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About g0ozs

  • Birthday 12/19/1965

Personal Information

  • Location
    Near Mendlesham in North Suffolk
  • Interests
    Clansman and Larkspur era radios, past owner of a Simca SUMB radio truck, now a Defender 90 GS
  • Occupation
    Telecommunications Engineer
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  1. Andy Thanks. The 6 to 12 pin cable had no braid to shell connection at the 12 pin end, which may explain the problem in part. Iain
  2. Andy Looks like we have a problem with the cable from Drivers Box Selector to Drivers position through the rotating joint being open circuit for the mic return pin (Clansman 12 way connector pin E) which should be connected on the driver's box. I do know enough to build the replacement cable having salvaged the mangled 6 pin to 12 pin cable (the 6 pin end being intact) and will write up what I found during the week. Do you remember if your installation included the ground (seems to be Larkspur Pin A) or used chassis return as implied by the diagram above not showing a ground via pin P of the 12-way plug (which is wired on both the DB and the DBS) Regards Iain
  3. I've found the EMER with the interconnections for a pure 12 pin harness and will trace the wiring to the 6 pin connector tomorrow - update to follow
  4. Thanks Andy. Is that the 12 pin end as it seems to have 4 connections and at least 4 more solder buckets ? Do you have the other (6 pin Larkspur) end as well as I need to make a replacement cable ? Regards Iain
  5. Josh It's basically a UK adapted US BC-1000 (also known as SCR-300) with different plugs and accessories so the battery boxes for those radios should fit. I got some new old stock in their boxes from an ebay seller in Greece about 5 years ago (who doesnt have them now). The case in its US form is CS-128-A if that helps HTH Iain
  6. Andy Do you happen to remember which 4 pins were connected on the Larkspur 6 pin connector going to the D Box - I have been asked to help get intercom working on a Chieftain which although 100% Clansman in the turret has lost its Drivers box and whatever was connected to the 6 pin Larkspur socket hanging beside where it was - I was shown a short cable with a 6 pin plug one end and a Clansman harness plug the other, but it was rather mangled and when tried with a driver's box and a headset that worked in the turret nothing was heard. So I expect I need to fix the adapter cable and knowing what's supposed to be there would be a good start .. Regards Iain
  7. Rob my 3 were all registered on arrival in the UK by the importing dealer, years before I had them. So I haven't had to attempt the process from first principles - and they were registered as 1959 manufacture, PLG, 4 wheel pickup, 4500cc, 3475KG GVW, 2 seats. I think things have changed since they were imported circa 1995-2005 (I bought my first in 2009 and it had been in the UK for around ten years by then) so more expert advice is called for. It may actually be better to treat it as a private HGV so as not to have to stay under 3500KG which is possible but tight. I did take some precautions although they were 1959 dated on the V5 so could in theory claim MOT exemption when I had them but because most were made later I always got a Class 7 MOT to be safe - they are (just) under 3500KG unladen in practice so at least back then could be used and MoTd as a pre-1960 vehicle which simplified things.
  8. Wally Best to get new cable if you can so it will not perish within our lifetimes if ever ! I would go to one of the major electronics suppliers like RS or CPC/Farnell e.g. https://uk.rs-online.com/web/p/cy-cable/0529576/ HTH Iain
  9. I have never found a serial number to year database. There was a breakdown of production by year in an issue of "Charge Utile" magazine - It was a 3 part article starting in No. 110 - they do turn up sometimes on E-Bay and I think the production breakdown was in the 2nd part. If I find my copy I will post the page here. Unfortunately the production (or at least French Army orders which is what it actually listed) only add up to just over 10,000 and the serials of the three I owned at various times were all in the 14,000-17,000 range. So whether they started from a number larger than 1 or used the same series for other vehicles besides the SUMB I dont know. If they did start above 1 it would be useful to know where they started. From memory of the article the vast majority were built in 1964 through 1966 with only hundreds before 1963 - presumably trials) and a few hundred a year after 1967 through to around 1970.
