Re: #airspyhfplus #swl #spyserver #raspberrypi - RPi, AirspyHF+ WellBrook Loop install and testing #airspyhfplus #spyserver #swl #raspberrypi

D R
 

Bazz - I agree with everything Nigel has said.  Wellbrook loops don't need height to work well (mine are mounted 400mm and 1200mm above ground level and work brilliantly) - just get them as far away from any houses as you can, even if it's only a few metres, and align them to minimise noise pickup from indoor generators like plasma TV sets and switching power supplies.

As regards modifying the 5030 loop, it would be simple to cut off the existing loop about three inches either side of the amplifier box and attach some Pex-Al-Pex heating tube or even just coax cable to the stubs to get a bigger loop and see how it works - my only concern would be that adding too big a loop will overload the amp if you have any strong broadcast stations nearby, and cause intermodulation problems (but then it's just a matter of trimming back the size of the loop until they disappear again).  Nothing ventured, nothing gained!  I'd be very interested to learn how you get on with your experiments.

Regards,
Dave


On Thursday, 12 July 2018, 22:46:28 GMT+1, Nigel via Groups.Io <poldhu1901@...> wrote:


Hi Bazz,

The Wellbrook loops are great, but they always benefit from being outdoors.
They don't need to be very high, and the directional properties of the loop aren't noticeable once you reach a couple of MHz.
Amongst other antennas I have a 5030 in the loft, not too bad, and a 1530 just strapped to a fence outside about 20 to 25m from the house and approx 1.8 m above ground, which is much better. I wanted to put the one outside on a rotator but the storms here soon persuaded me that would never be a very good idea:-)
These two are at right angles which tends to make up for the directionality at LF, so the 5030 is useful for this, but at higher frequencies it's no contest and the outdoor 1530 is always better.
There's really no point in swapping the 5030 loop for copper tube, by all means try it, experimentation is always fun, but whilst it matters for a transmitting loop for an active receive only loop it's probably not worth the effort.
Don't worry either that an outside loop will get nearer to another property as you move it away from yours, obviously that could be an issue but with so much RFI internally self generated these days, from switch mode PSUs etc, chances are you'll be much better off with it outside regardless, and you could always mount it at ground level, which Wellbrook has claimed is fine, and just move it about a bit to see what happens:-)

Nigel, GM8PZR


On Wed, Jul 11, 2018 at 10:58 AM, Bazz wrote:
Hi,
So I now have my Raspberry Pi installed with a AirSpyHF+ running across the network (kit in the loft).
It is connected to a internal ALA1530 Wellbrook loop at about 6M above ground in the loft.

It works fine, accessing it from the ground floor PC or laptop, but I am getting massive amounts of noise during the day.

I have some ferrites on order (FT240-43) but is there anything else I can look at as well?

I was listening to 80M last night with good results, though I think I need to move the loop higher still.
(need to wait to get my DIY rotator sorted, and might move it outside (after some weather sealing).

Also, anyone know if it's possible to change the loop on a Wellbrook with a copper loop, larger than before?
I have another Wellbrook loop the LA5030 I want to play with.

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