Ham antenna and other questions

my local (toyota) 4x4 club is looking into doing a group deal for the industry canada (canadian fcc) ham licenses, so that we can use VHF radios, rather than frs (i use uhf on frs frequencies) or cb while wheeling. here's the issues, i don't want to put some random dumb looking vhf antenna on my truck, i'm wondering if there are any vhf radio antennas i can get that will look similar to my 4' firestick

additionally, someone on my other forum was discussing using his Yaesu? as a repeater for his handheld, to the main repeater on that channel... does this make sense?

i'm looking at the yaesu ft-1900r right now, which seems to have the features i'm looking for...

also, my PA on my cb died on me, i am going to need to replace it, just curious if anyone has used any amplified pa speakers, and possibly an electronic airhorns?

long story short, my horn sounds like crap, rather than just put a different horn on, i want to put an electronic air horn on, such as what you hear on a police car

like this sound clip, near the end
http://www.youtube.com/watch?v=3Siktd9wTKg&NR

to clarify, i do NOT want to put a siren on my truck, just wondering if i can get the air horn, i figured it would have to be installed with a pa speaker of some sort, would probably be easier, and then hook that up to either the cb or vhf as a pa

my reason for wanting an amplified pa is the one that i've got on there right now, just isn't loud enough for what i use it for, for announcing things at paintball tournaments, or 4x4 meets

you can buy a 100watt pa/air horn/siren box on ebay. i don't know any other way to get the horn. i run a cb with the pa goin to a 1000watt amp turned all the way down on a 100watt pa speaker its so loud you don't know where its coming from in traffic haha as far as ham radio i know nothing about them

i specifically do NOT want the siren part, as i am not to be trusted with such items...

do you have pics or links to your setup? i would love to see it...

if yo had to guess how many of those 100w you are using, what would it be?

i don't know how many watts it would be but its always better to run an amp as low as you can that has more power than the speaker needs so you get the best sound possible and i'll take some pics tomorrow its too dark right now..

The repeater is possible. It takes some trick setup, but it is done all the time. Basically you set up a base station with a big antenna and all the Ham repeater gear. then when someone calls on the channel the repeater is set up on, the repeater takes that signal and broadcasts it at the full power of the base station. At home there is a repeater that puts out around 1000 watts if I'm not mistaken. It can be done with any frequency in theory, however in the states i believe that it is illegal to do it on CB, but don't quote me on that.

http://www.responderpse.com/d680-Carson-In-Cab-Electronic-Air-Horn-Kit.htm
i think this doesn't have a siren kinda want one now lol

yeah, i'm not planning on doing it with a cb, there is a limit to transmit power

407Link said:

http://www.responderpse.com/d680-Carson-In-Cab-Electronic-Air-Horn-Kit.htm
i think this doesn't have a siren kinda want one now lol

Click to expand...

that looks pretty good, but it doesn't seem to have a pa, which is something i really want... i don't see the need for 2 high powered speakers in my grill...

--weezl-- said:

additionally, someone on my other forum was discussing using his Yaesu? as a repeater for his handheld, to the main repeater on that channel... does this make sense?

Click to expand...

Was probably a feature called "Cross Band Repeat". It requires a full dual-band radio in the vehicle such as the FT-8800R.
You talk to it, say, on a UHF handheld, and it retransmits your signal over VHF. When a signal is received on VHF, it retransmits it back to your UHF handheld.

As for the antenna... I don't think there are any VHF ones (for a mobile anyway) that are big and obnoxious (comparatively speaking) like your Firestik CB antenna, the frequency is about 1/5th the wavelength. Simple laws of physics make them smaller (though if you get a gain antenna, it'll be taller than a 1/4 wave one, but still not fat like the helical windings on a Firestik).

I have one of these... is small & unobtrusive, seems to work fine without interfering with my other antennas, and is rather inexpensive to boot.
http://www.theantennafarm.com/catalog/index.php?main_page=product_info&cPath=191_192_200_450_452&products_id=1568

so it's not possible to repeat vhf directly back to vhf?

i found one marine fiberglass antenna that's 1.1m (about 3.6 feet, or 3'7") which is only about 5" shorter than my firestick, and won't be a hair sized whip antenna... if i were to do the smaller whip style, i would do a hood mount, one where the mount comes up between the hood and the fender, and sticks out the side kinda..

will the marine vhf antennas work on a regular vhf radio? i can't see it causing problems as long as it's tuned properly

what i might do: (cb antenna pictured)


alternatively i could put it in place of my truck's radio antenna, which i don't use, and is in the box of my truck right now... though 3 antennas might be fun...



this is the marine one i found, if i could find it in black it would be perfect (if it works for me)
http://www.alibaba.com/product-gs/289128775/1_1M_3_5dBi_OMNI_VHF.html

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Sorry for the cr@#y pics only got my camera phone

--weezl-- said:

so it's not possible to repeat vhf directly back to vhf?

Click to expand...

