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2 meter base station & distance?
- Thread starter Bearcat
- Start date
That simply means you need the biggest antenna YOU can manage mounted as high as YOU can manage and as much power as YOU can reasonably afford. A good preamp mounted at the antenna is also advised for optimum receive. there is NO hard and fast rule of what YOU need other than YOU deciding what YOU can afford or manage to install. As usual bigger and higher is better than small and low. It's all about maximizing gains and minimizing losses with everything from the power output to the coax cable losses etc.
When you say pre-amp...can a pre-amp be in the shack or are they just for antenna application?
If you put the preamp right at the antenna, it won't amplify the noise that impinges on the coax from the feedpoint all the way to the radio. If you install it at the radio, you may increase both noise AND signal, which you can do by just turning up the RF/AF gain.
Like Beetle said above the best place for a preamp is at the antenna feedpoint. Once a signal falls below the noise floor of your receiver or preamp it cannot be recovered. By placing a preamp at the antenna end of the cable you eliminate the losses of the cable and have a stronger signal for the preamp to work with.Having said that I did run a preamp at the shack end for quite some time and it worked great HOWEVER I had a relatively short run of LDF4-50 heliax cable and the losses were next to nothing even at 2m amounting to less than 1 dB so it was virtually like the preamp was at the feedpoint. I live in a rural area where noise levels are very low so there was zero noise pickup on the coax line as well. That is all gone now but I look forward to getting it all back bigger and better than ever in the summer.
Are all pre-amps the same? Any good ones out there? DX engineering has one for $139..I didn't know you mounted them at the antenna feed point until you guys mentioned it...but if I run really good coax and have a low noise level I could run it to the shack? I live in a very small town and up on a hill
BJ radionut
Supporting Member and 6m addict
Having a pre-amp at each location ( shack and Tower mounted) I can say the tower mounted pre-amp excels. I use them for 6 mtr's and the tower version works much better.
My coax run is very short ( less then 60 ft.)(LMR-400) and the pre-amp at the shack is almost never used.
The pre-amps in my rig are turned off and the tower mounted pre-amp is only thing used 90% of my operating time...I would expect the same if not greater results on 2 mtr's...as the comparable loss on 6 mtr's vs 2 mtr's....2 mtr's is even greater....
All the Best
Gary
My coax run is very short ( less then 60 ft.)(LMR-400) and the pre-amp at the shack is almost never used.
The pre-amps in my rig are turned off and the tower mounted pre-amp is only thing used 90% of my operating time...I would expect the same if not greater results on 2 mtr's...as the comparable loss on 6 mtr's vs 2 mtr's....2 mtr's is even greater....
All the Best
Gary
No not at the same time. The signal overload would be horrendous and cause all sorts of problems with the receive. You will start hearing commercial stations that are not even operating on 2m. Any preamp used must be capable of handling the full transmitter power BTW as it has to switch out of the circuit during TX.
Lol...noise pollution..so my preamp must handle whatever power I'm transmitting...learned something new!
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
That would depend on the antennas beam width usually noted in the specs. Nothing to worry too much about for your application.