The closeness of the sat dish might effect the TX swr some. I would be more concerned with people being
that close to the TX antenna on the grounds of RF radiation safety. It is clear that the people who installed
the dish are not current on the FCC rules on RF radiation.
Getting back to your question on coverage. That is the question here if I read this correctly. Lets ask a few
questions. First, how old is the installation? This goes to how many years the coax, connectors and antenna
have been out in the elements. If it's been more than 5 years or so, you may be looking at some careful
inspection of the entire antenna system.
Second question is how does your antenna compare to height with other objects and antennas around it?
This goes to how the antenna has fared with lightning strikes. I have seen some of the fiberglass models
take a hit and open up some of the internal elements. This reduces the gain of the original antenna
performance. About the only way to see this problem is to put the antenna on an instrument like
the "sitemaster" and look at the antenna frequency time domane plot. In most cases, unless you have a
plot of a good antenna, you may not see much difference. However it will make a major effect on
how well the coverage is.
Third question is have you made any receiver performance checks on the base radio itself? You need to
do this with the signal generator connected directly to the radio and see what the squelch threshold is.
Then connect the antenna and see if this trip point changes. You need to do this with a signal injection
coax fitting. This allows you to have like a T coax connector in line. It has a cap coupled connection
on the port going to the signal generator. One of the other sides goes to the radio. The third side is for
the antenna connection. The additional signal required to open the receiver with the antenna connected
is the de-sense that the antenna and the signals it is bringing in are causing.
If the antenna points to the problem of receiver sensitivity, you could have intermod problems, strong
signals near your receive frequency, or a host of combinations of other problems. It takes time and test
equipment to be able to narrow it down and point the direction on where to look for your problem.
Jim
avernus99 wrote:ok guys,there is a problem.I went to a site which have quantar repeater installed in the cabin at the roof top of the building as there was a fault complain indicating poor reception between walkie talkie's to walkie talkie's.Did basic checking and found no fault.But what i saw on the roof top was a satellite dish of half metre in diameter was installed near the quantar antenna..distance between both antenna's are a metre only.Would that be the cause of poor reception?