Cornishbloke Posted January 4, 2013 Share Posted January 4, 2013 I would like to run an HF radio in a vehicle (PRC320 or VRC 321). Do I need the "spacer" at the bottom of the antenna mounts or is this something that is used exclusively with VHF sets.The unit itself is this http://www.ebay.co.uk/itm/NEW-CLANSMAN-RADIO-RADIO-ARIEL-SUPPORT-MOUNT-ELEMENT-/200588406813?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D4642547728369579665%26pid%3D100015%26prg%3D1006%26rk%3D1%26sd%3D200588406813%26I have seen this which I've been told is appropriate for HF usehttp://www.ebay.co.uk/itm/CLANSMAN-RADIO-RACAL-ARIEL-MOUNT-PLASTIC-BASE-PLATE-/190516778101?pt=UK_Collectables_Militaria_LE&hash=item2c5baf5475apologies for not being able to get the pictures to work.Richard Quote Link to comment Share on other sites More sharing options...
g0ozs Posted January 4, 2013 Share Posted January 4, 2013 Richard The cylindrical metal spacer contains a matching transformer used with the TUUAM and a 2 metre rod antenna for VHF - it is needed with the TUUAM but should not be used for HF. For HF all you need is one of the No. 31 bases e.g item 190514803542 from the same seller) - I think the spacer 190516778101 is worth getting at the same time on account of being so cheap although I think it depends what the No. 31 base is actually mounted on whether it will be needed or not - without one to look at I can't be sure but I think it's meant for mounting directly on flat metal i.e. an AFV or a landrover wing rather than the landrover side stalks (see photo with e-bay item 261139124411 which shows the No. 31 base bolted directly to the ring of the side stalk) - for HF all that matters electrically is that the antenna is electrically insulated from the vehicle body and the wire to the ATU (TURF) is well spaced off any vehicle body metalwork as well as being insulated - the bowl insulators e.g. items 261139124411 or 190513313240 are used for this. Hope this helps Iain Quote Link to comment Share on other sites More sharing options...
Cornishbloke Posted January 4, 2013 Author Share Posted January 4, 2013 Thanks so much Ian - that backs up what I thought. The plan is to fit a working HF set into the Comms body of an RB44 and the base fits on to a mounting which is physically closer to the TUUAM box than a stalk. The coax runs from the radio through the inside of the body and out through a gland into the mounting. You can see these on the body currently for sale at Withams. I hope to begin the fit in Feb and am trying to get the bits together either at Stoneleigh or EBay. Once I've got a better idea of how the cable run goes I'll ask for advice on the insulators. Many thanks Richard Quote Link to comment Share on other sites More sharing options...
Chris Suslowicz Posted January 4, 2013 Share Posted January 4, 2013 The "spacer" is an insulated centering plate to make sure the aerial feeder is kept clear of the metalwork. Depending on what type of base is in use (and where it's mounted) you may also want a rubber gasket to stop water tracking under the base and getting into the vehicle. Some bases have a plain metal mounting flange, others are rubber coated. "gten98" on eBay will almost certainly have any bits you need; he's certainly got the thick stranded wire used to connect the aerial base to the ATU output terminal (it's not co-ax), and did have the plastic insulator "bowls" in packs of 100 that are threaded over the wire to maintain clearance from any metalwork. Chris. Quote Link to comment Share on other sites More sharing options...
airportable Posted January 5, 2013 Share Posted January 5, 2013 Any help? Mounted on the side arm of a URS in my Air Portable. Just see the insulated disc and gasket. Quote Link to comment Share on other sites More sharing options...
Cornishbloke Posted January 6, 2013 Author Share Posted January 6, 2013 Thanks to all of you who replied - I am getting my list for Stoneleigh sorted out! I hope to have the vehicle back from first plating and registration by the middle of February so I'll be able to ask more specific questions about the fit then. However I now have a good idea how the two systems (HF and VHF) work and what's needed. There are 4 antenna mounts on the RB44 communications body, one at each corner. Is there any preference as to which mounts are used for VHF and which for HF? I have seen these insulator bowls in use on Landrovers, would they be needed inside the body of the RB44 as by the look of it the cables run along paths already marked by cable ties or are they used only once the cable leaves the body through to the mount. This is a picture of the inside as it is, fitted for BMETS. I will rationalise it to three vehicle sets, perhaps with secure data, and a manpack option which will be much the same as the set up in FFR Landrovers. Any ideas gratefully recieved. Quote Link to comment Share on other sites More sharing options...
g0ozs Posted January 6, 2013 Share Posted January 6, 2013 Richard The VHF feeders are screened coaxial cables and can be clipped or tied to the inside of a metal body. The HF feed from the antenna base to the ATU is an unscreened wire - as you are metal bodied, unlike a soft top Landrover, you also need to keep it well away from the body and minimise the length inside - it may be worth researching what was done with AFV installations of the 321 or cheating and using a coax feed to a (non Clansman) 4:1 or 9:1 BALUN outside the vehicle next to the antenna base which will allow fully flexible placement of the radio. BALUNS are £20 to £40 ready made or a tenners worth of bits to build. MEL did actually make an auto ATU for the 321 that could be mounted remotely (comparable to the VHF TUUAM) and would have been ideal in cases like this but the army never bought it ! Regards Iain Quote Link to comment Share on other sites More sharing options...
Cornishbloke Posted January 7, 2013 Author Share Posted January 7, 2013 Thanks Ian . It's all getting clearer but it's a very complicated subject. Perhaps once I start my foundation course it will make more sense. Richard Quote Link to comment Share on other sites More sharing options...
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