[time-nuts] TNC connectors
GandalfG8 at aol.com
GandalfG8 at aol.com
Tue Jun 23 10:00:49 UTC 2009
In a message dated 23/06/2009 09:29:38 GMT Daylight Time,
david.partridge at dsl.pipex.com writes:
The T-Bolt manual recommends 75 ohm coax, so will a 75 ohm TNC mate with a
50 ohm TNC without problems? Though I suppose for a short run of cable,
50
ohm will be OK?
---------------------
Hi David
There's been some previous discussion on this, perhaps an archive search
will throw up past comments, and probably with usual Time-Nuts overkill:-).
According to the manual the Thunderbolt antenna input impedance is 50ohms,
despite their using an F connector, but they recommend using 75 ohm cable
on the basis that it tends to have lower loss for a given size.
Unless you're planning on really long runs I'd suggest just sticking with
50 ohm cable and connectors.
I've got a couple of commercial antennas that come with predefined lengths
of cable, 20 metres if I remember correctly, and these use RG58.
I'm not sure if you'll get a TNC to F type adapter anyway, so you might
have to revert to BNC on the cable at the Thunderbolt end.
The mounting pole thread seems to be fairly standard but not sure on
availability of threaded poles.
One option would be a stub mounting plate as sold for marine use, one
current ebay item for example is 250430681103, and a further search in the
marine section might prove useful.
regards
Nigel
GM8PZR
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