[ARC5] Ramping up questions

[Ian Wilson]

Someone once pointed out to me that the output matching network is really a
pi but with the 'load capacitor' being provided by the load. If your load
is actually a pure resistance, you can add capacitance to make the network
look like a regular C-L-C pi network.

73, ian K3IMW

On Aug 18, 2016 6:26 PM, "J Mcvey via ARC5" <arc5 at mailman.qth.net> wrote:

> Giving the SCR-274 system a final tune up, getting ready to run it  on AM
> for the first time, probably to contact one of the AM nets.
>
> I made a reasonable facsimile that measures about 4.5 -J 250 at 3 mhz .
> Technically I should decrease the capacitance, but it loads up fine
> with only 1/4 of the inductor used.
> Now that I have a completely unmodified antenna switch it reads out lower
> than the modified one I had before ( too much coupling to the thermocouple).
> According to the manual I should read about 2.5 amps into the phantom
> antenna which is a 100pf in series with a 5 ohm resistor.
>
> However, It maxes out around 2 amps. Is this about right? Do you guys  get
> more or less than that? I would think 3 amps might be possible,
> but how accurate is the meter?
>
>
>
> It doesn't like pure resistive 5 ohm loads -even with the inductor to
> zero. Whats up with that?
>
> I am running the system on a 25V/21 amp SMPS at the moment .
> How much sag in the TX b+ from the dyno should I get in cw mode? While key
> down, I monitored the cap of the  modulator tube and noted the voltage
> dropped
> to 500V. Idle voltage was 559V.  Is 500V  reasonable while running 25
> volts in? Will it be worse on 24V battery, or better with more available
> current?
>
>
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