marconi 6055c - Page 1
Forum section: electronics / testgear

author: electrolust
author_rank: Unknown
timestamp: September 18, 2020, 04:11:27 pm
content: anyone have a data sheet on marconi 6055c signal generator?

author: George Edmonds
author_rank: Frequent Contributor
timestamp: September 18, 2020, 06:26:48 pm
content: HiThe 605XX range of signal sources was made by Marconi Sanders, the documentation was very never good. They use a Gunn Diode to produce frequencies from about 800MHz up using various models.I may have a users manual for one of the rangeI have attached a scan of the relevant pages from a early 1980'sMarconi catalouge, it includes the B Sufi but not the C, I have no information on the C suffix, but I doubt is the specification has changed much.George G6HIG Dover UK

author: electrolust
author_rank: Unknown
timestamp: October 09, 2020, 12:51:15 am
content: Thanks, that was helpful.The insides are amazing, with the mechanical clockwork. Note the apparently broken gear tooth. I thought it was too precise to be randomly broken, and it turns out that is indeed intentional. As the gears are rotated, it eventually contacts one of a few pins embedded in the mated gear when the teeth line up properly. This provides the 2 stops at the lower and upper frequency ranges.Waveguide! For 2GHz! Well, this thing is ancient.The frequency accuracy is poor, but there's a VR that I hope is the adjustment for that. The frequency stability is quite poor: it wanders a lot. There's an FM mod input on the front, which seemingly can't be disabled. I wonder if it's picking up stray RF. But I imagine that it's a simple linear relationship between that input and the FM offset? If so, then at the low baseband frequency of that input I have a hard time thinking it's reacting to EMI. Maybe I just need to let it warm up more.Amplitude accuracy is ... nonexistent, since the scale goes from "min" to "max". :\ Per the catalog, this can be leveled via an AM input on the rear. Maybe that would be an interesting project.I thought the internals were very, very clean given its age. It even has a cal sticker only dating to 2000.

author: electrolust
author_rank: Unknown
timestamp: October 09, 2020, 12:52:50 am
content: pics

author: electrolust
author_rank: Unknown
timestamp: October 09, 2020, 12:53:51 am
content: pics

author: electrolust
author_rank: Unknown
timestamp: October 09, 2020, 01:00:39 am
content: spuriousharmonics @ f=850 setting (765 actual output) and phase noise @ f=1375 (actual output 1300). i see now that the frequency error is absolute, so that's a good sign to me it can be easily adjusted. Interesting that H3 >> H2.ignore the marker in the 2nd one, it's not meant to indicate anything. the center frequency just drifted away from it is all.

author: George Edmonds
author_rank: Frequent Contributor
timestamp: October 09, 2020, 04:40:32 am
content: HiWhen I checked I found that I have the Marconi manual for a 6055C.I can scan parts of it if requiredGeorge G6HIG Dover UK

author: electrolust
author_rank: Unknown
timestamp: October 09, 2020, 10:27:33 pm
content: If you can scan, that would be really great!

author: George Edmonds
author_rank: Frequent Contributor
timestamp: October 10, 2020, 08:02:17 pm
content: HiHere is the scan, sorry it is only 150DPI resolution, this is the maximum that my scanner will tolerate before crashing.George G6HIG Dover UK