pipe and feed to preamp.
The crossed parallel loop is made of same copper tubing ( bought on a roll, annealed so easy to bend,)
They are each of 1m square. THEY however are joined in a particular order..see pic at bottom.
This loop works the best as it has 4 loops in parallel ( much lower L for preamp ( hence more current flow to preamp) AND has a 4m square capture area ..see lz1aq website for more info..)
These work very well with ccw preamps!
Have also tried the cardiod ( spelt that wrong) from Chis ccw site for 160m.
This also works, but not as well as phased loops. Maybe I will try phasing 2 of then at new qth. They failed here..yes they worked well, but unfortunately impossible to null out the local smpsu noise AND have them pointed in direction of interest (Usa) and when feed againt the noise cancellation unit it destroyed the cardiod pattern.
This time next week we will be moving to Devon from London, there the garden is much bigger..I have 3 of these made up ( one 2 on one pole 90 degrees apart) I have made a delay line switching box which will allow them to be phased and switch directions n s e and west. This also gives them a much lower angle elevation, so much more suitable for dx. Depending upon noise floor I hope to try phased short hi Z verticals too..3 phased together 20m each apart should be equivalent to long beverage..(yccc design, all made and ready to try, but depends upon neighbours allowing one at end of their garden! maybe a tall ask in the first week of being there!! As is am wondering what they will say with a Marconi T going up for 160/80, hopefully not alot as only 2 poles and wire.
Simon
Above top photo of how i made parallel crossed loop. Below that wiring of said loop. Copy right lz1aq.
Nothing new in the designs.
The 3 circular parallel loops are each 1m dia ( i used 1/2inch copper air con pipe) separated by about 15cm. Supports were pvc plastic pipe from local diy store ( as is support pole.)
All 3 at bottom were joined together by same copper pipe and feed to preamp.
The crossed parallel loop is made of same copper tubing ( bought on a roll, annealed so easy to bend,)
They are each of 1m square. THEY however are joined in a particular order..see pic at bottom.
This loop works the best as it has 4 loops in parallel ( much lower L for preamp ( hence more current flow to preamp) AND has a 4m square capture area ..see lz1aq website for more info..)
These work very well with ccw preamps!
Have also tried the cardiod ( spelt that wrong) from Chis ccw site for 160m.
This also works, but not as well as phased loops. Maybe I will try phasing 2 of then at new qth. They failed here..yes they worked well, but unfortunately impossible to null out the local smpsu noise AND have them pointed in direction of interest (Usa) and when feed againt the noise cancellation unit it destroyed the cardiod pattern.
This time next week we will be moving to Devon from London, there the garden is much bigger..I have 3 of these made up ( one 2 on one pole 90 degrees apart) I have made a delay line switching box which will allow them to be phased and switch directions n s e and west. This also gives them a much lower angle elevation, so much more suitable for dx. Depending upon noise floor I hope to try phased short hi Z verticals too..3 phased together 20m each apart should be equivalent to long beverage..(yccc design, all made and ready to try, but depends upon neighbours allowing one at end of their garden! maybe a tall ask in the first week of being there!! As is am wondering what they will say with a Marconi T going up for 160/80, hopefully not alot as only 2 poles and wire.
Simon
Above top photo of how i made parallel crossed loop. Below that wiring of said loop. Copy right lz1aq.
John Tyler
Hi Simon
I have looked at both types of loop that you describe and show on a site linked to LZ1AQ. Could you tell me how the crossed parallel loop compares to the circular parallel loop with regard to being able to null electrical noise?
I hope the move to Devon has gone smoothly.
Very best regards,
John
I have looked at both types of loop that you describe and show on a site linked to LZ1AQ. Could you tell me how the crossed parallel loop compares to the circular parallel loop with regard to being able to null electrical noise?
I hope the move to Devon has gone smoothly.
Very best regards,
John