|I've found the BK 2630 to be a good test instrument. There have been complaints regarding frequency drift with these units but my particular unit stays well within its rated specification if I allow it to warm up for an hour or so. |
I bought the one which I have second-hand, and I knew going in that it is not a precision spectrum analyzer like others which I have. But this one is very good for quick testing of transmitter outputs for harmonics, oscillators, mixers, and EMI sniffing and identification.
I have a computer-based analyzer also, and between it and the BK 2630, each of them is best for certain tasks.
The computer unit is much more accurate, especially for close-in measurements but it requires setup each time i.e boot up computer, load software, initialize, etc. and then away we go. And the computer-based unit sweeps rather slow, especially on large frequency spans. It gets even worse with averaging in use. Further, there are many built-in spurious images with the computer unit. The BK has no spurious images which I can detect.
The BK unit is a good step back in time because it has none of these issues - it has traditional superhet and CRT architecture mixed with PLL frequency generation and so sweeps are virtually instant throughout its whole range. And with the tracking generator, it is very good for filter testing and other scalar network applications. Further, the BK is all in one box so no box(es)/usb cables & hubs/computer/display to lug around. The computer unit can become cumbersome this way especially with the separate tracking generator and cables.
Service info including schematic diagrams is available for this analyzer also, under the Hameg HM5011 name which is identical to this one.
After calibration, I've found the 2630 to be spot on for amplitude measurements.
What isn't so hot about the BK 2630 and its brethren are the frequency readout and the 20khz resolution bandwidth limit. So close-in detailed observations such as phase-noise etc. aren't really possible with this unit. Duplexer tuning for repeaters etc. can be accomplished but not easily due to the limited frequency display. It does do an excellent job of measuring amplitude to within +/- 10dbm, and you can count lines on the CRT centerline to get closer.
To sum up, the BK 2630 et al is a really great unit for quick checks of transmitters, oscillators, and other RF sources which don't require precise frequency measurements. These units can be found often at good prices second-hand and are worthwhile to have on your test bench. Understand what to expect from it and allow a good warmup period and you will be pleased.