I have a caravan with an extendable mast and two Parabolic Grid antennas:
The antennas feed a Milesight UR32 Router with both Telstra and Optus SIM cards
The ROuter feeds a small network in the Van for our mobile office.
We want to be able to use the grid antennas to access mobile broadband signal in as many ‘remote’ areas as possible. We can extend the mast to 9m/12m and then manually rotate it in the general direction of the best cell tower (determined by looking at Cellmapper.com or similar)
I am thinking there should be some way to connect a Spectrum Analyser or similar tool to the antenna when we set up at a location, and rotate the antenna while watching the analyser and thereby pinpoint the best antenna direction for maximum signal.
Maybe:
or
I need advice from people far more knowledgeable than me - but surely there is a better (ie quicker and more accurate) way to point an antenna than move it a bit and do a speed test, then repeat endlessly and try to remember the best position . . .
There is. Do just what you say, connect the antenna to a spectrum analyser and you should see all the signals within the spectrum analyser sweep range. The signals may eventually be digital but the carrier or transport medium is analog and that is what the spectrum analyser will see. You can rotate the antenna for Maximum signal strength. That is a start, the digital bit can come later.
One point. If several signals are anticipated make sure the analyser has a resolution bandwidth to separate signals of interest if that sort of thing is required.
Another point. Don’t go higher with the antenna and longer with the cable that needed or your cable losses may exceed the higher antenna benefits
Cheers Bob
Do you think either of the posted Spectrum Analysers have the specifications required? Or do I need to look at a higher end one? (Simple is better for me!)
Good tip re height vs cable length - thanks! We are very much in the trial and error stage here - lucky I like fiddling around with such things!
Hi Greg
There is only 1 spectrum analyser posted the other on is a software defined radio. Vastly different.
Check the link yourself. I did and the screen is pretty so so re resolution. Would be difficult adjusting for max signal but you could use the numbers I suppose if the refresh rate was fast enough.
Spectrum analysers of any quality can be VERY expensive but it is up to you, depending on how many stray $ are floating around. There are some hand held units around but I have had no reason to research the quality or details. You may get some clues from Element 14 or one of the test equipment suppliers, Emona comes to mind but no doubt there are others.
I suppose I have been spoiled in the past. The last one I used was a HP and a magnificent piece of work. I had to separate 2 tones 600Hz apart and their IM distortion products. To do this a resolution
bandwidth of 60Hz is required. Closest was 30Hz but this instrument went down to 10Hz. Fitted with tracking generator and all the bells and whistles. The down side? I believe the cost was somewhere north of $150k. Fortunately there are more affordable ones around but not with the performance of this one.
The ultimate choice is up to you but for antenna adjustment screen quality would be important. The beauty of a spectrum analyser is you can usually identify what you are looking at by the frequency in use.
As long as you can do this any instrument capable of displaying signal strength will do the job. Identifying what you are looking at and making sure that is the signal you want is the key.
Tip. Try for an instrument either with a display screen so you can see the pips or an analog meter. Believe me that is far easier than trying to track numbers on a digital display. They are usually too far behind anyway.
Another potentially awkward snag. Do the phone towers transmit all the time or only when required. In a quiet zone you may have to wait awhile. Coffee anyone?
cheers Bob
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