[Elecraft] KX3 on SSB Mobile

[Jim Brown]

On Sun,7/12/2015 10:32 AM, Dauer, Edward wrote:
> Installation - I have found someone who does mobile radio installations
> professionally, for police and commercial vehicles, and he¹s also a ham.

Remember that all of his professional work is for VHF/UHF, where there 
is FAR less possibility of interference to and from the vehicle's 
on-board electronics. He is unlikely to know about using ferrite chokes 
to avoid problems on HF, and he won't know that multiple turns are needed.

> Plan to meet him next week.  He¹ll have his own list, but I wanted to ask
> what my list should be ‹ other than installing the Hustler mount for the
> antenna, complete boding of everything to everything,

Complete bonding of the vehicle is the biggie -- my Toyota Sequoia is a 
bonding disaster, with elements of the body and frame insulated from 
each other by paint.

> direct DC taken from the battery (yes or no?)

Yes. Do NOT use the chassis as a return.  Do NOT bond the radio or the 
power amp to the car.

> , in-line fusing everywhere. . . . DC wiring shielded?

No, but use twisted pair. Buy black and white #10, put it in a drill and 
twist it.  Make the cable  long enough that you can wind multiple turns 
through a ferrite core, following the guidelines in 
k9yc.com/RFI-Ham.pdf   Place the choke near the battery.

> How about the control lines from the KX3 in the cockpit to the
> KPA in the rear cargo space?

Elecraft has connectorized for CAT5, which, if each signal is on a pair, 
offers good noise rejection.  Add a ferrite choke to these cables.

> Any special considerations?  What else should I be sure to have done?

Use a ferrite choke on the coax as close as possible to the antenna. DO 
bond the coax shield to the vehicle at the antenna -- that's your 
counterpoise -- and make sure that everything in the path is bonded. 
Example -- in an S80 Volvo I used to own, I used a license plate mount. 
I had to bond between the mount and the trunk lid, and also around the 
trunk hinges. More bonding would have improved both TX and RX, but I 
never got around to doing it.

> SSB  -  I have never used either the KX3 or the K3 on anything other than
> CW. I don¹t even know if the Mode switch works.   I saw on the reflector a
> couple of weeks ago a ³starter set² of audio settings for the K3.  Anyone
> have the equivalent advice for the KX3?

The laws of physics don't change between rigs.  Use the same settings 
for TXEQ that I posted for the K3 -- max cut of the three lowest bands, 
cut 6 dB on the 4th band. Depending on the mic and your voice, you might 
want more cut on the 4th band, and you might want a bit of boost on the 
top two bands, but not more than 6 dB.

Because the KX3 audio amp is intentionally designed to minimize current 
draw for backpacking, it is good to use the same settings for RXEQ. This 
will maximize the power available for speech.

> And despite the critique posted
> here recently, I have the Heil Pro headset that Elecraft sold with the
> rig.  But I don¹t want a headset while I¹m driving, right?

For county hunters, you might want to try to find places you can park. 
Hilltop locations can greatly improve your signal, and being parked 
allows you to wear a headset. Also, don't rule out CW, which will 
greatly improve your range. I've done a LOT of CW mobile, even when 
driving through Chicago rush hour traffic! I'm a leftie, so I put the 
paddle on top of the compartment between the two seats.

> So - what¹s a good mike?

See comments in previous threads.  Almost any good communications mic 
can be made to work fine by simply wiring it correctly.

> And should I try to get the KX3 audio output through the car¹s audio system

I would be cautious about that -- you could open up a can of worms with 
RFI or noise.

> (it¹s an old Bose), or buy a separate external speaker and
> mount it somewhere?

Many years ago, I found some little cube speakers at a hamfest, and 
bought ten of them. I recently mounted a pair of them to the headrest 
for use with my FM rig. That MIGHT be loud enough. Try the passive 
speaker first if you can find one, use the amplified speaker as a last 
resort -- again, that can of worms with noise from the vehicle's 
electrical system. One good alternative, if you can find them, are the 
battery-powered speakers that used to be sold for use with Walkman-style 
products. This eliminates the need for connection to the vehicle for power.

> What else am I not thinking of . . ?

Watch out for QRM TO your vehicle's computers. When I fired up 100W on 
20M, it crashed the computer in my Toyota Sequoia. I was driving through 
the desert in nowhere Nevada at the time.

73, Jim K9YC