Microphone and BFO questions

[Rolf Moberg, OH6KXL]

Hello!

Does somebody have first hand knowledge/experience from the following
topics? I now there are several modifications to KSB2 to increase gain.
KI6WX has done a great document how to modify it. It's found in

http://home.pacbell.net/johngreb/modifications_to_the_ksb2.pdf

My K2 has been on the air about one week now. KSB2 module has not been
built not yet. I have two extra microphones to use with K2. The one is
well known Yaesu MH-31 with RJ-45 connector in radio end. The other is
Heil Pro Set Plus headset with normal HC4 and HC5 elements. I'd like to
use BOTH of them (MH-31 and Heil) since there are situations where hand
mic is preferred over headset. Heil headset is normal version, not those
Icom or Elecraft model.

I know there are several modifications to increase gain. My question is:

Is it really required to modify KSB2 to get sufficient gain in recent K2
versions? My s/n is 4759. Please remember my mics, Heil headset and
MH-31. Gain should be adjustable enough to get suitable gain in both of
them.

In what order it would be recommended to continue?
1. Make KSB2 and install it
2. Install 8-pin mic connector MH-31 and do filter adjustments
3. Build adapter to connect Heil headset
4. Finally, to find it's not possible to use these mics with K2 and
order Elecraft models of headset and hand mic?

Finally. I ordered L31 to extend limited PLL range. I have problem with
my BFO lower limit. It is 4912.91 kHz now. It _should_ be 4912.7 kHz or
lower. Does the extending PLL range affect to BFO upper and lower
frquencies?

At once my BFO range was as it's required. In that time my 4 MHz
oscillator wasn't calibrated correctly. I'm optimistic that after
installing new L31 I'll get my PLL range according to specifications.
And after 4MHz oscillator calibration I have BFO range where it should be.


Rolf Moberg
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[Geoffrey Mackenzie-Kennedy-2]

Rolf,

My K2/100 is #3255 and I use the Heil Proset Plus (normal version) without
any modifications to the KSB2.  Get full spec PEP on all bands speaking in a
normal voice which the XYL says is quiet. Sorry I cannot comment on the
other mics.

73, Geoff
GM4ESD

----- Original Message -----
From: "Rolf Moberg, OH6KXL" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, May 10, 2005 6:15 PM
Subject: [Elecraft] Microphone and BFO questions

> Hello!
>
> Does somebody have first hand knowledge/experience from the following
> topics? I now there are several modifications to KSB2 to increase gain.
> KI6WX has done a great document how to modify it. It's found in
>
> http://home.pacbell.net/johngreb/modifications_to_the_ksb2.pdf
>
> My K2 has been on the air about one week now. KSB2 module has not been
> built not yet. I have two extra microphones to use with K2. The one is
> well known Yaesu MH-31 with RJ-45 connector in radio end. The other is
> Heil Pro Set Plus headset with normal HC4 and HC5 elements. I'd like to
> use BOTH of them (MH-31 and Heil) since there are situations where hand
> mic is preferred over headset. Heil headset is normal version, not those
> Icom or Elecraft model.
>
> I know there are several modifications to increase gain. My question is:
>
> Is it really required to modify KSB2 to get sufficient gain in recent K2
> versions? My s/n is 4759. Please remember my mics, Heil headset and
> MH-31. Gain should be adjustable enough to get suitable gain in both of
> them.
>
>

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[Mark J. Schreiner]

My previous email reply was bounced from Rolf (I think).  Here is the short version of my response:

I have the Heil ProSet Plus (normal version, bought last fall, long before I thought about buying a K2).  I also have a Heil GM4 (I think) which has the same HC4 & HC5 microphone elements that are in the ProSet Plus.  I now get great audio reports with both microphones but at first I didn't.  I had to modify the KSB2 by changing R14 from 1k to 10k.  Before I modified it the RF output seemed quite light and there was no reading on the ALC meter, which operates differently than what I was used to with other rigs, but it still didn't operate per the manual for the KSB2.  After the mod I'm getting up to 10W output on all bands and the ALC meter gives 1 to 2 bars as per the manual.  I cannot comment on the Icom mic.

Mark, NK8Q
K2 4786

>From: Geoffrey Mackenzie-Kennedy <[hidden email]>
>Date: Tue May 10 15:33:06 CDT 2005
>To: "Rolf Moberg, OH6KXL" <[hidden email]>
>Cc: Elecraft Discussion List <[hidden email]>
>Subject: Re: [Elecraft] Microphone and BFO questions

>Rolf,
>
>My K2/100 is #3255 and I use the Heil Proset Plus (normal version) without
>any modifications to the KSB2.  Get full spec PEP on all bands speaking in a
>normal voice which the XYL says is quiet. Sorry I cannot comment on the
>other mics.
>
>73, Geoff
>GM4ESD
>
>----- Original Message -----
>From: "Rolf Moberg, OH6KXL" <[hidden email]>
>To: <[hidden email]>
>Sent: Tuesday, May 10, 2005 6:15 PM
>Subject: [Elecraft] Microphone and BFO questions
>
>
>> Hello!
>>
>> Does somebody have first hand knowledge/experience from the following
>> topics? I now there are several modifications to KSB2 to increase gain.
>> KI6WX has done a great document how to modify it. It's found in
>>
>> http://home.pacbell.net/johngreb/modifications_to_the_ksb2.pdf
>>
>> My K2 has been on the air about one week now. KSB2 module has not been
>> built not yet. I have two extra microphones to use with K2. The one is
>> well known Yaesu MH-31 with RJ-45 connector in radio end. The other is
>> Heil Pro Set Plus headset with normal HC4 and HC5 elements. I'd like to
>> use BOTH of them (MH-31 and Heil) since there are situations where hand
>> mic is preferred over headset. Heil headset is normal version, not those
>> Icom or Elecraft model.
>>
>> I know there are several modifications to increase gain. My question is:
>>
>> Is it really required to modify KSB2 to get sufficient gain in recent K2
>> versions? My s/n is 4759. Please remember my mics, Heil headset and
>> MH-31. Gain should be adjustable enough to get suitable gain in both of
>> them.
>>
>>
>
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[Geoffrey Mackenzie-Kennedy-2]

Rolf,

About using the Heil Proset Plus, I forgot to mention ALC behaviour that
Mark, NK8Q, mentioned. With my particular K2/100 #3255 and with no KSB2
mods, the ALC indicator occasionally flickers when I speak in a normal
voice. If I speak louder, it shows a bar or two most of the time. I would
guess that Heil has put a fairly tight tolerance on the mic elements'
output, so I must conclude from the comments on the List that there appears
to be quite a wide variation in Tx gain (mic connector to PA} K2 to K2.
Where the carrier (BFO) is placed on the KSB2's filter skirt could well be
the reason for much of this. The Operator's voice characteristics and where
the mic is positioned would also enter the picture of course.

Here I monitor the Tx output with a 50MHz scope.

If I was to build another K2, I would start with an unmodified KSB2, and
take it from there.

73, Geoff
GM4ESD


----- Original Message -----
From: "Rolf Moberg, OH6KXL" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, May 10, 2005 6:15 PM
Subject: [Elecraft] Microphone and BFO questions


> Hello!
>
> Does somebody have first hand knowledge/experience from the following
> topics? I now there are several modifications to KSB2 to increase gain.
> KI6WX has done a great document how to modify it.

_______________________________________________
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Post to: [hidden email]
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