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K2: Very low output on 160m

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Ken Alexander-2

K2: Very low output on 160m

Hi All,

As usual, I decide to do something new with my K2
during a contest! I'll never learn!

Tonight, I'm trying 160m for the first time. Before I
go any further, I should mention that my K2 receives
extremely well on 160. However, when I hit the Tune
button to send some RF to my autotuner and get it
tuning, the indicated output is 0.3 Watts even though
the Power knob is set to 10 Watts. An external
wattmeter confirms this.

I replaced the antenna with a dummy load and got the
same result. RANT is set to OFF in case you're
wondering.

There doesn't seem to be a Troubleshooting section in
the K160RX manual so I'm at a loss to know what to
look at. Any help would be appreciated.

Thanks and 73,

Ken Alexander
VE3HLS
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Ken Alexander-2

Re: K2: Very low output on 160m

Hi Leigh,

Receive (80 and 160m): approx 35 mA
Tune (80m): 3.x Amps
Tune (160m): approx. 50 mA

This is bad, right?

73 - Ken

--- "Leigh L Klotz, Jr." <[hidden email]> wrote:

> Check the current draw as compared to 80m.
> If same as 80m but just low output, look in 160m Low
> pass filter. If
> low, then look for a drive problem, possible BPF.
> 73,
> Leigh/WA5ZNU
> On Sat, 1 Dec 2007 6:22 pm, Ken Alexander wrote:
> > Hi All,
> >
> > As usual, I decide to do something new with my K2
> > during a contest! I'll never learn!
> >
> > Tonight, I'm trying 160m for the first time.
> Before I
> > go any further, I should mention that my K2
> receives
> > extremely well on 160. However, when I hit the
> Tune
> > button to send some RF to my autotuner and get it
> > tuning, the indicated output is 0.3 Watts even
> though
> > the Power knob is set to 10 Watts. An external
> > wattmeter confirms this.
> >
> > I replaced the antenna with a dummy load and got
> the
> > same result. RANT is set to OFF in case you're
> > wondering.
> >
> > There doesn't seem to be a Troubleshooting section
> in
> > the K160RX manual so I'm at a loss to know what to
> > look at. Any help would be appreciated.
> >
> > Thanks and 73,
> >
> > Ken Alexander
> > VE3HLS
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
>

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Don Wilhelm-4

Re: K2: Very low output on 160m

Ken,

Yes, that is bad - you have no output on 160 meters. How about
receive? If it receives on 160 but not transmit, that narrows the
search area down considerably.

Check the frequency at TP1 with the internal probe and CAL FCTR after
you have tuned the K2 to 1800 kHz. If you find a frequency very far
away from 6715 kHz, the problem is with the VCO, and most likely the VFO
Range Select section - C75 must be selected and of a proper value (470
pf) to tune 160 meters.

73,
Don W3FPR
Ken Alexander wrote:

> Hi Leigh,
>
> Receive (80 and 160m): approx 35 mA
> Tune (80m): 3.x Amps
> Tune (160m): approx. 50 mA
>
> This is bad, right?
>
> 73 - Ken
>
>

Ken Alexander-2

Re: K2: Very low output on 160m

Hi Don,

It receives great on 160. The band was really hopping
last night.

I'll get back to you as soon as I figure out where
this probe plugs in and where TP1 is.

Thanks and 73,

Ken

--- Don Wilhelm <[hidden email]> wrote:

> Ken,
>
> Yes, that is bad - you have no output on 160 meters.
> How about
> receive? If it receives on 160 but not transmit,
> that narrows the
> search area down considerably.
>
> Check the frequency at TP1 with the internal probe
> and CAL FCTR after
> you have tuned the K2 to 1800 kHz. If you find a
> frequency very far
> away from 6715 kHz, the problem is with the VCO, and
> most likely the VFO
> Range Select section - C75 must be selected and of a
> proper value (470
> pf) to tune 160 meters.
>
> 73,
> Don W3FPR
> Ken Alexander wrote:
> > Hi Leigh,
> >
> > Receive (80 and 160m): approx 35 mA
> > Tune (80m): 3.x Amps
> > Tune (160m): approx. 50 mA
> >
> > This is bad, right?
> >
> > 73 - Ken
> >
> >
>

Ken Alexander-2

Re: K2: Very low output on 160m

6713.95 with the K2 tuned to 1800 kHz, CW. Is that
considered close or do I have some work to do?

73 - Ken

--- Ken Alexander <[hidden email]> wrote:

> Hi Don,
>
> It receives great on 160. The band was really
> hopping
> last night.
>
> I'll get back to you as soon as I figure out where
> this probe plugs in and where TP1 is.
>
> Thanks and 73,
>
> Ken
>
>
>
> --- Don Wilhelm <[hidden email]> wrote:
>
> > Ken,
> >
> > Yes, that is bad - you have no output on 160
> meters.
> > How about
> > receive? If it receives on 160 but not transmit,
> > that narrows the
> > search area down considerably.
> >
> > Check the frequency at TP1 with the internal probe
> > and CAL FCTR after
> > you have tuned the K2 to 1800 kHz. If you find a
> > frequency very far
> > away from 6715 kHz, the problem is with the VCO,
> and
> > most likely the VFO
> > Range Select section - C75 must be selected and of
> a
> > proper value (470
> > pf) to tune 160 meters.
> >
> > 73,
> > Don W3FPR
> > Ken Alexander wrote:
> > > Hi Leigh,
> > >
> > > Receive (80 and 160m): approx 35 mA
> > > Tune (80m): 3.x Amps
> > > Tune (160m): approx. 50 mA
> > >
> > > This is bad, right?
> > >
> > > 73 - Ken
> > >
> > >
> >
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
>
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> Elecraft web page: http://www.elecraft.com
>

Ken Alexander-2

Re: K2: Very low output on 160m

I hope that 6713.95 is OK because I just checked the
other VCO freqs at band edge and they're all off by
roughly the same amount, except for 15 and 10m, which
are both 0.97 kHz high.

