[Elecraft] Data mode and filters

[Jim Brown]

On Mon,5/11/2015 5:52 AM, Kevin Stover wrote:
> The K3's transmit IMD numbers aren't any better than any other manuafactuirers and probably worse than the 200W rigs because they use 24 or 50V finals.

That's true ONLY at full power. What matters a LOT more is IMD at the 
lower power levels required to drive power amps to legal limit. At 
reduced power levels IMD in the K3 is reduced significantly, while the 
IMD in the other rigs I've tested do NOT.  See K6XX's bench data in

http://k9yc.com/K6XXAmpTalk.pdf

Even more important, IMD is only part of the problem. An equally 
important part is the shaping of CW rise and fall times, which is what 
excites IMD. The K3's CW bandwidth is the best of all rigs tested by 
ARRL. Their closest competitor is the Kenwood TS-590S.

And then there's phase noise -- again, the K3 is in the top 3 rigs, and 
the recent synth board upgrade improved it by 5-6 dB.

See ARRL data here.  http://k9yc.com/TXNoise.pdf

And here's my measured data for a K3 driving a KPA500 and a Ten Tec 
Titan. Note that this includes the combined IMD products of the K3 and 
those amps. P3_Spectrum_Measurements.pdf and FTDX5000_Report.pdf

> Elecraft needs to quit messing with the spectacular receiver they built and work on cleaning up the transmitter. If that means dumping the 12V finals for higher voltage cleaner types so be it.

See above.

73, Jim K9YC