Use car AM/FM antenna for 2-way?

[jantman]

I'm about ready to put a mobile in my new truck (volunteer EMT, among other things). I really want to go slick-top, and definitely not drill any holes. I'm installing one VHF mobile, for now.

I'm sure I've heard a few times of people using their AM/FM antennas from the car stereo for 2-way, either via some sort of converter unit, or replacing the stock antenna with a stock "look-alike" for 2-way use. I was wondering whether anyone has heard of this, and has any idea of sources for parts, etc.?

Thanks,
Jason

[n7maq]

I'm about ready to put a mobile in my new truck (volunteer EMT, among other things). I really want to go slick-top, and definitely not drill any holes. I'm installing one VHF mobile, for now.

I'm sure I've heard a few times of people using their AM/FM antennas from the car stereo for 2-way, either via some sort of converter unit, or replacing the stock antenna with a stock "look-alike" for 2-way use. I was wondering whether anyone has heard of this, and has any idea of sources for parts, etc.?

Thanks,
Jason

http://www.sti-co.com/covert.asp
http://www.licenseplateantenna.com/

They both have AM/FM/VHF 2-way set ups.

Jim.

[Tom in D.C.]

One good reason for not trying to use the stock car antenna is
that the cable from the antenna to the radio is always a big
question mark as to impedance and quality. In the past the cable
often was nothing more than a black plastic tube with a copper
wire inside. Another reason is that you can't really use an antenna
whose length can be changed at any time for any reason.

Stick with the antennas listed above. They'll work fine and you
won't have to drill any holes.

[jantman]

After posting to another forum also, I think I'll go with one of the Sti-Co products which, as I first mentioned, provide a replacement for the factory whip. They also include RG-58/U feedlines.

Another reason is that you can't really use an antenna
whose length can be changed at any time for any reason.

HUH??? I assume you're talking about one of those old-style electric antennas that collapse? I'd never even thought about that...

[4n6inv]

Has anyone had any experience with the Sti-Co dual band disguise antennas? I'll be buying a new truck soon, and had considered not driving a rolling antenna farm. I've heard that the old Sti-Co's were not that great, but I've heard that they work really well, now. But; I haven't heard any feedback, or know of anyone that has used a dual bander. I'm looking specifically for the VHF - UHF combo - with broadcast radio reception capability.

[FireCpt809]

Ive installed numerous Sti-co antenna's. Ive never had a problem. They are very band specific and usually want a freqency for what you are using so it can be properly tuned at the factory. Ive had good SWR's on the V/U dual bands.

[Pj]

I have used single band look-alike antennas and they have been exellent. I haven't heard of any complaints with Sti-Co, other than they are expensive - but you are getting what you pay for.

They are great for the Impala DB cars, as they look natural.

[WB6NVH]

Okay, let me be the first to complain about Sti-Co. I admit that the most recent examples I purchased were back in the mid 1990's, VHF high band models which I used on some sheriff's unmarked Chevrolet Suburbans. Maybe they have cleaned things up somewhat in the years since, and I have only had experience with that model.

The antenna itself was a 1/4 wave metal rod slid inside a plastic rod which imitates the original broadcast antenna. Thus you have an 18" whip for the actual antenna. The antenna base structure where the cable exits was too long and too big and did not clear the inner fender structure, so we had to waste extra time routing out the inner fender and firewall brace area to get it to fit. This was supposed to be an exact replacement GM-style antenna. These antennas were the combination AM/FM/2-way style, with coupler, but the broadcast radio performance on both bands was pretty bad. On the good side, the antenna was a dead-ringer for the stock GM setup (above the body.)

You might be able to get these antennas from Tessco these days or another distributor. At the time, I contacted Sti-Co directly and received a rather snotty response that they refused to deal with any "end users" directly, and they sent us a bunch of unrelated PR rubbish about how proud they were to be a woman-owned company, as if that had any bearing on our inquiry, and didn't even suggest a distributor we could buy from. I finally discovered that one of our distributors had a Sti-Co account and we got them that way.

Sti-Co seems to be about the only game in town so you are stuck with them, more or less. The performance of the antenna was only fair, what you would expect from a 1/4 wave whip mounted where the broadcast antenna goes. I got cranky after that experience and from then on just built antennas with some of that sticky clear tape with the fine wire inside, sold for GM cars with defective in-glass antennas, running a 1/4 wave whip up the inside of the windshield glass at one edge. Worked just as well and there was no labor involved in removing expensive disguise antennas when the vehicles were surplused. Just left it there.

If you are only worried about drilling a hole, I would get an on-glass mount which is a lot cheaper.

There was also that body-coupler "Un-tenna" thing which I have never tried and haven't seen advertised lately, maybe someone has some experience with those.

[jantman]

Does anyone know of any companies other than Sti-Co that make them? I know someone who used to be a Sti-Co dealer, so I can have him look into it, but I'd also like to get an idea of how much they sell for...

[spectragod]

I've used Sti-Co on quite a few vehicles, my own included, never had an issue or a problem. Always had good service from their product.

