# British Siemans SB186x



## bpsparks (Nov 27, 2019)

I did my time at Southampton college in 1965/6 on Marconi gear, I clearly remember joining the BP tanker British Gunner 6 months later and being shown to the radio room by the departing previous RO to be confronted by a collection of rather antiquated Siemans equipment which was then 14 years old, luckily the "frog" had been replaced very recently by a Lifeguard which I was familiar with so I didnt have too many sleepless nights with the auto alarm bell constantly ringing.The equipment although old was very reliable and I found the G2 receiver console excellent, the rotary converter in the bottom of the T10 MF TX was a bit offputting until you got used to the note varying as you keyed. The SB186x HF transmitter looked like something from the ark, I assume that the original design was for it to be VFO controlled as there was a slow motion dial at the bottom of the front panel for no apparent reason, was this the case and was this transmitter adapted for crystal control later in its production life when the X was added to the type number ? This transmitter had another peculiarity in that it had no 4mc/s or 22mc/s so it cramped your style a little, and you had to remember not to touch the aerial coupling bar when the tuning bell push on the desk was pushed !
My last ship was the British Star and at last I sailed with the equipment that I had trained on,Marconi , which really was the best in my opinion


----------



## Harry Nicholson (Oct 11, 2005)

bpsparks said:


> I did my time at Southampton college in 1965/6 on Marconi gear, I clearly remember joining the BP tanker British Gunner 6 months later and being shown to the radio room by the departing previous RO to be confronted by a collection of rather antiquated Siemans equipment which was then 14 years old, luckily the "frog" had been replaced very recently by a Lifeguard which I was familiar with so I didnt have too many sleepless nights with the auto alarm bell constantly ringing.The equipment although old was very reliable and I found the G2 receiver console excellent, the rotary converter in the bottom of the T10 MF TX was a bit offputting until you got used to the note varying as you keyed. The SB186x HF transmitter looked like something from the ark, I assume that the original design was for it to be VFO controlled as there was a slow motion dial at the bottom of the front panel for no apparent reason, was this the case and was this transmitter adapted for crystal control later in its production life when the X was added to the type number ? This transmitter had another peculiarity in that it had no 4mc/s or 22mc/s so it cramped your style a little, and you had to remember not to touch the aerial coupling bar when the tuning bell push on the desk was pushed !
> My last ship was the British Star and at last I sailed with the equipment that I had trained on,Marconi , which really was the best in my opinion


Yes, the sliding bar would give a nasty shock; seem to recall it was used to adjust the effective length of an air coil for tuning. I used that TX on Brocklebanks 'Mahronda'in 1959 - if I remember correctly. I'd forgotten about the other details you mention. Well done for tweaking my memory - particularly the changing note of the rotary transformer.
Mahronda had a large pink neon on the bulkhead which would pulse with the keying - it seemed to me superfluous, but the cat was fascinated by the flicker.


----------



## djringjr (Feb 11, 2008)

Gentlemen Sparks, forgive the QRM from the uninitiated from a former North American Colony, who personally admits you have excellent tea and that we should have paid the TEA TAX centuries ago and forsaken USA tea dust in bags.

I'm fascinated by the tuning arrangement of the SB186x HF transmitter. May I ask someone to explain further details? I envision a device like a slide trombone on the overhead that had to be adjusted for maximum output, a neon bulb improvised for more visible indication of tuning, but relying on the minimum dip of plate current from the final amplifier - usually measured by cathode current and thus the neon bulbs were better accuracy for maximum power out because vacuum valves (toobes, I mean tubes) at resonance, exhibited minimum plate current, but maximum grid currents of the various screens within the valve - thus the cathode dip would not the be the best indication as grid currents would rise and the cathode current being the sum of plate plus all the grids, would not indicate plate current dip.

73
DR


----------



## david.hopcroft (Jun 29, 2005)

I joined the Lokoja Palm in November 1964 just out of drydock so no handovers. It had an SB186x HF Tx and the stalwart well engineered T10A MF transmitter. I remember well the tuning 'slug'. It needed to be full out for 16mhz, and quite a few inches at that. So when I stood up to change the G2 to its HF section, a serious collision was always possible. Luckily I learned that lesson very quickly. I have only found this picture. You can just make out that the 'slug' extended nearly the width of the cabinet. If anyone has a photo of the Radio Room on the Lokoja then I would be very pleased to have one. The room was at the back of the wheelhouse, and there was no inside route from cabin to Radio Room.

