[All] K9YC's RFI Tutorial Bears Fruit

[alorona]

Now and then I have used Jim K9YC's "A Ham's Guide to RFI, Ferrites, Baluns, and
Audio Interfacing" as a reference but very recently I finally read the whole
thing straight through, and it finally dawned on me that Jim advocates putting a
common-mode choke right at the feedpoint of the antenna. The reason he gives is
that most 'balanced' antennas are not in perfect balance due to the antenna's
surroundings, and this imbalance makes the feedline pick up more noise. Much of
his paper consists of measured data of many kinds of chokes, but I built what
seemed the simplest effective choke -- 15 turns of solid THHN electrical wire
bifilar wound on a #31 toroid-- and put it near the feedpoint of my  dipole.

I say 'near' because for mechanical reasons the closest I could put the choke
was about 12 transmission line feet from the feedpoint. I use all-homebrew 500
ohm open-wire line.

I finally got the antenna up Saturday and  have been tuning around the low bands
and it appears that my noise floor has indeed dropped. Whereas in this noisy
location I have had the REF LVL of the P3 set to -114 dBm on 40 meters for some
time, I now have to drop the REF LVL to -118 dBm to move the noise floor to the
same location on the bottom of the display. There is a similar outcome on 80
meters. But man, I just picked up another half S-unit of noise floor last
weekend.

This K9YC is a smart man. Another change I've made since reading his entire
paper was replacing  my 'shielded' speaker cables (which nonetheless were always
bothered with RF buzz whenever I transmitted on 40) with simple unshielded
twisted pair, and it looks like my buzz problem is pretty much gone.

Two changes which have improved the station by a lot. Thanks, Jim.

Al  W6LX
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[K9QJS]

I want to write two K3 macros, one for selecting the front panel Mic (MH2) and setting Mic gain and speech compression, and one for selecting the back panel mic (Yamaha CM500) and setting mic gain and speech compression.

>From my reading of the K3 programmer's reference, I know the following:

- Mic gain command is     MG010    (000 to 060)  
- Speech compression is CP016     (000 to  040)
- Mic select is MN053
- changing VFO A UP or DN

… but I am not sure how to more discretely select front panel mic or back panel mic, and not sure about whether I need to use the MN255 to exit the MN command series.  

A potential command sequence is MN053;UP;MN255;MG010;CP016    …    if currently set on the front panel mic to change to the back panel mic, I think.   Though avoiding use of UP and DN would be preferable.      

I have entered two macros that I got from the Programmer's Reference, the SPLIT+2 and the CLEANUP, and they work just fine.

Advice is appreciated.

73,
Hoop
K9QJS



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[N7US]

I have macros that do that with my logging program, DXLab, specifically its
rig control program, Commander.  I have them uploaded to the DXLab Yahoo
reflector files website,
<http://groups.yahoo.com/group/dxlab/files/Command%20Sequences%20%26%20Slide
rs/Elecraft/> .

I do it by toggling two choices within the same macro (call a User-Defined
Control in Commander).

You could run just Commander without using the other features of DXLab if
desired.

http://www.dxlabsuite.com/ 

73, Jim N7US

-----Original Message-----


I want to write two K3 macros, one for selecting the front panel Mic (MH2)
and setting Mic gain and speech compression, and one for selecting the back
panel mic (Yamaha CM500) and setting mic gain and speech compression.

>From my reading of the K3 programmer's reference, I know the following:

- Mic gain command is     MG010    (000 to 060)  
- Speech compression is CP016     (000 to  040)
- Mic select is MN053
- changing VFO A UP or DN

. but I am not sure how to more discretely select front panel mic or back
panel mic, and not sure about whether I need to use the MN255 to exit the MN
command series.  

A potential command sequence is MN053;UP;MN255;MG010;CP016    .    if
currently set on the front panel mic to change to the back panel mic, I
think.   Though avoiding use of UP and DN would be preferable.      

I have entered two macros that I got from the Programmer's Reference, the
SPLIT+2 and the CLEANUP, and they work just fine.

Advice is appreciated.

73,
Hoop
K9QJS




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[Dick Dievendorff]

Hi, Hoop!

Generally you will want to use MN255; to close the menu, or your K3 will end
up with a CONFIG menu on the VFO A display after you've pressed your macro
button. (try it!)

MIC select doesn't work when in Mode CW, but that's pretty clear from the
VFO B marquee display.

Some menu items are supported by MP (menu parameter) with distinct values.
MIC SEL (MN053) isn't one of them, so you may use a sequence of DN and UP,
but it's simple enough.

Since you don't always know what the current selection was before you push
the macro button, you can use a sequence of DN; commands to get to the first
menu choice and then a specific number of UP commands to choose an item:

MN053;DN;DN;DN;MN255; will select the front panel.
Add one UP; after the three DNs to select the rear panel microphone.

The three DN commands move from whatever selection you had before to the
first choice, FP.  If you had input FP, RP, or LINE IN, three DNs are enough
to move you to the first choice: FP, and extra DN commands don't do anything
after the selection is already at the "bottom".  This technique works on
several multi-choice items where there are more than two choices.

Sometimes, for simple Boolean (on/off) functions, DN and UP just alternate
between the choices. Fortunately that's not the case here.

So your macro might say MN053;DN;DN;DN;MN255;CP016;MG010; for your front
panel mic and MN053;DN;DN;DN;UP;MN255;CP016;MG010; for rear panel mic.

Test these with a "local" K3 Utility macro button and then transfer them to
the K3 after you have them set to your liking.

73 de Dick, K6KR


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of J.K. Hooper
Sent: Sunday, November 18, 2012 9:15 AM
To: Elecraft Reflector
Subject: [Elecraft] K3 Macros for mic switching ?

I want to write two K3 macros, one for selecting the front panel Mic (MH2)
and setting Mic gain and speech compression, and one for selecting the back
panel mic (Yamaha CM500) and setting mic gain and speech compression.

>From my reading of the K3 programmer's reference, I know the following:

- Mic gain command is     MG010    (000 to 060)  
- Speech compression is CP016     (000 to  040)
- Mic select is MN053
- changing VFO A UP or DN

. but I am not sure how to more discretely select front panel mic or back
panel mic, and not sure about whether I need to use the MN255 to exit the MN
command series.  

A potential command sequence is MN053;UP;MN255;MG010;CP016    .    if
currently set on the front panel mic to change to the back panel mic, I
think.   Though avoiding use of UP and DN would be preferable.      

I have entered two macros that I got from the Programmer's Reference, the
SPLIT+2 and the CLEANUP, and they work just fine.

Advice is appreciated.

73,
Hoop
K9QJS



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[Jim Brown-10]

On 11/17/2012 12:10 PM, Al Lorona wrote:
> This K9YC is a smart man.

Thanks for the kind words, Al.  But it all comes as the result of a lot
of serious study, and of listening to others who have done the same.  
W1HIS was the guy who I first saw articulate the significance of using a
serious common mode choke at the feedpoint, and he published a serious
tutorial on the topic. The only thing he got wrong was that his winding
instructions were wrong because he didn't know how to measure the chokes
accurately, and he didn't quite understand the chokes at the time he
wrote it.  he also didn't know about the newer #31 material, which I
knew about because of my previous research.

Likewise, much of what I've learned about RFI, including the importance
of twisted pair in rejecting RFI, is the result of learning from other
members of the EMC Working Group of the AES Standards Committee, of
which I've been Vice-Chair for ten years, (especially Neil Muncy and
Bill Whitlock), and from studying the work of Henry Ott.  They're the
smart guys!

73, Jim K9YC
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