[Elecraft] Here is the real nitty-gritty on how the KAT500 works

[w1ie at jetbroadband.com]

GA All,

 

Around last December, I posed the question on how does the KAT500 actually works. This is the answer I received from Dick at Elecraft, the person who designed the software for the KAT500. Most likely he probably wrote it too. There was, however, a request from Eric, Elecraft CEO,  when the info was sent to me and I had wanted to know if it was ok for me to pass this info around. 

 

Hi Jerry,

 

Eric, our CEO says

 

  >>> Sure. But note that Dick does not have time available to answer questions on this as he is tied up on other work. <<

 

Thanks for asking in advance.

73,

Doug

 

So please do not ask Dick anymore about this subject. As you will see, Dick went into great detail on how the KAT500 works

 

From: Dick
Date: Fri, Dec 13, 2019 at 1:40 AM
Subject: RE: Question about the KAT500 capability.
To: Elecraft Support <support at elecraft.com <mailto:support at elecraft.com> >

Here is how the KAT500 storage allocation works.

EEPROM storage for ATU settings is pre-allocated by frequency.  I’ve called “the storage area for the six ATU settings for a given frequency segment” a “bin” because the word is often used in the program and documentation.

Each “bin” has room for 6 ATU settings.  Each of these 6 ATU settings contains bits for the ATU relays (L, C, side, ATU bypass and ANT relays) plus an SWR measured when the ATU was bypassed.  The antenna number (ANT relay bit  settings) is included in the  ATU setting, so we don’t need to preallocate something like 2 ATU settings for ANT1 and 2 ATU settings for ANT2 and 2 ATU settings for ANT3 in a 6-setting bin.

Thus you can have 5 ATU settings for ANT 1 in the bin for 1801-1810 and one ATU setting for ANT2 in the same bin. The next bin for 1811 thru 1820 might have 3 settings for ANT2 and 2 settings for ANT3 and one empty.

The most recently used ATU setting is moved to the front of the bin when you tune to that setting.  When you have a “full” bin, all 6 entries have ATU settings, and do another tune, it might push out the oldest setting.  No  duplicate settings are stored in any given bin. 

There is bin storage pre-allocated for all frequencies between 1.501 and 60 MHz.  We have MARS, CAP, and a few other commercial/military customers.  We didn’t know ahead of time what the frequencies would be for all these customers. MARS customers aren’t always allowed to tell us the exact frequencies they use.  So we allocated storage assuming a continuous range between 1.5 and 60 MHz. The ATU isn’t a transmitter, we aren’t constrained to the ham bands.

 

For 80 meters the “bin width” is 20 kHz.

Bin 1 is 3001 thru 3020 kHz

Bin 2 is 3021 thru 3040

Bin 3 is 3041 thru 3060, etc.

 

The 80 meter ham band is 500 kHz wide (3500-4000). At 20 kHz per bin, there are 25 “bins” for the 80 meter ham band.

 

3481-3500 one bin, 6 ATU settings.

3501-3520 one bin, 6 ATU settings

3521-3540 one bin, 6 ATU settings.

 

The ATU overall from 1.5 to 60 MHz has room for 1530 “bins” each containing up to 6 ATU settings. That’s just over 12,000 ATU settings.   But most of these are outside the ham bands.

 

Here’s an excerpt from a planning spreadsheet: Our “160 meter band” goes from 1501 through 3000 kHz, 80 meters goes from 3001 through 4800, etc.

 

The frequencies ranges and band names match the K3.

 


Band
Name

Ham
Band
Start

Ham
Band
End

Ham Band Width

Lower Limit

Upper Limit

Band
Width

Bin
Width

 

Bin Count

	
								
 

		

160

1800

2000

200

  1501

3000

1500

10

 

150

	

80

3500

4000

500

3001

4800

1800

20

 

90

	

60

5330

5405

75

4801

6000

1200

20

 

60

	

40

7000

7300

300

6001

9000

3000

20

 

150

	

30

10100

10150

50

9001

13000

4000

20

 

200

	

20

14000

14350

350

13001

17000

4000

20

 

200

	

17

18068

18168

100

17001

19000

2000

20

 

100

	

15

21000

21450

450

19001

23000

4000

20

 

200

	

12

24890

24990

100

23001

26000

3000

20

 

150

	

10

28000

29700

1700

26001

38000

12000

100

 

120

	

6

50000

54000

4000

38001

60000

22000

200

 

110

	
								
 

		

73

 

My de Dick, K6KR

Best regards,

 

Jerry, W1IE