It's possible, but not real practical from a vehicle (at least at power levels of a watt or so and above). The frequencies are so close to each other that it's difficult to prevent blocking (desensing) the receiver with the transmitter.

Fixed-station repeaters use a large cavity resonator apparatus to allow simultaneous in-band receiving & transmitting. Such an apparatus isn't practical in a vehicle (and they tend to not like vibration either).
Repeating cross-band, the filter requirements are far less stringent (components can fit within the confines of the radio itself), due to the larger separation in frequency.


As for the marine antenna, I see no reason you can't use it as long as it can be tuned for resonance on the freq you want to use it on.


Edit:
I remember some years back Radio Shack sold a "simplex repeater" device that could work on any typical radio in band. I don't know if anything like that is available still or not though.

It worked by recording the audio from a received signal, then when the signal drops (squelch closes), it then would automatically key up the radio's transmitter and replay the recording followed by a beep signal. Wasn't real practical with long conversations though, and if you happen to be in simplex range of the other person, you'd be hearing everything twice lol.

For an antenna, a good 5/8 whip on 2m (144-148 mhz) is 52" long. It's not a fat fiberglass rod, though, it's a steel wire whip. Diamond makes one, the M285S or M285SNMO, from www.aesham.com . If you're getting a radio that's multi-band capable, you probably want to get an antenna with matching capabilities. Most VHF/UHF multiband mobile antennas are about 30-36" long.

For a VHF/VHF (simplex) repeater, the most economical option is a sound-recorder type. Argent Data Systems ( www.argentdata.com ) makes a nice one that can be remotely controlled by the keypad on your portable. Just hook it up to the mobile rig in your truck, take your HT with you, and you've got an instant mini-repeater.

I've never seen a ham radio with a built-in PA amplifier. You'll have to look elsewhere for something like that.

Spott
KC7JXF

thanks for the replies (and pics)

the recorder repeater doesn't really sound feasable to me... though now that you mention it, i remember seeing UHF repeaters you could put in a truck, on ebay, they more or less worked like a normal one, set your radios to tx on say 430 and rx on 435, then set the repeater to rx on 430 and tx on 435 so you wouldn't have the echo...

if you were to do the simplex repeater like you were saying, 4x4, you would have the garbled transmission like someone "walked on you" wouldn't you? (if you were in range of both repeater and other person)

Spott, at this point, i'm honestly just looking at the vhf for a radio, i've got a pretty decent uhf handheld that i use, and i don't know how much cross band repeating i am going to do... though it might be nice to be able to have my local club all using uhf (or even FRS for that matter, as it's technically UHF) and be able to repeat that out to anyone at home who might want to check on our progress/status while in the bush...

as for the pa, i didn't so much mean an amplified output, just a regular pa out like a cb, but it makes no real difference, i can always use the CB's output for the PA, just get a better speaker... i suppose, thinking about it, i could just use a cheap car stereo amp for it eh? a 20$ pyramid amp with line level inputs from the cb, and that hooked up to a more powerful speaker in the grill? then the question is how to hook the horn up to it...

a lot of this whole thing happened when our last outing into the snow got us stuck, lost, and broken... we found our way onto a snomobile trail, cliff up on one side, cliff down on the other, the only way around was across a clearing that had not been driven on, drifts of snow 4 feet deep saw about 2-3 hours of digging to get the first truck across, then the rest were ok, a few people (me) got stuck as i popped out of the new rut... the next hill saw a blown tire, then we got lost, then the trail disappeared under more snow drifts... we were supposed to be aired back up and almost back to town by 5pm, didn't get out of the bush till midnight, and i had been up like 38 hours by the time i made it to bed... people were worried about some of us, as some of the guy's had wives waiting for them and we didn't find an area with cell reception till about 10pm (5 hours later than we were supposed to be home)

by the time we exited, we were all starting to run low on food and water, though we banded together and shared what we did have

Yes, the simplex repeater would repeat back a garbled transmission if two of you "doubled" into it with similar signal strength.
The other thing is you have to pay attention for the presence of the "beep" signal it gives. If you don't, you might get "squashed" by the repeater repeating another's transmission when you were actually hearing that person directly.

Like I said, it's quite cumbersome, but can work in some instances (you'll certainly want a separate channel to carry on your conversation if you're within range of each other).


Glad to hear you & everyone made it out of there OK.

thanks, it was an interesting day for sure... the worst damage anyone got was the blown tire, though we all came home with some custom pinstriping, sadly i was one of the older vehicles there, with the 07... there were guys there with like 09's and 2010 tacos...

one guy, the one who blew the tire, i think his was BRAND new, 2011, and he got some BAD pinstriping, one of them, right from marker light right around the back, a good 1/8" thick the whole way and fairly deep, through the clear for sure, not through base though...

our main reason for using the vhf is for close communications, secondary would be to contact home for issues, i THINK there are a few repeaters in the area that i can actually pickup on my phone, on an app i've got (5-0 radio, and police radio app) i know one of them i can add any web based radio on, using just a url