OASIS CAN 14 RF Failure Evaluation
	23 May 2002

 	Radio Type: RNET450
	MDL: K44GNF1001A
	S/N: 163FVA4325SL
	TNC Type: UMPAD ver4.2D
	S/N: U2126

A - I physically inspected the chassis in the OASIS lab

	1 -	A wire from the radio, Pin 8, TXD,  had been pinched.

B - I made return loss measurements on the three RF ports.

1 -	The packet RF port return loss was intermittent. The connection demonstrated a large variance in return loss when the 90° BNC connection was mechanically agitated. I made three return loss measurements as I agitated the connection.
I suspect the 90° BNC adapter at the radio is problematic.
Plots "Packet Port_1, 2, 3.dat" are measurements as the 90° BNC adapter is moved around in different positions.
	Plot "Packet Port X 3.dat" is the above overlaid, Green is Plot 1, Blue is Plot 2, and
	Red is Plot 3.

	None of the individual measurements are out of spec but the variance may be an 
	indication of a problem.

2 - The ARGOS RF port is within spec.

3 - The GPS RF port is within spec.

4 -	I removed the shrink tubing and removed the 90° BNC adapter and DC block and
made two other return loss measurements.
Plot "Packet Port 4" is the RF port with BNC connector only.
Plot "Packet Port 5" is the RF port the DC block installed.
	There were no noticeable differences when either connector was mechanically
agitated.

Plot "Packet Port X 2.dat" is the above overlaid, Green is Plot 4, Blue is Plot 5.

C - The radio/TNC unit was removed from the chassis and taken to the RF lab.
	I physically inspected the radio/TNC/GPS unit and found no anomalies.

	1 - The radio was connected to a 13.8VDC power supply and IFR FM/AM Service 
	Monitor for test purposes. 

	The following measurements were recorded.

	FM = 461.7822 MHz	12 dB SINAD = -104dBm
	PO = 3W	IRX = 22ma
	ITX = 1.06A
	
	The FO should be 461.7875 MHz and the receive sensitivity should be > -110dB.

	I was concerned that the FTX was so far off so when I rechecked it, it was constantly 
	changing, swinging through FO. Then it would settle high or low.  The receive sensitivity 
	didn't vary. I am going to continue to monitor the radio for the next week and 
	measure its parameters. Then I will troubleshoot it.

	I am not going to check the TNC until the radio test is completed.