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Worldspan 7th August 2019 23:06

Ships' working frequencies
 
Of course, all ships had 500, 512 and 410 (the latter for DF but I never used it) and I seem to remember that the working frequencies were 480, 468, 454 and 425. Are these correct?

Was it the case that a ship with, say, an Oceanspan could transmit on all of the working frequencies but was permitted to use only two? I mean were just two frequencies allocated to each ship? And if it was two, were they always paired the same … perhaps 480 and 454? Or was a ship with a transmitter that had all of the working frequencies free to choose which one was best?

Memory lapse!

Thanks in advance. W

Papa Bear 7th August 2019 23:49

It seems to me that, if I remember correctly I had the above MF freqs and could use whichever I desired. John L.

Paul Braxton 7th August 2019 23:54

Ships were fitted with all the frequencies you quote; all with dedicated crystals, in the case of the Oceanspan transmitter, say, until the later transmitters with synthesised drives came along. That gave you a bit of leeway. If you were working Nitonradio/GNI, for instance, you would probably go for 468, his working frequency being 464, or Landsendradio/GLD, who was on 438 and would often use 425 from the ship. It got a bit congested in European waters (Scheveningen/PCH was on 461, so you would use 468 or maybe 454 with him. Hopefully the relative distances between stations would lessen problems with interference). That's how I used to work, anyway. Somehow it worked out alright.

Wismajorvik 8th August 2019 02:08

Quote:

Originally Posted by Worldspan (Post 2996471)
Of course, all ships had 500, 512 and 410 (the latter for DF but I never used it) and I seem to remember that the working frequencies were 480, 468, 454 and 425. Are these correct?

Was it the case that a ship with, say, an Oceanspan could transmit on all of the working frequencies but was permitted to use only two? I mean were just two frequencies allocated to each ship? And if it was two, were they always paired the same … perhaps 480 and 454? Or was a ship with a transmitter that had all of the working frequencies free to choose which one was best?

Memory lapse!

Thanks in advance. W

In the early sixties vessels I sailed on had only two working MF frequencies. On one vessel the transmitter had selectable LC oscillators as a back up to the crystals but unfortunately the inspector discovered that these had been retuned to the ‘missing’ working frequencies and adjusted them back to the original frequencies. The limit of two frequencies was frustrating as often a coast station after a traffic list would advise listening to a specific frequency, which you may not have,

Ron Stringer 8th August 2019 09:02

In the UK a ship was only licensed by the GPO to use two of those four available MF working frequencies. This was supposedly to ensure that there was a distribution of traffic on any particular working frequency but I fail to remember the reasoning behind this.

Of course many ships were able to use all the working frequencies but such use was outside the terms of the ship's radio licence. Some GPO surveyors were keen to insist that crystals for unlicensed frequencies were removed (this was even more stringently applied to the MF R/T frequencies, especially on fishing vessels) but most paid little attention.

The this caused a problem for ships spending time on the US Coast, where 448 kHz was a commonly requested/demanded working frequency by coast stations. Most such vessels carried a crystal for 448 kHz, either installed in the transmitter or secreted in a drawer.

Tony Selman 8th August 2019 09:21

That's interesting Ron on two fronts. All the ships I sailed on had all the crystals installed and I can never remember a surveyor saying I should use only two. To be honest that is the first time I can recall hearing that. I spent a lot of time on the US Coast over the years and can never recall using 448 or being requested to. At this distance I can't ever remember as ship having the 448 crystal secreted in a drawer. What years was this relevant?

Ron Stringer 8th August 2019 11:30

Tony,

The 448 experiences were 1960s during which time I sailed on/near the US on 4 ships where US stations (especially USCG stations accepting OBS and AMVER messages) regularly directed me to 448 kHz. Which none of the ships carried.

Whether or not shipowners could obtain permission to use additional frequencies on application to the GPO I don't know, but I suspect that was the case, since I sailed on and visited ships with a full frequency complement. However the norm was for only two of the four to be assigned by the GPO's licensing branch. The notices of allocation were processed by a section of the MIMCo supplies department which ordered up the appropriate crystals and delivered them to the shipyard where the transmitter was to be fitted.

