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Re: [TenTec] Omni VI low TX power

To: tentec@contesting.com
Subject: Re: [TenTec] Omni VI low TX power
From: Ken Brown <ken.d.brown@verizon.net>
Reply-to: tentec@contesting.com
Date: Sat, 27 Mar 2004 17:03:56 -1000
List-post: <mailto:tentec@contesting.com>


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

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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