# Keying Marine reserve transmitter



## johnvvc (Feb 8, 2008)

Now here’s one for you R/O’s…

I’m trying to put together a ham radio station to operate on the old mf cw band (410 – 512 kc/s). Our license now allows operation between 472 and 479 kc/s. Ideally I would like to use old marine equipment – keeping the dream alive – reliving my youth – call it what you will !!!

A gentleman here on SN has very kindly given me a JRC NSC-16 Reserve Transmitter which would be ideal. This has a connector at the rear through which the 24 volt dc supplies are connected, leaving two wires which presumably are for keying. I would have assumed that these would either be shorted or one or both taken to ground. I have carefully tried the various combinations but nothing works. There is a 24 volt octal based relay inside which I presume is a keying relay, I’ve removed it and checked its operation on 24 volts and its fine, in any event no voltage appears at its base when it’s plugged in. 

Now my problems are twofold. Firstly I have no paperwork at all on the transmitter – I’ve searched everywhere on the ‘net, the only reference I can find is to a guy in the States who is also using a JRC on this band but that’s a newer model and appears to be very different. Tracing the wiring is not easy as it appears that when this tx was built they only had red wire – it’s full of thick looms and almost all the wires are red!

So a problem which should be relatively easy to sort out is proving to be anything but…

Now I’d just love someone on here to come up and say they sailed with this beast and they know all about it – they have the Manual and they will drop it in the post - but I suspect that’s not going to happen...(Jester)


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## GW3OQK (Jun 10, 2010)

I'm going to be one of those who replies without answering your question.

Some of my vintage equipment is the same and I just cut all the lacing cord of the wire looms so I could trace by hand and eye. Later plastic cable ties tidied it up. Is the transmitter valve or solid state? It would be nice to see some pictures. 

I've made a few contacts on 473 using my T1154.
73, Andrew


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## johnvvc (Feb 8, 2008)

Thanks for the replies.

This transmitter is all solid state, made in 1977 according to a plate on the side and is designed to operate from 24 volts.

The wiring loom is held together with plastic tie wraps and I have been progressively snipping these to try and open the loom and make sense of the whole thing. The fact that most of the wires are red doesn't help!

There are two relays inside, one 'very' large one which comes in when I switch from A1 to A2 and another smaller one which plugs into an octal base which I suspect may be a keying relay.

I have briefly onsidered physically closing the relay by hand to confirm that it does key but as my 24 volt psu can output ~1Kw the fireworks could be spectacular so I've refrained !!!

I'll upload some pictures later - after I've reduced their dimensions...


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## johnvvc (Feb 8, 2008)

Some pictures of the JRC transmitter to give some idea of what the beast looks like, I'll post some more of the insides as soon as I've reduced them in size...


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## BobClay (Dec 14, 2007)

That rear plug J201 looks like an after fit John. Something to replace whatever fitted into that square cut hole .. or is that just me ?


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## johnvvc (Feb 8, 2008)

Bob, I did think that myself. 

When (if...) I get this sorted I may change that for a Bulgin or something similar...


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## BobClay (Dec 14, 2007)

As I'm sure you know you'd crack this with a circuit diagram in minutes. I'm inclined to go with GW3OQK, not that that's of much help to you. But sooner or later you're going to need a diagram anyway.

(Smoke)


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## johnvvc (Feb 8, 2008)

Some more pictures of the JRC transmitter...

digi 1 - this gives a general view of the innards of the transmitter looking from the top. The small relay which I'd assumed, wrongly it appears, was a keying relay, can be seen fixed to the side of the compartment housing the oscillator. It has a pair of contacts that are connected to the oscillator board. You can just see a crystal in there...

digi 2 - most of the components are on the back panel. The big relay, this really is quite big, can be seen at the bottom of the back panel just to the left of the big toroid. This is connected to the variometer so would appear to be in the transmitter's output ? 

digi 3 - this is a close up of the big relay...

digi 4 - this is the bottom of the chassis and you can see I've already been in there having a whale of a time with my snips !!!

RS651400 - yes vvc is part of my ham call - gw3vvc - I sat my RAE in Adelaide around October '66. Now I'm sure the age fairy has been here when I've been fast asleep and pinched some years - I can't be that old surely !!! Mind you the wife says we're not old - we're elderly - not too convinced it sounds any better tho'

I did contact JRC. I seem to remember I mailed their Offices in JA who forwarded my mail to their European division who were unable to help. I have also mailed JARL so just waiting to see if anything comes of that. Presumably there must be some sort of R/O forums in JA where there might be guys who like to own and maybe still operate these old rigs but I've not found anything yet... I have also mailed the ROA guys so I've a few irons in the fire...

As Bob says a circuit/Manual would be handy.


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## freddythefrog (Dec 15, 2007)

Hello John
I have sent you a PM ref the JRC EM TX
73.s de freddythefrog


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## johnvvc (Feb 8, 2008)

freddythefrog said:


> Hello John
> I have sent you a PM ref the JRC EM TX
> 73.s de freddythefrog


Hi John,

Thanks for that, nothing arrived here yet - mind you it's all uphill !

