I've had this same issue installed my first vehicle radio TR-7850 (50W FM). At PTT I measured at the rig 10.2VDC (engine on) and my memories got wiped out as well ass got feedback my TX was dropping out. It was due to the 12AWG speaker wires I used and the length of the run (about 13' with all the twists and thru firewall under the mat, etc). I installed 8AWG construction cable and all this went away. At PTT I now measured 13.7VDC (engine on).
Now I run multiple rigs IC-7000 and IC-2800 and only install 8AWG wires that (I buy from Tower Electronics - very flexible). At DC voltage - wire acts like a resistor. [The equalizer resistors on power supply pass transistors can be 12" 30AWG that will drop 1V.] Truck design industry - recommends for 12-28VDC current/fusing per wire size per 20ft length. Wire Gauge; Protective Device Size; Maximum Current (Amps) 18 AWG; 10 AMP Fuse/Circuit Breaker; 8 A 16 AWG; 15 AMP Fuse/Circuit Breaker; 12 A 14 AWG; 20 AMP Fuse/Circuit Breaker; 16 A 12 AWG; 25 AMP Fuse/Circuit Breaker; 20 A 10 AWG; 30 AMP Fuse/Circuit Breaker; 24 A 8 AWG; 12 Gauge Fusible Link; 80 A 6 AWG; 10 Gauge Fusible Link; 108 A 4 AWG; two12 Gauge Fusible Link; 160 A Often if more current is needed we will double up the wires/cables into "O"ot gauges with 200/250A fuse links (especially to Starters) until we see only uVolts of drop. FYI, your battery should see no more than a maximum 14.2VDC with engine on (and minimum of 13.8VDC), more voltage and you will cook your battery and likely have a regulator problem. --- In dstar_digital@yahoogroups.com, "w0rmt" <w0...@...> wrote: > > So I took the radio our of the truck and plugged in into the control head and > power supply for my other 800 in the house and it worked fine. Therefore the > radio itself must be fine, meaning that the SWR of the system in the truck is > high and/or the power supply in the truck is problematic. > > I did notice that when the truck is running, the power to the rig is a bit > high (14.5V). When keyed on high power and when the truck is off, voltage > drops from 12V to 11.6V. I think I might need to invest in a voltage > regulator. Any suggestions? > > 73 de Bud > W0RMT >
