Diamond D3000N discone measured gain patterns

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TMAYER

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Nov 25, 2019
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Good evening,

Does anyone have measured gain (patterns) for a D3000N discone antenna that they are willing to share?

The datasheet states a nominal 2 dBi gain, but I am skeptical that is true across the full frequency range, and also would expect rolloff as elevation angle increases until hitting a null at zenith. Any measurements are appreciated, with or without the whip attached.

Would you expect as low as -10 dBi gain above 1 GHz and 20-30 degree elevation angle? Is there any type of ground plane that can be used to improve the gain if attaching to a tripod/mast?


Thank you!
 

Ubbe

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The gain figure are probably true, equal to a 1/4 GP, if measured at a maximum point regardless of elevation angle.
The directional pattern are about the same as 1/4GP antenna cut for the frequency but only at the lowest frequency the discone are designed for. Higher up in frequency a discone starts to raise the directional loob up in the sky and drop in coverage at the horizon.

If you mostly focus on receiving 150-900MHz you can cut all elements a certain procentage that equals the difference between 150 and the lowest frequency the discone are designed for, usually 100MHz, to get it to lower the loob and work better at the higher frequencies.

If you have a large discone for 100Mhz and up it probably will have -10dBi at 1GHz at the horizon.
The discone are a design that have no groundplane that can be increased to help the elevation angle being pushed down to the horizon. The antenna stops working like a discone below it's designed frequency range and just worsk as a big metal object in the air and will receive as such. You can add a whip on the top that will work as a vertical GP antenna with the discone as a groundplane at frequencies where the discone do not work.

/Ubbe
 

devicelab

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I can tell you that it works pretty good on 1090 Mhz albeit with a proper bandpass filter and amplifier. (Granted, it's performance isn't as good as my DPD 1090 Mhz vertical but that's a tuned antenna.) I haven't used it above that frequency otherwise. It's a very solid antenna and when paired with LMR400 -- it picks up everything -- noise included. :p
 
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