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Erratic output on 160m

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Robin Kiszka

Erratic output on 160m

Hi -

My K2 has a 160m option as well as the SSB Option. On all bands, 80 - 10m I get good SSB transmission. Using a dummy load and watt meter I can see the SSB transmission is stable and varies between dips of 4-5 watts up to peaks of 13 watts (I'm not using the 100W PA).

This is not the case on 160m. On CW I get a sold 15W out on 160m, but when using LSB I see the watt meter is hovering between 0-2 W, but when I whistle into the microphone it goes all the way up to 15 W. The question is then why is 160m so lacking in response to voice when compared with the other bands that have far more sensitivity. I am using the delivered MH2 microphone.

I have disabled the antenna tuner, but this makes no difference. It's as if the gain from the microphone is not getting through to the 160m option.

Any suggestions would be welcome.

Thanks and 73
Robin
OZ6ABM / 5P5R

Don Wilhelm-4

Re: Erratic output on 160m

Robin,

There is no difference in the K2 SSB generation from one band to
another. That means it the K2 is capable of full power in CW mode, and
the K2 works fine on SSB on all other bands, it should work just fine in
SSB on 160 meters.
Is there any chance that your wattmeter is responding differently on 160
than it is on other bands?
A quick look at the RF output with an 'oscilloscope would tell you the
proper answer - just compare the waveform on 160 meters with that
obtained on 80 or 40 meters.

73,
Don W3FPR

Robin Kiszka wrote:

> Hi -
>
> My K2 has a 160m option as well as the SSB Option. On all bands, 80 - 10m I
> get good SSB transmission. Using a dummy load and watt meter I can see the
> SSB transmission is stable and varies between dips of 4-5 watts up to peaks
> of 13 watts (I'm not using the 100W PA).
>
> This is not the case on 160m. On CW I get a sold 15W out on 160m, but when
> using LSB I see the watt meter is hovering between 0-2 W, but when I whistle
> into the microphone it goes all the way up to 15 W. The question is then why
> is 160m so lacking in response to voice when compared with the other bands
> that have far more sensitivity. I am using the delivered MH2 microphone.
>
> I have disabled the antenna tuner, but this makes no difference. It's as if
> the gain from the microphone is not getting through to the 160m option.
>
> Any suggestions would be welcome.
>
>

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Robin Kiszka

Re: Erratic output on 160m

Hi Don,

I doubt there is any problem on the watt meter as it's working fine on other radios for 160m.
Another reason I suspect it is a K2 issue is because the K2 bar graph LED hardly lights on 160m SSB Tx, whereas on 80m and up I can easily get 4 or 5 bars with normal LSB speech on Tx. It's like the radio is deaf to the microphone on 160m.

73
Robin
OZ6ABM / 5P5R

Don Wilhelm-4

Re: Erratic output on 160m

Robin,

It is possible for the K2 to have lower transmit RF gain on 160 meters,
but then since you can obtain full output by whistling into the
microphone the K2 RF cahin has adequate gain on 160 meters. The highest
gain through the K2 transmit stages is normally at 40 or 30 meters
although some show the highest gain somewhere between 80 meters and 40
meters. In any case, if you get any bars at all on the ALC indication
that is sufficient for full output. You might want to try increasing
the compression a little - I normally run the compression on my K2 at
3:1 - that will bring up ;;the average power for you.

73,
Don W3FPR

Robin Kiszka wrote:

> Hi Don,
>
> I doubt there is any problem on the watt meter as it's working fine on other
> radios for 160m.
> Another reason I suspect it is a K2 issue is because the K2 bar graph LED
> hardly lights on 160m SSB Tx, whereas on 80m and up I can easily get 4 or 5
> bars with normal LSB speech on Tx. It's like the radio is deaf to the
> microphone on 160m.
>
> 73
> Robin
> OZ6ABM / 5P5R
>
>