[Elecraft] K3 QST March review

[wayne burdick]

> Gene W3ZZ (who owns a K3) is saying the
> two rigs have very comparable RF performance.  I might quibble that he
> omitted BDR in his table but perhaps that's more of an HF issue than 
> VHF
> (Gene's focus in the VHF column).  For both Phase Noise and BDR, the K3
> exceeds the 5000 by ~15 dB (not insignificant if you're in a
> multi-transmitter environment or have a strong local neighbor).

The article also claims -132 dBm MDS for the K3 on 20 m with the preamp 
on. That's either a typo or a possible test error. The specified 
typical value is -136 dBm, and I just measured -138 dBm on my lab K3.

There are two common measurement errors that can result in an 
underestimate of MDS:

1. Leaving the AGC turned ON when using the "XG1" method (injecting 1 
uV and using the K3's dBV metering function). At the default settings, 
AGC definitely kicks in below 1 uV.

2. Noise pickup by the signal generator cable in its OFF setting. This 
can result in a higher noise floor. Better to connect a direct 50-ohm 
terminator with no coax, if available.

73,
Wayne
N6KR

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