K3 FW V3.30 NR notes

Firmware version 3.25

Fx(1-4)-y(1-4)

x(selects values of Beta (gain), decay, and delay (how long the NR
algorithm waits to process a signal))

y(selects amount to processing of signal 1(Dry, unprocessed)- 4(Wet, processed))


Notes :
All selections 61 taps.


Firmware version 3.27

Fx(1-4)-y(1-4)

x(selects the length of the filter)

y(selects values of Beta (gain), decay, and delay (how long the NR
algorithm waits to process a signal))

Notes :
F1 = 121 taps, F2 = 91 taps, F3 = 61 taps, F4 = 31 taps
Noise reduction less aggressive with more taps.
The 3.27 NR F3-1 is *identical* to 3.25 NR F1-4.
The 3.27 NR F3-2 is *identical* to 3.25 NR F2-4.
The 3.27 NR F3-3 is *identical* to 3.25 NR F3-4.
The 3.27 NR F3-4 is *identical* to 3.25 NR F4-4.

The 3.27 NR F1- is "lighter" than the 3.25 NR.
The 3.27 NR F2- is a little lighter than the 3.25 NR.
The 3.27 NR F4- is "heavier" than the 3.25 NR.


Firmware version 3.30

Fx(1-4)-y(1-4) as 3.27 above

M Fx(5-8)-y(1-4) as 3.25 above

K3 mods completed

K3 Ser: 1293
Arrived: 20/7/2008

Mods carried out:

1) 10/01/09

K3 AF Mod kit, Rev B

2) 30/08/09

K3 Synthesizer ALC Modification

K3 AF Output Mod Kit, Rev C

Improving the Immunity of the Rear-Panel RS232 and Audio Connectors to RF

KPA3 12V Sense Mod, Rev B

K3 Extreme Signal RX Protection Mod

3) 02/10/09

KRX3 Installed

KRX3 Subout connector keyed

Front panel microphone circuit modification

K3 Negative ALC and Ext Band Data Pull-up Mods, Rev B: REMIOUPGD

4) 31/10/09

K3 VFO Noise Mod, Rev C

IF Output Buffer Gain Modification

K3 KRX3 (sub rx) filter choice

I wanted an 8 pole filter for 0Hz offset to allow true dual rx without the 'slow beat' audio problem.

I had the option to pay $90 extra to SWAP the stock sub rx 2.7K 5 pole for an 2.8K 8 pole and of course I'd have to spend another $125 to match it in the main rx.

In the end I paid $125 extra, kept the stock 2.7K 5 pole and bought another 2.1K 8 pole . I already have a 2.1K 8 pole in the main rx, so having one in the sub rx will allow me to lock the rxs together with a vert and a horiz antenna and listen to both at the same time without 'audio beat'. I also paid $30 extra to get the new 2.7KHz matched (-0.93KHz offset) with the existing one. So hopefully I can get the best of both worlds for not too much outlay.

I recon the 2.1KHz 8 pole roofing filter will be sufficient for SSB/DATA/CW in the sub rx. I'm sure the DSP filter width can more than handle DATA/CW inside a 2.1K roof. SSB through the 2.1KHz is fine (better if the shift is adjusted down 200Hz or so), but it excels on a busy/noisy band. Even in this configuration it should still beat most other radios out there.