2M DIPOLE ANTENNA
- Thread starter JGWall
- Start date
Doesn't matter a whole lot, at a very fine level, bare elements are superior. Indoors, uninsulated is fine. Outdoors, insulated can help keep the copper from corroding. But practically it's not going to make much of a difference. For insulated outdoor use, you'd want something that is UV-resistant or it will break down pretty quickly.
thank you
Back when cars had bumpers, the were plans for a mobile 2 meter dipole that could be bumper mounted. It was basically 12 gauge electrical wire in plastic plumbing pipe. Pipe caps sealed both ends so there were no problems with weather on the antenna. It worked quite well but the elimination of old style bumpers made mounting a problem.
i am trying to make dipole that I want to put on vehicle but I dont wont it be easily seen like a big antenna on the roof so i was thinking i could make a 2meter dipole and put it verticaly on the side of the vehicle and then just rune the coax in by the window but i dont know how that would work
I would think it would react with the metal on the side of the car and give a very high swr. If you want stealth maybe a little ground plane for UHF might work a lot better. One other thought I had was maybe one of those old style FM car antennas. Not sure about the ohm they used but you might be able to modify it and get it to turn up on 2 meters.
could i use a uhf ground plane on vhf too ?
Short answer is no. You could however, make a shorten vhf antenna using a loading coil.
Ok thank you
G7RUX
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- Jul 14, 2021
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I have done this in the past on a large metal vehicle…it does work but there will be an interaction between the antenna and the bodywork. In short it will act as a reflector, meaning you’ll end up with little power in the direction of the opposite side and the detailed performance will depend on how close to the body the antenna is mounted; basically the closer it is then the more interaction and the more unpleasant the result.
if you are looking for a low visual impact then a shortened monopole is likely the tidiest and best all round performance you’ll get, unless you can get away with a quarter wave monopole (around half a metre long) on the roof.
An antenna cut for 2m will work reasonably well on 70cm since 70cm is the third harmonic of 2m (3 times 146 is 438 MHz, not perfect but will work ok-ish.) An antenna cut for 70cm will not work well on 2m, although a 5/8 or 7/8 on 70cm will be usable on 2m with some fiddling.
However, what I would suggest particularly with antennas is to give it a go and see what happens. If transmitting, start at low power levels and check the match before going “full beans!”
mmckenna
I ♥ Ø
Covert Bumper Antenna - 406-512 MHz
sti-co.com
Sti-Co is expensive, so making your own is a MUCH cheaper option.
Putting it inside the vehicle, especially up against body metal, is going to be very problematic. As others said, the metal will interact with the antenna and detune it, plus it'll be really directional. It likely will not be much better than a portable radio used inside the vehicle.
If you put a vertical antenna in the back window, it can work in some cases. However, tinted windows often use metallic film that will block the signal. Defroster wires will do the same thing.
I know, you don't want an ugly outside antenna, but a basic 1/4 wave antenna is very low profile, blends in well if installed correctly, and will work a thousand times better than what you are planning.
Plus, a 1/4 wave VHF antenna will work as 3/4 wave on UHF, and actually work pretty well.
If you give us some more details, we might have some other suggestions;
Brand/Model of car.
Type of radio you are using
What your install skill set is like.
There are options, but some are vehicle specific, and the exact solution will depend on the intended use.
the van is a big gmc vanCovert Bumper Antenna - 406-512 MHz
Sti-Co is expensive, so making your own is a MUCH cheaper option.
Putting it inside the vehicle, especially up against body metal, is going to be very problematic. As others said, the metal will interact with the antenna and detune it, plus it'll be really directional. It likely will not be much better than a portable radio used inside the vehicle.
If you put a vertical antenna in the back window, it can work in some cases. However, tinted windows often use metallic film that will block the signal. Defroster wires will do the same thing.
I know, you don't want an ugly outside antenna, but a basic 1/4 wave antenna is very low profile, blends in well if installed correctly, and will work a thousand times better than what you are planning.
Plus, a 1/4 wave VHF antenna will work as 3/4 wave on UHF, and actually work pretty well.
If you give us some more details, we might have some other suggestions;
Brand/Model of car.
Type of radio you are using
What your install skill set is like.
There are options, but some are vehicle specific, and the exact solution will depend on the intended use.
im planning to travel some next week so i thought i would only use a little handheld radio see if i could pick up some things i also have yaesu ft212 rh and a radioshack htx 212 but i think i will only take a baofeng uv82
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mmckenna
I ♥ Ø
On a full sized van like that, a simple chrome 1/4 wave VHF whip mounted on the roof will be nearly invisible unless someone is specifically looking for it.
Plus, on top of a perfect ground plane like that, it's going to work very well.
I run 1/4 wave VHF whips on top of all my personal vehicles. They are often more "low profile" than the purpose built low profile antennas.
mmckenna
I ♥ Ø
Ah, OK.
hand held radio, put it under the seat when you are not using it.
You could also just tape a thin piece of wire up the inside of one of the windows.
G7RUX
Member
- Joined
- Jul 14, 2021
- Messages
- 395
I often use a handheld radio with a commercially available mini mag mount antenna when I’m in a “job” vehicle that I cannot reasonably fit a better antenna to and it works fine for most purposes.
if you are short on cash I would suggest a SignalStick and a suitable small mag mount base since you can also use the Antenna on the top of the radio.
if you are short on cash I would suggest a SignalStick and a suitable small mag mount base since you can also use the Antenna on the top of the radio.
