[TenTec] Omni VI low TX power

[Ken Brown]

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> Try plugging a voltmeter into the 12v accessory RCA jack on the rear of the Omni. 
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Hi Mike,

Voltage at accessory power RCA PHONO jack: Receive or key down with PWR 
at minimum = 13.6 VDC
                                                                        
                               key down RF output set to 10 W = 13.5 VDC
                                                                        
                               key down RF output set to 20 W = 13.4 VDC
                                                                        
                                 "        "      "        "       "    " 
 30 W = 13.3 VDC
                                                                        
                                 "         "     "        "       "    " 
 40 W = 13.2 VDC
                                                                        
                                 "        "       "        "       "   
 "  50 W = 13.1 VDC
                                                                        
                                 "         "      "         "      "     
"  60 W = 13.0 VDC which is maximum output, when the radio has been 
turned on for hours.

Then if I turn the rig off for 30 minutes and do it again, starting at 
maximum PWR setting, RF output is 78 watts.
                                           key down RF output 78 Watts = 
12.9 VDC
                                             "        "      "      "   
     50 Watts = 13.1 VDC
 
So it appears to me that the drive to the finals is too low when the rig 
gets warm, and if turned off for a while the drive goes up and power out 
goes up. The supply voltage drop through the connectors and wires is the 
same at the 50 watt level either way. So the resistance in the power 
supply leads and connectors is not changing siganificantly after being 
turned on for hours, yet the output goes down. Maybe if the voltage drop 
was a bit lower the output power would be a full 100 watts when first 
turned on, still it seems that something else is causing to power to 
drop after the rig has been left on for a while.

Any comments on this?

Ken N6KB



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