DC Power Cable Change
As with all DC power cables supplied with modern 100 watt transceivers losses can be significant due to the lead length and the line fuses and with this rig the additional RFI filter which is supplied with the Euro/UK version. The lead itself is about 9' long which is more than twice as long as required by most people in a home shack environment. The new lead which I have made is only 4' long and is made with double cables of the same rating as the original lead and uses a single 20Amp blade fuse in the positive line close to the PSU. The difference is immediately apparent when monitoring the drain voltage of the PA devices which can be seen on the rig's metering menu when running "Full Power on FM or CW key down"
I checked the RF output from the rig with the RF POWER set to 100% and with full carrier using the original lead and the new lead, both leads connected to the same binding posts simultaneously on the 30 amp power supply and using a power meter and 50 ohm non inductive dummy load. The rig produces it's full specified output at 13.8v but when the supply was reduced to 12.0v a different story emerged. The original lead provided an output of only 70 watts and the new lead an output of 90 watts indicating clearly the losses in the stock combination. I have two of these rig's and the results were the same on both. It should be noted that nothing is gained by exceeding a supply of 13.8v
See the pictures below..................
This is the original lead and filter
RFI Filter with the lid removed
This is the new 4 way cable and the lower picture shows the new 4 pin rig plug
I have just made another DC lead the same length as the one above but using twin cable "doubled up" which is readily available on e bay etc.
It should be noted that if the transceiver is being used in an "Auto" environment using a car or truck battery that a fuse "MUST" be fitted in the "Negative" lead as well as the "Positive" lead so in these circumstances the supplied lead should be used.