base antenna selection

[Ett1033]

What are the advantages/disadvantages of a fiberglass omni or an exposed dipole omni directional antenna.
(VHF 150.XXX Base station 110W)

Thanks,
Ett1033

[va3wxm]

The folded dipole style is nice for lightning/static arresting because it's DC grounded. And the all-metal construction makes in more robust (IMHO).

[bernie]

My two bits worth:
In deciding which antenna to use there are many factors to be concedered.
One of these is the environment.
We have had very poor results with exposed dipole antennas on repeaters, or on sites because of the salt corrosion. (the price for living in Hawaii ) Causes noise on repeaters.
Perhaps this is not a problem for you.
An advantage of the exposed dipole antenna is that it can be dissambled to get it on a roof top. It is somewhat inconvienent to get a 22' stick in an elevator.
The radiation pattern is very important. The antenna has to be selected for the best coverage for your area.

I would go for the station master if the application was on a building or tower in town, a mountain top would require study.

[MicorRT]

I've seen Phelps Dodge Station Masters (Fiberglass) and DB 244 (folded dipole) ant.s last 20+ years. My belief is you can't go wrong with a quality ant either way... How every I believe that the fiberglass ant.s aren't affected by ice as much. (I have only been able to compare between PD stationmasters and DB224s no other brands).

[Cowthief]

Hello.

You hit the nail on the head, QUALITY!
If you buy the $39.98 radioshack special you get $39.98 worth of antenna.
If you buy phelps-dodge, or decibel, or other quality products, you will have less trouble in the long run.
There are monopole, folded dipole, discone, end fed longwire, center fed dipole longwire, etc, each has its use.
The longwire is usually horiz' polarity, but CAN be other.

[wa2zdy]

There are monopole, folded dipole, discone, end fed longwire, center fed dipole longwire, etc, each has its use.
The longwire is usually horiz' polarity, but CAN be other.

The "center-fed dipole longwire" only works on front programmable railroad spectras.

The end fed longwire is not an antenna you will see in land mobile installations. (Just so you're not wondering . . .)

[mr.syntrx]

The end-fed longwire is occasionally seen in land mobile, but I doubt CT will ever see it. How often will he call the Royal Flying Doctor Service, for example?

[Jim202]

Bear in mind the word quality. Years ago when the name Phelps Dodge was the number one, top of the line company, you had some very good quality antennas. The fiberglas stick poles were made with quality. The had bees wax filling the inside space of those poles. They actually inverted the pole before the bottom was sealed and poured hot wax into them.

Today you can't find one of the poles that is made in the wax fashion construction. All the companies have cut just about every corner there is to cut in order to put in the least amout of material and labor to keep cost down.

I will say that I have installed some lower cost pole antennas and only had them last about 3 to 6 months up on a hill or mountain top. The constant movement from the wind flexing them kills the cheaper antennas. The flexing seems to break open the internal connections.

I won't mention the name, but they come in a red / black striped container. Bottom line, don't buy on just price alone. You need a large stiff pole to survive wind and ice. When I have shaken the antenna and hear the internal parts just rattleing around, you know it is only a matter of time before something comes apart.

Jim

[wa2zdy]

The end-fed longwire is occasionally seen in land mobile, but I doubt CT will ever see it. How often will he call the Royal Flying Doctor Service, for example? :)

Indeed I suspect you are correct. I'd think the land mobile service in the land down under includes HF where end-fed random wires might well be common. Here in the US, we don't consider HF operations commonplace in the land mobile service.

Note also that to be properly called a "long wire" it must be several wavelengths long and exhibit gain off the end. Otherwise it's just an end-fed wire, usually of random length with a coupler.

And of course the term "center-fed dipole longwire" is one I've never heard before - in 30 years of ham and commercial radio. That's probably why they only work with cowpoker's front programmable RR Spectra.

Thanks for the input Mr Syntrx. I hadn't thought of your situation in Australia and I should have, as it is certainly an important use for radio.

[batdude]

My stationmasters are DC grounded... at least that's what the book from Celwave RFS says....

( that's all i use here on the atlantic coast - aluminum + paper mill = rotten antenna if you go with an exposed dipole...)



doug