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Discussion Starter #1
I'll admit straight away that I am not an ex mariner, but I do look after the Marine Radio Collection at Internal Fire- Museum of Power in West Wales. I would be very interested to hear from anyone who has any knowledge or experience or perhaps sailed with the Marconi Challenger. There won't be many as, to my knowledge, Marconi only sold about 12 units fro and 18 - 20 production run.
Its a 1.5KW SSB/CW/MCW transmitter, probably technically the best Marconi made, but a marketing disaster! (too much, too late!) The Challenger we have together with the console came from the "Pride of Calais". We have next to no do***entation - with so few units being sold manuals are very rare. The Instruction manual we have is missing some essential pages. The Conqueror, apart form the finals is very similar, some circuits are identical, so the Conqueror manuals have helped. We are within an ace of having it working, and as mentioned above, I would be very interested to hear from anyone with any knowledge, anecdotal or otherwise, of the Challenger. Many Thanks - Michael.
 

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Welcome to SN Michael and hope your search is successful.
1.5Kw transmit power for a cross Channel ferry?
The mind boggles!
 

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Discussion Starter #3
I thought it seemed excessive at first, but Board of Trade regulations apply. Vessels over a certain displacement, carrying more than so many passengers (I don't have the actual numbers at my fingertips) were required to carry this equipment.
Michael.
 

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Thanks for your private msg, Michael. Glad to know you got your namesake working. If I ever get my hands on an Apollo, I'll be sure to drop by, look at your manuals. Thanks again.

Paul
 

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I thought it seemed excessive at first...
The radio regs circa Oceanspan Mk.1 time was British registered ships on 500kc/s communicate with the nearest UK coast station on low power and from memory for the Oceanspan that would've been 25 watts.
Note the engine side of your museum is well represented on you-tube. Any chane of same for the Marine Radio side?
 

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To Michael Oceanspan.
Can’t help too much with tech details.

I commissioned 3 Challengers on Southern Shipping Corporation of India, at KSEC shipyard in Busan S.Korea 1985.

The aerials were AS9 vertical with wire emergency across the Monkey Island space. Using the manufactured internal MF taps, you could set up loading for the AS9 aerial MF 410 through to 512khz, but could not get the full range on the wire aerial. You could get 410 to 480 or changing internal taps 454 to 512. Long story short, I added an internal tap between the fixed ones. It did seem to be an easier transmitter to tune, though on MF during sea trials the MF gonio did creep.
The associated RX was the Oceanic, with keypad channel entry as well as the classic rotary tuning knob.

Beyond that I am afraid memory fails me

I used to sign off with No use getting older if you don’t get wiser.
I think I used to be wiser

Peter

Revisited your photo, I think the Oceanic RX is in the bottom left of your console.
 

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Discussion Starter #7
Commissioning Challenger

Hello Peter,
Thanks for your thoughtful reply. I do intend to write an article on the restoration of our Challenger, and will cover the Challenger history in general by way of background.
With your three for Southern Shipping Corporation, we can account for 6 out of the 12 (or so) Challengers actually sold. However, the provenance of the one in Australia is unkown.
Our antennas are a 40 metre Inverted L for Transmit and a slightly shorter Long wire for receive. We have a stainless HF vertical to add to the antenna farm at some time in the future.
You are right about the Oceanic, although the one in the picture is a fully working example, I am very nervous about using for extended periods. I know this is contrary to shipborne use where it would have been on 24 hours every day. However, at the risk of digressing - we had (still have) another Oceanic, a dead one. Breifly, I believe the pathology before we obtained it was, 1) Stopped working one day, owner probably checked a few obvious things, turned it off and on a few times, 2) Finally disovered that the 5Volt rail had gone sky high, 3) Replaced the 5Volt pass transistor, 3) Still didn't work, sold it to us. I strongly suspect that the 5Volt Pass transistor failed short, rather than open, thus dumping 20(ish)Volts across the 90 odd TTL ics, all of which are soldered in - a nightmare to repair. According to my research, this is not an uncommon failure point with Oceanics. The pass transistor on our working one does get very, very hot, so rather then invite failure I avoid using it at present. A single TO220 style pass transistor for over 90 TTL devices is bound to be struggling. The long term intention is to fit an external, more substantial 5Volt supply with over voltage clamp and current limiting (both omitted from the Oceanic design). Aside from this shortcoming, it is a very capable and pleasant receiver to use.
Michael.
 

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Discussion Starter #8
R651400; Note the engine side of your museum is well represented on you-tube. Any chane of same for the Marine Radio side?[/QUOTE said:
The Radio side is not prominent on YouTube. However see www.gb2mop.org for the Museum's Radio web-site. (MOP: Museum of Power), The Museum's main site is www.internalfire.com
Both sites are in need of some updating, but with only 24 hours per day!!!! For instance, the Oceanspan is now fully operational and inegrated with the associated Atalanta and Mercury receivers.
If you read Practical Wireless, the April 2017 and April 2018 issues have a bit more background on the Museum's Radio activities including the Oceanspan's story.

