It might be more trouble than it's worth. Use a good multiband antenna for vhf and uhf and a specific antenna for 800 (2 antennas total) would be my suggestion. Then use a diplexer to filter the 800 frequencies out of the multiband antenna. Numerous threads exist on this subject if you do some searches.BillQuinn said:is it possible to hook up 4 antennas into one scanner? Low,vhf,uhf, and 800MHz? thanks!
The antennas usually figure out a way to interact badly.BillQuinn said:is it possible to hook up 4 antennas into one scanner? Low,vhf,uhf, and 800MHz? thanks!
I notice you say "almost always". Is there any way to overcome this? I mean, if I have something with a roof the size of a Suburban or Excursion, can I overcome the interaction problem with distance, or is it more of a phasing thing that occurs regardless of antenna proximity?Don_Burke said:The antennas usually figure out a way to interact badly.
A single multiband antenna will almost always outperform a multiple antenna setup.
Some wicked things can happen when two versions of the same signal meet up in the cables. Sometimes they will add and sometimes they will cancel. There is also the effect of one of the signals going up the cable to another antenna and bouncing back to the receiver. The lengths of the cables come into play here.af5rn said:I notice you say "almost always". Is there any way to overcome this? I mean, if I have something with a roof the size of a Suburban or Excursion, can I overcome the interaction problem with distance, or is it more of a phasing thing that occurs regardless of antenna proximity?
As discouraging as it is, I keep coming back to this question because the performance difference between a multi-band antenna and a single bander is really profound, so it would seem worth it to find a way to make this work.
Don_Burke said:Some wicked things can happen when two versions of the same signal meet up in the cables. Sometimes they will add and sometimes they will cancel. There is also the effect of one of the signals going up the cable to another antenna and bouncing back to the receiver. The lengths of the cables come into play here.
If I had my heart set on a multiple antenna setup, I would take a page from the cable TV systems and use a small preamp on each antenna, not for the gain, but for the isolation. A triplexer or quadplexer would probably be a good idea, although I suspect it would be a PITA to get right.
At work I use dedicated scanners on dedicated antennas. The antennas do work after a fashion on the other frequencies, but only as a backup. I consider that to be a simpler way to go.
Like I said, wicked things can happen.prcguy said:It actually overloads many of my scanners and sometimes I end up just connecting the antenna for the particular band of interest.
prcguy
zz0468 said:Aside from the occasional cable tv applications, I just don't know of anyone in the professional world who uses multiple antennas to one radio without tedious engineering and calculation, which includes the cable lengths involved, and the physical spacing between the antennas. Antenna stacking is done all the time, but it's for a single band, if not a single frequency. What you're wanting to do is generally considered unworkable.
I would suggest a single wide band antenna, such as a discone, and if performance is unsatisfactory, use a high quality low noise amplifier.If you really want to do it right, and money is no object, separate receivers for each antenna/band.
prcguy said:Cable lengths are not critical when using specific frequency antennas into a diplexer or triplexer. The roof of the vehicle mentioned is plenty large enough to arrange several antennas with minimal interaction. A Discone mobile? I've seen that and its not very pretty.
prcguy
af5rn said:Two big questions though: Can I run a diplexer or duplexer backwards, attaching the scanner to the input and the antennae to the outputs?
And can I duplex a scanner and a transceiver into the same antenna? They make devices to run a CB transmitter and your AM/FM radio off the same antenna, so I would think so...?