On monday night I reworked the audio slightly so the audio ground was correct, and redrew the schematic. This is the working update.
This design has always had bad capacitive pickup from hands, rediculous lead lengths connecting the tube to the osc. cap and coil, and refused to oscilate if not connected to ground through my scope (which has always had it's ground connected to the cathode and probe connected to the plate).
And so after doing the audio rework I pulled the parts for the osc. and modulation, and experimented again with osc. design using shorter lead lengths. My interpretation of bob's statement "bypass the B+ supply" did not work, but I came up with something that does work, and has killed the hand capacitance effect on the tuning cap and reduced it on the osc coil. It can now oscilate with the scope probe disconnected form the scope, but not with the probe disconnected from the circuit. Modulation is about the same, and is likely going to be experimented with more in the future. I intend to test the capcitance,resistance, and inductance of my probe in soon to see what parts will mimic it's effect on the circuit.
this is the present design...
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darklife I would recommend plate modulating or even using the second grid rather than using the first grid. That would reduce FMing and also give you much cleaner audio. You should only drive the tube at 1/4 of it's maximum output power, that way your modulation will swing your carrier both negative and positive with your audio which is the proper way to run AM.
If you run the tube to full power and then modulate it then there is nowhere the audio can push the carrier into the positive territory, thus resulting in only dropping carrier power with modulation peaks.
A brief brush up on AM transmitting basics will help you out on this.
Also beware of over-modulation as that will cause bad distortion.
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I will try to implement modulation of that sort. I did initially try second grid modulation on the first design, but it killed the osc. if I rember right. I will try it again with the new osc. design I'm running.
I want to keep this design limited to one tube if I can, and this is just so I have something good to listen to on my old tube radios.
I don't have one bit of Tube or RF design knowledge. My forte is trouble shooting and repair, and being a sophmore EE student my only design knowledge relates to OP AMPs and is not very detailed (especially in the RF frequency range). I was thinking before you posted that the 0 modulation RF power should be around 50% so the output is high with modulation of a fairly high percent.
I've used my non-equational knowledge of tube circuit design to get this far, and plan to keep playing with my design in hopes of improving it. This design came about from a "get enough monkeys with enough typewriters together and you get the work Shakesphere" type of scenario. I'm basically comeing up with things to try, testing them, and accumulating/refining/building upon the stuff that works or seems to work.