David

+


----------



## bpsparks (Nov 27, 2019)

Harry Nicholson said:


> Yes, the sliding bar would give a nasty shock; seem to recall it was used to adjust the effective length of an air coil for tuning. I used that TX on Brocklebanks 'Mahronda'in 1959 - if I remember correctly. I'd forgotten about the other details you mention. Well done for tweaking my memory - particularly the changing note of the rotary transformer.
> Mahronda had a large pink neon on the bulkhead which would pulse with the keying - it seemed to me superfluous, but the cat was fascinated by the flicker.





Harry Nicholson said:


> Yes, the sliding bar would give a nasty shock; seem to recall it was used to adjust the effective length of an air coil for tuning. I used that TX on Brocklebanks 'Mahronda'in 1959 - if I remember correctly. I'd forgotten about the other details you mention. Well done for tweaking my memory - particularly the changing note of the rotary transformer.
> Mahronda had a large pink neon on the bulkhead which would pulse with the keying - it seemed to me superfluous, but the cat was fascinated by the flicker.


you have jogged my memory about the neon on the aerial feeder as there was one on the British Gunner as well but I do not know why, I dont remember having trouble tuning the SB186 using the meters on the front panel although it was a long winded process tuning each stage for max o/p whilst keeping away from the aerial coupling bar ! We didnt have a cat onboard that I knew of but what the Indian crew had back aft was anyones guess


----------



## bpsparks (Nov 27, 2019)

djringjr said:


> Gentlemen Sparks, forgive the QRM from the uninitiated from a former North American Colony, who personally admits you have excellent tea and that we should have paid the TEA TAX centuries ago and forsaken USA tea dust in bags.
> 
> I'm fascinated by the tuning arrangement of the SB186x HF transmitter. May I ask someone to explain further details? I envision a device like a slide trombone on the overhead that had to be adjusted for maximum output, a neon bulb improvised for more visible indication of tuning, but relying on the minimum dip of plate current from the final amplifier - usually measured by cathode current and thus the neon bulbs were better accuracy for maximum power out because vacuum valves (toobes, I mean tubes) at resonance, exhibited minimum plate current, but maximum grid currents of the various screens within the valve - thus the cathode dip would not the be the best indication as grid currents would rise and the cathode current being the sum of plate plus all the grids, would not indicate plate current dip.
> 
> ...


The coupling bar adjusted the effective inductance of the coil in the pi tank cct which together with the aerial tuning variable capacitor brought the aerial cct into resonance, there was a thermocouple r/f ammeter in series with the aerial to monitor the aerial current but of course depending on the length of the aerial the current would vary considerably between bands and it could be useful in some instances to have a visual monitor as well I suppose, before coupling in the aerial the anode current had to be dipped and you had to go back and forward between dipping anode current and coupling in the aerial as they interacted to a certain degree


----------



## gwzm (Nov 7, 2005)

I sailed with the SB186 in 1964 on Brocklebanks SS Malakand/GOFP, built 1942. She was fitted out out with a mix of mostly old gear running off batteries/rotary converters. The SB186 never gave any bother but, as others have noted, it could bite back with RF burns when tuning up, unless you were very careful. The other thing was polishing the brass dials with Brasso to keep them looking shiny. The other bit of Siemens equipment was a swinging-loop DF in the chartroom. it was suspended from the deckhead with a receiver above head height. and the loop was turned by a "steering wheel" beneath. It actually worked quite well but you felt like a u-boat commander using it. The other oddities were Marconi Reliance TX which acted as both main and emergency MF TX and a WWII vintage Marconi B28 (CR100) RX. I used the B28 most of the time in preference to the Redifon R50M which drifted terribly.
Happy days,
gwzm


----------



## bpsparks (Nov 27, 2019)

gwzm said:


> I sailed with the SB186 in 1964 on Brocklebanks SS Malakand/GOFP, built 1942. She was fitted out out with a mix of mostly old gear running off batteries/rotary converters. The SB186 never gave any bother but, as others have noted, it could bite back with RF burns when tuning up, unless you were very careful. The other thing was polishing the brass dials with Brasso to keep them looking shiny. The other bit of Siemens equipment was a swinging-loop DF in the chartroom. it was suspended from the deckhead with a receiver above head height. and the loop was turned by a "steering wheel" beneath. It actually worked quite well but you felt like a u-boat commander using it. The other oddities were Marconi Reliance TX which acted as both main and emergency MF TX and a WWII vintage Marconi B28 (CR100) RX. I used the B28 most of the time in preference to the Redifon R50M which drifted terribly.
> Happy days,
> gwzm


