Ok, so I'm new to all of this, and loving my RTL-SDR thus far.
I want to attempt the long wire antenna. I've got the RTL-SDR kit.
I have old telephone wire; I've stripped the ends, at one end, and twisted them all together to create a terrible "single core". I'm going to attempt to stuff at least part of that into the female SMA that comes with the SDR, then run that out in the yard (impatient and don't want to wait for Amazon etc delivery of a SMA to BNC et al dongle).
Question: is it actually stupid and dangerous to not run a second wire to ground? Will that risk actual electrical damage to the SDR and/or PC? Or is it more just about noise reduction? (Ignoring the normal risks like lightning etc).
Could this ground, if needed, just run off to a tap pipe I have nearby?
(I'm loosely following this video:)
My proposed jerry rigged wire antenna
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vk3ymml
- Forum Owner
- Posts: 462
- Joined: Sun Aug 28, 2022 4:48 pm
- Location: Melbourne
Re: My proposed jerry rigged wire antenna
Hi Lingfish
What frequency range are you attempting to monitor, I am aware that rtl-sdr units can deal with a range however a longwire would only suit Shortwave / HF Amateur bands
What frequency range are you attempting to monitor, I am aware that rtl-sdr units can deal with a range however a longwire would only suit Shortwave / HF Amateur bands
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lingfish
- Posts: 8
- Joined: Thu Aug 29, 2024 12:57 pm
Re: My proposed jerry rigged wire antenna
Heya!
Pretty much anything below 100 mhz I'd say.
I went ahead and tried it -- literally jammed some tiny fencing wire into the centre of the SMA, alligator clipped that to the terrible RJ11 I'd scavenged, and ran it outside along the ground... made a difference! I saw some FT8 at 10.1364mhz, some clock at 10mhz, and some Japanese radio elsewhere (could have been local, but didn't seem like it).
I've tried to replicate it today, with an extension (and more alli clips lol), but couldn't. I assume time of day, as yesterday's mild success was around 6pm+.
Doing a second (smaller) run clipped to the shield part of the SMA and along the floor as a counterpoise greatly reduced the noise floor too, fascinating.
I need to source some speaker wire. I used to haev boxes and boxes of cat 5 and 6, but I think Ms insisted it go away; didn't need it for years, now I do! Also need to find some SMA to 'something else" (BNC, wire block) to do the connections a tad better. Probably eventually end up doing some balun/unun, but that's for down the road.
Pretty much anything below 100 mhz I'd say.
I went ahead and tried it -- literally jammed some tiny fencing wire into the centre of the SMA, alligator clipped that to the terrible RJ11 I'd scavenged, and ran it outside along the ground... made a difference! I saw some FT8 at 10.1364mhz, some clock at 10mhz, and some Japanese radio elsewhere (could have been local, but didn't seem like it).
I've tried to replicate it today, with an extension (and more alli clips lol), but couldn't. I assume time of day, as yesterday's mild success was around 6pm+.
Doing a second (smaller) run clipped to the shield part of the SMA and along the floor as a counterpoise greatly reduced the noise floor too, fascinating.
I need to source some speaker wire. I used to haev boxes and boxes of cat 5 and 6, but I think Ms insisted it go away; didn't need it for years, now I do! Also need to find some SMA to 'something else" (BNC, wire block) to do the connections a tad better. Probably eventually end up doing some balun/unun, but that's for down the road.
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vk3ymml
- Forum Owner
- Posts: 462
- Joined: Sun Aug 28, 2022 4:48 pm
- Location: Melbourne
Re: My proposed jerry rigged wire antenna
Sounds like your looking more at Shortwave / HF radio than scanners, I can create a sub forum for this
A good site to monitor is the International T-index website as it will give you some idea on HF conditions via: https://www.sws.bom.gov.au/HF_Systems/6/9/1
The wire your using might need bearing to the wire, see if you can remove any other protective layers so you get a decent connection.
Furthermore I've had great success in the past with a Slinky-Dipole antenna
Probably best raise the antenna off the ground, but have a ground wire and a peg so the antenna is earthed, this probably will gain further results.
A good site to monitor is the International T-index website as it will give you some idea on HF conditions via: https://www.sws.bom.gov.au/HF_Systems/6/9/1
The wire your using might need bearing to the wire, see if you can remove any other protective layers so you get a decent connection.
Furthermore I've had great success in the past with a Slinky-Dipole antenna
Probably best raise the antenna off the ground, but have a ground wire and a peg so the antenna is earthed, this probably will gain further results.