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PE1RKI RA18H1213G amplifier.
Posted: Tue Dec 24, 2019 9:01 pm
by G4EWJ
Can anyone tell me how the external bias pin works on this please.
It seems to go through a resistor to a pot, so it's possible that you connect it to 12v, but I'd like to be certain.
Brian
Re: PE1RKI RA18H1213G amplifier.
Posted: Wed Dec 25, 2019 9:55 am
by G3GJA
Hi Brian
Connect the pin to 12v. Internally it goes to a 3 terminal regulator and then a pot to adjust the bias.
I found that there's a 'sweet spot' where the shoulder performance is best. Be prepared for a much higher quiescent current than the data sheet suggests.
I've built one each for 23cm, 70cm and 2m using modules from Enigma Components. The linearity seems proportional to the number of gain stages in the module so the 2m works best. With a 10dB gain antenna the NoV ERP limit is easy to get to on 2m.
Happy Christmas & 73 for the New Year
Clive G3GJA
Re: PE1RKI RA18H1213G amplifier.
Posted: Wed Dec 25, 2019 11:57 am
by G4EWJ
Thanks Clive. Merry Christmas.
Brian