However, does the extra gain on an antenna impact the transmitter at all? If the transmitter comes shipped with a standard GP antenna, are there any risks of using an antenna that's too powerful for a small 5watt transmitter? Or are there transmitters that should be only be used with certain antennas? Or is just a matter of different antennas for different results?
Many thanks, everybody here has been so helpful!
Free Radio Forever!
Gain of an antenna has no effect on the transmitter itself if properly designed. The antenna can have as much gain as physically possible and the transmitter will just see it as just an ordinary output load. Only thing that matters is making sure the SWR is low. A high SWR can burn up output transistors and cause other problems. There is no requirement for what kind of antenna should be used with a transmitter as long as the SWR is low, the antenna is designed for the frequency you wish to use, and it matches the output impedance which is almost always 50 ohms for broadcast equipment. The transmitter expects to see a non reflective 50 ohm load, anything that fits that requirement will work with it. Even a dummy load. Of course the three antennas I mentioned earlier will match very close to an 50 ohm load though a small balun may be needed.
im running a homemade copper j-pole. i will tell you from experience, the suits dont immediately recognize it as a pirate. somebody i know got popped and the suits admitted to being stumped by the antenna and wanted to know more about it. it can pass as a ham radio j-pole to most hams even.
the jpole has some other kickass benefits. 1) its dc grounded by design. if you get hit by lightning it will run down the pole. 2) it shoots its signal out like a lighthouse towards the horizon, where you want it. 3) its got gain 4) you can build it with plumbers tools out of copper pipe
the downside is it has to be tuned and requires some knowledge of how it works to tune it.
i used a jpole and the coverage was excellent. the added benefit of the jpole is the way it beams out the signal. many antennas have lobes where part of the signal is just shot up towards the clouds. jpoles tend to act like a lighthouse and beam the signal towards the horizon which is what you want.
Hi, I have a 5w fm transmitter already and have built a dipole using a measurement calculator online, I haven't got an swr metre, just wondered if I buy one how would I be able to make sure that it is tuned correctly ? Thanks
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