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SDR Radio Fun ($149 USB tuner with range from 100khz to 2Ghz!)

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Cliff Matthews:
Saw a fun video today from Budd Churchward's YT channel called "Strangest Thing On SDR Radio". While I'm not a HAM, I found it amazing (In Canada almost illegal?) all that a pocket-able device can hear..

TheBay:
I've got an SDRplay, amazing bit of kit! Anyone interested in any form of radio I urge you to get one!  :-+

Cliff Matthews:

--- Quote from: TheBay on September 17, 2015, 01:34:20 pm ---I've got an SDRplay, amazing bit of kit! Anyone interested in any form of radio I urge you to get one!  :-+

--- End quote ---
I was wondering about an antenna for it, does it have to be long? My back-yard's only 25ft deep...
Would you have any tear-down photo's or pcb shots?

Nerull:

--- Quote from: Cliff Matthews on September 17, 2015, 11:19:53 pm ---
--- Quote from: TheBay on September 17, 2015, 01:34:20 pm ---I've got an SDRplay, amazing bit of kit! Anyone interested in any form of radio I urge you to get one!  :-+

--- End quote ---
I was wondering about an antenna for it, does it have to be long? My back-yard's only 25ft deep...
Would you have any tear-down photo's or pcb shots?

--- End quote ---

Your antenna is going to be frequency-band dependent. There is no magic antenna that will receive everything from 10m band (28MHz) to ADS-B (1.09GHz), at least not well. You need something tuned to the frequency you want to listen to. Antennas are generally some fraction of a wavelength long, so the higher the frequency, the smaller your antenna will be.

A 5/8 wave antenna for 28MHz (10m wavelength) is going to be 6.25m long. A 5/8 wave antenna for 144MHz (2m wavelength) will be 1.25m, etc.

My mobile VHF/UHF antenna on my truck is a little Comet SSB-1, which is a close-enough-to 1/4 wave antenna on 144MHz and a close-enough-to 1/2 wave antenna on 440MHz (70cm) and is only about 40cm tall including the base. Its not got the gain of a larger antenna but it works well enough for my needs.

This all gets a little more complex when you start looking at other antenna types. My antennas are all monopole and require a ground plane. There are dipoles, loops, helical, yagis, bow ties...

Nerull:
There are also telescoping antennas which allow you to change the length to suit different bands. They're almost certainly not going to be as good as a band-specific antenna but they're far more flexible.

https://greatscottgadgets.com/ant500/

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