Re: Latest Build, Mods and results.

brad martin
 

Just an idea, Ignore CW tone all together and focus of SSB.  Now if I understand right SSB output power is based on the audio in volume.  You yell into the mic you put out more power, you whisper you get less.  At least thats how its showing on my SWR meter and my power supply amp meter.  The CEC firmware can already do WSPR on its own with a push of the PTT button.  What if we implemented a tune feature that just produced a 700khz tone on SSB and you can vary the output power by simply (I assume) changing the output voltage/duty cycle of the tone.  Thinking it would go something like this, Change mode to tune, Push PTT to send a tone,  In the software it will change the duty cycle to generate 1W out on the band you are on.  On 40m that may be a 10% duty cycle where on 20m it may be 60%.

For me I am OK at best with hardware mods and a better coder.  Now off to clone CEC firmware repo to see if it can be done.

73,
Brad
KG5SPR

On Wed, Jun 13, 2018 at 11:25 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
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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