Longwave Antenna Reception For Apartment

Useful information regarding antennas for SDR products.
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gccradioscience
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Joined: Sun Mar 24, 2019 8:44 pm

Longwave Antenna Reception For Apartment

Post by gccradioscience » Sun Mar 24, 2019 9:06 pm

I have an RSP 2 Pro, but the antenna that I am using is a LF Engineering Gain Probe H-900 which covers 10 kHz to 30 MHz, but the VLF reception on the RSP 2 Pro is not that good when I try to receive NAA on 24 kHz just to see how the antenna and receiver performs. I wish I could put the gain probe outside the apartment, but I not able to.

Is there any suggestions or solutions into improving VLF reception? I used the Hi Impedance antenna connection using the Noo Elec balun, and still no good results on VLF. My next plan is to buy one of those low noise amplifiers and connect it between the antenna and the RSP 2 Pro.

Best Regards,

Adam E. gccradioscience
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Mike2459
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Re: Longwave Antenna Reception For Apartment

Post by Mike2459 » Sun Mar 24, 2019 11:21 pm

I'm reluctant to say this but I think there is very little you can do. E field antennas don't do well indoors. You might get some improvement with a mag loop antenna but not much, IMO. Any additional amplification will amplify both signal and noise, the signals will remain buried. You could try unplugging all the electronics in the apartment unfortunately your computer is likely one of the major sources of the RFI. I have an E-field antenna located 50' from the home, it still receives some RFI generated in the house.

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gccradioscience
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Re: Longwave Antenna Reception For Apartment

Post by gccradioscience » Sun Mar 24, 2019 11:44 pm

That is true, A magnetic loop will do well for long wave then, yes, because I remember that I used a home made magnet loop for one of my portable radios which is the DX-398 and it was picking up a long wave broadcast signal for the first time since last year. I will work on finding more magnetic loop antenna solutions. I hope that I can put up at least a small PA0RDT antenna outside the apartment window since I live on the ground level. I might just simply show the land lord what the antenna is going to look like before I install it. But for the time being, I have to use magnetic loop antennas. Let's hope someone with good RF faraday antenna skills comes out with a good antenna for noisy office buildings and apartments.

Best Regards,

Adam E.
gccradioscience
Virginia Beach, VA
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g1hbe
Posts: 494
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire, UK

Re: Longwave Antenna Reception For Apartment

Post by g1hbe » Mon Mar 25, 2019 9:11 am

Hi Adam. I had exactly the same problem years ago but a Wellbrook 1530 loop saved my hobby. The noise with outdoor wire antennas had grown over the years and was reaching S9, blocking all but the strongest signals. I tried a remotely-mounted E-field 'probe', but it was just as bad as the wires. So out came my chequebook and a Wellbrook was here within days. Even in the shack it provided several S-points of noise reduction, and mounted outside at gutter height it got the noise down to an indicated S1.
It works well from about 30 KHz to 30 MHz.
As I have an interest in even lower frequencies, I built an 'almost copy' of the Wellbrook using a 3 ft plastic hula hoop and a plastic electrical conduit junction box. 5 turns of wire inside the hoop with the ends feeding my own version of the simple PA1M balanced amplifier. To ensure a good LF response (below 50 kHz) I used a 73 mix ferrite for the output transformer as the usual 43 type does not work well at LF. I stuck a capacitor acrossthe output to roll off the strong MW signals. This was selected on a 'suck-it-and-see' basis.
This loop can see all the way down to below 16 kHz and can easily receive the SAQ transmissions on 17.2 kHz if you are interested in that kind of thing.
Attachments
16.400 KHz.jpg
16.400 KHz.jpg (60.21 KiB) Viewed 65656 times
photo 7 small.jpg
photo 7 small.jpg (356.78 KiB) Viewed 65656 times

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Andy

gccradioscience
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Re: Longwave Antenna Reception For Apartment

Post by gccradioscience » Mon Mar 25, 2019 7:03 pm

Yeah, I was looking at that too. I have plans in buying one of those antennas. The Wellbrook is a real good long wave antenna, and I wish that they could come out with different other antennas that look like a ferrite loop stick instead of a loop antenna for better portability. Portability is best for small apartments like this. Like the Kaito KA-35 that I still have, but needs a loop element, and I believe I used to use one of these small active loop antennas, right now I am going to have to find more loop antenna projects. I will try to see if I can save up for a Wellbrook loop antenna. I live in the North American continent, so I have to deal with North American sales.

Adam E.
gccradioscience
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Fredenando
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Re: Longwave Antenna Reception For Apartment

Post by Fredenando » Mon Mar 25, 2019 7:41 pm

I have made a "copy" of the Wellbrook and for now I have it hanged on my bedroom roof lamp with well results compared with an EF-SWL wire antenna in the exterior...

I use it with an RSP1A and a RTL-SDR V3 + SpyVerter R2...

https://www.george-smart.co.uk/projects/wellgood_loop/

Fernando, EA70104FD
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Mike2459
Posts: 318
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Re: Longwave Antenna Reception For Apartment

Post by Mike2459 » Tue Mar 26, 2019 12:50 am

DCF77 (Mianflingrn, GE) 77.5 khz heard this evening in eastern Ohio (US).
Screenshot taken in between thunderstorm crashes south of Atlanta GA (600 miles away)
Received on RSP2, and home built mini-whip with an excellent ground.
DCF77.JPG
DCF77.JPG (73.69 KiB) Viewed 65555 times

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mike0agner
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Re: Longwave Antenna Reception For Apartment

Post by mike0agner » Sat Jun 01, 2019 11:17 pm

If you are in the US, you would do well to consider the W6LVP loops. They're nowhere near as expensive as the Pixel or Wellbrook, and Larry's customer service is exemplary. He has been known to fit filters into the amp if you have nearby AM, FM or TV stations that might cause overloading issues. Here is his web page

https://www.w6lvp.com/

and here are some eHam comments

https://www.eham.net/reviews/detail/13215

Mike
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adamhenry
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Re: Longwave Antenna Reception For Apartment

Post by adamhenry » Tue Aug 06, 2019 11:02 am

I take an apartment in rent and see they something like this https://www.george-smart.co.uk/projects/wellgood_loop/
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