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[AMPS] Antenna System Power Ratings Question

To: <amps@contesting.com>
Subject: [AMPS] Antenna System Power Ratings Question
From: johnf@futurenet.co.za (John Fielding)
Date: Tue, 20 Oct 1998 18:17:49 +0200
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There are PL-259's and PL-259's.  Some of the far eastern stuff is "real
crap".  If you use geniune Mil-Spec types like real Amphenol's or other
reputable makes you should no problem.  I melted the socket on the back of
my FL-2110Z three times before replacing it with a N type connector.  Then
no further problems.  It seems amps and connectors are no different to
other items we buy. You get what you pay for. Caveat Emptor!

John    ZS5JF

----------
> From: Jim Reid <jreid@aloha.net>
> To: amps@contesting.com; henry@qth.net
> Subject: [AMPS] Antenna System Power Ratings Question
To: <amps@contesting.com>
> Date: Tuesday, October 20, 1998 12:12 AM
> 
> 
> Aloha Big Gun HF amp users,
> 
> At what power levels do you have to start worrying about
> antenna system components?  All our "stuff": PL259's, N's,
> 9913,  LMR-400,  typical commercial antennas,  switches,
> even the Top Ten devices remote switches,  etc.  are all
> fine up to and somewhere above the 1500 watt CW,
> RTTY continuous output level.  Some antenna tuners
> are rated to 3kW;  at least one soon to be for sale,
> the Ameritron ATR-30 will handle a real 3 kW,  or
> at least so I am told.  I suppose it will have S)239 sockets,
> so maybe they are good to at least that power level.
> 
> Any comments on the topic?   Up to what powers will
> the usual componentry live,  and at what power do you
> have to start upgrading to large hardline,  perhaps
> home brew antennas,  tuners,  etc?
> 
> I calculate that at 3 kW,  for example,  in a 50
> ohm system, with say 2:1 vswr, the RMS voltage
> will be 548 volts;  peak voltage, 1.414 times that,
> or at  775 volts,  and the RF current will be about
> 11 amps.
> 
> Typical good RG8 size coax is rated at 4000 or 5000
> volts breakdown,  and yes, as the vswr increases,  this
> rating drops,   so also the power handling capacity.
> 
> In a balance feed/antenna system,  using, say 450 ohm
> twin line,  and still 2:1 vswr (band edges,  say), the voltage
> increases to an RMS of 1640 volts,  and peak of 2325 volts,
> and the current,  of course drops to about 3.6 amps.
> 
> Amidon High Power baluns still use the SO239 socket
> on units rated at 10 kW,  I believe.
> 
> It would seem the lowest lost system would be the twin line
> feed and balanced tuner,  a la,  old Johnson AM kW Matchbox. 
> 
> Just curious,
> 
> 73,  Jim,  KH7M
> On the Garden Island of Kauai
> 
> 
> --
> FAQ on WWW:               http://www.contesting.com/ampfaq.html
> Submissions:              amps@contesting.com
> Administrative requests:  amps-REQUEST@contesting.com
> Problems:                 owner-amps@contesting.com
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<html><head></head><BODY bgcolor=3D"#FFFFFF"><p><font size=3D2 =
color=3D"#000000" face=3D"Arial">There are PL-259's and PL-259's. =
&nbsp;Some of the far eastern stuff is &quot;real crap&quot;. &nbsp;If =
you use geniune Mil-Spec types like real Amphenol's or other reputable =
makes you should no problem. &nbsp;I melted the socket on the back of my =
FL-2110Z three times before replacing it with a N type connector. =
&nbsp;Then no further problems. &nbsp;It seems amps and connectors are =
no different to other items we buy. You get what you pay for. Caveat =
Emptor!<br><br>John&#009;ZS5JF<br><br>----------<br>&gt; From: Jim Reid =
