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What is the best antenna for these RF remote modules?

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dxpwny

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What is best antenna for these RF remote modules

I am playing around with these RF modules I got off Ebay. These:

**broken link removed**

Ebay item #401183214030

are 315 MHZ. I tried a 1 foot 22 solid copper wire wound around a pencil, then hung loose ... and that worked from my basement to my attic.

Just wondering if there is a better antenna style that could get me more range.
 

Re: What is best antenna for these RF remote modules

You can get more range, but only by making the antenna much more directional and physically much larger.
That usually turns out to be not very practical.
 

Re: What is best antenna for these RF remote modules

Having fiddled about with these sort of things for years, the basic expression is range varies as the reciprocal of size. The smallest I might have seen would be 100mm long time 3mm diam coil- range 20 m. Size 2m wide times 4m long (flat Yagi), range 2kM. You pay your money. . . .
Frank
 

Re: What is best antenna for these RF remote modules

chuckey said:
... the basic expression is range varies as the reciprocal of size. ... 100mm long time 3mm diam coil- range 20 m. Size 2m wide times 4m long, range 2kM.
Frank
Click to expand...


Isn't your second example of greater size - and your saying it achieves greater distance. Maybe it's a language / translation issue. I am just not clear about what your saying.
 

Re: What is best antenna for these RF remote modules

dxpwny said:
Isn't your second example of greater size - and your saying it achieves greater distance. Maybe it's a language / translation issue. I am just not clear about what your saying.
Click to expand...
Its perfectly clear.

To build a higher gain antenna you require two things, directionality, and a larger physical sized antenna.

You can build a matchbox sized antenna and be happy with a 20 meter range.

Or you can use something like a couple of full sized TV antennas pointed directly at each other, and it will work over a much longer distance.
 

Re: What is best antenna for these RF remote modules

Log parasitic or spiral log elements
 

Re: What is best antenna for these RF remote modules

Log parasitic or spiral log elements
Click to expand...
Why? Remote modules are small band and run perfectly with impedance matched resonant antennas.
 

Re: What is best antenna for these RF remote modules

A small yagi is probably the simplest and easiest thing to make.

**broken link removed**
 

Re: What is best antenna for these RF remote modules

I seem to always have in mind high directability and power in-mind =/
 

Re: What is best antenna for these RF remote modules

First off all deepest apologies to OP, range varies as aerial size. Despite trying to loggon for days to correct my stupid typo, Browser + site + Google Chrome have stopped me. Removing Chrome has opened the site up again. Is not software great?
Frank
 

Re: What is best antenna for these RF remote modules

chuckey said:
First off all deepest apologies to OP, range varies as aerial size. Despite trying to loggon for days to correct my stupid typo, Browser + site + Google Chrome have stopped me. Removing Chrome has opened the site up again. Is not software great?
Frank
Click to expand...

Spiral and log parasitics are not complicated & dimensions can be made accordingly.
 

Re: What is best antenna for these RF remote modules

Spiral and log parasitics are not complicated & dimensions can be made accordingly.
Click to expand...
The purpose of logarithmic antennas is still mysterious for a small band application. Their trade-off between bandwidth and gain is towards high bandwidth and low gain. If you have the room to implement multiple antenna elements, you'll make a Yagi with high gain and moderate bandwidth.

In my world, sub-GHz remote modules are usually associated with portable and other small devices. A 315 MHz Yagi or log periodic antenna with > 0.5 m dimensions is rarely wanted in these applications.
 

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