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Ptarmigan radio and trivid Info wanted


stevenea0038

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Hi

 

See this which I researched previously

 

http://hmvf.co.uk/forumvb/archive/index.php/t-23340.html?

 

You might also find the installation guide for the FV-432 version useful

 

http://www.fv432.co.uk/manuals/fv432manuals/2350T254/5895-H-515-302%20fv439%20electrics.pdf

 

Unfortunately the Triffid doesn't work on the amateur bands as far as I know. The system was based on Siemens technology and had three operating bands with different RF heads and antennas. The bands were low UHF, High UHF and low Microwave and the documented frequency ranges do not include anything available for amateur use (I think Ofcom might sell you some of the high UHF channels in a 4G mobile spectrum license auction soon, however).

 

The Triffid is only the radio link part of the much larger Ptarmigan system which was a transportable early cellular radio system. So you would likely also need the separate telephone exchange and the "single channel radio access" (SCRA) base station equipment and antennas providing VHF local access, before a complete setup could be reconstructed in anything like a useful form. As far as I know each exchange had triffid links to SCRA base stations so you would really need a minimum of 4 vehicles, a field telephone and a SCRA "mobile" connected

 

telephone-exchange-wire-triffid-UHF-radio-triffid-wire-basestation-VHF-SCRA

 

to get a complete working demonstration of a Ptarmigan call (and that just to a fixed line wired to the exchange)

 

If it can be retuned I suspect the best useful standalone demo station for a show would need to be fitted out with a scaled replica antenna optimised for 70cm or 23cm and probably all that would work in a reasonably standalone way without using excessive bandwidth or several more Bedford-loads of kit is the "engineering order wire" voice link between the Triffid stations themselves or the wired link between the Triffid and a co-located access node or exchange.

 

If it is just desired to have lights on and signs of life, then because of the licensing / frequency issue I'd strongly recommend connecting adequately rated dummy loads via good quality coax to all the RF ports on the equipment in the TRC-471 before powering up if you want to get to the point of at least having the lamps and dials active for show purposes.

 

If it's desired to actually communicate off site and a licensed amateur radio operator is available, probably the best thing is to build a scaled antenna for 70cm (probably about 1/4 smaller than the low UHF or 1/3 bigger than the high UHF) and fit an amateur transceiver (or ex PMR radio tuned for 70cm) somewhere out of sight in the cabin, because even if the heads could somehow be retuned to 70cm and 23cm the modulation is likely incompatible with much else than another Triffid and requires much wider channels than are usual in amateur service. If a license is not available then a scanning receiver can be used to copy (for instance) APRS location tracking data on 433.800 to get some relevant sounding noises

 

Regards

 

Iain

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A few more Triffid links

 

http://www.qsl.net/gm8aob/pages_2/triffid.htm

 

http://armyradio.com/UK-TRC-471-Transportable-UHF-Radio-Relay-Equipment-Triffid.html (updated)

 

http://www.armedforces.co.uk/army/listings/l0085.html#PTARMIGAN

 

http://www.ofcom.org.uk/static/archive/ra/topics/spectrum-strat/future/strat00/chapter3.doc

Look at 3.3.6

 

It's also worth reading Alistair Mitchell's article on the BAOR BRUIN system as it was in many ways a proof of concept for Ptarmigan/Triffid even if more a "quick fix" while waiting for Ptarmigan/Triffid than a direct evolutionary predecessor

 

http://www.royalsignals.org.uk/articles/bruin/bruin.html

 

regards

 

Iain

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Looking at the block diagram in

 

http://www.fv432.co.uk/manuals/fv432manuals/2350T254/5895-H-515-302%20fv439%20electrics.pdf

 

Capture.jpg

 

page B4 (Chap 1 Page 4) it occurs to me that you could, if you have two UK/TRC-471 heads for the same band, connect them via a suitable attenuator (2 x 60dB units in series would do nicely) without the antennas to get a local connection between the two halves of the station sufficient for the EOW handsets to communicate and without radiating.

 

This is the same principle as the Test Set, Condition for the Clansman radios, although the TKC probably wouldn't work up to UHF. Suitable 60dB 50W or bigger attenuators with N-type connectors are readily available and not hugely expensive however.

 

Regards

 

Iain

5895-H-515-302 fv439 electrics_19.jpg

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  • 4 weeks later...
Hi

 

See this which I researched previously

 

http://hmvf.co.uk/forumvb/archive/index.php/t-23340.html?

 

You might also find the installation guide for the FV-432 version useful

 

http://www.fv432.co.uk/manuals/fv432manuals/2350T254/5895-H-515-302%20fv439%20electrics.pdf

 

Unfortunately the Triffid doesn't work on the amateur bands as far as I know. The system was based on Siemens technology and had three operating bands with different RF heads and antennas. The bands were low UHF, High UHF and low Microwave and the documented frequency ranges do not include anything available for amateur use (I think Ofcom might sell you some of the high UHF channels in a 4G mobile spectrum license auction soon, however).

