Re: ALE, WINLINK and uBitX

Gordon Gibby <ggibby@...>

I looked at the datasheets and the transconductance (change in drain current per change in gate voltage) seems unaffected by drain voltage, so the power increase would be proportional to voltage increase.   I think I've got a 19V laptop supply and maybe a 24V so may try this (gingerly).    

I haven't tried this yet, but is the decline in output at higher bands mainly due to decreasing drive effectiveness?   If so, cranking up the drive potentiometer for higher hands might give more output....

and for the server applications, WINLINK actually provdided a way for the audio drive to be set for each band, so it could be compensatorially reduced on lower bands, allowing the bitx to be more successful across several bands.   

It is still a less than mighty transmitter. 

digital connections such as psk,  olivia,  ft8  etc are made for such transmitters!   And this time of the cycle, 80 and 40 meters are king at night.


From: <> on behalf of Gordon Gibby <ggibby@...>
Sent: Sunday, December 31, 2017 9:49 AM
Subject: Re: [BITX20] ALE, WINLINK and uBitX

​I think you'll get about double the power when you double the voltage.   Not certain, but I think the transconductance of the device is possibly constant and so changing the voltage linearly increases the power.  

The power will still drop off at higher frequencies.

Remember the two heatsinks of the uBit are both at the same DC potential but NOT at the same AC potential


From: <> on behalf of tausciam@... <tausciam@...>
Sent: Sunday, December 31, 2017 9:44 AM
Subject: Re: [BITX20] ALE, WINLINK and uBitX
On Sat, Dec 30, 2017 at 06:36 pm, Gordon Gibby wrote:
ext move will be to go up to 19 or 24 vdc on the PA.
What is the expected wattage out when you do that?

I'm beginning to suspect it'll be far more robust as a winlink device than PC ALE, but at least we now know it CAN do that.

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