K7DYY Jr Again

[flintstone mop]

Hello fellow AM lovers
I was wondering if anyone is using a VFO with their K7DYY Jr.? I have a late 50's Globe tube type VFO. Would that be too much drive? The VFO might have a lot of harmonics. Would that drive the JR bizzzerk and it would blow its cork?/ FET?
I don't think I have to worry about isolating the VFO, as I have my audio system connected with no problems.
I am going crazy trying to track down QSO's with the handful of xtals I have on hand.
Thanks
I also sent Bruce an email with the same inquiry.

Fred

[steve_qix]

Here's one that should work just fine :-)  Simple, effective, cheap, easy !



The complete info (with more pics and schematics is Here )

Regards,

Steve

[flintstone mop]

Thanks for the reply Steve,
Bruce said a number of folks are using tube-type VFO's with the Class D and with good success. He recommends shunting the output of the VFO with a 2.7K resistor to bring down the RF level and lower the Z.
I'll give my Globe VFO a whirl and see if the Tx likes the output, which could have too many harmonics. My economics doesn't allow any fun right now.

Fred

[WD8BIL]

Phred,
I don't think you'll hafta worry about harmonics on the singleband transmitters.

[flintstone mop]

This is a samll report on using a VFO with the "JR." It works FB OM.
I sent the following to Bruce Franklin about the ability of the JR to produce 200 watts

Hi Bruce
I was watching some posts on AMFONE about the JR and someone said that they adjusted the power to 200 watts. I did the same thing and the audio went to HELL. I was wondering why the little guy was sounding so awful. I went through my entire audio chain to find the problem, then I experimented with a tone generator right into the audio input of the transmitter and adjusted the power up and down with a 1khz tone and noticed that once the power was nearer to 150 watts the waveform cleaned up and the modulation increased dramatically!!! I was hearing  and seeing a raspiness to the audio. It was a beautiful waveform all the way down to 40hz. 5khz seemed to be the upper limit of the response. With a well adjusted mic/processing, the transmitted audio will come close to a Flex radio or Class E transmitter.
Amazing little transmitter. A real handful of power.

It may not be a good idea to increase power from the "factory settings".
Fred

[ve6pg]

..Fred...I've ordered the 300 watt version, for 160....where did u plug in the vfo?....i shud have mine, by the end of December...Tim..sk...

[w1pe]

I have the 300 watt version and there is no input for a VFO.
You have set frequencies that Bruce puts in. He said that there will be no VFO input for the Sr model. I sure do love my 9 lb shoebox. It really works and I am told sounds good...

Bob W1PE

[flintstone mop]

Yup Guys
UNfortunately the Class D was the only broadbanded tranmitter he made that covered the entire 80M.
Is he making Class D for 160M? I was tempted to get a miracle box for 160M, but it was segmented for different parts of the band.
Fred

[KF1Z]

Yup Guys
UNfortunately the Class D was the only broadbanded tranmitter he made that covered the entire 80M.
Is he making Class D for 160M? I was tempted to get a miracle box for 160M, but it was segmented for different parts of the band.
Fred

Yes.