Tks for the reply,I was warned by the previous RO not to touch the coupling bar whilst keying !.Like you I didnt have any problems with the TX the only problem I had in 9 months onboard was a dead EF55 buffer valve in the T10 MF TX whilst on passage from Grain to Fagerstrand in Norway, had to send the TR using the E7 emergency 500 TX. Surprised that you had a rotating loop DF maybe the Bellini Tosi system wasnt around when she was built, the BT system was a vast improvement, when I left the sea I worked for a firm doing small boat radio,radar, autopilots etc and the rotating loop setup was not so accurate as a calibrated BT job. Regarding the B28 RX it was a good set just as well you had it if the R50M was your main RX, I had one of those horrible things on the British Duchess and ended up pulling the slow motion drive to bits and stuffing lots of the thickest grease into it that the engineers could find which made it usable until we paid off in Antwerp and the firm replaced it with yet another R50M despite me asking for a R408. On the British Star, which had Marconi gear , was a CR300, I have no idea why it was fitted,but it could have been useful if the Atlanta had failed as the only other RX was the basic Alert with 500 only.It is 50 years ago when I came ashore but still remember the good days at sea


----------



## Ron Stringer (Mar 15, 2005)

bpsparks said:


> Tks for the reply,I was warned by the previous RO not to touch the coupling bar whilst keying !.Like you I didnt have any problems with the TX the only problem I had in 9 months onboard was a dead EF55 buffer valve in the T10 MF TX whilst on passage from Grain to Fagerstrand in Norway, had to send the TR using the E7 emergency 500 TX. Surprised that you had a rotating loop DF maybe the Bellini Tosi system wasnt around when she was built, the BT system was a vast improvement, when I left the sea I worked for a firm doing small boat radio,radar, autopilots etc and the rotating loop setup was not so accurate as a calibrated BT job. Regarding the B28 RX it was a good set just as well you had it if the R50M was your main RX, I had one of those horrible things on the British Duchess and ended up pulling the slow motion drive to bits and stuffing lots of the thickest grease into it that the engineers could find which made it usable until we paid off in Antwerp and the firm replaced it with yet another R50M despite me asking for a R408. On the British Star, which had Marconi gear , was a CR300, I have no idea why it was fitted,but it could have been useful if the Atlanta had failed as the only other RX was the basic Alert with 500 only.It is 50 years ago when I came ashore but still remember the good days at sea


The Bellini-Tosi system patents were owned by Marconi from early in the 19th century, so Siemens and other D/F manufacturers were stuck with rotating loop systems which were perfectly usable and accurate but far less accomodating in their installation siting.


----------



## bpsparks (Nov 27, 2019)

Ron Stringer said:


> The Bellini-Tosi system patents were owned by Marconi from early in the 19th century, so Siemens and other D/F manufacturers were stuck with rotating loop systems which were perfectly usable and accurate but far less accomodating in their installation siting.





Ron Stringer said:


> The Bellini-Tosi system patents were owned by Marconi from early in the 19th century, so Siemens and other D/F manufacturers were stuck with rotating loop systems which were perfectly usable and accurate but far less accomodating in their installation siting.


Interesting what you say about the patent on the BT system, when we were installing them on yachts we sourced the crossed loop from a firm on the Isle of Wight but always had to get the gonio from Marconi, it was a small box with just the 360 degree control on the front and we hooked it into an SP radio rx, it worked very well,we could not really use the rotating loop due to all the rigging producing serious siting error

regards Tim J


----------



## bpsparks (Nov 27, 2019)

david.hopcroft said:


> I joined the Lokoja Palm in November 1964 just out of drydock so no handovers. It had an SB186x HF Tx and the stalwart well engineered T10A MF transmitter. I remember well the tuning 'slug'. It needed to be full out for 16mhz, and quite a few inches at that. So when I stood up to change the G2 to its HF section, a serious collision was always possible. Luckily I learned that lesson very quickly. I have only found this picture. You can just make out that the 'slug' extended nearly the width of the cabinet. If anyone has a photo of the Radio Room on the Lokoja then I would be very pleased to have one. The room was at the back of the wheelhouse, and there was no inside route from cabin to Radio Room.
> 
> David
> 
> +


tks for the pictures, brings back happy memories of my little radio room on the old British Gunner
Tim J.


----------



## david.hopcroft (Jun 29, 2005)

I never had any trouble with the 186 on the Lokoja Palm, nor did I even know about the coupling bar. The main G12/13 receiver was at right angles with the key in front of that, so was never anywhere near the 186 when keying. Having to keep guardship at Sapele, I used it for quite a few Interflora SLT's for ex-pat sawmill people !!

