Newbie coming to the party!!!

General discussions
John Hill
Posts: 4
Joined: Fri Nov 11, 2016 1:13 am

Newbie coming to the party!!!

Postby John Hill » Fri Nov 11, 2016 1:24 am

I have just clicked my order for an SDR and will be watching for the van to arrive at our gate! :D

No doubt there will be a lot for me to learn and a few days to wait, meanwhile I am thinking of what antenna I should be putting up for HF listening, mainly 3 to 20Mhz.

I am in a small country town with only a small plot of land, just enough room for a 30 metre or so long wire but I have become interested in a magnetic loop antenna of, say, 3 metres diameter.

Is there anything special I would need to know about the SDR for this antenna?

Thanks

John
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g,3vds
Posts: 12
Joined: Thu Nov 10, 2016 11:10 pm

Re: Newbie coming to the party!!!

Postby g,3vds » Fri Nov 11, 2016 2:31 pm

Hello John
The subject of aerials could fill several libraries. Your first bet for the frequencies you mention is about 50ft or so of wire. To connect this you'll need an adapter to couple it to your sdr. This could be an SMA male to pl259 female.. the wire will plug into the pl259 and you're in business.
You could then improve on this with an aerial tuner. They go quite cheaply on eBay
Good luck
Roy
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G3VDS, NE5R

g1hbe
Posts: 224
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Newbie coming to the party!!!

Postby g1hbe » Fri Nov 11, 2016 2:38 pm

Welcome aboard.
I'm sure you'll be impressed once you've got used to the various features. As for your aerial, is it tuned or wideband? If it's wideband you may see various images or 'ghost' signals appearing where they shouldn't be. A tuned loop would reject these, but a wideband one will let everything through at once. Some kind of selectivity between a wideband loop and the RX would help clean things up.

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Andy

Devotech
Posts: 9
Joined: Mon Sep 19, 2016 5:32 pm

Re: Newbie coming to the party!!!

Postby Devotech » Fri Nov 11, 2016 7:31 pm

I made the antenna described here:
http://www.sdrplay.com/community/viewtopic.php?f=8&t=687#p2670

I wound the toroid myself and used really cheap electric fence wire. Works amazing!!

If you cant see the pictures in the link try logging out and looking again! ;)
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John Hill
Posts: 4
Joined: Fri Nov 11, 2016 1:13 am

Re: Newbie coming to the party!!!

Postby John Hill » Tue Nov 22, 2016 6:36 pm

Hi again, my SDRplay has arrived and is installed. For various reasons I am using it at our suburban house with a 10 metre high vertical with just two radials.

Local interference is very obvious which my LAN cables seem to be feeding in to the system so that is something to be addressed.

I would like to monitor a few (say 3 or maybe 5) frequencies but I dont think SDRuno can do that? Whatever, much exciting learning to be had with my new toy! :lol:
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John Hill
Posts: 4
Joined: Fri Nov 11, 2016 1:13 am

Re: Newbie coming to the party!!!

Postby John Hill » Wed Nov 23, 2016 7:18 am

Today I discovered how to start more than one VRX which was quite exciting but somewhat disappointed when I learn that all VRX can only be tuned within the 2Mhz spectrum block related to the first VRX. Oh well, I had hoped to monitor the primary and secondary frequencies of some aeronautical broadcasts but the separation is great than that.
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sdrplay
Posts: 606
Joined: Wed Jan 07, 2015 7:58 am

Re: Newbie coming to the party!!!

Postby sdrplay » Wed Nov 23, 2016 1:29 pm

All VRXs must be within the bandwidth specified in the main window, which can be up to 10 MHz

Best regards,

SDRplay Support

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John Hill
Posts: 4
Joined: Fri Nov 11, 2016 1:13 am

Re: Newbie coming to the party!!!

Postby John Hill » Thu Dec 01, 2016 4:24 am

Thanks sdrplay, I found the 10 MHz. Right now I am trying to couple the SDRplay to a 46" square non-shielded loop. I am using a small unknown origin toroid and a few turn of wire and although I get some visible effect on the SDRuno waterfall it is not, yet, really dramatic. More experimentation to be done! :D
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g1hbe
Posts: 224
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Newbie coming to the party!!!

Postby g1hbe » Thu Dec 01, 2016 11:27 am

Hi John. I love loops. Tuned ones are nice to twiddle but the constant re-tuning as you move from band to band can get tiresome. Wideband ones are more convenient but need an amplifier as the loop produces a lower signal than a tuned one(I use a Wellbrook loop). When I was homebrewing loops, I found that one turn of the loop should pass through the toroid and the secondary that feeds the RX needed 4 to 6 turns to get the match right to 50r.
If your toroid is of unknown origin (aren't they all?) and results are poor, you may have picked up an unsuitable ferrite mix or even a dust iron one.
Don't forget that the RSP2 has a high-impedance input which is flat from VLF to 30 MHz, and two 50r SMA's which go up to 2GHz but drop off below MW. Have fun, and remember that with SDRUno, there's a button for everything - it's just a matter of finding it! :mrgreen:

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Andy


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