Very first setup

Useful information regarding antennas for SDR products.
Frosty11
Posts: 4
Joined: Sat Dec 30, 2017 9:29 pm

Very first setup

Postby Frosty11 » Sat Dec 30, 2017 10:06 pm

I'm planning my first setup, but need to know what I should get for my needs.

I'm focusing on HF amateur bands, HF Oceanic traffic and VHF/I'VE airband as well as ADS-B. A discone seems to work well above 30 Mhz (according to research) but would you agree.

I wouldn't be happy with a long wire running all over the place for HF reception so what other options are there? Is there a vast difference in roof mounted, external antennas and loft ones? I see that the Wellbrook loop antennas have a indoor and outdoor option. Just curious.

Thanks
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Roger
Posts: 167
Joined: Fri Dec 29, 2017 7:59 pm

Re: Very first setup

Postby Roger » Sun Dec 31, 2017 5:03 am

Discones work well and they are not expensive. Good for VHF and UHF but some people use them on lower frequencies.

When it comes to HF it is a tradeoff between physical size and performance. Bigger is better. Limited space antennas can work well if they are properly designed. We are at the bottom of the solar cycle now so you want antennas that work well below 15 MHZ. The other factor is noise. Atmospheric and band noise are always there but local Radio Frequency Interference (RFI) is a big problem in today's world. There are so many electronic devices generating RFI that interferes with radio reception, especially on the HF bands. Televisions, computers, switching power supplies, light dimmers and a host of other devices. The closer you are to your dwelling the worse the noise pickup will be. A wire strung around the inside of your house will be almost useless on HF.

A good compromise antenna is a well designed loop antenna. These are about 1 Meter (3 feet) in diameter and have a small, high quality, amplifier built in. You can locate the device a good distance from your house or even on the balcony of an apartment and use coax or CAT5 wire (on some models not all) back to your radio. Wellbrook and DX Engineering Pixel Pro's are the best products but they are around $500 US. You can build your own using kit parts as well.
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Frosty11
Posts: 4
Joined: Sat Dec 30, 2017 9:29 pm

Re: Very first setup

Postby Frosty11 » Sun Dec 31, 2017 8:54 am

Roger wrote:Discones work well and they are not expensive. Good for VHF and UHF but some people use them on lower frequencies.

When it comes to HF it is a tradeoff between physical size and performance. Bigger is better. Limited space antennas can work well if they are properly designed. We are at the bottom of the solar cycle now so you want antennas that work well below 15 MHZ. The other factor is noise. Atmospheric and band noise are always there but local Radio Frequency Interference (RFI) is a big problem in today's world. There are so many electronic devices generating RFI that interferes with radio reception, especially on the HF bands. Televisions, computers, switching power supplies, light dimmers and a host of other devices. The closer you are to your dwelling the worse the noise pickup will be. A wire strung around the inside of your house will be almost useless on HF.

A good compromise antenna is a well designed loop antenna. These are about 1 Meter (3 feet) in diameter and have a small, high quality, amplifier built in. You can locate the device a good distance from your house or even on the balcony of an apartment and use coax or CAT5 wire (on some models not all) back to your radio. Wellbrook and DX Engineering Pixel Pro's are the best products but they are around $500 US. You can build your own using kit parts as well.


Thanks for the prompt reply. Away from RFI makes sense, like outside of the house. But is the height of the antenna a factor. I have an external garage that has a height of around 9 feet. Also will there be a trade off in signal loss because I'll be running a longer coax?
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g1hbe
Posts: 367
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire, UK

Re: Very first setup

Postby g1hbe » Sun Dec 31, 2017 9:47 am

I use a selection of antennas for VHF/UHF and mostly a Wellbrook 1530 loop for VLF to 30 MHz. It is mounted at gutter height at the furthest point at the rear of the house. Random wires are a no-no here as the amount of noise from local devices clobbers everything. The loop ignores most of the noise and enables the signals to sit above a mostly quiet background. If you are handy at home construction a loop similar to the Wellbrook can be made in a day.
On VHF, discones are 'jack of all trades' but master of none. I've never been too keen myself but they do work. My VHF antennas consist of: A home-made nest of dipoles with elements cut for 900 MHz, 450 MHz, 250 Mhz and 145 MHz. This is in the loft.
Keeping it company is a wire dipole cut for 50 MHz, diagonally polarised. This picks up a lot of noise and doesn't get used much.
Outside on the main mast is a homebrew yagi for 450 MHz which is almost permanently selected as there is a lot of PMR (analogue and digital) stuff at around this frequency. There's also a 2.4 GHz loop yagi for general SHF poking around (on a different RX).
Needless to say there are a couple of switch-boxes in the shack to sort it all out. These are low-loss manual 'satellite switchers' and seem to have a flat-ish response to at least 2 GHz. The 3 antenna inputs of the RSP2 are handy.

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Andy


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