EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Dawn on March 18, 2014, 10:52:21 pm
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I've wondered about this as they are now fetching some reasonable prices used. Racal and Marconi are two companies that have been relatively unknown in the states as RF test equipment outside mil/avionics and occasional rebrands such as Motorola many years ago until the 90's and latter involvement with IFR.
So these units are plentiful in mil and defense contractor surplus and are seeing well maintained disposal over the past few years. I see variations on the 9008, 9008M, and 9008A. I'm disregarding the 9009 series for the moment.
I have some questions to those of you that are knowledgeable about these units.
First, what is the 9008A designation?
Internally, the dates and boards are concurrent with the others, but the cosmetics are different. The A unit I'm inside of on the bench is dated '88 inside while the plain 9008's were made well into the 90's from manual notes. That rules out a newer/improved model designation.
I can see no other difference between an A and non A unit outside the case is not portable with a bail and differently made as for shelf or rack use. All internal boards are the same prefix otherwise preceding the revision letters.
Both have battery and battery charging capability.
Was the A strictly meant to be a fixed or bench unit with different cosmetics or is there a difference? The A designation doesn't appear in any catalog that I've found either, just the M version and both with or without remote and battery options. These units don't have the usually mil or gov't contract NSN number on them, so they aren't specially made for the US gov't by contract specifications which sometimes will add a letter or be designated with a different model number from the commerical versions and have two switches that cover 4 voltage ranges like the original model.
The "M" designated units have not only a 300hz low pass filter cutoff, but a specific notch at 150hz. That smells with M for military as it's the standard subaudible FM tone coded squelch is 150hz unlike the industry standards. Letter designations don't take into account remote control or battery options.
So, I'm left with wondering what's the difference between the Racal/Dana 9008 and 9008A.
Anyone can identify this unit?
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I'm afraid I can't speak with any authority on this but I always assumed they were all pretty much the same design. I have the M version here with the 150Hz notch filter. I've never needed the 150Hz notch though...
I think the A version is just packaged differently to allow it to be rack mounted easily. But that really is just a guess... I've only ever used the 9008 and 9008M versions here in the UK.
What I can say for sure is that these meters are excellent in terms of providing very clean demodulation of both AM and FM. The one I have here is remarkably good with extremely low distortion. I usually connect to the rear of the instrument and use it as a demodulator rather than use it to measure FM deviation or AM depth etc :)
Also, the build quality is excellent inside. A real labour of love with wonderfully neat wiring etc :)
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I have to admit, that the interior is quite impressive in build. Racal and Marconi never had much of a presence here. When I got into the industry in the 70's, a us importer in NJ was relabeling Canadian Marconi and the HF products were being distributed by a marine company that became the sole source after about '72 for land mobile or motorola branded test euipment marconi parts if they were no longer in stock. Racal opened up a plant here in my state as computer peripheral equipment that only lasted a few years under Racal-Milgo before the shuttered the plant in the 80's. It wouldn't be until the AMPS cellular phone days that Marconi raised their heads in the states with RF test equipment aimed at service facillities. The experience left a lot of shops with very bad taste in their mouth as equipment only 3-4 years old had no parts available or were designed with end-of-life components that couldn't be independently sourced, many from Siemens. We had a room with 8 service monitors taken out of service within few years. When they took over IFR, that worried a lot of people in the industry and probably propelled sales of HP and eased General Instrument (OEM Motorola test) in at higher cost.
Dana to my knowledge never really was a blip on the radar. They hit the road running in the late 70's and early 80's with some very advanced counter/timers, but priced for the development labs. Some Dana equipment I seen in civil aviation shops and also used by our FAA, but beyond that, it was mil contractors that used their equipment, not service shops.
Besides the origins of this A model, I also have to wonder about the exclusion of de-emphasis that otherwise in a similar instrument would be selectible for 75us/750us for narrow band FM and for Broadcast with an instrument that can read up to 100khz deviation. I don't know if our standards are the same as those elsewhere, but you could bet on that being part ...even the Marconi unit of a wide band unit not only intended for narrow band service.
I bought this unit mainly because AM even on upper end instruments is either a very simple averaging circuit with no controlled ballistics or depends on an o-scope for polarity and symmetry rather then a quantified value. AM is generally an afterthought unless it's in broadcast monitoring equipment.