 

The Triffid is only the radio link part of the much larger Ptarmigan system which was a transportable early cellular radio system. So you would likely also need the separate telephone exchange and the "single channel radio access" (SCRA) base station equipment and antennas providing VHF local access, before a complete setup could be reconstructed in anything like a useful form. As far as I know each exchange had triffid links to SCRA base stations so you would really need a minimum of 4 vehicles, a field telephone and a SCRA "mobile" connected

 

telephone-exchange-wire-triffid-UHF-radio-triffid-wire-basestation-VHF-SCRA

 

to get a complete working demonstration of a Ptarmigan call (and that just to a fixed line wired to the exchange)

 

If it can be retuned I suspect the best useful standalone demo station for a show would need to be fitted out with a scaled replica antenna optimised for 70cm or 23cm and probably all that would work in a reasonably standalone way without using excessive bandwidth or several more Bedford-loads of kit is the "engineering order wire" voice link between the Triffid stations themselves or the wired link between the Triffid and a co-located access node or exchange.

 

If it is just desired to have lights on and signs of life, then because of the licensing / frequency issue I'd strongly recommend connecting adequately rated dummy loads via good quality coax to all the RF ports on the equipment in the TRC-471 before powering up if you want to get to the point of at least having the lamps and dials active for show purposes.

 

If it's desired to actually communicate off site and a licensed amateur radio operator is available, probably the best thing is to build a scaled antenna for 70cm (probably about 1/4 smaller than the low UHF or 1/3 bigger than the high UHF) and fit an amateur transceiver (or ex PMR radio tuned for 70cm) somewhere out of sight in the cabin, because even if the heads could somehow be retuned to 70cm and 23cm the modulation is likely incompatible with much else than another Triffid and requires much wider channels than are usual in amateur service. If a license is not available then a scanning receiver can be used to copy (for instance) APRS location tracking data on 433.800 to get some relevant sounding noises

 

Regards

 

Iain

 

Hi Iain, 'tis I who has recently acquired a Bedford MJ complete with the Triffid element of the Ptarmigan system. Everything powers up but I am very much feeling myself through what is obviously a very complex system. I took the uni down to the Royal Signals Museum last month ans I was fortunate to meet with Mike Butler who was involved in the development of the Ptarmigan system. I am thrilled to bits with what I have but I am not a radio buff and I really want to understand more about the kit I have. I am involved as part of the organising team for the Capel Military Show held every July in Capel, Surrey. I also have the good fortune of knowing Les Thackers quite well as we both have Daimler Ferrets. I would really appreciate the opportunity of speaking with you regarding my Bedford MJ unit and I can be contacted on 07966 194484. Best Regards - Graham

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Graham

 

I am maxed out tomorrow - I can give you a call Saturday - what time is best ?

 

I know Les (he drove up to Suffolk for a PSU once!)

 

I have only theoretical knowledge of Ptarmigan/Triffid but will be happy to help as much as I can

 

Regards

 

Iain

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Iain, sorry the late response. Let's leave a catch up call until next week. In the meantime I wish you and your family a wonderful Christmas and a peaceful, prosperous and healthy New Year.

 

All the very best - Graham

 

PS I also have a further query and that is with regards to the voltage input to the Depot Storage Unit FV 790842 which is located on the rear of the comms cabin. The curious connector is five pins with only three connected as pos, neg and earth. There is a small twin contact bayonet fitting light bulb which indicates when the power is 'on'. The ravages of time have removed any indication of whether the bulb is 240V or 24V.

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Graham

 

Best wishes for Christmas to you and your family too

 

There is a 5-pin 24V connector used in quite a lot of RACAL kit - I think without one to hand it is based on a 14mm or 16mm diameter shell and was used by RACAL for a lot of non-clansman stuff. It seems odd to have +, - and separate ground for a 24V DC supply though. If the bulb is intact seeing if it glows when powered by a 24V battery out of circuit is probably the safest way to find out - visual inspection as to whether it is a filament bulb or a neon may also be a clue - a neon could only be 240V

 

Regards

 

Iain

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Graham

 

It appears from this http://www.ebay.ie/itm/Ex-Military-Land-Rover-Carawagon-Depot-Storage-Unit-FV790842-/131134003226 that it was a mains float charger - so I guess it is 240V - if the bulb measures open circuit to an ohmmeter it is likely a neon.

 

For others interested there are fairly clear photos at http://www.thexmod.com/item_detail.asp?id=20915

 

Regards

 

Iain

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Hi Iain, the mystery of the voltage input for the Depot Storage Unit has been solved. I had notice that the socket labelled up for the de-humidifier was not powered up when the box was serviced with 240volts. I then traced back the cable through the conduits to its start point and I was amazed to find that it terminated/originated at the internal cable on the rear mounted Deport Storage Unit. Had I been been somewhat more attentive I perhaps ought to have noticed that the la labeling of the cable as it emerged from the de-humidifier socket had the same designation - P306 - as the cable at the Deport Storage Unit .

 

Let's see if we can have a natter early in the New year.

 

All the very best - Graham

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  • 2 weeks later...

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