K1VRA

Get better sound from your Mobile Ham Radio

Although I usually have only 1 rig in the car, sometimes I want to use a hand-held, too.  But the speaker in my handheld units are almost never adequate in the noisy environment of an automobile.  Some years ago, I purchased a pair of 3" wide-range speakers that were a perfect fit in some un-used speaker mounts in the dash of my Olds 98.  I connected them to my VHF rig, and I liked the way these speakers sounded so much that when I got rid of the car I kept them.  Another way to handle the problem is to use a "cassette adapter" and use the car's sound system for the HT.  I couldn't do this because my present car only has an AM / FM radio - no cassette player!  Many newer vehicles have CD players, so that's not an option, either.

Perfectly fitting speakers for any car are available from a number of manufacturers and, by using existing, unused speaker openings (most cars have several), you avoid adding extra clutter in your car (XYLs like this) while gaining impressive sound from your rig.

My last vehicle had an un-used 4" x 10" speaker opening in the center of the dash.  Sometimes this size speaker can be difficult to find, so I removed the steel filler plate, drilled two 3" holes in it and mounted both of my 3" widerange speakers side-by-side.  Actually, the 2 speakers do not have to be close to one another; just make use of any available openings.  In my Olds, they were on opposite ends of the dash but, as long as you maintain proper phase, they'll sound fine.

Try installing two ham rigs (or a rig + a scanner) in your car.

Another feature I wanted was to be able to re-configure the speakers so that, when used with only 1 rig, they could be connected either in parallel or in series.  Why? Because not all rigs work best with the same speaker impedance, and sometimes you get a slightly different "sound" from 2 speakers connected in series than when the same 2 speakers are connected in parallel (you kinda need to hear it to "get it").  So I added a switch to change the connection.

In Figure 1, when S1 is set for parallel connection, J1 feeds both speakers in parallel or, when you connect a 2^ND rig to J2, the speakers will automatically operate independently, with 1 speaker connected to each rig.  When S1 is set for the series connection, J2 is disabled so use it for your "secondary" rig.  (NOTE: The 'commons' of each rig will be connected together - it's up to you to determine if this is OK with your rigs.  This shouldn't be any problem with a hand-held.)

For best results observe speaker polarity as shown or the sound will cancel when used with a single radio.