Hello Ken,
I have mixed up input and output.
So the correct values are 1.1mH **next to the tubes** and 201µH **next to the
50 Ohm load**.
C stays the same.
See RFsim screenshots.
Sorry for the inconvenience.
73
Clemens
DL4RAJ
>-----Original Message-----
>From: [email protected]
>[mailto:[email protected]] On Behalf Of Clemens Paul
>Sent: Saturday, October 17, 2015 6:49 PM
>To: [email protected]
>Subject: LF: RE: TX Toroid Material
>
>Hi Ken,
>
>I believe two of your component values are off.
>I calculate 201µH for the L next to the tubes,625pF for the
>shunt C and 1.1mH for the second L .
>For the 201µH L I would use iron powder (Amidon #2), for the
>1.1mH #43 ferrite.
>Use the mini toroid calculator to find the appropiate size
>regarding number of turns and
>allowed flux with safety margin.
>
>73
>Clemens
>DL4RAJ
>
>
>
>>-----Original Message-----
>>From: [email protected]
>>[mailto:[email protected]] On Behalf Of Ken
>>Sent: Saturday, October 17, 2015 5:41 PM
>>To: [email protected]
>>Subject: LF: TX Toroid Material
>>
>>Dear All. I am having problems with the choice of material for
>>the output network of the 475kHz Valve TX. The network is an L
>>? C ? L, ?T? network with an input impedance of 2100 ohms and
>>a load of 50 ohms, for this configuration the input L is
>>7.7mH, shunt capacitance is 117pf, and output L is 1.1mH. The
>>PA design using a 6146 low power or 813 high power work fine
>>when simulated using LT spice IV. When testing in the real
>>world using the 6146 there is in excess of 800v rms rf on the
>>network side of the anode coupling capacitor, but nothing
>>after the input L. I can only conclude that I using the wrong
>>type material for the toroids, I used the largest size
>>(unmarked) toroid which gave me a modest number of turns. I
>>have checked the Amidon tables and Iron Powder because of the
>>low AL values, which leaves Ferrite, which mix would you
>>recommend? The simulations give me output powers 90W for the
>>6146, and 300W for the 813. I would be grateful for any core
>>material advice .
>>
>>
>>
>>Ken Wright.
>>
>>M0KHW
>>
>>
>>
>>
>
>
T-LowPass_475k_schematic.gif
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T-LowPass_475k_S11+S21.gif
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