  10. Iain Most of what I know about US handsets is from Brooke Clarke's site http://www.prc68.com/I/H33.shtml and his other pages. The H33 (12 pin connector) and its relatives seem to have a carbon microphone (which needs a DC supply to work) and a lower impedance earphone - having said that German versions of H33 for the SEM-25 and SEM-35 radios which are mostly what turn up in European surplus stores and ebay auctions do have a higher impedance dynamic microphone - I know because one did not work as the operator headset of a SB-22 telephone exchange ! The more recent ones with 5 pin connectors for PRC-25, PRC-77 and later sets are covered by http://www.prc68.com/I/U229AA.shtml http://www.prc68.com/I/H250.shtml and http://www.prc68.com/I/Images/H161ASch.jpg - These seem to present 500 to 1000 ohms to the audio output of a radio as a headset and about 150 ohms as a microphone so are probably within the compatible range. The Clansman loudspeakers are 60 ohms so any higher impedance should be OK. The microphone impedance should not be critical - what matters is that the microphone does not need DC power if it will work with an unmodified lead (the set does provide power on pin C at 18-24V depending on the type, limited to a few mA, so will power a modern electret microphone, but this is not connected to normal headgear. It is less likely that the set could power a vintage carbon one for which a separate battery and transformer coupling as in a field telephone is a better plan. Microphone audio levels need to be in the range of 20 to 40mV peak into the radio if I remember rightly but the sets have audio automatic gain control and are not at all fussy. HTH Iain 73 de G0OZS
  11. Ideally you should get EMER C472 from VMARS or another archive which is the Clansman Headgear technical description that includes circuits. In summary the transducers in the original 1970s series of headsets and handsets are all 300 ohm impedance and of dynamic (magnetic) type, the PTT is a 2 pole switch both connecting the microphone to pin A when pressed and connecting Pin F to ground/ The two earphones are independent each being connected between pin D and ground or pin F and ground. Handsets with one earphone and speakers are driven from pin D (left ear). Colour coding is not quite standard between headsets - the commonly available Pressil Switch replacement cables terminated with a 7 pin plug are: PIN COLOUR A RED MIC B GREEN MIC C No Connection (Is power from radio if you need to operate an electret) D ORANGE AUDIO OUT (Left Ear) E White (connected to screen of cable) GROUND F Black PTT G BLUE AUDIO OUT (Right Ear) The later ANR headsets did need power so pin C was connected through.
  12. Barrie I have also bypassed the transformers (UnUns?) to allow direct feed of a quarterwave whip on 4m and 6m. They do appear to have an impedance matching role because the 1/4 wave looked nothing like it should to an antenna analyser until the transformer whatever it is was bypassed. One slight caution - the pigtail from the antenna clamp to the tag in the matching unit is getting to be a significant part of a 1/4 wave at 2 meters and is somewhat coiled when assembled, so the correct resonant length of rod is a bit less than expected - this is noticeable on 4m and expect will be quite significant on 2m. Iain 73 de G0OZS
  13. Ken is about 20 miles SE of me near the coast - I know him well ! 73 de G0OZS
  14. Clive I wont make it there this year - if you do see Mike Buckley and his friends that used to operate a large HF station near the main road please pass on my regards Iain 73 de G0OZS
  15. Peter What was originally fitted in late 1950s / early 1960s as new build probably R-113 VHF (http://www.greenradio.de/e_r113.htm) or if early R-111 (https://www.radiomuseum.org/r/b_8865_r_111r11p_11.html) - Command tanks may also have had R-112 HF https://www.radiomuseum.org/r/b_8865_r_112r11p_11.html. If modernised in later years after mid 1960s quite likely R-123 (P-123 in Cyrillic) became nearly universal as a late cold war Soviet/Warsaw Pact VHF tank and APC set. The R-123 was around by the early 1970s and even has a (US) manual for use of captured kit see: http://radionerds.com/images/c/ce/R-123M_User_Manual_English.pdf I have one from Poland and it works surprisingly well to this day !
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