Michael.
 

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Discussion Starter #12
First of all Andrew, thanks for your response. Hazel waxes lyrical about your performance at MOP, for some reason my wife and I were not present on that occasion, I can't remember why, but I have seen the YouTube clip before and recommend it to anyone who wants to escape the modern phenomenon of digital Tape) loops for rhythm section - brilliant. Michael
 

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Discussion Starter #13
Paul, I'd spent so much time up to my elbows in the Oceanspan's insides that it was first thing that came to mind when asked for a username! Next username will have to include Challenger as over the last few months I have become intimately acquainted with its insides!
Michael.
 

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Hi Michael. Oh, I can relate to that. So much time, immersed solidly inside the 'Span at college, trying to find the faults which the instructor had put on; little bits of screwed up paper in relay contacts, missing valves, dud valves; the list went on and on, but boy, did we know all about it by the end! (Well, yes, we did...)

Funnily, on actually sailing with the thing, which I did every trip for the first several years after I started out, with the exception of my first, junior trip when I had the Crusader to try and figure out, there were hardly ever any reasons to go back inside it again. Even when it ran hot after hours of keying, trying to raise Portishead on 12 MHz from the South Pacific. Only fault I can remember was a dud 8MHz crystal, inserted into the spare position on the front panel for working R/T into the agents at Matarani, in Peru. Last thing you might suspect as being faulty. I still have the offender, in a bag of other memorabilia. Strange, what you retain.

You had to be very aware of the weight of the transmitter section, before allowing it to come all the way out at you. 80lbs, if I remember rightly. And you had to be very aware of the lethal 600 volt HT on the three O/P 807's topcaps, of course, which, although thankfully I never had to verify, could apparently throw you across the room, as in the story of some luckless student gleefully and somewhat cruelly, (usually when you were at the teetering point of it coming out of its cabinet), by the instructor, Frank Mayoh, for those who may remember him.

Cocky sod, sometimes, Frank. (Sorry, but you know it's true, if you're listening!) Let me find out the hard way, how hot Z77's in the Salvor actually run, by standing close behind, watching my inept attempts at fault finding, letting me burn my fingers, getting one out: "just to check if it's a dud..." Good days.

I wish you luck with the Challenger, a beast I hadn't heard of until your thread. The Commandant/Conqueror was a beaut, especially after I'd done the 2 week course up in Govan, Glasgow on them. What a joy to have all that power and especially stability after the 'old girl' with the red and blue knobs!
 

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Discussion Starter #15
Paul, While not wishing to stray too far off topic, you mention the front panel crystal socket on the Oceanspan. What I've done with ours is feed an Arduino based VFO output into the external Crystal socket, that puts us on the Amateur Bands, but not 14MHz as this falls in the cracks in the 'span's tuned driver circuit. Ours was a VIIE (Emergency) which I reverted to Main Transmitter status. It had the 24VDC Dynamotor which was noisy, so built a 650VDC mains supply which is a bit quieter and doesn't drop 100Volts when transmitting. Both units are heavy, unfortunately we don't have the very rare Marconi extension rails which means we can't work on the transmitter when it is live which is fine for Health and Safety but it make it very difficult to adjust the tuned circuits which, if you remember, are on the bottom of the transmitter. If I could do that it could be put onto 14MHz quite easily!
Back on topic, I think I mentioned that do***entation is rare for the Challenger, fortunately we have a full set of manuals for the Conqueror which, apart from the final stages is remarkably similar to the Challenger - sufficiently so to enable me to sort out its last mysteries. (The main console is now giving me headaches!) We are now waiting for parts and hope to have it gracing the airwaves in a few weeks time.
Thanks for comments - Michael.
 

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Must be quite a blast, working with all that gear from the venerable Marconi Company. I wouldn't mind getting my hands on some of that again, for old times' sake. Funny you mentioning the extension runners on the Oceanspan. I don't remember them, but I guess we must have had something similar at college.

Hope you get the Challenger up and ready to transmit again soon.

Paul
 

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Discussion Starter #17
Progress Report

After a short holiday I found that an MRF393 had arrived at the museum to replace the unobtainable CTC BAL0000L10 (Dual NPN power transistors). This was fitted to the driver section and when fed with HF from my signal generator now produced a much greater voltage swing which increased a little with frequency. I was a little uneasy about this transistor as it is only specced from 30 to 500MHz and I am going to use it below 30MHz, they still cost nearly £100.00 and it's the museum's hard earned money. On the other hand the MRF393 and 392 are the only bipolar NPN transistors I could find in a 744A-01 package. The other option of using two separate power transistors, while technically feasible would require an unacceptable (at this stage) amount of hardware modification. However, it seems to have worked out OK.
Also 4 x 4cx350s arrived. after carefully setting up screen voltages (400V) and bias (-27V) with the old valves still in place, I replaced one of the old valve with a new one and nothing bad happened, in fact a considerable amount of antenna current was generated. Emboldened, I replaced a second old valve wiht a new one and was rewarded with and even more considerable amount of RF into the dummy load. The anode current on the two old valves is just a little below that of the new valves so I think they are probably contributing something to the output. After quickly trying to load into the antenna (45 Metres of inverted L), I found it wouldn't load. I suspect there is a minor fault in the antenna circuit that I will address on Friday and fit the remaining two new valves.
A further update will follow on Friday/Saturday.

