Re: Latest Build, Mods and results.

Jerry Gaffke
 

Pot RV1 on the uBitx varies output power.

VK2ETA came up with a way of using the shoulder of the 45mhz crystal filter to vary the output power. 
 https://groups.io/g/BITX20/message/46235
and wrote software to implement it:  https://groups.io/g/BITX20/message/50215
I believe this has also been incorporated into the KD8CEC firmware.
Requires no hardware mods.  This only works for SSB transmissions and not for CW,
though could be extended to CW if signal CW-KEY were injected into the second mixer instead of the first mixer.
No easily discernible change to the audio, though will be some variation in the audio response:
    https://groups.io/g/BITX20/message/50265
    https://groups.io/g/BITX20/message/50279

The uBitx.net site is getting rather large.  To say there's some sort of solution there
is becoming akin to saying there's a solution in one of the 52000 posts in this forum.
My best guess is that Dr Bill is suggesting an implementation involving a new PC board
controlled by extra pins from the Raduino to run some relays that select various 
preset attenuators.

There are plenty of other ways to do this, most involve hacking in some sort of attenuator.

Jerry, KE7ER


On Wed, Jun 13, 2018 at 07:14 am, K9HZ wrote:
Check uBITx.net.  Already there. 

 

Dr. William J. Schmidt - K9HZ  

 
On Jun 13, 2018, at 12:07 AM, brad martin <emclinux@...> wrote:

Isn’t there a pot that controls the output power? If so you could make a low power switch that is just adding a resistor in parallel or series depending on the circuit. I’m just walking and thinking here so don’t have the schematic easy to get.

Brad
On Tue, Jun 12, 2018 at 6:47 PM Nick VK4PLN <nickpullen@...> wrote:
Ah, too easy, I was hoping it was done via software and able to TX a much lower power carrier for tuning, not the full 15W...
Any ideas and thoughts?

 

 

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