I would steer away from a homemade antenna on the inside of the glass, you'll wash the inside of the vehicle with RF, if you have a late model vehicle, that can cause a lot of issues.

Glass mount on VHF is equally crappy.

Generally speaking, $150 or so for a single band antenna and $300 or so for a dual band is about the norm. You get what you pay for.

As far as a bad attitude from the factory...??? I have never had that issue, maybe it's a get what you give kinda thing.

SG

[4n6inv]

Interesting. I'm not as concerned abou the price as I am the performance. I've heard that the earlier models were nothing more than "Dummy Loads". I've heard that the newer "single band" antennas were great. I haven't heard any feedback about dual band antennas. Generally speaking; dual band antennas don't perform very well on both bands. I was just hoping for a "smoking gun" solution. I guess you can't have your cake and eat it, too. But before I spend $300.00 on a dual bander; I wanted to ask.

[Will]

License Plate Antennas manufacture, one, two and three Band O.E.M. mast antennas. Jeff runs the place an is a good guy to deal with.

I have a few customers with their dual band setup with the 31 inch factory rod antenna.

US Communications
1899 S. Santa Cruz St.
Anaheim, CA 92805

Contact: Jeff
800-435-9800 714-978-9150

Be sure to tell Jeff that Will sent you.



[quote="n7maq]

http://www.licenseplateantenna.com/

They have AM/FM/VHF 2-way set ups.

Jim.[/quote]

[Pj]

Sti-Co use to sell direct, then went to dealers, and now will sell direct again (As well as dealers). When I called around, Stico had the best price...as many dealers where added on $10-$50 or more for profit (which is/was a concern for Sti-Co).

When I delt with them, they were pretty cool. Haven't used a license plate antenna though, seems like it could be neat.

Anyone have a pic on what the radiating elements look like?

[FireCpt809]

Ive installed one plate antenna.. It was a dual bander Front plate was VHF rear was UHF. It had 2 coupler boxes one for the V and U. It has a coax that had to have the braid grounded and the center went to a ring terminal that was attached to the plate at the screw hole. The plate had to have the back sanded clean for good contact.

It worked OK but the department that used it was a repeatered UHF system

[USPSS]

COMPROD COMMUICATIONS LTD.

The AM/FM antennas Rock. Most of the Feds use them now.

They work for both 2-way and the goodtime radio very well. I have a low band on my 2007 Silverado and it works extremely well, double stubbed so I have .5 in 39 & 42.

Stan

Not an endorsement by Kenwood USA Corporation

[Wowbagger]

I'd like to find a 'plexer that would allow me to feed everything below 800MHz to one spigot, and everything above 800MHz to another spigot, so that I could use the same antenna for my dual band ham gear and my phone.

Yes, the antenna wouldn't be perfect for the phone, but it would be a damn sight better than the antenna on the phone, inside a big metal box.

However, I've yet to find one that wasn't VASTLY more expensive than adding a second antenna and looking more like a cop car than I do now - unlike some people I *don't* want to have a rolling antenna farm if I don't have to.

[Pj]

The closest I have comes is the Diamond MX3000....1.6 to 162/UHF/800-1.3?

VHF 144-170, and UHF rocks. I am taking a hit on 800 RX compared to the 3db gain antenna I had before (each radio had its own antenna). 55db isolation on the triplex.

However, right now those 3 radios (VHF Astro Spectra, UHF GE Orion, 800 Astro Spectra) are being ran off of a Diamond low profile dual band V/U antenna...the 14" verison.

I am going to throw my old 800 antenna up there and see if I am taking the hit off the triplex or the antenna (pretty sure the triplex, but you never know).

Specifications:

Port: LPF/BPF/HPF
Frequency (MHz): 1.6-160/350-500/850-1300
CW W: 400/200/100
PEP W: 800/400/200
Loss dB: .2/.3/.4
Isol dB: 55/55/55
Mix Connector: N-Jack (F)
Port connector: PL-259 & 12" 5D cable/PL-259 & 12" 5D cable/N-Male & 12" 5D cable

Specifications:

Bands: 2m/70cm
Gain dBi: 2.15/2.15
Watts: 100
Height: 13.8"
Mount: NMO
Element Phasing: 1-1/4l, 1-1/2l

[Wowbagger]

Yes, I'd thought about the Comet, but the problem I have is that all my radios have one connector for VHF/UHF - indeed, how many modern radios have separate connectors for VHF and UHF?

I'd end up using a second diplexer to bring the VHF and UHF back together, and taking yet another hit.

I'd prefer either:
a) a diplexer for below 500 and above 500MHz
or
b) A triplexer for 1.8-50/144-440/800-1900

where the actual used for the HF side would be those rare occasions when I actually have to have my Children's Band in the car (to talk to folks who aren't licensed for amateur service).

I'd take the hit for chicken band and for cell service.

[Will]

Jeff has some very good couplers/diplexers that may be better suited to the bands you need. You can ask him directly at 800-435-9800