J


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## macve3gro (Oct 14, 2016)

Greetings to all. i have a couple of pieces of Marconi Marine equipment and a couple of piece of JRC equipment to put on the air on 472-479 kHz. Always glad to exchange info on getting this stuff to work. 73. Harry, VE3GRO


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## 5TT (May 3, 2008)

I sailed with one of these, the only completely solid state reserve TX I came across, I had trouble with it too, it would often blow the main 24v fuse. Meter it and all looks good, pop a new fuse in, works fine, full power, until the next time you want to use it, blackened fuse again.

It turned out to be a sharp edge on one of the PA transistors, it had bitten through the mica washer and was occasionally shorting there.

Unfortunately I can't help with any information, other than it worked well when it stopped blowing fuses.

= Adrian +


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## Jonathan H. (Jul 3, 2015)

John

Just picked up a JRC Jax 12 Weather fax off E-Bay. Thankfully seller accepted a sensible price for it on a best offer. Anyhow, this is similar vintage to your transmitter (July 1979) and is actually in lovely condition for age. Runs off 220v which I haven't tested yet. When I got it home and gave it a wipe over, it had a brand new and sealed fax roll fitted in it, which kind of says to me it was origanally bought 2nd hand as a working unit. The seller's uncle had bought it years ago at an auction and just stored it away in a heated shed.

To cut a long story short, if you find a source of old JRC manuals, please let me know as it would ideal to obtain one for it.

Thanks,
Jonathan


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## Naytikos (Oct 20, 2008)

A few thoughts, with apologies to any who thought of them first......

1. The big relay that operates when you switch from A1 to A2....could it rather be a switching relay for the 24V DC power? This Tx will draw a heavy current which the front panel power switch doesn't really look robust enough for.
2. The toroid transformer may be part of an inverter circuit developing a high +Vcc supply, say 100V or above. 
3. The 2SC436 transistors can dissipate 200W and are rated for +Vcbo 300V Ic 30A. I guess that those four are your power output devices.
4. I cannot see whether there are individual crystals but assume so. It seems very likely that the small relay is, in fact, the keying relay and it simply switches an amplifier transistor following the actual oscillator. 
5. MCW may be accomplished by modulating the +Vcc line by a simple flip-flop audio oscillator using the 2SC410 or 412s. A bit crude and reminiscent of valve (tube) techniques, but it would enable the output transistors to operate in class C.

A nice-looking transmitter!


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## Varley (Oct 1, 2006)

Wouldn't square wave modulation make compliance WRT harmonic content needlessly difficult?


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## johnvvc (Feb 8, 2008)

Thanks to all those who have posted here with suggestions and comments re the JRC tx, and to those I never acknowledged - my apologies. Why is it that central heating always fails when it's cold ? In our system the domestic and the heating water are both pumped so when the pump failed everything stopped. A replacement Grundfoss and all is back to normal - and I'm back in the shack!

Naytikos - I initially thought the smaller relay might have been a keying relay though it's contacts will be fairly low current but it could always drive something else down the line. The big relay would sound like a machine gun going off if it folowed the keying! In any event it appears to be connected to the wiper on the antenna tune switch which selects the taps on the variometer. Most of the components on the back panel are connected 'dead-bug' style with just a couple of tag strips thrown in so tracing the circuit is not easy.

I'm waiting to hear from a couple of guys so I'm still hopefull that a circuit or something might appear. For now I'm refraining from opening up wiring looms any further...

Incidentally R651400 I'd hang on to that JST 135. I did read somewhere that JRC is pulling out of the ham market so JRC kit will become scarce...

macve3gro - I pm'd you a few days ago, just wondering what JVC equipment you have - dare I hope you have an NSC-16? (K)

Incidentally ftf tells me this transmitter was originally fitted on the Dart 8 which had a full JRC station.

Thanks again for your comments.


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## johnvvc (Feb 8, 2008)

Naytykos - >>> I cannot see whether there are individual crystals but assume so <<<

Sorry I didn't comment on that.

There are individual crystals for each frequency though most have been removed. The crystals are ~3.6 mc/s and appear to be mixed with another 3.1 mc/s crystal to give the appropriate transmit frequency. 

This transmitter was recently used on 502 kc/s. The actual crystal in there is 3.602 mc/s and when mixed with 3.1 kc/s gives a difference frequency of 502 kc/s.


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## richardwakeley (Jan 4, 2010)

Hi John,
I have come up with the handbook for a similar JRC Reserve Tx, the NSD-1175N.
Originally this would have been mounted in a console like JSS-200, with Main Tx, Rxs etc. Keying was by the BK signal via a photocoupler in the reserve Tx. I think the plug on the back of your NSC-16 is original JRC, even though it looks like it's retrofitted in a different size cut-out, the NSD-1175N looks the same.
The relay in NSD-1175N is not for CW keying, it's in the PTT circuit, as this Tx also had A3E on 2182.
See attached block diagram.
Maybe it's not so useful, as I think your Tx is an older one, but the keying circuit may be similar, i.e. keyed by an external BK voltage.


