Random wire questions

Useful information regarding antennas for SDR products.
DGW_UK
Posts: 2
Joined: Mon May 01, 2017 10:36 am

Random wire questions

Postby DGW_UK » Mon May 01, 2017 11:16 am

Hi All,

I'm new to SDRPlay and new(ish) to SDR in general. I have a 25 foot long or so piece of speaker wire connected to the P terminal running out of an upstairs window to the top of a wooden swing seat. The GND and N are attached to a hot water radiator pipe in the same upstairs room (I'm assuming this set up is OK?).

1) does the random wire need to be straight - ie would it be better to add more wire even if this needs to run in a semi-circle or U shape around the garden?

2) there is another post about proximity to transmitting antennas. I have a small wireless weather station and alarm that probably work on around 400MHz and 800MHz - will this cause a problem? how far away should I keep the random wire from those?

cheers, d.
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g1hbe
Posts: 187
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Random wire questions

Postby g1hbe » Tue May 02, 2017 8:18 am

Hi d. That random wire is perfectly good, but you may find it picks up lots of noise from your house and those of your neighbours. It's not a good idea to bring a receiving antenna directly into your home for this reason. Much better to use a length of co-ax from the Hiz port to a point in the garden furthest away from the house where there is minimum noise. As long as the coax is not too long you can probably do this without using baluns or transformers.
You weather station should not be a problem as it uses tiny amounts of power.
Andy.

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Andy

DGW_UK
Posts: 2
Joined: Mon May 01, 2017 10:36 am

Re: Random wire questions

Postby DGW_UK » Tue May 02, 2017 9:33 pm

Hi Andy, thanks. The coax sounds like a good idea, I'm assuming the random wire goes to the centre core which goes to P, would the coax shielding go to N and GND?
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g1hbe
Posts: 187
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: Random wire questions

Postby g1hbe » Wed May 03, 2017 8:23 am

Yes, link N & G and take the coax outer to it. To minimise noise, try earthing the far end of the coax outer or the receiver end, or both. Noise can enter your system via several ways and there seems to be no hard and fast rule in practice.
If your coax is more than about 10m, then a pair of 9:1 transformers may be called for. One at the antenna end to transform the impedance down to 50r, and one at the RX end to get it back up to Hi-z again.

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Andy

ekendraed
Posts: 8
Joined: Sun Apr 16, 2017 5:52 am

Re: Random wire questions

Postby ekendraed » Sun May 07, 2017 9:56 am

For the RSP2, does one still need a 9:1 Balun since the SDR already has a HiZ port for HF?

Ant views?

4S7EF
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awoodeye
Posts: 1
Joined: Sun May 07, 2017 2:05 pm

Re: Random wire questions

Postby awoodeye » Sun May 07, 2017 2:25 pm

New user and confused, where are the instructions if any??

I can not locate the connection information to the hi z antenna port. There are not any lettering on the connector that I can see. Looking at utube clips have not given me that info.

I have been able to get most of it to work and even hooked to the 9mhc if output of my yaesu ft dx 3000 to see the output. SSB signals are inverted as I had to use USB to decode LSB signals on 40 meters.

QUESTION: I seems that they should have an analog control which allows tuning in a continuous manner up or down "the band" without having to keep entering different numbers, does this feature exist or did i miss it? I was thinking that you should be able to start at 3.5 mhc and go up to something like 15 mhc in a smooth sweep.

Enjoy, Woody N4MQ Va.
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ekendraed
Posts: 8
Joined: Sun Apr 16, 2017 5:52 am

Re: Random wire questions

Postby ekendraed » Sun May 07, 2017 2:58 pm

https://youtu.be/YAtT97Ash8E


Wonder if this helps. No 9:1 unun is recommended but they do suggest using a 1:1 balun
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Paul
Posts: 49
Joined: Fri Feb 17, 2017 9:52 am

Re: Random wire questions

Postby Paul » Sun May 07, 2017 4:07 pm


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ekendraed
Posts: 8
Joined: Sun Apr 16, 2017 5:52 am

Re: Random wire questions

Postby ekendraed » Mon May 08, 2017 12:31 am

Thank you Paul

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SanJacinto
Posts: 6
Joined: Sat Dec 31, 2016 9:06 pm

Re: Random wire questions

Postby SanJacinto » Fri May 26, 2017 5:30 pm

I have the land and space at my location to string up 300 meter long beverages, however I really didn't want them running all over my pastures. I while doing some research on BoG's, I came across the website of a Ham who has been doing some experimenting with LoG's, (Loops on the Ground).

Excellent LoG Information: http://www.kk5jy.net/LoG/

I've built one myself using his instructions, using it for low band HF. Works like a champ. I opted to purchase the materials to construct the transformer he describes. I probably spent a little more than the cost of purchasing a single Beverage transformer but I now have the supplies to build 10 of them, ferrite cores and all.

I highly recommend this solution to anyone with space constraints or who doesn't want their livestock and deer tangled up in wire. Or who has a spouse that isn't as excited about antennas as you are. :)

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