# Maritime Radio Day 2020



## R651400 (Jun 18, 2005)

MRD 2020 info *here*.
Interesting radio room. 
Someone give me a breakdown on the gear pse.


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## Troppo2 (Jun 25, 2018)

R651400 said:


> MRD 2020 info *here*.
> Interesting radio room.
> Someone give me a breakdown on the gear pse.


That's a Redifon R408 main rx in the right hand console.

The ant switch box is also Redifon..

An awful layout....


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## R651400 (Jun 18, 2005)

Thanks T2.. GTZB were a big customer of Redifon in the 50's. 
Well constructed with abysmal performance.


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## Troppo2 (Jun 25, 2018)

I sailed with a 408 on the Baron Murray/GWES. Awful.


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## duncs (Sep 8, 2008)

MIMCO fitted the R408 as an advance on the Atalanta, I think for SSB, prior to their Apollo. I sailed with it once, but I cannot remember if I used it for SSB link calls. From memory, I can't think of any problems with it. A far cry from the dreaded R50M!


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## DickGraham (Oct 2, 2017)

The only time I sailed with an R408 was my first ship Mysia/GYZA but I still remember that the plastic scale ribbon used to jump the drive cogs and so there would be an 'offset' on the tuning which I think could be checked using the calibration function - or you could just 'bang' the handle to get the scale to jump back!


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## R651400 (Jun 18, 2005)

Only got as far as the R50M of which there has been enough posted on other SN threads.
One thing I have noticed however and maybe just my own perception is how poky radio rooms had become on new builds post my own sea time.


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## duncs (Sep 8, 2008)

I have to disagree with that R65. Some of the late 70s early 80s ships I sailed on had really smart radio room/accommodation. A nice big cabin, with an adjoining door into the radio room.
I can well remember, a Star boat, with the radio room behind the bridge. To this day, I believe, that the designers had forgotten the radio room, and stuck it in the bridge toilet as an afterthought. Redifon, R50M etc gear.


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## Ron Stringer (Mar 15, 2005)

By the time that stocks of Atalanta receivers ran out, the long-promised and long-overdue Apollo was still not available, leaving MIMCo with a headache. What receiver to supply as a stop-gap with Crusader stations on UK ship's (where type approval was mandatory) until Apollo became available?

The answer was the R408, which MIMCo, with gritted teeth, had to buy in from Redifon.


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## Ron Stringer (Mar 15, 2005)

Posts #7 & 8

Went aboard a large tanker with a radio room about 4m X 5m. There were benches along all four bulkheads, leaving space only for the door and a large storage cupboard. The radio gear was scattered around these benches in a most inconvenient manner.

The owner's radio superintendent was aboard so I asked why they had not used a console installation instead of spreads fitting the equipment. It would have made for a much better operating arrangement and taken up a fraction of the space.

He was indignant at my criticism and rejected it outright. "It's taken me years of fighting for the radio department to be given more space in the accommodation and I'm not going to give them an excuse to cut it back again."


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## duncs (Sep 8, 2008)

Ron Stringer said:


> By the time that stocks of Atalanta receivers ran out, the long-promised and long-overdue Apollo was still not available, leaving MIMCo with a headache. What receiver to supply as a stop-gap with Crusader stations on UK ship's (where type approval was mandatory) until Apollo became available?
> 
> The answer was the R408, which MIMCo, with gritted teeth, had to buy in from Redifon.


The Atalanta was no use for SSB. OK, you could tweak the BFO, but still no use for SSB. The Pennant was designed to go with the Crusader. I've never sailed with it(the Pennant), and wonder if anyone did. The R408 was quickly bought as a stopgap. They(MIMCO), also bought the 'Nebula', much better again.


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## Varley (Oct 1, 2006)

I sailed with the Pennant (and got as close as one could to a fatal shock without being deaded by it). Mine remained faulty due reluctance of Chelmsford to send a crystal filter. I could get it to work by shocking the filter into operation (electrically - perhaps it was wreaking revenge) but chance to use it was rare. Telephone calls were rare - cost. And one could only use the Pennant on the prescribed paired frequency. Suspect Chelmsford knew it was a turkey and weren't prepared to support it to any appreciable expense. A pity it was the only bit of inoperable kit I handed over on Stonehaven - several times. As involvement increased I could not maintain the same boast. The Digiflop on Conoco Europe comes to mind. the Port engine movement recorder on Eurofreighter may have been another - certainly for a couple of trips.

Was Nebula before Apollo? I did sail with the R408 on Texaco Denmark (Crusader). Not markedly different from Atalanta to operate but, again, not much R/T work in the early 70s.


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## duncs (Sep 8, 2008)

Nebula rx. yes I think MIMCO bought it as being better than the R408, for what was becoming more popular for SSB calls. I think their Apollo then took over.
Had a Nebula retrofitted in '72, excellent rx. British coast stations also used them.


