[Antennas] From transmission lines to tuners
John McClain
[email protected]
2002年12月22日 07:37:32 -0700
Doesn't the Yaesu FC-20 tuner also have a fan?
John
K7SVV
[email protected]
K1 #1378, K2 #2569, SST 20, Rock Mite 20, Rock Mite 40, Nor'Easter
----- Original Message -----
From: "Adam Farson" <[email protected]>
To: "Antennas Reflector" <[email protected]>
Cc: "George, W5YR" <[email protected]>
Sent: Saturday, December 21, 2002 11:05 PM
Subject: RE: [Antennas] From transmission lines to tuners
> Hi George,
>> Interestingly enough, the T-network autotuner in the Yaesu Quadra
1kW
> amplifier has a small cooling fan. The autotuner insertion loss is
0.5dB.
> Thus, for 1kW at the antenna socket, the input power to the tuner is
> 1.124kW. The power dissipation of the T-network for this case is
1124 - 1000
> = 124W.
>> This is certainly sufficient to warrant a fan - especially as the
tuner is
> quite compact, as illustrated here:
>> http://www.qsl.net/ab4oj/quadra/quadra.html
>> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
>> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of George, W5YR
> Sent: Thursday, December 19, 2002 15:30
> To: A10382; Antenna reflector list
> Subject: Re: [Antennas] From transmission lines to tuners
>>> Wonder why every tuner I've ever seen or used has NOT had a cooling
> fan? Or even a ventilated cabinet?
>> Wonder if all the info about "tuner loss" is maybe a little
inflated?
> A KW into a tuner with 60% loss means that the tuner must dissipate
> 600 watts - not likely. Even 20 watts of continuous power loss would
> make the tuner cabinet too hot to touch in a few minutes.
>> Models of typical tuner configurations with realistic Q values for
the
> components show typical losses in the fractional-dB range, as one
> might expect. Of course, this was for "sensible" tuner applications,
> NOT loading a 5 ft whip at 1850 KHz with a KW.
>> 73/72, George
> Amateur Radio W5YR - the Yellow Rose of Texas
> In the 57th year and it just keeps getting better!
> Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
> K2 #489 IC-765 #2349 IC-756 PRO #2121 IC-756 PRO2 #03235
>> ----- Original Message -----
> From: "A10382" <[email protected]>
> To: "Antenna reflector list" <[email protected]>
> Sent: Thursday, December 19, 2002 3:24 PM
> Subject: Re: [Antennas] From transmission lines to tuners
>>> > While it's impossible to have true 100% efficiency, the tuners
> tested had
> > losses as high as 60% on some bands -- and these were the 'better
> quality'
> > tuners.
>>> - - -
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