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Circular Polarization Antenna Design

C

chrisdiack

Guest
Greetings from New Zealand.

We are permitted to operate Low Power FM transmission in New Zealand at an EIRP of 1 Watt.

I'd like to design a lightweight antenna for use in a non-hostile invironment made from aluminium or perhaps eventually stainless steel once I have perfected construction and proved that it has no VSWR problems.

I understand so far that such antennas exhibit negative gain... no problem, as long at the field strength measured falls within the regulations... which brings me to a point.

Our radio inspectors measure vertical polarization only... any thoughts here regarding anomalies regarding measurement and propogation?

All advice and construction details for a person with the "... make it youself and save having to buy it..." bug, welcomed.

Thank you :)

Chris Diack
http://www.classicgold.co.nz
 
chrisdiack said:
We are permitted to operate Low Power FM transmission in New Zealand at an EIRP of 1 Watt. ... Our radio inspectors measure vertical polarization only.
Click to expand...

If NZ radio inspectors measure only received fields to determine compliance, do they allow for the fact that reflections in a terrestrial VHF propagation environment could augment a compliant, free-space radiated field to a value that might be non-compliant at the point of measurement -- even if the EIRP radiated on that path was 1 watt, or less?

RF
 
As a "make or buy" decision, making one antenna, testing it, and redoing it will cost way more in time than just buying it. Now, maybe you want to learn, or want to make 1000 later and sell them, in which case it is a different situation.

My advice, don't spend 100 dollars of time to save 10 dollars.
 
NE Miss Radio said:
My advice, don't spend 100 dollars of time to save 10 dollars.
Click to expand...

That is good advice only if in either case, such an installation in NZ (or anywhere else) meets the standards of the regulatory agency that apply there.

If not, legal sanctions may be assessed to such operators/operations.
 
Are there any similar stations on the air now legally in NZ? If there is one you might be able to see what kind of antenna they are running via the NZ (version of the FCC)'s website. Is there a radio equipment dealer in NZ? They might have a used "NZ accepted antenna". The cost of materials and fabrication not counting your time might make a used one one a deal. My dad has a saying "don't try to reinvent the wheel". NE Miss Radio is correct, whatever you do make sure the regulators at happy.
 
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