chevpol Posted September 22, 2008 Share Posted September 22, 2008 heres one for all the bleeps out there, I have a 3 piece antenna, I assume the numbers that are on the sections are for frequencys? the numbers run from 36 all way up to 59, it has a stock number :-5985-99-103-7356. it is not a whip ariel, so am I right in assuming it is for a static mast? will try to post a picture asap the first section is 35" long,, second section 25" and final 23" Mark Quote Link to comment Share on other sites More sharing options...
chevpol Posted September 23, 2008 Author Share Posted September 23, 2008 ok chaps and chapesses!!! as promised, a couple of shots of said antenna, any ideas? the last shot isnt fully extended. Mark :tup:: Quote Link to comment Share on other sites More sharing options...
fv1609 Posted September 23, 2008 Share Posted September 23, 2008 (edited) ok chaps and chapesses!!! as promised, a couple of shots of said antenna, any ideas? the last shot isnt fully extended. Mark :tup:: If I've got it right the max length is 83 inches & min is 35 inches. So for a 1/4 wave that gives an adjustable range of 35-82 Mhz. Edited September 23, 2008 by fv1620 Quote Link to comment Share on other sites More sharing options...
AlienFTM Posted September 23, 2008 Share Posted September 23, 2008 36 - 60 MHz is the frequency range of Larkspur VHF sets (though I have a feeling some manpacks did not cover the entire band). ISTR the A41 had a folding antenna which the second picture reminds me of, but I do not recall any need for an antenna base unless this part of a vehicle mounting kit for an A41. We were going to get Clansman PRC351/2s to replace the B set VRC353 in our Scorpions when I left: ISTR they came with a vehicle mounting kit to enable connection of the manpack to the external antenna base. Maybe this is the equivalent for the A41 or similar? Quote Link to comment Share on other sites More sharing options...
84KB11 Posted September 23, 2008 Share Posted September 23, 2008 Snap, I have one that looks identical to this antenna. My numbers also run from 36 to 59, although my NSN is 5985-99-103-7358. I may be wrong, but my understanding of these antennas are that they are for use without ATU's. The numbers on the sections are the operating frequency. The basic idea is that you extend the antenna to the required frequency number for use. Also, do not be fooled by the length, if you gently shake the antenna you will here it has "stuff" inside. I think this is some kind of loading coil to give the correct operation. No idea what radio they were intended for, but have used it with some modern sets, working on the above theory, and it seems to function well. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted September 23, 2008 Share Posted September 23, 2008 The basic idea is that you extend the antenna to the required frequency number for use.Yup Also, do not be fooled by the length, if you gently shake the antenna you will here it has "stuff" inside. I think this is some kind of loading coil to give the correct operation. I've got one somewhere, don't think there is a coil there. As the chosen length is 1/4 wave that is optimum for the RF to be radiated. If the range I quoted corresponds to the appropriate radio there would be no need to add inductance. Just looked up the NSN gives a VAOS of ZA50448 Quote Link to comment Share on other sites More sharing options...
58 BE 88 Posted October 29, 2008 Share Posted October 29, 2008 It's the radiating element of the Larkspur VHF elevated antenna kit. This is mounted at the top of a 27 foot telescopic mast on a special base that has a co-ax plug (Burndept pattern 4) for connection to the radio and a dished base with three "notches" equally spaced. The notches are to retain three support guys which are partly made of steel cable which when errected as the top three guys for the mast, form an elevated groundplane. The whole thing, when extended so that the numbers on the rod equal the required frequency in megacycles, forms an elevated 1/4 wave Marconi antenna with the additional height and groundplane producing greater range compared to a vehicle mounted whip. This kit was most commonly used with the C42 but any Larkspur radio covering the range can also be used - therefore B47, A40 and A41. There is a complementary "low band" version covering 23 - 38 Mc/s that has a longer radiating element and longer steel sections in the support guys which would be used with the C45, B48 or A42. Although it's simple and works well, the big operational snag is that you have to pull the mast down to change frequency. The Clansman equivalent is the Elevated VHF antenna kit commonly known as the "pineapple" that sits on the later 8m mast. This is a broadband design that covers 30 - 76MHz and so gets round the frequency changing problem although at slight loss of efficiency. Andy Quote Link to comment Share on other sites More sharing options...
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