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## Wismajorvik (Dec 29, 2011)

I sat in the R408 final test dept. for a few days. There was a large bin of scrapped variable capacitors with mangled vanes which had been rejected principally by several testers who couldn’t get the hang of setting up the tracking. Slow agc was tested by tuning into BBC 200Khz then removing the antenna and checking the time for receiver noise to re-appear, ten seconds. never came across the rx after that. The 551 which I did use commercially was another strange beast with its add-on units.


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## Ron Stringer (Mar 15, 2005)

Varley said:


> Telephone calls were rare - cost. And one could only use the Pennant on the prescribed paired frequency. Suspect Chelmsford knew it was a turkey and weren't prepared to support it to any appreciable expense.


The ITU in its wisdom, at the 1959 WARC (I think) whilst making arrangements for a maritime SSB radiotelephone service, re-allocated each of the Maritime HF R/T bands so that the frequencies were assigned so as to produce radio channels of paired frequencies. Each channel had a 'transmit' frequency for the ships and a corresponding 'transmit' frequency for use by the coast stations. The details of this arrangement were published as Channel tables in an Appendix to the Radio Regulations.

The administrators who comprise the participants at ITU meetings assumed that these HF R/T channels would be used in a similar fashion to the recently introduced VHF R/T channels. Rather than telling ship's operators to transmit on 157.130 MHz and listen on 161.730 MHz, on VHF coast stations they just said "go to Channel 26". Very simple and a reasonable proposal if propagation conditions at HF were as reliable and consistent in both directions as they are at VHF.

Unfortunately this ideal does not exist on HF, where propagation conditions frequently produce situations where, whilst a ship might be able to hear a coast station very well on the assigned frequency in the 8 MHz band, the coast station might not be able to hear the ship on the paired 8 MHz ship transmitting frequency. However the different propagation conditions on the ship transmitting frequency in the 12 MHz band might produce an excellent received signal at the coast station. So the R/T call could be made with the ship transmitting in the 12 MHz band while listening on the 8 MHz band. This was known as 'cross-band' working and was common practice in marine radiotelegraphy ('Morse' communication), being both well-known and regularly-used by both ship's radio officers and coast station operators. The experience and knowledge of the administrators at the ITU (with respect to matters concerning HF R/T communication) mainly came from the fixed, long-range, point-to-point radio services that were in use for many international telephone calls at the time. They did not employ cross-band working as a matter of course as did the maritime service.

The then technical director at MIMCo did not have a maritime operating background either, and he saw great opportunity to produce a ship SSB radiotelephone station using a single, very stable frequency generator that would provide the necessary source for the transmitter and, since the paired frequencies in each band were a constant offset, simply step this to produce the local oscillator signal for the associated receiver used to make such calls. So he produced a spec for what became the "Crusader" transmitter and its associated "Pennant" receiver.

Worked wonderfully, just like a VHF in that the operator just had to select the transmitting frequency, the receiver did not have to be tuned because it was automatically set to the pair of the transmitting frequency. As long as propagation conditions allowed.

In practice, on many, many occasions this was not so. If you only had a "Pennant" receiver for SSB use, you were lost if the only workable arrangement was cross-band working. It would often not be possible to establish communication with both stations transmitting within the same HF band. Even if it could be set up, if the call conditions deteriorated whilst in progress, it would often have to be abandoned. The receiver could only be tuned to comply with the ITU channel arrangement and to no other. 

This inflexibility made the "Pennant" very unpopular with ships' R/Os, who were used to applying their hard-earned skills to overcoming difficult communication conditions. They were frustrated by the inflexibility of the "Crusader"/"Pennant" arrangement. Fortunately for MIMCo (and their R/Os) the "Apollo" receiver came available and was able to fill the role of a ship's SSB R/T receiver while also serving as the main radiotelegraphy receiver.


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## IMRCSparks (Oct 1, 2007)

Re #8 
Duncs,
This could be the radio room in the bridge toilet? Buenos Aires Star/GJNZ. 

Must have been 1979 and my first ship solo. It was certainly an eye opener after six months as Junior in a fairly modern radio room for the time (Norse Pilot/GOVQ). Did the scrap run from Newhaven UK to Kaoishung on the BA Star with lots of adventures in between. 

Definitely no room to swing the ships cat. I guess ergonomics hadn't been invented back then. I am a left handed (sometimes left footed) keyer which meant that I had to rest my right elbow on the key, across in front of my body and over my keying arm in order to adjust the controls on the R50M during a QSO. A frequent requirement due to the tendency of the R50M to drift as the ship rolled. Great fun though!

I was clearly well ahead of time though, wearing of a sun hat to protect me from the searing rays of the 20W desk lamp!

Kevin.


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## duncs (Sep 8, 2008)

In its day, I thought the 'Apollo' was a great receiver. I liked it.


