Batboard

Does anyone know if a broadband VHF antenna is available that will cover the 2m ham band & 150-160MHz band? Is it possible to combine a 2m ham repeater & a business band repeater on a single antenna with a combiner? Is this even legal? Since tower space is scarce or expensive, I was just kicking around some ideas...

As a starting point, it occurs to me that the usual bandwidth of a 6db gain VHF antenna is on the order of 6 mHz, which would mean the amateur machine would be limited to transmitting on the top end of 147 mHz if the commercial repeater's frequency did not exceed 154 mHz. If you put the ham repeater on 146 then the commercial's top frequency would come down another mHz, to the low end of 153 or thereabouts.

If you throw enough money at the antenna/combiner question you can do anything, such as the FM broadcast antenna setup (multiple transmitters and 20 mHz bandwidth) on the top of the Empire State Building in NYC (if indeed it still exists), but most of us don't have those kinds of resources.

I have found that most folded dipole antennas designed for 150-156mhz work reasonably well on the high end of 2 meters.

A proper combiner with circulators for the two systems may in the near term cost significantly more than another duplexer and simply renting space for another antenna and line.

As far as I know there are no legal issues involved as long as each station operates within the specs/rules for its respective service.

Don't forget that unless you own both systems anything that goes wrong with the "other" repeater is likely to be blamed on you directly or indirectly. Sometimes it is just not worth the trouble.

The antenna would not be an issue and to get an approximate price on the combiner give TX/RX (or one of the other companies) the system frequencies and transmitter power and you will know exactly what the combiner will cost you.

Legally with the FCC there are no issues, but some tower companies also charge for the square footage inside the shelter if its a shared space. Make sure the footprint won't get too big or you will be paying there too.

[quote="KS4VT"]...Legally with the FCC there are no issues...quote]

If a licensed HAM transmits on a commercial frequency that he also holds a license for, I see no problem.

If a user of the licensed commercial frequency transmits on a HAM frequency and does not hold a HAM license, I think that would be a problem? Right?

Even an unlicensed ham can transmit on the business band if he has a license for it. Having one license does not imply any permission to operate in another separately-licensed band.

Of more importance is the equipment that would be used. An amateur transceiver may not be stable enough, or narrow-band enough, to be used on commercial frequencies, although the reverse would probably be OK.

Bob M.

Amateur repeater is a Quantar. Commercial repeater is an MTR2000, narrow band on 151.985. I am licensed for both.

Bob N.

if you have the money get the combiner setup and you're good to go.

motisking wrote:

KS4VT wrote:...Legally with the FCC there are no issues...quote]

If a licensed HAM transmits on a commercial frequency that he also holds a license for, I see no problem.

If a user of the licensed commercial frequency transmits on a HAM frequency and does not hold a HAM license, I think that would be a problem? Right?

The question wasn't asking if the users capabilities were legal, the question was if it was legal to COMBINE the ham repeater and commercial repeater on a common antenna/feedline. That answer is yes, it is legal to do that.

I would have guessed that it was legal, but I wasn't sure. Thanks...

Yes its legal; there are no limitations on the use of a combiner, except for the technical limitations.

We have public safety and business users in our TX/RX combiner. When we get the $$ for expanding the thing, we will put the two 449 amateur repeaters in it.

As long as everyone keeps their rigs clean, and the combiner cans are up to spec, there is nothing to worry about.

Mike in CT
KM1R

Telewave has an excelent broadband antenna for your application.

ANT150F2 covers 148 to 174 in it's stock tuning and is available tuned to a lower range.

http://www.telewave.com

You still need a combiner also.

Some sites have a master receive antenna system with filtering.

you'll want another reject can tuned to the ham transmitter on the commercial RX, and another reject can on tuned to the commercial TX on the ham reciever.

http://homepage.ntlworld.com/martin.ell ... ystems.htm
http://www.emrcorp.com/images/tech_pape ... 36-44).pdf

http://www.decibelproducts.com/collater ... ations.pdf