The checking of fitted Vs licensed frequencies was also 1960s and precautions against any such problems used to be part of a shore technician's pre-survey checks prior to a visit from the GPO Radio Surveyor. On the South side of the Tyne, only one of the two regular surveyors had this particular bee in his bonnet but normally we didn't know until the last minute which one would be turning up to do the survey.

Later, whilst working at the Chelmsford office I saw reports of similar problems at other ports. Fortunately transmitter design evolved to a state where it was not potato limit the working frequencies and the problem went away.

Varley 8th August 2019 11:39

I know there were a lot of Irish in Macaroni Ron but I didn't realise Chelmsford had had to impose a potato limit.

(Weren't the allocated frequencies licensed according to whether you were a high traffic ship or not?)


(Did you know you can tell the polarity of a DC supply with a potato?)

jimg0nxx 8th August 2019 12:52

When I started in 1962 using the old Oceanspan with a variable LC oscillator you could tune any MF frequency desired. On joining a ship so fitted I would note the readings on said oscillator and avail myself of all working frequencies(illegal of course). Never had any comeback. On passenger vessels I sailed on fitted with Globespan all working frequency crystals were available.

david.hopcroft 8th August 2019 20:22

In the early 60's, my main MF Tx was a T10A, and I really can't remember how many it had. Later whilst at GKZ our working frequency was 484. I never directed anyone, but the vast majority opted for 480, especially the ubiquitous Russians with OBS messages.

David
+

majoco 9th August 2019 03:46

If I recall, the "Sir William Walker" Stevie Clark's collier only had 425 and 468 KHz as working frequencies but as time actually at sea was limited to the Tyne to Shoreham and back again so it was fairly rare to actually send any real messages other than a T/R - VHF and MF telephone calls were made frequently. Blue water ships had a full complement of crystals and some oddball spares too.

Worldspan 11th August 2019 00:20

Thanks for all the interesting replies. I do believe that on 'Orontes' we were limited to two working frequencies although I can't remember what they were.

But on this matter, were such working frequencies always issued as, say, 480 and 425? I mean were they always paired in the same way? I confess that I'd never heard of 448 as a working frequency.

W

Wismajorvik 11th August 2019 01:08

On a number of vessels it was possible to increase the signal level to the receiver by adjusting the tuning on the powered off transmitter. This was useful when attempting to copy wx or tfc list from a distant mf cs. The larger transmit aerial coupling signal into the rx aerial. Therefore it would be beneficial to use a working frequency close to the cs frequency, (if you had one).
Off topic, on my first ship the hf tx was only equipped with 6,8,12 and 16Mhz.

Ron Stringer 11th August 2019 09:22

Quote:

Originally Posted by Worldspan (Post 2997093)
I confess that I'd never heard of 448 as a working frequency. W

448 kHz as a working frequency for ships was only available for use in Region 2 (North and South America) as set out in ITU Radio Regs, not in other Regions - another potential source of conflict at GPO inspections. I suspect that allocation might have been because it had been in common use by US ships when the Radio Regs were amended to define the Maritime Mobile frequency band and its uses. Such anomalies are not uncommon in the Regs when proposed international changes conflicted with existing uses in a major member state and a deal was done to get round the problem.

A similar example was the designation and use in the USA of some of the two-frequency maritime VHF channels. There, only the lower frequency of the pair was made available for marine use, the higher frequency having been allocated to railways prior to ITU setting out the international frequency plan in Appendix 18 to the Radio Regs. This meant that certain of the VHF channels above Channel 16 were not available to most ships in US waters but were commonly used by local ships and coast stations.

Tony Selman 11th August 2019 10:11

I spent a fair bit of time regrettably pounding across the North Atlantic on the Cunard cargo ships. If anyone was going to be allocated 448 it would have been them. To the very best of my knowledge with a gap of over 50 years I do not recall either the frequency being allocated or me ever using it. I will though ask a couple of R/Os who were on the run and they might refresh the little grey cells. One, almost unbelievably, spent nearly his while life on the North Atlantic so I am sure he will know.

R651400 12th August 2019 07:55

The only time I came across 448 as a MF working frequency was on a WW2 US built US liberty and later two post WW2 US built Niarchos tankers which makes me think it could have originally been a FCC/North American frequency allocation.
Never came across it on any UK/European build.

david.hopcroft 12th August 2019 12:11

1 Attachment(s)
Ref #13

Wismajorvik..

