[amsat-bb] Re: SMA connectors

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Thu Feb 23 12:18:12 PST 2012

Hi, (name/call?)!

> My two cents worth- using an SMA to BNC adaptor does not address the
> mechanical problem of an antenna or a coax flexing the SMA chassis connector-
> especially the plastic HTs- I had to do a number on my VX5 which is a metal
> case HT.

The original two-part SMA-to-BNC adapters had no plastic/rubber
cushions to help lessen the stress on the SMA connector.  There
has been an adapter made by KC2BHO for some time, and now
the Diamond adapter I referenced earlier, that have something
to help with that.  Putting the large AL-800 telescoping whip on
these HTs, even with the better SMA-to-BNC adapters, is probably
not wise.

For the typical duckie antennas, smaller telescoping whips, or
coax - these newer adapters are adequate for most hams.  It is
still possible to put too much stress on the SMA connector with
this adapter and whatever is connected to the adapter.

> I'd suggest a pigtail SMA to BNC for connecting to a coax for mobile
>  use (even then I tie the pigtail to the HT case with a rubber band or ??)

In the past, I'd use this suggestion whenever I wanted to use an
AL-800 (or similar large) telescoping whip with an HT that had an
SMA connector.  Now I use a short coax jumper with BNCs onto
the adapters on my HTs.  Once I put those Diamond adapters on
my TH-D72A and TH-F6A, I don't remove them.

> As for  the HT antenna all you can do is be careful or brace the antenna a
> bit. My 74  year old hands and eyes had quite a time repairing the broken
> center conductor  to circuit board, not to mention just getting to the
> location. The SMA is a  great RF connector for fixed-in-place applications.


I don't think anyone is questioning whether the SMA is a good
RF connector.  Its use on our ham HTs has been questioned
for a long time.  I see other connectors used on non-ham HTs.
I have a few commercial Icom VHF and UHF HTs that are in
this non-SMA group.  Why not consider those for our HTs?
SMA connectors are smaller, which is probably the big point
for their use with our HTs, but certainly not rugged.



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