eHam Forums => Mobile Ham => Topic started by: KB9TQN on December 05, 2000, 01:02:17 PM

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on December 05, 2000, 01:02:17 PM
I recently got a Pryme speaker/mic for my Yaesu VX-150. It's great but in the car they're all but useless unless I take the radio off my belt, something which for me basically negates the reason for getting a speaker/mic.

Does anyone know if there's a speaker/mic available with an antenna on it? Any tips on building one? My speaker/mic is the Pryme SPM-602. It has three holes at the top under some rubber and a headphone jack at the bottom next to the cable. I'm thinking if I have to build one I'd use one of the top holes for a BNC antenna connector and desolder the headphone jack and run some thin coax through it to a BNC-SMA adapter on the radio.

Title: Speaker/Mic plus antenna?
Post by: KG4GAV on December 06, 2000, 01:11:02 AM
Motorola and some other radio mfgs make speaker mics mainly used for public safety (police, etc) which are heavy duty and have an antenna on them.  Check with a local radio shop, they will have the pinouts on the mic and may be able to put a 3 conductor phono plug and an SMA antenna jack on for you, or at least tell you what wires are for what and let you put your own plugs on.  

They may even have one that works fine but has a broken connector where it attaches to the radio, which you would have to cut off anyway, and you could get a better price than buying one new.  

Also, check with Yaesu. They have the Vertex line of (commercial) radios that use some of the same accessories as the amateur line.  See if they have something that is made that way.

In my opinion, if you are inside a vehicle, the antenna being on a spkr/mic vs on your belt will not make *that* much difference, and do you really what the radiation going straight through your head?

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on December 07, 2000, 11:59:25 AM
Thanks I'll check out the local shops! Actually I'm not transmitting much just listening. I noticed when the antenna had a clear shot at a window I could receive everything I wanted so I thought an antenna on the speaker/mic might be the best option.

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on December 19, 2000, 12:10:46 AM
Just a little update to my speaker/mic antenna project. After seeing how much used Motorola speaker/mics with antenna connectors cost I decided to modify my Pryme SPM-602.

So far I've taken out the headphone jack near the bottom of the speaker/mic to make room for the coax. Luckily I found a ready made SMA-BNC adapter cable that's three feet long (Catalog number 940-1183) on the Radio Shack web site. Once that arrives I have to figure out how to modify the rubber cover strip on the top of the speaker/mic in a way that doesn't totally destroy the thing. ;)

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on December 21, 2000, 10:25:49 PM
It's done! The cable from Radio Shack came today and after a frustrating hour the project was complete.

I had some trouble running the coax through the speaker/mic. It took a little wiggling of the cable but everything ended up fine inside the case. The real problem was making a hole in the rubber covering at the top of the speaker/mic. First I thought I could make a slice and slip the coax through. Unfortunately that didn't work. I ended up just cutting a hole in the rubber hoping I didn't cut too much and tear the rubber in half. Once I had a hole the right size I carefully put the rubber in place around the edge of the case and the BNC connector and put the speaker/mic back together. I put the screws in and added some rubber cement as a sort of filler for the headphone jack hole at the bottom where the coax comes out and the hole at the top where the BNC connector is.

So far everything works fine. Audio is good and reception is good. To finish it off I need to get a 2m antenna to replace the 2m/440 antenna I have on there now. I have some pics on my site. Take a gander if you want.

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on December 25, 2000, 04:07:15 PM
Well I discovered a little problem with my design. First of all it looks pretty bad. Once the joy of not breaking anything wore off I realized that it just looks darn ugly! Next I discovered the clip isn't really strong enough for the top heavy speaker/mic now. I tried adding a metal clip from one of my broken radios but that still wasn't enough.

Oh well it didn't hurt to try! That's what ham radio is all about!

Title: Speaker/Mic plus antenna?
Post by: W0FM on May 23, 2001, 03:46:04 PM
I am in the commercial radio business and you just hit on what I was about to say.  Motorola does not manufacture a speaker/mic for use with VHF radios for that very reason.  The longer VHF rubber duck makes the mike top heavy and cumbersome.  All the Motorola speaker mics are designed for 450 MHz and higher. I've had customers experimentally attach VHF antennas to UHF speaker/mics in desperation, then end up stuffing the whole works in a drawer.  73, Terry

Title: Speaker/Mic plus antenna?
Post by: KB9TQN on May 23, 2001, 04:01:47 PM
If I ever came up with a workable solution I was planning on using a Miracle Baby for the antenna. It's small and the reception is still pretty good which is all I really need.