[FARC] HT's In Vehicle

[David Matthews]

Hi Kirk -

kirktal7237 at msn.com wrote:

 > ...HT speaker distortion when the volume is turned up high enough to 
overcome road noise...

A common problem.   Some external HT speaker-mics have a 1/8" jack you 
can use to feed an external speaker instead of using the tiny one inside 
the speaker mic.  When I was doing this with an old Alinco DJ-160HT, I 
built a splitter cable, so I didn't have to run the speaker wire along 
the mic cable.   Because the HT probably doesn't have a very powerful 
audio amp, you'll need to select a high-efficiency external speaker. 

 >  ...and constant intermod on the 146.73 and 147.06 repeaters...
 >  

A common problem with HT's that have wideband receivers.  Many of the 
HT's designed for 2-Meters-only don't suffer from this.  A few years 
ago, I had this problem when an HT as a mobile rig and solved it with an 
MFJ-714 Intermod filter.  See 
http://www.mfjenterprises.com/Product.php?productid=MFJ-714  In fact, I 
think I may still have this filter around here somewhere and would be 
willing to part with it for a fraction of the cost of a new one.  Let me 
know if you're interested.  Some people use PAR filters to kill intermod 
caused by high-power paging transmitters.  See 
http://www.parelectronics.com/amateur.htm    Of course, if your problem 
stems from strong nearby transmitters inside the 2 meter band, then 
neither of these solutions will help.

 > Additionally, most HT manufacturers make a cigarette lighter battery 
charger for vehicles.
 > Can someone tell me is this for charging only or can it be used to 
operate the HT while driving?

Depends on the model of HT you're using. 

 > I know, cigarette lighters shouldn't be used because they are not 
designed for the heavier current draw
 > of ham radio equipment. 

Shouldn't be a problem for an HT (which probably draws less than 1 
amp).   Your main concern with using this is possible ignition noise... 
and this depends on the vehicle, the charger cable, and the radio:  Some 
charger cables have built-in hash filters.  Some cars don't generate 
much hash.  Some HT's aren't bothered by it.   Your mileage may vary  :-)  

73 de K3MV