Antennae question

All else being equal, is a 200 watt antennae better than a 50 watt antennae? Does the 200 watt antennae need a larger amp to increase performance, or would simply using the 200 watt antennae have better results?

What do you mean a 200 W antenna? Are you transmitting or receiving? What kind of radio, what frequency or wavelength?

I don’t think there’s a common consumer item that is a “200 watt antenna”…

Specifically this antenna:

vs this one:

Now that Ive found that second link, it appears the other one is a 150 watt, not a 50 watt.

Someone made a statement that there is no advantage to receiving or transmitting with the 201B vs the 3900. If all the wires and amp and radio are the same, is the 200watt anyenna any better? Or are they equal?

Okay, I understand what you’re asking now. The 200-watt vs. 150-watt figures are what the antenna is rated as being able to handle as a maximum. If you’re transmitting at anything less than 150 watts, either antenna should be able to handle your needs, “all else being equal.”

With no difference in reception or transmission? They would perform equally well?

No reason why not. Power ratings are what they say they are. It is like asking whether a lampshade rated for a 60 watt globe will perform as well with a 25 watt globe as a lampshade rated for a 25 watt globe.

Any reason how one antenna might provide better reception based on its internal construction? One seems to be just a flexible metal rod. The other looks more complicated.

They appear close enough to the same that I would pick based on cost, installation, and other factors.

the spec you want there is the “gain” … (usually stated in dB ,its the improvement on a quarter wave monopole … that is, a quarter wave of the exact frequency being measured… )
The gain can be better for some frequencies than others.
The 150 Watt one says it is from 1 to 7 dB gain, within the rated bandwidth, changing across that bandwidth… This may help you choose between them.

One might be 7dB at the wrong frequency and only 1 dB right frequency, , while the other may be 5 dB at the right frequency… So it can be misleading to just go off maximums.

Anything that improves the power handling on a given passive device like an antenna would simply mean it conducts better. If all else was the same, I’d go for more metal in the air.

OK, the two antennas are designed for different purposes - so they are not directly comparable.

The AS-3900A/VRC is a vehicle mounted design. It needs to be mounted on a vehicle. It won’t work as well if it isn’t. The vehicle body supplies a groundplane.

The COM201B is a standaone antenna that has a base plane provided by either the tripod (if the ground mounted version is used) or by three spokes (if tower mounted).

The COM201B has slightly better VSWR, but there isn’t a lot in it. That will mean very very slightly better performance, but you would be hard pressed to actually see it.

After this, there isn’t a lot to directly compare. They are both centre fed dipoles, and will have for all useful purposes pretty much the same electrical charateristincs and radiation patterns. The power ratings are going to be all about maximum voltages, and maybe currents. If you are within the design ratings it will make difference to the actual performance.

Thanks for the replies. For the record, we have both antennas.already. There was a little debate over the benefit of connecting the 201B antennas and using them while halted for long periods or just using the standard humvee antennas. Some claimed the 201s were better, others claimed they were only better if raised higher into the air. It was also suggested that the vehicle antennas do not have the same omnidirectional capability of the 201s because the metal vehicle has a directional effect on the antenna. Personally I have no idea about antennas. But I know where to go to settle a debate.

I can’t see the datasheet without joining the site, blech, but for equal engineering quality I would expect a standalone antenna to perform better than a vehicle mount unless you’re just getting more height with the vehicle mount, or your ground with the standalone is awful. A vehicle mount usually has to make compromises to keep the size of an antenna for VHF of a reasonable size, and these usually limit its performance. A standalone antenna can usually be bigger and rely less or not at all on inductive loading to be resonant at your desired frequencies, which will give it better gain.

Vehicle mounted antennas do tend to perform better in the direction where the signal travels over the body.

However both these antennas are centre fed dipoles, and although designed to work with a groundplane, I would expect the effect to be less than you would see with a simple loaded whip. But antenna design involves a certain amount of magic, so just how much less is another matter.

Bolding mine.

My experience was with PRC-77s on M151s & CUCVs. So different from your situation but not too. Our operators were also radio maintenance techs, so they had a bit more theory & knowledge than your basic grunt mike-&-CEOI-jockey radio operator.

With the whip mounted on the right rear corner of the vehicle there was a notable improvement in signal reception and transmission across the vehicle. So best performance was diagonally towards the left front corner, worst was away from the vehicle’s right rear and the other directions were intermediate. The effect was mostly noticeable only when comms were difficult. If you were thinking “Gosh, why do my radios suck today?” a quick look at the map might lead you to turn the jeep around & try again.

This was pre SINCGARS, so I have no idea how its digital nature would affect performance. I also don’t know where on your vehicles (HUMVEE I assume) the antenna is mounted.