I can't remember if it had a fixed loop or a BT, but I sailed on a much newer ship later that had the fixed loop in the chart room. I did have occasion to use it one dark and stormy night in the North Sea. The results came out good. The Capt said nothing, but an aside from 2/O said they were good. 

David

+


----------



## bpsparks (Nov 27, 2019)

david.hopcroft said:


> I never had any trouble with the 186 on the Lokoja Palm, nor did I even know about the coupling bar. The main G12/13 receiver was at right angles with the key in front of that, so was never anywhere near the 186 when keying. Having to keep guardship at Sapele, I used it for quite a few Interflora SLT's for ex-pat sawmill people !!
> 
> I can't remember if it had a fixed loop or a BT, but I sailed on a much newer ship later that had the fixed loop in the chart room. I did have occasion to use it one dark and stormy night in the North Sea. The results came out good. The Capt said nothing, but an aside from 2/O said they were good.
> 
> ...


we were sailing along the Portugese coast and I foolishly bet the 3/O that I could get a fix on the Lodestone within so many miles of the noon fix ,I wasnt far out but I lost a few cans of beer ! Happy days

Tim.J


----------



## Luiz Carlos Bitencourt (Nov 28, 2018)

bpsparks said:


> I did my time at Southampton college in 1965/6 on Marconi gear, I clearly remember joining the BP tanker British Gunner 6 months later and being shown to the radio room by the departing previous RO to be confronted by a collection of rather antiquated Siemans equipment which was then 14 years old, luckily the "frog" had been replaced very recently by a Lifeguard which I was familiar with so I didnt have too many sleepless nights with the auto alarm bell constantly ringing.The equipment although old was very reliable and I found the G2 receiver console excellent, the rotary converter in the bottom of the T10 MF TX was a bit offputting until you got used to the note varying as you keyed. The SB186x HF transmitter looked like something from the ark, I assume that the original design was for it to be VFO controlled as there was a slow motion dial at the bottom of the front panel for no apparent reason, was this the case and was this transmitter adapted for crystal control later in its production life when the X was added to the type number ? This transmitter had another peculiarity in that it had no 4mc/s or 22mc/s so it cramped your style a little, and you had to remember not to touch the aerial coupling bar when the tuning bell push on the desk was pushed !
> My last ship was the British Star and at last I sailed with the equipment that I had trained on,Marconi , which really was the best in my opinion





bpsparks said:


> I did my time at Southampton college in 1965/6 on Marconi gear, I clearly remember joining the BP tanker British Gunner 6 months later and being shown to the radio room by the departing previous RO to be confronted by a collection of rather antiquated Siemans equipment which was then 14 years old, luckily the "frog" had been replaced very recently by a Lifeguard which I was familiar with so I didnt have too many sleepless nights with the auto alarm bell constantly ringing.The equipment although old was very reliable and I found the G2 receiver console excellent, the rotary converter in the bottom of the T10 MF TX was a bit offputting until you got used to the note varying as you keyed. The SB186x HF transmitter looked like something from the ark, I assume that the original design was for it to be VFO controlled as there was a slow motion dial at the bottom of the front panel for no apparent reason, was this the case and was this transmitter adapted for crystal control later in its production life when the X was added to the type number ? This transmitter had another peculiarity in that it had no 4mc/s or 22mc/s so it cramped your style a little, and you had to remember not to touch the aerial coupling bar when the tuning bell push on the desk was pushed !
> My last ship was the British Star and at last I sailed with the equipment that I had trained on,Marconi , which really was the best in my opinion


Dear Mr Sparks: Could you please tell me who were the BRITISH STAR Shipowners? And, if possible, other details of that ship (photos, dimensions, etc.). Thank you in advance. Luiz Carlos Bitencourt (From Santos Port/Brazil-South America).


----------



## bpsparks (Nov 27, 2019)

Luiz Carlos Bitencourt said:


> Dear Mr Sparks: Could you please tell me who were the BRITISH STAR Shipowners? And, if possible, other details of that ship (photos, dimensions, etc.). Thank you in advance. Luiz Carlos Bitencourt (From Santos Port/Brazil-South Am





Luiz Carlos Bitencourt said:


> Dear Mr Sparks: Could you please tell me who were the BRITISH STAR Shipowners? And, if possible, other details of that ship (photos, dimensions, etc.). Thank you in advance. Luiz Carlos Bitencourt (From Santos Port/Brazil-South America).


British Star was owned by BP Tankers


----------



## Luiz Carlos Bitencourt (Nov 28, 2018)

bpsparks said:


> British Star was owned by BP Tankers


Thank you very much.


----------



## Luiz Carlos Bitencourt (Nov 28, 2018)




----------

