From: "Clemens Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <08B5A81DD2D14C84874DD10EEB145569@lindavideo> <4DC3B18B20A94764A9ADCC2B5453447A@Clemens0811>
In-Reply-To: <4DC3B18B20A94764A9ADCC2B5453447A@Clemens0811>
Date: Sat, 17 Oct 2015 19:07:26 +0200
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Subject: LF: RE: RE: TX Toroid Material
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Addendum:
Assuming an unloaded Q of 200 for the inductors and a Q of 1000 for the capacitor
there are at the 300W level  around:
2083V peak across the first L at 2.4A and 18W power dissipation
2090V peak across the shunt C at 2.8A and 4W pwr diss.
1720V peak across the second L at 0.4A and 2W pwr diss
Total loss is 24W or 0.37dB or 8.1%

73
Clemens
DL4RAJ 


>-----Original Message-----
>From: owner-rsgb_lf_group@blacksheep.org 
>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Clemens Paul
>Sent: Saturday, October 17, 2015 6:49 PM
>To: rsgb_lf_group@blacksheep.org
>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: owner-rsgb_lf_group@blacksheep.org 
>>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Ken
>>Sent: Saturday, October 17, 2015 5:41 PM
>>To: rsgb_lf_group@blacksheep.org
>>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
>>
>> 
>>
>>
>
>