I'm building my uBitX v5 and have a couple of questions about power supply voltage.
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First, what are the minimum and maximum supply voltages that the uBitX is happy with? ?I may be powering the radio with a 12AH AGM battery that's kept charged by a solar panel. ?I'll probably set low voltage cutoff for the solar controller at 11.8 or 11.9 volts under load (I've seen that listed as 2 amps when transmitting). ?The float voltage will be 13.6 to 13.8 and there might be monthly excursions of 14.2 to 14.4. ?Some specific longer life AGM batteries are spec'ed to have a regular duration equalization charge - DataSafe 12HX330FR, for example - and I see no harm in occasionally taking any AGM battery to its maximum rated voltage (cyclic versus float).
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If the uBitX isn't happy with that range (the LM386 could be either a 12 or 18 volt chip as the schematic just has "LM386"), I can control the voltage delivered to the receive section with an XL6009 buck/boost converter (maximum input is 3 amps). ?The XL6009 can hold the voltage to 12.0 volts or whatever makes the radio happy ;-)
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Second, what's the maximum safe voltage for the PA? ?I could use 2 XL6009's, with one set for the receiver and the other set to the PA's maximum safe voltage to squeeze a few more watts out of it. ?I plan to have a fan running on +5 for RX and +12 for TX so there's some degree of cooling between transmissions.
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I've not been active on HF for a long time but did have some articles published back when I had antenna space. ?I'm supposed to be talking with a tree guy this week and I may soon have antenna space again ;-)
Published articles:
"Gilding the Lily", 73 Magazine, October 1980
"Converting the Sears 40 Channel SSB CB Rig to 10 Meters", Cover Article, CQ Magazine, November 1980
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John
WB4HLZ
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