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Marconi Challenger

26K views 89 replies 17 participants last post by  maltesejohn 
#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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#30 ·
Hang on! #18 : The Marconi 'Alert' receiver didn't have 24V capability, did it? My memory must be going a bit off. Just can't remember much about it now. Obviously you had the 'Salvor' on 24V but the receiver? Don't think so. In that case, did you have the capability of receiving anything at all without the ship's generator being operational? Anyway, the rude comments about the 'reserve' receivers stands. They were heaps of c..p! (In my humble; don't want to hurt anyone's feelings!)
 
#31 ·
Michael: Just re-read your posting a few weeks back on the 'Oceanic' receiver, of which you have two at MOP. Now that set has all the IC's embedded firmly into the PCB, by the sound of it. Why didn't they do the same with the associated 'Challenger', I still find myself wondering. If you want the board fixed, just send it out here, along with all the IC's... love doing work like that. And for such a good cause!

Paul
 
#33 ·
Mike, last night about 2020 you were weak and unreadable in Penllergaer but I heard the loud and clear reports you were getting from Holland and France. By 2052 the ionosphere favoured you and I thought the quality of modulation perfect. A previous station with heavy AVC, clipping and filtering was unpleasant to copy, but no doubt effective in army communications.

As for the Alert, somebody remarked that switched on or off the result was the same. However, it met the specification for a watchkeeping receiver, and if ships used CW instead of MCW it had no chance. Auto Alarms were more sensitive. I often used the DF for 500 watch whilst away on HF.
73, Andrew
 
#34 ·
As has been said, the Alert operated from 24V and met the regulatory requirements (if maybe not the operational requirements) for a 500 kHz emergency and watch-keeping receiver. It was designed to receive MCW signals only, on the assumption that stations would comply with the the current ITU Radio Regulations requiring use of that type of signal on 500 kHz. Transmitters of the same era, such as Oceanspan, only produced MCW signals when 500 kHz was selected. Later designs would permit the operator optionally to select CW.

I was a firm believer that MCW was the mode to use for distress and safety calling and never used CW on 500 kHz - the purpose of a call was to attract attention so it made sense to me to make as much noise as possible! I believe auto-alarm receivers were not required by regulations to respond to CW and some designs did not.

So although the Alert was rubbish as a communications receiver, it could serve in emergency for communication with nearby ships involved in providing assistance to your ship when you were without mains power. That is the function required by the regulations.

Having said that, I much preferred to sail with Mercury/Electra rather than Atlanta/Alert since I was happier having two decent receivers for MF use than one excellent one teamed with a dud. When the ship's power went down, I still felt capable of dealing with things and keeping the radio room operating.
 
#37 ·
Hello Ron

I sailed a lot with the next generation of rx'ers: Apollo/Sentinel/Lifeguard N.

The Sentinel was good as a MF working rx, and I used the Lifeguard N (with BFO) as a 500 watchkeeping rx.

I was only thinking of your comments re main tx'ers not being powered from the emergency gene circuit the other day...what a great advantage that would have been - run the whole radio room on that circuit....

On my first ship, both rx'ers automatically switched to 24v if the mains failed....another excellent idea, way ahead of its time...

But, of course, typical parsimonious shipowners....and an IMO dominated by Panama and Liberia...
 
#35 ·
Challenger Transmitter Working - Replies.

A few of you have raised points about Challenger and associated equipment.
Andrew, I am pleased that you were able to listen in on VMARS on Wednesday evening, Conditions were atrocious, not just atmospheric noise, but adjacent stations overlapping our transmissions and tuning up nearby. However, it was a great pleasure to run the Challenger for an hour and to get some very encouraging reports. Oddly, and this applies to my home station in Llangeler as well, there are a number of stations in the Swansea and Merthyr area that are barely audible at the best of times, yet at the same time we have no trouble with the rest of the country or even northern Europe - geography I guess. Will we see you at the Crank-Up this weekend, Sat and Sun? ( I doubt I will be able to demonstrate the Challenger as with everything else running in the Museum, there won't be enough amps left for me!)
Earthing: At present it is earthed to the lattice mast, which is in turn well earthed. A good method I found with the Oceanspan was to connect the ground side to the tin roof covering the Radio and Telehone areas and about 10 metres or so below the horizontal part of the inverted L. I tried it briefly with the Challenger, but didn't seem to be any improvement. It is something to be addressed during the winter shutdown as there is scope to improve the antennas, in particular the receive side. We can get out far better than we can receive.
Paul: Oceanic and IC sockets. Most of the more common (cheaper?) ics in Challenger are in fact soldered directly to the boards. Only the bigger ones such as the 40 pin Divider and Synthsizer chips are in sockets and, guess what, these are the ones that cause problems! It is actually the same in the Oceanic: most ICs are soldered, but the processor, EEPROMs and a few larger chips are socketed. I might take you up on your offer and send you the Oceanic boards and a bucket-ful of TTL.
As you like my pictures so much, attached are left, right and top views of the RF unit.
Finally, I must mention that this project has only been successful through the generosity of EIMAC (now part of CPI) who actually donated the four 4CX350s to the project. The museum would have found it difficult to justify the cost of £1000.00 + worth of valves.
73 all - Michael.
 

