Radioshark to Car Antenna

**theminor** · 02-27-2006, 03:55 PM

I got the radioshark hoping to achieve AM and FM integration with Roadrunner (see this plug-in. Well it works, but as everyone has determined, the radioshark's reception is horrible. I found this antenna hack and I want to use this process to wire the radioshark to my car's antenna. Inside the radioshark is a single-wire FM antenna and an AM antenna coil. My question is this: does a car typically share the same antenna for AM and FM or is the external antenna for FM only (with AM using an internal coil of some sort)?

Also, how should I wire the antenna? The car's antenna connector is basically a coax cable, which means it has 2 conductors: an outer negative shield wire and an inner positive signal wire. Since the radioshark antenna only has one FM conductor - the antenna wire itself - how do I connect the two? My initial idea is to solder the radioshark's antenna wire to the car's antenna-coax cable's center. Or maybe the other way around (this woudl do nothing for AM, but I'm assuming that all radios use an internal coil-type AM antenna).

Basically I don't know anything about this and any help woudl be appreciated!

**numbers** · 02-28-2006, 12:49 AM

I realize that my background is in 2.4GHz, but even in the 100MHz range I would not expect it to be acceptable behavior to use 2.5mm jacks and standard wire to carry signals, or to attach anything to the end of a preexisting antenna. I would try to find some sort of cheap adapter or something with a socket you can cut off that will accept your car's antenna connector. Preferably something with a few inches of cable still attached since I'm not sure what impedence coax cable to recommend you use. Remove the stock antenna and attach the center lead of the new socket in it's place. Run a wire from the nearest ground location to the shielding of the cable.

**theminor** · 02-28-2006, 08:13 AM

Great - thanks very much! I assume that I should just leave the AM coil alone then?

**numbers** · 02-28-2006, 01:12 PM

I wouldn't know. Sorry. Radio isn't my thing.

**godraj** · 04-22-2006, 11:50 PM

how far did you get with this? I've tried a few things and I was uncessful. Any ideas?

**theminor** · 04-23-2006, 08:07 AM

I haven't gotten very far. I haven't really tested much though because I haven't yet moved my CarPC into the car. What have you tried godraj and what has not worked?

**numbers** · 04-23-2006, 09:59 AM

Originally Posted by theminor

What have you tried godraj and what has not worked?

Perhaps I can be of some assistance.

**godraj** · 04-23-2006, 10:16 PM

So far what I did was take the radioshark apart and put it into a smaller case. Then I used the FM copper wire that the radioshark comes with to solder onto the tip of a motorola plug. Then I took another wire and used that to go from the shielding of the motorola plug to a ground location to the car. After all this my reception didn't change at all. I get a few stations really clear, but other stations that I would get on a HU I nolonger get on the radioshark. Also I've noticed that when I'm driving i hear lots of static, if I'm stationary it gets a little better. The pic is of the radioshark in the new housing. Any suggestions? And in advance I appreciate any help you guys can offer.

**theminor** · 04-24-2006, 07:24 AM

So does the tip of the moterella now connect to your car's antenna? That is, does your car antenna now run into the moterolla plug you made? I plan to do exactly the same thing, only I'll use a coax female plug soldered to the radioshark and then I'll run coax cable to the car antenna jack, center connected to the antenna and shielding connected to ground. Is this your setup?

**godraj** · 04-24-2006, 10:07 AM

Yes, that's basically my setup, and it didn't affect the reception at all. I was looking over the link that you posted, and it seems that this person decided to use 2 wires, both which are soldered to the board. 1 wire looks like it's going onto the FM side, and the wire is going onto 1 of the AM connections. How do you think that will affect the reception?

Also, why will you use coax cable and coax female adapter? The motorola plug is what the car antenna jack plugs into.