[Lowfer] WD2XKO WSPR-15

[Pat Bunn]

Storm line is just arriving here but the worst is 25 miles north. Hope it misses you Dex. 

Pat

N4LTA



Dexter McIntyre W4DEX <dexter.mc at gmail.com> wrote:

>One more sequence from the drifter then QRT.  Storm line is getting 
>close and winds already gusting to 30+ mph.
>
>I've spent way to much time trying to reduce the drift in the old 
>FT817.  I really don't need to be improve it for what I mainly use the 
>rig for.  It's just one of those problems that isn't necessary to fix 
>that turns into a time consuming challenge.  I've tried running the rig 
>with a fan blowing on it, running it with the cover off, with and 
>without fan, and trying to insulate the tiny plug in reference 
>oscillator board from the chassis heat plus some I've likely forgot 
>about. But what has come as close to stabilizing it at much as anything 
>else was applying a hint from Mike, WA3TTS.  He informed me that the rig 
>has an internal voltage regulator that reduces the input to 9.6 volts.  
>I assume it was designed to work on that low of voltage because of it is 
>capable of operating from an internal 12 volt battery pack.  With 13.8 
>volts from a 25 amp Astron there was more heat being dissipated from the 
>voltage regulator than from the radio being in transmit mode.  I put the 
>covers back on the radio and added 6 power diodes in line with the 13.8 
>volts then measured 9.4 volts at the radio.  It seems to work well at 
>that voltage and the WSPR-15 drift is alternating between 1 and 2 Hz per 
>15 minute sequence.  Not bad for a $75 radio with bad final FETs and no 
>TCXO. 
>
>Dex
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