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#36 ·
Bring it on! Very willing to help out with the boards. I worked for many years in various types of electronics factories, after I left the sea in '82, manufacturing equipment and doing lots and lots of PCB work, including the dreaded surface mount types. In fact, was still working at all this as recently as 2007, until we emigrated to NZ. Soldering in the 80-odd pin surface mount IC's by hand onto a brand new board was quite challenging (no pun intended). So the offer is a genuine one. Thanks for the photos as well, and taking the time out to reply to all these posts.

Best regards, Paul
 
#42 ·
I don't think I have been with an emergency supply that was not three phase although I had one with a battery supply which switched the three wire AC lighting into one two wire DC battery supply (not VG when fluorescent lights had been added to the lighting network!).

If you take the 'old' list of equipment that must be capable of being supplied from the emergency supply it is true that to some that meant 'only' the emergency supply - we had an amusing but expensive exhibition of how that, when applied to the rudder angle indicator, could precipitate excitments.

On more 'sophisticated' ships the reverse mistake was made. Anything is more secure if run from the emergency supply. But when, for instances running steering gear telemotor pumps from a supply not also capable of supplying the steering gear pumps themselves or when, similarly, supplying the thruster controls from the emergency supply then in both the possibility (actuality) of crippling the ship occurs in the event of an emergency supply (only) outage that would have otherwise left the vessel seaworthy. On the knockings of my career we also finally worked out why the standby generator would not start for the surveyor during a routine docking. The luboil priming pumps were fed from the emergency supply and the primed luboil pressure was interlocked with the start-up. The emergency generator was secured for surveys of its own again making outage of the emergency switchboard a potential 'fatal' single failure mode.

I am happy to say that current rules mean, in simple terms, that such essentials now 'find' an available supply if there is one.

In general terms three or single phase is decided by consumption but I would not like to rely on that criterion alone as lots of little loads might end up on one phase over time leading to unbalance. In the same way that houses are fed from alternate phase with neutral down the street (in an urban supply) unbalance is better avoided. I cannot immediately think of a 440V single phase load and to run the whatever from the domestic supply (main or emergency) usually introduces a set of transformers into the FMEA.

(Sorry - this is a hobby horse of mine, or was).
 
