To improve reception with my Grundig Satellit 800, I ran 50 feet of insulated telephone wire around the perimeter of my 8 foot x 12 foot sun room which serves as my radio shack. The loop runs over the tops of window frames and? book cases about 7 feet in the air and connects to the wire clips on the back of the Satellit 800. I tried connecting the wire to a 9:1 unun and then to the coax connector on the back of the 800, but saw no noticeable improvement. The Satellit 800 has three inputs: two wire terminals, pl239 connector, and the whip antenna.

For additional about the horizontal room loop:

So the question: is there anything I can do to improve this indoor antenna setup?

Probably not in its current setup. Usually the best thing you can do is to get that wire away from household RFI and while outdoors is the obvious way to do that it is not easy. Best thing usually is to scout best locations in your house to look for places where signals are strongest and noise the weakest, then put your radio or antenna there and if it is not near your radio use coax to import the cleaner signal to your radio.

This is all very general info...trial and error is usually what you have to do in addition to looking for ways to minimize RFI.

Jay

Jay,

Thanks for your reply.

Due to a fortuitous power outage that killed not only the power to the house but to the entire neighborhood, I discovered, by running the Satellit 800 off internal batteries, that most of the noise that I am hearing at my location is either receiver noise or atmospheric noise.

I was wondering if putting this -- -- in line with the horizontal room loop might offer any improvement. Apparently you can detach the indoor whip antenna and connect coax to the back of the box, and it will act as an amplifier/preselector, but since it will amplify both signal and noise will there be an overall gain? If you have had any experience with this device, I would be glad to hear about it. Reviews seem to be that people either love it or hate it.

In addition, I have found that this -- -- does a decent job of digital signal processing the audio coming out of the receiver and improving the perceived signal to noise ratio of the audio coming through my headphones.

Nevertheless, it's fun to tinker, and I appreciate your reply.

In terms of the MFJ there are times it will help and times it will make things worse and that is exactly why people's comment about it vary. It does have the benefit of pre-selection (although broad in nature rather than frequency-specific) and variable gain and those factors may help. But it also may set a noise floor that is higher than that in your radio and in that case it may make reception worse. And there are other variables which can make it better or worse than your SAT 800 wth its own antenna or your loop that are hard to predict so once again we come back (unfortunately) to trial and error. It is very likely it may help on some signals and not on others so if the cost is not an obstacle it could be considered to be another tool in the toolbox to use when it helps.

As for the BHI I have not had the pleasure of using one of those but the comments are very favorable on it. I know from experience in general that DSP processing (the kind you are talking about here, not general DSP as used in a radio) can do remarkable things in terms of noise reduction and my intuition is that it may be a remarkable line of products, but again, I have no personal experience with their things. They do look nice though.

Jay

Well, Jock:? I have just discovered this groups.io loop forum, and found so many familiar references, authors, and plenty more I didn't' know about.?
My first comment is about horizontal orientation of small loops.? I have never had good results until I make the plane of the loop vertical.?? The receive pattern is a wide, along the plane of the loop with a "null" perpendicular, if it's balanced.? And it doesn't need to be that big.
My opinion as to what you need is a wide-band single turn loop, OR a multi-turn tuned loop, either can be of "shielded" design.? OR read up on the "Moebius" (or "Mobius") loop.? All these loops are very carefully balanced, and have a high rejection of local electrical noise, and can have a deep null perpendicular to the plane of the loop.? Most, if not all small loops, would benefit from a very carefully designed, balanced pre-amp, having a balanced input and an un-balance (coax) output. Single-turn loops especially. The pre-amp can be powered at the receiver end through the coax using what we hams call a "bias-T".?
I build my multi-turn resonate tunable loops with a 4 foot wooden cross frame so I can have the tuning capacitor (and/or pre-amp) at the bottom.? Again, the loop needs to maintain BALANCE.? I feed this tuned loop directly without a pre-amp for now, using a "balun", a "balanced to unbalanced" transformer-like device that converts the balanced antenna output to an unbalanced coax feedline.? Otherwise, the feedline conducts more noise to the radio.? But the low signal strength is just enough, greater than that of a a single-turn un-tuned loop!?
The best balanced loop pre-amps will have a balanced input in my opinion, but some have the balun before a single-ended pre-amp, And commercial loops with great pre-amps are available, some are expensive in the $ 500 US range.
If you look at the shielded loop and mobius designs, you will note that the shield breaks at the exact center of the loop.? And the Mobius crosses the connections at the center.? Look in the files section in this forum using some search terms above.?
About YOUR loop:? If you were to hang a shielded loop, it you can also experiment by trying the Mobius configuration by simply crossing the wire / shield at the exact center.?See what works best.? You may stumble on better performance, but the problem with stringing up a "balanced" loop around a room parameter is the proximity metal objects upsetting the balance, and the ballgame is off.?
If you have a yard or balcony , or even a window, you can make a smaller frame or hula hoop, or copper-pipe (hexagional?) loop... shape it like a flag?? It ain't critical as long as you keep it balanced! Buy or build the pre-amp?.??

Good luck
Pete n2exg

Hi

Shielded vs non shielded.

No difference at all.. dont bother with shielded..been tested many times..waste of time and effort..

Simon g0zen ( mag loop Simon.) and yes i have made both..

On Tue, Apr 5, 2022 at 08:25 PM, Simon wrote:

Shielded vs non shielded.

No difference at all.. dont bother with shielded..been tested many times..waste of time and effort

I agree with Simon, adding a shield introduces lots of additional problems (the main one being lowering the loop self resonant frequency due to the additional capacitance) and it doesn't improve the noise immunity of a receive loop.

'Mobius' style loops are also problematic, and don't perform any better than a single turn loop.



Regards,

Martin

Relax.? I'll do the panicking.

开云体育

Please show/describe your 4’ multi-turn frame antenna. ??