On 1/12/2014 10:26 AM, Matt Zilmer wrote:
Wiring to the KXPA100 is 8 AWG, with two "transfers" to APPs at a relay enclosure for power control in the trunk. The source is the Civic's battery. The KXPA is located in the trunk.
Several thoughts about this. First, noise pickup on the power wiring will be greatly reduced by making it twisted pair. Second, unless the SWR is REALLY high, much less power will be lost in coax than in the DC wiring. Third, ALL of this wiring should have common mode chokes on it to further minimize noise pickup and RFI.
My strategy would be to locate the amp based on convenience, on making the DC cable shorter, and on the practicality of paths for routing the needed wiring.
I would use the best quality coax I could fit into the available wiring routes. This is an application for the best quality transmitting coax with a heavy copper braid shield. Remember that the shielding provided by coax depends upon a shield that has very low resistance and very good uniformity. Belden 9258 would be a great choice -- it's a RG8X form factor (0.242-in o.d.), with #16 stranded copper center and a 95% copper braid shield.
Finally, there is probably little benefit to bonding the radio or the amp to the frame of the vehicle. Thanks to the excessive application of paint and the use of lots of non-metallic parts, chassis bonding of modern vehicles is flaky at best, and a train wreck at worst (it is in my 2006 Toyota big SUV). Indeed, one of the major challenges in a modern vehicle is finding enough conductive structure to form a counterpoise for an HF antenna.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