#43 ·
Hello Michael, Paul and others
I have been absent from SN for quite a while but finally decided to reset the password and login and I am very glad I did.
I was a MIMCo man probably because of their East Ham depot being just up the road from the college.
I have been fascinated by the exchange of messages and suffered quite a nostalgia hit recalling Commandants, Crusaders and Conquerors and even the Alert and Auto Key and the Monitor that was not much good as a reserve receiver but quite able at picking up AM stations as I recall when on route to ZSC.
I never came across the Challenger or associated equipment although I did have the Spector/Apollo on one ship.
I recall attending Glasgow depot attending a Crusader course the tutor whose name I don't recall had a favourite saying 'doom, gloom and despondency'.
Apart from a very short coastal voyage on the Thos Harrison's Defender/GTRT I never had the pleasure of serving with any of the Oceanspan series with the separate Mercury and Electra receivers or with the Atlanta.
My time being mostly Commandants and Crusaders with the Atlanta, Apollo and Nebula or that trusty Redifon R408 (?) something or other job.
Apart from one trip on the Denholm's Joya McCance/GPDA which had Swedish gear I didn't get my hands on a kilo watt transmitter before my one only experience with the Conqueror on the Texaco Rome/MSLJ.
I recall the Conqueror with Nebula being capable equipment that is until it suffered a fault in the power supply for which we carried no spares.
I managed to get a MSG to MIMCo HQ and my relief brought out the necessary items.
I spent many hours requesting QSP on 500 using the Reliance.
It was probably the rugged even basic build quality of Marconi equipment pre seventies that allowed us to keep things going.
I recall on the Texaco North America/GNEL transiting the Malacca Straits when the transmitter whip antenna on the funnel was struck by a lightening bolt which fried, frazzled or melted items in the Salvor, Monitor and other sundry gear in the ancillary rack, curiously the Auto Key was unaffected with just a few burnished contacts.
I managed to survive the bolt from the blue as it chose to go down the earthed reserve antenna switch route in the aerial box and not that for the main antenna which saved the Apollo and Crusader.
I remember quite a few happy weeks rebuilding everything with it all working when I paid off in the gulf thanks to sturdy Marconi kit.
I only came across more sophisticated equipment during my last few years at sea when on the Esso Mersey/GPUY which had Kelvin Hughes gear the main transmitter and receiver having synthesised units any frequency at the turn of switches.
Fortunately as I recall nothing failed as I might not have had much chance with the AVO and terminal screw driver although I managed to acquire an oscilloscope.
Thanks again Michael and others for the forum post and maybe there will be future instalments.
A visit to MOP will have to be done if only for another nostalgia fix and maybe even the chance to get personal once more with the Oceanspan as I am sure Michael you would be able to plant a few devilish faults much like the lecturers once did.
Hopefully I will catch GB2MOP or yourself Michael and QSO.
Many thanks
73's
de Rvator
M0ITR
 
#47 ·
Marconi Challenger - Rvator

Hello Rvator, nice to have you join the forum. Since the Challenger has been operational, there's not been a lot more to report, partly because the museum is closed for the winter and doesn't re-open until next Easter with a weekend crank-up. Also this is the time when maintenance, new displays and infrastructure changes can be done. As to the Challenger another reason for not using it much is that our 3 phase inverter is not quite up to the job and will trip out if I am not careful! The museum's electricity supply is right on the limit when the museum is open so this is another issue to be addressed over the winter. More interesting things: as it stands the challenger can only be used on 3.5Mhz and 1.8Mhz Amateur bands on USB, the higher amateur bands fall in the cracks between marine bands. I'm going to make a small modification to the band oscillator which generates the MHz component of the wanted frequency. It runs at between 41.7 and 66.7 MHz and is then mixed down to the required frequency. I shall pull the crystals out for the upper marine bands from 6MHz to 24MHz and use a DDS module controlled from an Arduino to inject the correct frequency for the higher amateur bands according to the band switch position.
The MHz component of the digital display is hard wired by diode or gates to the bandswitch so to get the correct digital display the diodes will have to be reconfigured. Nothing major and nothing irreversible.
For LSB operation I shall use a spectral inversion technique. A very interesting device was described in Practical Wireless in January this year. It is fitted in the microphone input and audio output and converts USB to LSB and vice-versa. When you think about it, the reason you can't resolve LSB with a receiver set to USB is that the carrier insertion is on the wrong side of the sideband resulting in unintelligible audio. With a clever bit of signal processing that a PIC processor can do, the audio spectrum is transposed to make it intelligible to a USB receiver. Conversely, if the transmit USB audio is transposed it can be resolved on a LSB receiver. Its not an unknown technique, but Ron Taylor (G4GXO) developed this PIC based device for users of commercial and military equipment which is usually limited to USB. If it is successful then I will make another unit for the Kelvin Hughes Zealand M-1250 transmitter which is my big winter project.
Finally, for Paul who like pictures, here is one of the challenger in action.

Best wishes to all - Michael (GW7BBY/GB2MOP)
 

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#48 ·
Hello Michael
I think you can label your speech inverter as "Privacy" equipment. Some passenger liners had that for AM, but an r/o could resolve it with judicious passband tuning and the BFO.

Latest project here is a homebrew 50w AM/CW valve vfo, buffer, PA rig with 5B/254s. I'm using it on the lower bands.
ATB, 73, Andrew
 
#50 ·
Happy Christmas, Mr. Oceanspan!

Just wanted to thank you for the Challenger photo you posted recently. I've been unable to log in for a while, so could neither access the photo nor reply until today, when those nice people at SN have given me a new password.

