Batboard

Hello,

Does anyone have a calibration procedure for the R2001/8/9D internal terminated power meter? I am looking for adjustments for R7 and R23 Level and Offset.

Thank you,

Sam

repeater builder has the D service manual with the alignment

Jrv,

Well I looked at that previously and there is no mention of a calibration procedure for A17 the wattmeter board in that manual. There are two pots R7
Gain and R23 Offset. The question is how to set them. I thought that there might be someone on the board that has done this calibration before. Does anyone have any comments on how accurate this unit really is at levels below 10 watts?

Thanks,

Sam

On the A/B/C units, the dummy load, and hence the RF sampling circuit, are all inside the RF input module (A11) where the step attenuator resides. As this is a very well shielded and sealed module, it's not something that can be readily adjusted in the field. The mfgr had test jigs for such assemblies as well as proprietary (i.e. non-published) procedures. It's likely going to be quite difficult to open the RF module, supply the various signals, and make any adjustments. Whatever you adjust is likely to change when you button it back up.

There are a LOT of adjustable components inside these units that are undocumented and never discussed in any alignment section. For example, neither power supply is mentioned in the A/B/C alignments but they both are in the R2001D manual.

Many of the op-amps in the R2001 have both offset and gain/level adjustments. Typically with zero input, the offset is adjusted for zero output, and with a known input, the gain is adjusted for the desired indication.

Bob M.

the calibration for the wattmeter on the D series is in the later version of the service manual.
The one on the Repeater Builders site is an earlier version that is also missing the option boards as well as well as some of the adjustment procedures.

The service manuals on a lot of service monitors can be very version specific and incomplete at the best of times. Not to mention mistakes in the alignment/calibration and other areas of the manuals.