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SB270 70cms elements


#1

This product isn’t made anymore, and I could do with a replacement set of 70cm elements after several hundred activations of use and abuse. I can’t find anything online - but I really should have asked here first I guess. If anyone can help / wants to do a deal, please reply on here or send me a PM. Many thanks.

I bet there’s plenty of sets of 70cm eles for the SB270 sat around unused - but where to find them…?


#2

My data book of aerial plans says

6mm OD aluminiium tube (available B&Q in 1m lengths, you need 2x 1m)

elements lengths:
281mm
284mm
290mm
293mm
324mm
352mm

Measure twice, cut once. File a chamfer on the ends so they slide into the boom easier.


#3

Would’t mind the complete antenna. Made a HB beam ( https://m0ukd.com/homebrew/antennas/144mhz-2m-portable-yagi-vhf-beam-antenna/ ) which works well electrically, but mechanically it is a bit of a nightmare getting all the elements to stay in place when assembling the antenna in anything other than calm conditions. I have got some clips to try when the warmer weather comes ( Hoping to do a Backpackers from G/NP-001 ) , so any suggestions for a mechanically sound 2m beam that only disintegrates when it is suppoed to would be much appreciated.

73

Paul


#4

I have a sb??? used a couple of times then left in the garage, I cant find the book to see what version it is. It’s a 5 or 3 element and has crock clips to join the wire to the mast.


#5

Would be very interested - will e-mail


#6

Well it’s either the original SOTA Beam, or the SB5 by the sounds of it. But not the SB270 that would be of particular interest to me.

If I don’t find anyone that has the 70cm elements (and is prepared to sell them), then I’ll try some of that Block and Quayle stuff Andy suggests to see if I can fashion a replacement for the one particular element that is beyond repair.


#7

Can’t be much more difficult than re-stringing and then tuning your guitar.
You could, of course, ask your drinking buddy for help :slight_smile:


#8

Surely all you need is some TIG rods, a few nylon bolts, a tube of superglue, and some basic hand tools.

I have a set of 70cms elements but I’d prefer to hold on to them, I’m sure if you got really stuck, I’d be able to counterfeit some.

73, Colin


#9

ISTM that some very accurate drilling is needed, beyond the capabilities of “hand tools” (in my hands, at least). I assume a decent drill press would do it if you make a jig to hold the nylon bolt.

I thought that the nylon bolt idea was absolutely brilliant and it is a great pity that this simple and elegant design was discontinued. SOTABEAMS no longer sells SOTA beams :frowning: I am surprised that it wasn’t commercially viable to continue it, even if sales volumes were modest. The materials cost seemed very small. Once the cutting and drilling jigs are made I would have expected it to be pretty easy to put together, and the final assembly was always left to the customer.

My SB270 isn’t used as much as it should be, but I’m not parting with it.


#10

If you could “counterfeit” me the reflector (largest) element, then I’m in business!

Just realised I’m going to need to build a 70cm version of the MFD under the new FMAC rules too!


#11

I can not see why, Tom. We have been using the standard MFD on 70cm for years.
73
Rod


#12

Yeah that may work courtesy of fx3 (or L/3 : L for lambda, the symbol for which isn’t on my android). I can’t remember if I’ve tried that before or not. Need to crack on and repair the existing MFD - Jimmy has mangled something on it!


#13

I had the same idea when one of my pins vanished in deep heather on MW-002 several years back.
No way I could find suitable bolts despite much searching. I bought a metre of nylon studding and Locktited a steel nut on the end; not elegant but it works.
73
Rod
Edit. I only used 2.5 cm


#14

Hello Tom,
I activated G/NP-031 Birks Fell and the temperature on the summit was -2 before any wind chill was taken into account. I thought that I had pegged down my SB270 sufficiently, sat down to play radio and… timber!!!.. You no doubt know the rest. Anyway I ordered some replacement elements and I do have a 2M element spare that your more than welcome to have. It can be cut to length easy enough and I’m sure this will suite your needs fine.

If you haven’t got sorted let me know and I will send this to you.

73 Chris M0RSF


#15

You have given me the “Eureka moment” Chris! I have the 2m els for the SB270 myself, but never use them, because if I want a 2m beam, I use the SB5.

Cheers.