Thanks for all your work with the iconic Mimco equipment this past year or so. I have been really pleased to know the 'Span, in particular has had a rebirth. And the Challenger project has really interested me as well. Well done indeed. I guess you'll have some time over the winter months to get some more work done while the museum is shut. Good luck with all that you do, and keep the photos coming in!

Wishing you and yours a great festive season and a healthy, prosperous and very happy 2020.

All the best, Paul
 
#51 ·
Hi Paul, thanks for the festive greetings and apologies for not responding sooner. We have been away over Christmas and have just returned home. Over the winter shutdown I shall be modifying the Challenger for the higher amateur bands that fall in the cracks between the available marine bands, and will also add LSB capability.
The next big job will be the Kelvin Hughes Zealand M1250 transmitter (see picture). The receive side is working well, I've not yet tried the transmitter. I've provided a 3 phase supply, and the loom appears to be present to connect it to the console. We have all the manuals, the 4CX1500B is present but of unknown provenance, we also have a spare exciter also with its 4CX1500B present. I know a small PSU repair is needed. Hopefully it will soon be on the air, it is a 1.5KW transmitter, synthesized ( I don't think any mods will be needed for amateur bands, but will have to add LSB at some point) It provides for more modes than the Challenger: AM, ISB, DSB, USB, CW. However, before someone jumps on me, I'll be starting a new thread for this one shortly.
All best wishes to everyone for the New Year, we might even get to chat on the air!

Michael. (GW7BBY/GB2MOP)
 

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#52 ·
Welcome back, Michael sahib. Nice picture of the new setup. Wondering what all that silver 'jewellery' is on the front of the TX. Looks quite alien, all those loops and bangles. I dunno, all this new-fangled stuff...

That looks suspiciously like a Nixie tube readout on the unit at the top centre, the one directly below the GURK callsign plaque. Incidentally, what was the ship which that one comes from?

Being a bit of a freak for all things valve, I counted my blessings, receiving a Nixie tube clock kit from a U.K. electronics firm for Christmas. Just got it done, up and running and it far exceeds my expectations. So nice to see the rounded, gently glowing numerals again, first seen back in the late '70's, on the Marconi Apollo RX.

Good luck with the work upcoming. Paul.
 
#55 ·
Re Kelvin Hughes

Just a quick reply, before staring a new thread. Paul, the "jewellery" on the kelvin Hughes equipment is KH's take on control handles - its different and feels good to handle! (Pic Attached)
No, there are no Nixie tubes, just good old numbers printed on a disk to give a "digital" readout - see pic of M1250 Synthesizer and Receiver.
GURK was "RFA Orangeleaf" - another pic.
Troppo - nice to hear someone who sailed with KH Kit.
And Duncs, I've heard of NERA, in fact I think we have a cannibalised Nera ATU from I don't know what in our store. I'm not familiar with it.
OK Really going to start that new thread for KH.
Best wishes to all - Michael.
 

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#62 ·
Hi trotterdotpom, a lot of the historical information I have is cir***stantial or passed on by others and I am always pleased to receive corrections or supporting comments. However, I have it on good authority that 6 challengers were fitted to 6 Australian bulk ore carriers in the early to mid 80s. It is not hard to guess that these were BHP ships. A bit of digging shows that 6 ships, Iron Whyalla, Spencer, Prince, Pacific, Newcastle and Kembla were built in the period 1981 to 1986. These were built about the time that Challenger was being sold and so are the most likely to have Challengers installed. I also believe from another source that the Challenger and accompanying Marconi console in private hands in Melbourne came from Iron Kembla.
As I say, any information anecdotal or otherwise from the dim recesses of R/O's memory banks is welcome!
Best Wishes - Michael.
 
#70 ·
were fitted to 6 Australian bulk ore carriers in the early to mid 80s. It is not hard to guess that these were BHP ships. A bit of digging shows that 6 ships, Iron Whyalla, Spencer, Prince, Pacific, Newcastle and Kembla were built in the period 1981 to 1986. These were built about the time that Challenger was being sold and so are the most likely to have Challengers installed. I also believe from another source that the Challenger and accompanying Marconi console in private hands in Melbourne came from Iron Kembla.
As I say, any information anecdotal or otherwise from the dim recesses of R/O's memory banks is welcome!
Best Wishes - Michael.
Hello Michael

The Whyalla, Spencer and Prince had Conquerors
Pacific, Newcastle and Kembla had Challengers
 
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