Well all limits sure can be stretched. I been runing more then
2 kW on 144 MHz using N connectors with no problem, as
long as they are dry inside, but I would not recomend it since
ofcourse it´s way above the limit and therefor not safe.
Rich said: That N doesn´t leak water. Well, sure they do. At
least where I live all connectors (even properly installed) will
leak water. However, 7/16 seems to be the best out of the
bunch in that respect.
You need to waterproof. I use first one layer of electric tape
then one layer of this rubber tape stuff that sort of glues
together (don´t know the English name) then finaly another
layer of electric tape. That joint can be permanently in water
an not leak.
Now, if we only are talking low power (1 - 2 kW on HF) I worry
too much, N UHF or whatever will work. You can even just twist
the ends together (no connector at all (hi) and it will work just
fine.
On HF nobody will ever notice.
73, Jim SM2EKM
--------------------------------------
-----Ursprungligt meddelande-----
Från: i4jmy@iol.it [SMTP:i4jmy@iol.it]
Skickat: den 21 november 2000 22:40
Till: 2@vc.net; ve3tu@rac.ca; k6uj@pacbell.net; amps@contesting.com
Ämne: Re: [AMPS] Hi Power Connectors
I believe it.
For a few minutes, I've done tests with N up to 6 Kw @ 100 MHz
(continuous
carrier) with no failures or damages.
This is possible with properly installed N connectors althought I
wouldn't
anyway raccomend to use more than 800 W @ 100 MHz with this type of
connector.
Up to 30 MHz there is instad a wide margin when using an N at 1500W.
Connection pin size is not all that matters since allowable RF current
is
different than a mere DC rating.
PL259/SO239 is a bit awful under this perspective and one shouldn't be
misleaded by its size assuming the manageable power is larger than that
of
N, at least above 30 MHz .
Also isolation is a bit meaningless parameter because 1500W @ 50 Ohms
are
only 275V.
What counts, under reasonable limits, are impedance, materials, small
size,
mechanical precision etc. and this is valid in all RF connectors, EIA
flange
included (good inners made with berilium make a big difference compared
with
lower quality ones)
For the same reason large vaacum relays for RF are rated for much
smaller
currents at higher frequencies.
A 30A DC can easily drop to less than 10 A @ 30 MHz and some other non
vacuum switch, looking smaller but impedance constant and mechanically
precise, allows much more power already at 30 MHz and expecially above.
By the way, 1500W represent only 5.5 A @ 50 Ohm and both PL259 and N can
perfectly withstand it below 30 Mhz.
Power apart, N has other mechanical advantages that insure a much bigger
long term reliability than PL does.
Good cables and good connectors shouldn't be a matter to spare money
but a
desiderable form of good investment.
World instead goes different and some mental habits are unchangeable in
front of anything.
Supported by the tradition to spend money in more visble devices (i.e.
expensive aluminium with lossy traps, weak but tall towers, or rigs with
miriads of leds and knobs), cheap cables and cheap connectors have
always
been a good business for traders and also a nice source of poorer
results
and failures.
73,
Mauri I4JMY
----- Original Message -----
From: "measures" <2@vc.net>
To: "Steve" <ve3tu@rac.ca>; "Maurizio Panicara" <i4jmy@iol.it>
Cc: "k6uj" <k6uj@pacbell.net>; "AMPS" <amps@contesting.com>
Sent: Tuesday, November 21, 2000 8:49 PM
Subject: Re: [AMPS] Hi Power Connectors
> >
> I have put 7kW PEP through a BNC on 160m.
>
> cheers, Steve
>
> - Rich..., 805.386.3734, www.vcnet.com/measures.
> end
>
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