Michael
 

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Welcome back, Michael, and hope your holiday set you up for further work with the transmitters. Sure it has. I only wish I was there to give a hand and have some fun doing so, but it's a bit of a long haul. The one thing I remember about any of the Marconi gear was how well built it always was, and how (at least as far as I was concerned) rewarding it was to work on it. I know some people have other memories, but I must have become a 'good Marconi Man', or something, because I always staunchly defended the company and its equipment, and still do. Having recently had to go inside my Atalanta to replace a screen feeder resistor to the two RF valves, I welcomed the floodgates of memory lane opening. For a few minutes, as I tried my best to emulate the beautiful work done by the original builders of the set, I was back there, at sea again, even having the same adrenaline rushes as I did then, knowing that if I cocked up, I would be without a receiver, at worst, or having to 'make do' until we finally berthed somewhere where some 'real engineers', as I sometimes thought of them, Radio Holland in the Caribbean, or good old AWA in Australia, could come down and repair my repairs, so to speak. (It never happened, fortunately, but there was always that frisson of concentration at the forefront of the mind, possibly a throwback echo of the ridicule and scorn seemingly heaped on one at college for cockups).

Having names assigned to pieces of equipment was an interesting move by the company. Who could forget the Lifeguard, or the Salvor, Reliant, Globespan, et al. Wasn't sure about the Commandant, though. I suppose it harked from the Commander, but Commandant? Hmm.... But it was a really neat transmitter, if you weren't after the higher power of its big brother, the Conqueror. It was one of the best equipment courses I ever did, the Commandant, and then Spector, telex equipment. Riding the Glasgow subway every morning over to Govan and surrendering oneself to a hard day's work with a very enthusiastic tutor... Way to go! My only regret now is that I chucked my carefully annotated Marconi Equipment Manuals for both that gear and also the Apollo and Radiolocator radar. Beautifully (if I dare say so) drawn waveform diagrams and tiny printing all over those lovely pull-out cct diagrams and blocks, lost forever to the weather's vagaries at the local tip. A work of art and something I was proud to have been a part of. Why I did that, I'll never know. There was plenty of room, after all, up in that dimly lit attic.

All that information, yet we never even had access to an oscilloscope at sea, at least I never did. The old 'diode probe' was a good substitute, however, especially if you'd taken the trouble to go through the test points on the cct boards, carefully recording the readings. Almost as good. I sometimes wonder at the frugality, if that's the right word, of some of the shipowners, not supplying such things, as well as the short-sightedness (as I saw it) of only having an Alert, or only slightly more useful, Monitor, as 'reserve receivers', both of which would have been totally useless for any serious work. Another Atalanta would have been a real luxury.

I know there was the requirement to have 24V emergency capability, but even so, an Alert, for Goodness' sake? Crossing the Pacific, all those thousands of empty miles, filled with nothing but static and lightning crashes at night, and an Alert, listening hopefully and doggedly out on 500kHz. Yes, I do wonder.

All those tales, from cocky Greek-employed R/O's and the like: radio rooms filled with wondrous racks of state-of-the-art, gleaming and very sophisticated and powerful transmitters and receivers, and a handsome, film-star salary for the privilege of having to make do with all that. But I wouldn't have changed a thing, thinking back. Not even the Alert, or the inadequate Monitor. Who could fail to be comforted, sitting there listening to the rythmic clicking and whirring of the cams on the Autokey, for example, as it went through its cadence of deliberate distress keying sequences, watching the pretty-coloured front panel lamps blinking in time to the mechanisms inside? Knowing it would faithfully key away into the old Salvor until the batteries failed and you went out to board the last boat away:

(Old joke): R/O, standing on the disappearing boat deck, watching the lifeboats pulling away, seeing the Captain in one.

"I thought you were supposed to be the last one to leave a sinking ship!!"

"I am..."

Best of luck with your transistors and soldering iron. (Or do they just fit into a base socket, I wonder?)

Paul
 

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Discussion Starter #19
Hi Paul,
My, we are waxing lyrical tonight (today) aren't we! Interesting you mention the old 1097(?) Autokey. We have one in the 1959's radio room and one of my Winter projects will be to get it going. Another is the Autokey 2X in the Pride of Calais radio room. That, of course, is all TTL sequenced by and EPROM. The idea is to reprogram the EPROM to send out "CQ CQ CQ de GB2MOP". Shouldn't be too hard. Actually, the projects aren't that hard, the problem is finding the time!
Best Wishes - Michael.
 
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