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## duncs (Sep 8, 2008)

Bloody hell Kevin, It almost could be. But I see you have space behind your chair, so, obviously, you had a huge radio room. Mine was on the 'Montevideo Star', ex 'Newcastle Star'. But you bring back memories, same gear. I had the chippy make me a wee shelf under the desk for the key(right handed). It gave me a bit more desk space. Imagine my embarrassment, when the guy who relieved me, like you, was left handed! I didn't have time to alter things, so had to leave it to him.

Best rgds, Duncs


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## Buck Taylor (Apr 19, 2019)

I think the designers were told that the Radio Officer along with the Radio room was being phased out in favour of the emerging GMDSS set up. I was on a newbuild in the early 90's and not only were there no Radio room but no accomodation for the R/O. At the last stages of building they squeezed a cabin of sorts between two existing cabins on the bridge deck with hardly enough room to swing a cat. The "communication" set was on the bridge with Inmarsat A and Inmarsat C as the main forms of communication. 2 vhf sets, a 200W debeg R/T where the CW board had been removed. The technicians who worked for the electronics informed me that CW wouldn't be necessary as all ships were going GMDSS.....At the time there were only 2 earth stations equipped to handle satellite emergencies, Chatham, USA and one in Denmark. Most of the seagoing ships were still using CW and were a long way from fitting the GMDSS gear. The long and the short of it was, if I heard a distress from a ship on CW nearby I had no facilities to answer. Later I heard that it was forbidden to communicate with ships in distress, but to inform the rescue authorities half a world away...


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## Criffh (Feb 27, 2006)

duncs said:


> Bloody hell Kevin, It almost could be. But I see you have space behind your chair, so, obviously, you had a huge radio room. Mine was on the 'Montevideo Star', ex 'Newcastle Star'. But you bring back memories, same gear. I had the chippy make me a wee shelf under the desk for the key(right handed). It gave me a bit more desk space. Imagine my embarrassment, when the guy who relieved me, like you, was left handed! I didn't have time to alter things, so had to leave it to him.
> 
> Best rgds, Duncs


Duncs, didn't the Newcastle Star/GVRS have a compact main tx made by Mullard, which arced and sparked if there was the slightest trace of salt on the deckhead insulators? Also no radar on GVRS when I was on her Oct 69 - May 70.

Rgds... Cliff


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## duncs (Sep 8, 2008)

hi, Criffh, She had a new paint job and new name, still GVRS. Oceanspan VI fitted. Rest Redifon gear. The dreaded AL7 A/A, R50M main rx. Only one bank of batteries. Span LT was 24V from batteries, and after hours trying to raise GKA, in the Pacific at Christmas, batteries would start to fade. Had to switch off span and wait for batteries to charge. I don't know what like, when you were there, but for me, it was the worst station it was my misfortune to sail with.
We had been fitted with a Decca radar. It gave no problems.

Best rgds, Duncs


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## R651400 (Jun 18, 2005)

Participant list to date *here*


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## Larry Bennett (Aug 28, 2005)

Sadly myself as G4HLN or GB0GKB will be unable to take part in this year's MRD. Hope there will a couple of others who will represent GKA. Hoping to activate something special for the 100th anniversary of the UK's long-range maritime radio service later in the year, hopefully GB100GKT or GB100GKU.
Larry +


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## R651400 (Jun 18, 2005)

No question MRD's going to be a dwindling event year by year and because of this I put it to the organisers it might be an idea to open it up to international DX contest status with them showing little or no interest.


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## GW3OQK (Jun 10, 2010)

Larry, can a GB callsign be allocated to someone like me, ex r/o? I'd go on air more than usual if I had an attractive callsign. Perhaps our friends at the Museum of Power would let me use the Oceanspan or Conqueror. On previous years activity only seemed to start in the evenings. I wonder if Tony 'ZRJ will be on.
73, Andrew


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## Larry Bennett (Aug 28, 2005)

GW3OQK said:


> Larry, can a GB callsign be allocated to someone like me, ex r/o? I'd go on air more than usual if I had an attractive callsign. Perhaps our friends at the Museum of Power would let me use the Oceanspan or Conqueror. On previous years activity only seemed to start in the evenings. I wonder if Tony 'ZRJ will be on.
> 73, Andrew


Andrew,

GB callsigns can be reserved 'on-line' via the OFCOM website - any non-standard callsign requests such as GB50 or GB100 have to be tendered by direct communication with the licensing unit. You have to give a good reason for the use of the callsign and what the suffix stands for. I know some of the coast station guys use GLV, GLD and GKZ on occasions, but if you can come up with a suitable 3-digit suffix I'm sure OFCOM will be happy to let you use it for MRD. Special callsigns are only valid for 28 days however.

Hopefully Tony will be taking part, I will contact him over the next couple of days.

Larry +


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