[RFI] Radar Engineers RE240A verification data notes

[vk3od at yahoo.com]

I managed to pick up a RE240A at a reasonable ham price.
I just wanted to verify the units performance using a signal generator. I don't have access to the specs or sensitivity figures. Hopefully this data will be useful for those who bought one up one of these units and need to verify the units performance. This is the older Model not the current 242.
I used R&S SML01 signal generator with 1khz AM modulation for  MDS.  I used my ears rather than a RMS meter/noise distortion meter  to detect the MDS level. I have good hearing and can typically hear -130dbm AM modulation in most receives that can detect that level. I used the ARRL procedure methods.
I don't have a reference unit whose performance is known to be perfect, and my figures might not be typical of a fully service and calibrated unit. I have also not confirmed these figures with Radar Engineers and probably will not  be able to get access to any verification data.
These figures might not be correct since its just a quick bench test even though my unit anecdotally appears to be working. My ears are certainly not calibrated!
There is a +- 6db variation across the various frequency ranges.
MDS - HF -1.8 to 90mhz -100dbm average.MDS - VHF - 88 MHZ   to 108 mhz -95  Dbm  average. Sensitivity drops in this range and there are other sensitivity "holes" across the range.MDS - VHF - 100 MHZ  TO 550 MHZ -105 DbmMDS - VHF - 550 MHZ  TO 100 MHZ -105 Dbm
These figures above are using the standard filter bandwidth not using the "narrow bandwidth" and I dont know the IF filter bandwidth. I will try and measure it later.
To read "20" on the S-meter with the preamp off averages -85 Dbm  with +- 6dbm variation depending on frequency.
I used this level because this is basically the minimum signal level that you can see on the scope,  1 division of 5 divisions.
The preamp gain gives  about 10db of gain between on and off using 1 division level as the reference level.
Full scale S-meter reading of "100"  is typically -75Dbm +- 5 Dbm almost close to S9 if -73Dbm is used as a reference level. This with the preamp on.
You can read higher levels if you turn off the pre-amp and vary the gain, which typically has a 0 to 30db gain variation. At this level of "100" the unit will read to 3 scope divisions.I did not want to blow the preamp since I dont know what the units limits are. You  can vary the gain and turn the preamp off. I did not want to risk blowing the front end!
I did do 1 test  on 144mhz and these are the figures.
Preamp on -78dbm  full 5 divisions on the scope screen.Preamp off -70dbm full 5 divisions on the scope screen.
Again I dont know the history of this unit and if it  represents typical performance. A member of the reflector  was kind enough to forward me a manual, thanks.
Any discussions or suggestions on the units performance are welcome. 
Has anyone changed the battery in one of these units? It looks like you have to pull the whole unit apart to change the battery?
73VK3OD