[ARC5] SCR-183/-283 4-5 MC Coil on 75 MTRs

[AKLDGUY .]

> Note that the max plate dissipation is 5W, not 6.25W. The 6.25W
> number appears in the RCA data sheet under typical conditions:
> 6.25W plate input, 4W RF output. This means that the plate dissipation
> is 2.25W, comfortably under the 5W limit.
>
> 73, ian K3IMW

Yes I think you're right. All parameters except the grid current are at
their limits for 6.25W, so one could take a risk and push the grid a little
harder to squeeze an extra 3 watts output. In ICAS service that might be a
risk worth taking. If the aim is genuine QRP operation, it's probably
better to hold at 4-5W output to avoid accusations of cheating. Interesting.

73 de Neil ZL1ANM


On Thu, Jul 10, 2014 at 2:48 AM, Ian Wilson <ianmwilson73 at gmail.com> wrote:

> Note that the max plate dissipation is 5W, not 6.25W. The 6.25W
> number appears in the RCA data sheet under typical conditions:
> 6.25W plate input, 4W RF output. This means that the plate dissipation
> is 2.25W, comfortably under the 5W limit.
>
> 73, ian K3IMW
>
>
>
> On Tue, Jul 8, 2014 at 4:59 AM, AKLDGUY . <neilb0627 at gmail.com> wrote:
>
>> > Look up the operating data and the plate characteristics for a 12J5.
>> Then
>> do the calculations for Class C.
>> >
>> > 73 de Brian, VK2GCE.
>>
>> Thank you Brian.
>>
>> I think I can actually do better than that. I have the RCA Transmitting
>> Tubes manual for 1956 (price one dollar!) and it lists the maximum CCS
>> ratings for the 1626 when used as RF Power Amplifier and Oscillator -
>> Class
>> C.
>>
>> Unfortunately it doesn't give typical operating conditions, hence my
>> questions about plate current and bias resistor.
>>
>> Max plate voltage, current, and dissipation are 250V, 25mA, and 6.25W. I
>> think I could probably run it at 5W and get between 3 and 4 watts out of
>> it.
>>
>> 73 de Neil ZL1ANM
>>
>>
>> On Tue, Jul 8, 2014 at 7:14 PM, Brian Clarke <
>> brianclarke01 at optusnet.com.au>
>> wrote:
>>
>> > Hello Neil,
>> >
>> > Look up the operating data and the plate characteristics for a 12J5.
>> Then
>> > do the calculations for Class C.
>> >
>> > 73 de Brian, VK2GCE.
>> >
>> > On: Tuesday, July 08, 2014 4:48 PM, You asked:
>> >
>> >
>> >  Referring specifically to the BC-xx-230 model:
>> >>
>> >> How does one determine the setting for the roller inductor?
>> >> Has anyone tried using the 1626 triode for VFO and PA?
>> >> If so, what B+ and bias resistor did you use?
>> >> What is the optimum 1626 PA plate current for CW?
>> >>
>> >> Any other useful hints?
>> >>
>> >> 73 de Neil ZL1ANM
>> >>
>> >
>> >
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>