Was it one of these ……... Seimens SB186 ?

David
+

cajef 12th August 2019 12:44

Quote:

Originally Posted by Wismajorvik (Post 2997097)
Off topic, on my first ship the hf tx was only equipped with 6,8,12 and 16Mhz.

I had the same on the Clan Maclennan, can't remember which make of transmitter, it could well have been the same as posted by david.hopcroft above from faint memory it looks familiar.

Wismajorvik 12th August 2019 14:21

Quote:

Originally Posted by david.hopcroft (Post 2997361)
Ref #13

Wismajorvik..

Was it one of these ……... Seimens SB186 ?

David
+

That was it. 60 watts if I recollect.

david.hopcroft 12th August 2019 20:12

1 Attachment(s)
You pulled out a tuning slug - right out for 16mhz - and cracked your head on it each time you got up from the chair to throw the switch to change the G12 from MF to HF !!

It was here - GWWJ - Outside only access to the Radio Room. You may be able to see the door just behind the bridge wing.

David
+

gwzm 13th August 2019 11:56

I've just had a quick squint in my very tattered PMG Handbook 1961 edition, page 71, para 82 where it says "All ship stations equipped to work in the authorised bands between 405 and 535 Kc/s must be able to:
(a) send and receive class A2 emissions on 500 Kc/;
(b) send, in addition, class A1 and A2 emissions on at least two working frequencies;
(c) receive, in addition, class A1 and A2 emissions on all the other frequencies necessary for their service.
The provisions of (b) and (c) do not apply to apparatus provided solely for distress, urgency and safety purposes."

From which: (b) means that ships weren't limited to only two of the working frequencies 425, 454, 468 and 480 Kc/s while (c) covers the point if 448 Kc/s is required, although I never heard of it.
That said, as far as I can recall, every ship that I sailed on had all four MF working frequencies.
Happy days,
gwzm

Ron Stringer 13th August 2019 13:13

Quote:

Originally Posted by gwzm (Post 2997551)
(b) send, in addition, class A1 and A2 emissions on at least two working frequencies;
(c) receive, in addition, class A1 and A2 emissions on all the other frequencies necessary for their service.
The provisions of (b) and (c) do not apply to apparatus provided solely for distress, urgency and safety purposes."

The ITU Radio Regulations and the UK Radio Rules did not specify the maximum number of frequencies that had to be available for transmission, only the minimum provision. However as standard the UK GPO only licensed two MF working frequencies in the 1950s and 1960s. I assume that additional frequencies were obtainable if the owners applied for them, because I sailed on and encountered vessels that had all 4 of the listed frequencies. One was a Shell tanker and I suspect that, being major company with its own radio superintendent, they had some clout in getting their way. I also sailed with ships of smaller companies that did not have that advantage (or couldn't be bothered to ask).

I sailed with the Oceanspan I, which had variable MF oscillator tuning using a miniature 'starting handle' to wind up the frequency required. That was no problem when working any station - whatever they asked for you could give them.

I also sailed on vessels that had crystals fitted for all 4 working frequencies but only 2 of which appeared on the Ship Radio Licence (one of which instances caused me some hassle with the Aussie radio surveyor in Melbourne).

Para. c) above really has no relevance since it applies to provision on the ship for reception, not transmission.

As I said, as time passed and technology moved on, such small matters faded into the background and the GPO Radio Surveyors found something else with which to torment us shore technicians.(Jester)

gwzm 13th August 2019 13:28

Para 730 of the Multilateral Telecommunications Act, October 1947, states "In addition the frequency 512 kc/s may be used in Regions 1 and 3 and 448 Kc/s in region 2."
Later on, The Code of Federal Regulations of the United States of America 1949-1984 states "The frequency 448 kc/s will not be available after July 1, 1970."
So, it looks like 448 Kc/s pre-dated most of us.

Happy days,
gwzm

Ron Stringer 13th August 2019 22:20

Quote:

Originally Posted by Varley (Post 2996569)
I know there were a lot of Irish in Macaroni Ron but I didn't realise Chelmsford had had to impose a potato limit

My smarter-than-me phone substituted 'potato' for 'possible'. Don't ask me why.

Varley 14th August 2019 00:57

Apple will tell you that is impotato.


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