Right up to 108Mhz I think you mean. Yes I know. I mentioned that to RSM but they said NZ has older radio equipment here compared to other countries, and can't handle the same filtering.
I can accept that for a 10,000 watt broadcast on 108Mhz, but it's absolute nonsense to suggest that increasing the power by 3db from 0.5 to 1 watt is going to break through the filters that are currently filtering out the 0.5 watts. 10 watts would not interfere with anything 1Mhz away with any age equipment. Although perhaps Marconi's first invention may have had trouble in the late 1800's.
Ross.
----- Original Message -----From: Steve JepsonTo: LPFM_Radio@...Sent: Friday, March 09, 2007 7:40 AMSubject: Re: [LPFM] RSM Comment on Power etc.
The ILS issue is an Excuse there are FMs in Other countries running 10s of Kilowattsrunning right up to 107 as well obv some hidden agenda inside the RSMS----- Original Message -----From: Ross LevisSent: Thursday, March 08, 2007 11:52 PMSubject: Re: [LPFM] RSM Comment on Power etc.
It's absolutely rediculous to think that 1 watt or even 10 watts on 107.7 is going to affect professional equipment over 1MHz away. It must be some sort of political thing.There was some argument by RSM that there are some aging equipment being used in aviation, but even so, even ancient valve technology of the 1960's are much more narrowly filtered than that.Regarding circular radiation antennas, I want some! I've discussed this at length with a someone who makes his own FM antennas.You see, the regulations allow 500mw in both planes, that is horrizontal and vertical plane. Only transmitting in the vertical plane means radios need a vertical antenna to receive the signal best.A circular antenna radiates in all planes vertical, horizontal and everything in between. Because of this, the gain the the antenna is -3db less than a single plane antenna because the power is spread in other planes, but in reality you get as many listeners as you did before, due to people using slant antennas, or bits of wire lying on the floor, etc. They will receive your signal much better.But, according to a radiation meter, you are now only transmitting 250mw eirp, so you can now double the transmitter power and transmit 1 watt in 2 planes legally. It will definately increase coverage, and you'll also find much less fluttering while driving.It's well known that horizontal radiation travels much further than vertical due to the magnetic waves of the Earth, and they also pass through trees much better.However, I believe circular antennas by design have some gain in one direction, so unfortunately you need 4 antennas at 90 degrees to each other to get a full 360 radiation pattern.They are not cheap, however, as they need precise measurements to get the radiation rotating properly. A slight mis-measurement can cause phase problems. But I hope to have 4 of these one day.Ross..
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