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SMA antennas

If you have a handy that uses an SMA female socket for its antenna then this may be of interest to you.

I know lot’s of people will have bought an SMA male to BNC female adapter to use with their handheld. I dislike these as depending on the type purchased they can place undue strain on the SMA on the radio top plate. Also the build quality of some of the adapters from BV land is, shall we say, lacking. Much better is to make/buy a patch lead with an SMA male on end and whatever on the other. This way the leverage is reduced.

The downside is that most SMA plugs are designed for thin coax, RG-174 size as opposed to RG-58. You sometimes find small patch leads with an SMA male and a piece of flexible low loss microwave coax in the junk boxes at rallies. But you may need to look hard to find one at a good price. And you have to find a BNC or whatever that fits RG-174/RG-188 style cable. Or get something to crimp onto RG-316.

In 2008 W. H. Westlake were selling an SMA plug for RG-58 sized coax and I bought one and made up a patch lead with it and a BNC trailing socket on the far end. My VHF/UHF SOTA antennas terminate in a BNC plug for the FT-817. This patch leads means that I can use any antenna with any of my handhelds. I’ve wanted another of these connectors for some time but Westlake has been out of stock.

Hosanna in excelsis! Westlake had them on the stand at Blackpool for only £2.50 and I’ve stocked up. So if you want to make some patch leads that use coax thick enough to see on a mountain top you know where to go. The connector fits the same way as a BNC does with a waterproof compression screen fitting. 3 years of regular use and mine is still firmly attached to the cable which should ease the worries of those who lack a deft touch and find any form of precision connector crumbles at the slightest touch.

Andy
MM0FMF

In reply to MM0FMF:
Hi Andy

I used one of the SMA/BNC adapters for a while, but then got two of the short patch leads from Garex for both my FT-60 & Wouxun 4m handies. The only problem I’ve found with those is that doing them up as tight as possible with my fingers (I don’t fancy getting a spanner to them!) is still not quite enough and after a bit of moving around with the antenna lead attached, they start to loosen off. I guess a quick pinch with a spanner would do the trick, but I just haven’t summoned up the courage yet! Must admit, I do prefer them to the adapter though.

73
Jonathan
M6HBS

In reply to M6HBS:

Huber & Suhner do a proper torque wrench (1Nm ISTR) for tightening SMA connectors. However, any 8mm open spanner will do if you just nip it up.

Andy
MM0FMF

In reply to MM0FMF:
I bought some recently on eBay that are RG58 compatible. I’ll post the link when I get home tonight. Pretty decent quality, I also bought the ratchet crimper from the same guy!

Adrian
Mm0tai

In reply to MM0TAI:
http://stores.ebay.co.uk/The-Allendale-Stores/_i.html?_nkw=sma+rg58&LH_SellerWithStore=1&LH_TitleDesc=1&_armrs=1&_dmd=2&_from=&_ipg=&_sasi=1&_sop=1&_vc=1

In reply to MM0TAI:

If you have a Maplin handy they’re £2.34 for the RG58 crimp type. If you don’t have a crimp tool, take it round to your local computer shop, they should have an old BNC ethernet crimp tool lying around unused they’ll probably let you use, or even buy cheap as chances are they’ll never use it again. While you’re at it, make a silly offer on all their BNC plugs they won’t need as well.

http://www.maplin.co.uk/sma-crimp-plugs-26627?ordercode=MM55K

P.S. Add a bit of heatshrink sleeving to act as a strain relief where the cable goes into the connector.

Ian.