&lt;<font color=3D"#0000FF"><u>jreid@aloha.net</u><font =
color=3D"#000000">&gt;<br>&gt; To: <font =
color=3D"#0000FF"><u>amps@contesting.com</u><font color=3D"#000000">; =
<font color=3D"#0000FF"><u>henry@qth.net</u><font =
color=3D"#000000"><br>&gt; Subject: [AMPS] Antenna System Power Ratings =
To: <amps@contesting.com>
Question<br>&gt; Date: Tuesday, October 20, 1998 12:12 AM<br>&gt; =
<br>&gt; <br>&gt; Aloha Big Gun HF amp users,<br>&gt; <br>&gt; At what =
power levels do you have to start worrying about<br>&gt; antenna system =
components? &nbsp;All our &quot;stuff&quot;: PL259's, N's,<br>&gt; 9913, =
&nbsp;LMR-400, &nbsp;typical commercial antennas, =
&nbsp;switches,<br>&gt; even the Top Ten devices remote switches, =
&nbsp;etc. &nbsp;are all<br>&gt; fine up to and somewhere above the 1500 =
watt CW,<br>&gt; RTTY continuous output level. &nbsp;Some antenna =
tuners<br>&gt; are rated to 3kW; &nbsp;at least one soon to be for =
sale,<br>&gt; the Ameritron ATR-30 will handle a real 3 kW, =
&nbsp;or<br>&gt; at least so I am told. &nbsp;I suppose it will have =
S)239 sockets,<br>&gt; so maybe they are good to at least that power =
level.<br>&gt; <br>&gt; Any comments on the topic? &nbsp;&nbsp;Up to =
what powers will<br>&gt; the usual componentry live, &nbsp;and at what =
power do you<br>&gt; have to start upgrading to large hardline, =
&nbsp;perhaps<br>&gt; home brew antennas, &nbsp;tuners, =
&nbsp;etc?<br>&gt; <br>&gt; I calculate that at 3 kW, &nbsp;for example, =
&nbsp;in a 50<br>&gt; ohm system, with say 2:1 vswr, the RMS =
voltage<br>&gt; will be 548 volts; &nbsp;peak voltage, 1.414 times =
that,<br>&gt; or at &nbsp;775 volts, &nbsp;and the RF current will be =
about<br>&gt; 11 amps.<br>&gt; <br>&gt; Typical good RG8 size coax is =
rated at 4000 or 5000<br>&gt; volts breakdown, &nbsp;and yes, as the =
vswr increases, &nbsp;this<br>&gt; rating drops, &nbsp;&nbsp;so also the =
power handling capacity.<br>&gt; <br>&gt; In a balance feed/antenna =
system, &nbsp;using, say 450 ohm<br>&gt; twin line, &nbsp;and still 2:1 =
vswr (band edges, &nbsp;say), the voltage<br>&gt; increases to an RMS of =
1640 volts, &nbsp;and peak of 2325 volts,<br>&gt; and the current, =
&nbsp;of course drops to about 3.6 amps.<br>&gt; <br>&gt; Amidon High =
Power baluns still use the SO239 socket<br>&gt; on units rated at 10 kW, =
&nbsp;I believe.<br>&gt; <br>&gt; It would seem the lowest lost system =
would be the twin line<br>&gt; feed and balanced tuner, &nbsp;a la, =
&nbsp;old Johnson AM kW Matchbox. <br>&gt; <br>&gt; Just =
curious,<br>&gt; <br>&gt; 73, &nbsp;Jim, &nbsp;KH7M<br>&gt; On the =
Garden Island of Kauai<br>&gt; <br>&gt; <br>&gt; --<br>&gt; FAQ on WWW: =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp;<font =
color=3D"#0000FF"><u>http://www.contesting.com/ampfaq.html</u><font =
color=3D"#000000"><br>&gt; Submissions: =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;<font color=3D"#0000FF"><u>amps@contesting.com</u><font =
color=3D"#000000"><br>&gt; Administrative requests: &nbsp;<font =
color=3D"#0000FF"><u>amps-REQUEST@contesting.com</u><font =
color=3D"#000000"><br>&gt; Problems: =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp;&nbsp;&nbsp;<font =
color=3D"#0000FF"><u>owner-amps@contesting.com</u><font =
color=3D"#000000"><br>&gt; Search: =
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nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<font =
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color=3D"#000000"></p>
</font></font></font></font></font></font></font></font></font></font></f=
ont></font></font></font></font></font></font></body></html>
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