[Elecraft] New K3EXREF results

[Edward R. Cole]

See my test results of the K3EXREF:
http://www.kl7uw.com/K3EXREF.htm

When installed and referenced to a good 10-MHz external source the 
TCXO will be periodically corrected in frequency to keep the K3 on 
frequency.  The display on REF*CAL merely indicates the value the 
TCXO has been offset to keep the radio on frequency and is not the 
freq. error.   You need to measure the RF frequency with an accurate 
freq. counter to measure that.  I have a counter that is locked to a 
Rubidium good to +/- 5E-11 and the max error at 50-MHz was +2-Hz (2/50,000,000)

The value displayed on REF*CAL will start at 49.380 and they shift 
over about 30-minutes as the TCXO heats and stabilizes.  K3EXREF 
keeps the radio on freq throughout this warm-up.  Without K3EXREF the 
radio would shift freq with the TCXO (within 1ppm = +/-1E-6).

Before the K3EXREF was available you had the option to entering a 
fixed offset to correct frequency (which should be done after the 
TCXO has warmed up and stabilizes).  The number displayed is a 
similar offset but now controlled periodically by the external 
reference source, keeping the K3 more accurate.


73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-?
DUBUS Magazine USA Rep dubususa at gmail.com
======================================