SWL VERTICAL ANTENNA

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SWL VERTICAL ANTENNA

Postby m3bsf » Thu Aug 01, 2019 11:02 pm

Due to space limitations I want to use a vertical antenna for my HF Short Wave Listening 0 ...30 Mgs two options could be a Discone or a Sigma Scan King SE1500, looking for suggestion's/thoughts/ideas any help much appreciated.
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Re: SWL VERTICAL ANTENNA

Postby Chris P » Fri Aug 02, 2019 9:09 am

neither a discone or scan king will be much use on HF a loaded vertical or mini whip such as the PA0RDT or perhaps a wellbrook loop ( if you have the cash available)would be my suggestion
Regards Chris aka G8FFF nipper or tazmin88
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Re: SWL VERTICAL ANTENNA

Postby JGR » Fri Aug 02, 2019 12:33 pm

Totally agree with Chris, the discones are basically deaf on HF and a random wire traced up a pole would work much better.
If you really need a compromise then look out for this "Scanking HF Discone 0.05 To 2000 MHz Antenna" it will perform far better on HF than most discones but it will never match that of a wire or dedicated loop.
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Re: SWL VERTICAL ANTENNA

Postby m0lsx » Fri Aug 02, 2019 1:49 pm

m3bsf wrote:Due to space limitations I want to use a vertical antenna for my HF Short Wave Listening 0 ...30 Mgs .


What are you listening with? Is it a radio designed for use with a external antenna only. Something like a homebase Yeasu, Icom etc. Or a portable radio designed to work on a small telescopic whip, with the ability to plug an external wire antenna into it?

The best known SDR, the one at the University of Twente in Holland uses a small one meter whip & that pulls in signals great.

Personally I normally use wires, preferably with a balun, as that decreases electrical noise. I also like the ability to place an earth stake at the feed point (balun) too. As that again reduces QRM a little more & every little helps.

With my portable radios I use 10 meters of wire at the most as more only increases the noise levels & the chances of overload. If you go onto the BDXC (British DX Club) website & look at what most of their active loggers use, it is normally a portable radio with a few meters of wire. Personally I crocodile clip the wire to the collapsed antenna, as I have found I get the best results that way.

Another good option for RX with a portable radio is a inductance fed loop frame antenna. Back in my free radio days in the 70's & 80's when SW was much more active than it is now, I had several different SW loops & found they were great on the congested bands. Now I just use them on MW. But they are a good antenna & simple to make.

One antenna I have found to make a really good RX antenna is a miracle whip with a few meters of extra wire crocodile clipped to it. The inbuilt tuner brings most weak stations in loud & clear.
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Re: SWL VERTICAL ANTENNA

Postby m3bsf » Mon Aug 05, 2019 2:27 am

Thank you for your reply's my Radio is a Realistic DX - 394 "B" , would it be better if I had wire all the way round the guttering of my house at roof level [just above bedroom windows] ?
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Re: SWL VERTICAL ANTENNA

Postby m0lsx » Mon Aug 05, 2019 10:57 am

A long wire is not essential. I use to run around 50 meters of wire. But now in general, I run around 10 - 15 meters of wire, but run in the best way possible.

Use Coax to get your antenna away from your homes electrical noise. Use a balun to provide a way of reducing electrical noise a little. Run the antenna from ground level & feed it against an earth stake, so that again reduces electrical noise.

10 meters of optimised antenna will always beat 50 meters of poorly situated antenna sitting close to a lot of electrical noise, with none of it filtered off.

The other advantage a length of wire away from the house has, is radials.
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Re: SWL VERTICAL ANTENNA

Postby m3bsf » Tue Aug 06, 2019 2:03 am

MOLSX Thankyou for your help/comments there are some ready made SWL Antennas on eBay should I buy one of those not sure I have the confidence to build one myself, would maybe have a go if I had detailed instructions.
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Re: SWL VERTICAL ANTENNA

Postby m0lsx » Tue Aug 06, 2019 3:20 pm

You can buy a balun, 9:1 is the normal. Try to get one with a earth terminal on it, as the earth stake makes some difference to the noise level.
The antenna it's self is simply a random length of wire. As I said, I tend to use around 10 meters, with thin wire, this works well on a fiberglass 10 meter roach rod. Although you could use any support.
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Re: SWL VERTICAL ANTENNA

Postby m3bsf » Tue Aug 06, 2019 7:05 pm

Thanks Alan, I will check this out and get back to you
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Re: SWL VERTICAL ANTENNA

Postby Scan125 » Mon Aug 19, 2019 12:33 pm

I've used long wire (not that long) feed via a coax from the house study up outside to the rear roof gutter. Run is about 20m in total. The long wire then runs from roof gutter height across the back garden to 6ft fence height (used to run across to a tree at same height as rood gutter height).

I used to use a 9:1 balun but then got an MFJ-957 antenna tuner. At first I used it with the balun but then found I got far better control, tuning and noise exclusion with the balun removed. I've since upgraded to and MFJ-959C antenna tuner/preamp unit.

As others have mentions a good earth via a ground steak is most desirable if you can do this. Screwfix and Toolstation sell these.
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