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## richardwakeley (Jan 4, 2010)

*JRC Reserve Tx*

More pages from the NCT-1175N book.
If you PM me your address I will send you the whole book. But reading the book more carefully, I can see that it's a later model, a lot different from the NSC-16. 
Richard


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## richardwakeley (Jan 4, 2010)

Here's a JSS-200 console. The panel at right is where the reserve Tx was mounted, but it has now been removed and replaced with the GMDSS MF/HF gear, JRC JSS-800.


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## Troppo (Feb 18, 2010)

Really neat.


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## richardwakeley (Jan 4, 2010)

I hope you're referring to my retrofit radio gear, and not my boiler suit


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## johnvvc (Feb 8, 2008)

Richard,

Thanks for the various postings.

>>> ...the keying circuit may be similar, i.e. keyed by an external BK voltage. <<<

I had initially assumed that merely taking a keying line down to earth might have keyed the transmitter but some further circuit tracing would suggest that an external BK voltage is needed as you say.

Thanks again and have PM'd you.


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## Troppo (Feb 18, 2010)

richardwakeley said:


> I hope you're referring to my retrofit radio gear, and not my boiler suit


Ha! Yes, the JRC stations were very well done.


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## 5TT (May 3, 2008)

Same console, different gear.

This was Safmarine's Venture / ZTVE in 1980 / 81.

That is my Katsumi EK-150 keyer which is still in use with my older gear on the amateur bands today and top right is the reserve TX discussed in this thread.

= Adrian +


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## trotterdotpom (Apr 29, 2005)

5TT said:


> Same console, different gear.
> 
> This was Safmarine's Venture / ZTVE in 1980 / 81.
> 
> ...


I remember that console with "Kelvin Hughes" stamped all over it. I note that there is no real morse key there. In the event of a distress, would you first have to type the Help message into your flash Harry morse machine?

John T


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## johnvvc (Feb 8, 2008)

Isn't there a morse key on top of the console - perhaps the original...?


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## trotterdotpom (Apr 29, 2005)

Didn't see that, Johnvvc. Is there a Q code for "Where is my stepladder?"

John T


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## BobClay (Dec 14, 2007)

There is a Q code for: 'Oh f**k, I've fell off my stepladder.'

QFU'up.

(Jester)


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## 5TT (May 3, 2008)

That was indeed the original JRC branded key stowed on top of the console, it was very nicely made key too although I never actually used it.

= Adrian +


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## richardwakeley (Jan 4, 2010)

Yes, the standard JRC key with those consoles. I have kept one as a souvenir, maybe will use it if I ever get back on the amateur bands in retirement.
Thanks for the photo '5TT'. That's actually a slightly different console - JSS-20.
Was that with an external Main Tx? My photo shows JSS-200, with Main Tx at left, Main Rx and antenna selection etc. in the centre.
I have removed the Reserve Tx and Reserve Rx and replaced them with the JSS-800 components, including the new battery charger. It was an option for installation in an existing JRC console in the Radio Room, very convenient for using the existing AC/DC supplies, antenna etc. Also, the Main Tx and Rx were still available for use - a few companies kept on the R/O for a while. For non-JRC consoles, it came in it's own cabinet. The controllers, printers etc. are on the chart table. This was on Canadian Transport Co's City of Alberni. Forgot the callsign, I wasn't the R/O by that time. Just escaping from the gantry cranes for a photo op when my father visited the ship at Portbury Dock.


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## Troppo (Feb 18, 2010)

....great W/T gear...crap GMDSS gear....


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## 5TT (May 3, 2008)

> Was that with an external Main Tx?


The TX synthesizer was in the console on the left side and the rest was external as per attachment.

I can't remember what valves it used now but ran comfortably at the legal limit.

Interestingly the TX synth was continuous coverage up to 30 mhz, it wasn't restricted to marine bands only.

= Adrian +


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## johnvvc (Feb 8, 2008)

Hi,

Not too sure if there should have been a link in your post?

In any event after what seems like hundreds of emails sent a gentleman in JARL (the Japanese equivalent of our RSGB of course) came back and said he had a mate in JRC who was going to see what he could do... Now I'd already mailed JRC and they'd said they had nothing and referred me to their agents on the Continent so I wasn't very hopeful. In the event the gentleman from JARL came back to say his mate had located a cct diagram so that should make life a lot easier!

Thanks for your mail.


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## R651400 (Jun 18, 2005)

Apols for lack of clarity. By this I meant this thread popped up when browsing.
35 years since I was a member of TIARA so doubt there won't be many of the old Gaijins I knew left..
Will give the RAM a shoogle and see if I can come up with a name that may still be sinking the saki.


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