koØm
05-28-2013, 10:46 AM
Greeing to all,
I have an interest in building an amplifier around a GS35-b Triode tube, I am going to make this a multi-band amplifier. I have the complete Tank circuit from a Drake L4-b and, I am trying to use this as my output network.
As with any project, there are some issues, the band switch has been repaired because the contacts that are in use for the 10 meter band have been fried. I serviced the switch and, indexed the useless contacts out of the line of fire; this left me with the ability to only support 4 bands. 80 meters thru 15 was a complete no-go.
I dumped the vertical 80 meter coil and re-worked the rest of the tank coil and switch; I added a tap for fewer turnes at 10 meters, used the old 10 meter tap at the 15 meter switch etc. Coming to the end of the coil, where the 40 meter tap was, that tap is now connected to the load gang. In position "10 m" all the taps are shorted out except 2 turns; in the "40 m" position, none of the taps are shorted by the switch and the whole coil is active in the network.
I am working with a MFJ-259 Analyzer (the first model) and, with a Plate load of about 2500 ohms, (planning on running about 4000 volts at 500 mills) all ham bands fall into tuning range.
Now that you have the setup, here's the question: "For a given frequency, if your circuit tunes with more capacitance (Tune) in one position but also tunes in another position with more turns on the tank coil but less Cap on the Tune side, what could be said about the coil, the, Q and which position for that "Given Frequency" would be best to tune at"?
Mel
koØm
.
I have an interest in building an amplifier around a GS35-b Triode tube, I am going to make this a multi-band amplifier. I have the complete Tank circuit from a Drake L4-b and, I am trying to use this as my output network.
As with any project, there are some issues, the band switch has been repaired because the contacts that are in use for the 10 meter band have been fried. I serviced the switch and, indexed the useless contacts out of the line of fire; this left me with the ability to only support 4 bands. 80 meters thru 15 was a complete no-go.
I dumped the vertical 80 meter coil and re-worked the rest of the tank coil and switch; I added a tap for fewer turnes at 10 meters, used the old 10 meter tap at the 15 meter switch etc. Coming to the end of the coil, where the 40 meter tap was, that tap is now connected to the load gang. In position "10 m" all the taps are shorted out except 2 turns; in the "40 m" position, none of the taps are shorted by the switch and the whole coil is active in the network.
I am working with a MFJ-259 Analyzer (the first model) and, with a Plate load of about 2500 ohms, (planning on running about 4000 volts at 500 mills) all ham bands fall into tuning range.
Now that you have the setup, here's the question: "For a given frequency, if your circuit tunes with more capacitance (Tune) in one position but also tunes in another position with more turns on the tank coil but less Cap on the Tune side, what could be said about the coil, the, Q and which position for that "Given Frequency" would be best to tune at"?
Mel
koØm
.