73 - Ken

--- Ken Alexander <[hidden email]> wrote:

> 6713.95 with the K2 tuned to 1800 kHz, CW. Is that
> considered close or do I have some work to do?
>
> 73 - Ken
>
>
>
> --- Ken Alexander <[hidden email]> wrote:
>
> > Hi Don,
> >
> > It receives great on 160. The band was really
> > hopping
> > last night.
> >
> > I'll get back to you as soon as I figure out where
> > this probe plugs in and where TP1 is.
> >
> > Thanks and 73,
> >
> > Ken
> >
> >
> >
> > --- Don Wilhelm <[hidden email]> wrote:
> >
> > > Ken,
> > >
> > > Yes, that is bad - you have no output on 160
> > meters.
> > > How about
> > > receive? If it receives on 160 but not
> transmit,
> > > that narrows the
> > > search area down considerably.
> > >
> > > Check the frequency at TP1 with the internal
> probe
> > > and CAL FCTR after
> > > you have tuned the K2 to 1800 kHz. If you find
> a
> > > frequency very far
> > > away from 6715 kHz, the problem is with the VCO,
> > and
> > > most likely the VFO
> > > Range Select section - C75 must be selected and
> of
> > a
> > > proper value (470
> > > pf) to tune 160 meters.
> > >
> > > 73,
> > > Don W3FPR
> > > Ken Alexander wrote:
> > > > Hi Leigh,
> > > >
> > > > Receive (80 and 160m): approx 35 mA
> > > > Tune (80m): 3.x Amps
> > > > Tune (160m): approx. 50 mA
> > > >
> > > > This is bad, right?
> > > >
> > > > 73 - Ken
> > > >
> > > >
> > >
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
>
> >
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
>
> _______________________________________________
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> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
>
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> Elecraft web page: http://www.elecraft.com
>

Don Wilhelm-4

Re: K2: Very low output on 160m

In reply to this post by Ken Alexander-2

Ken,

That frequency is considered very close to the nominal value - the VCO
frequency is not the problem.

Now, you are in for some Transmit Signal Tracing on 160 meters. Get out
an RF Probe (I believe you got one with your K2) and turn the K2 manual
to Appendix E and look for 'Transmit Signal Tracing'. For now, ignore
the parts that tell you to set the K2 to 40 meters, but do connect a
good dummy load - we will come back to the preliminary measurements if
required. Start instead at the points listed below the midpoint of the
first column of page 14. Do those measurements in order, switching
between 80 meters and 160. When you find a point where the RF voltage
on 160 is substantially lower than that on 80 meters (higher is
generally OK) - stop, you have found the troublesome stage and more
detailed investigation is to be done at that stage.

73,
Don W3FPR

Ken Alexander wrote:

> 6713.95 with the K2 tuned to 1800 kHz, CW. Is that
> considered close or do I have some work to do?
>
> 73 - Ken
>
>
>
> --- Ken Alexander <[hidden email]> wrote:
>
>
>> Hi Don,
>>
>> It receives great on 160. The band was really
>> hopping
>> last night.
>>
>> I'll get back to you as soon as I figure out where
>> this probe plugs in and where TP1 is.
>>
>> Thanks and 73,
>>
>> Ken
>>
>>
>

Ken Alexander-2

Re: K2: Very low output on 160m

Hi Don,

OK, the tests are underway.

Key down signal @ pin 4, U10: 80m; 0.058 160m; 0.055
Key down signal @ pin 6, U9: 80m; 0.205 160m; 0.695
Key down signal @ W6: 80m; 0.025 160m; 0.018
Key down signal @ D1 anode: 80m; 0.023 160m; 0.016

I remember a thread a long time ago about what is
considered a "normal" reading, and I recall that range
of what was considered acceptable was much larger than
I would have thought. Thus, I will leave the
interpretation of this data to you, with my thanks!

73 - Ken

--- Don Wilhelm <[hidden email]> wrote:

> Ken,
>
> That frequency is considered very close to the
> nominal value - the VCO
> frequency is not the problem.
>
> Now, you are in for some Transmit Signal Tracing on
> 160 meters. Get out
> an RF Probe (I believe you got one with your K2)
> and turn the K2 manual
> to Appendix E and look for 'Transmit Signal
> Tracing'. For now, ignore
> the parts that tell you to set the K2 to 40 meters,
> but do connect a
> good dummy load - we will come back to the
> preliminary measurements if
> required. Start instead at the points listed below
> the midpoint of the
> first column of page 14. Do those measurements in
> order, switching
> between 80 meters and 160. When you find a point
> where the RF voltage
> on 160 is substantially lower than that on 80 meters
> (higher is
> generally OK) - stop, you have found the troublesome
> stage and more
> detailed investigation is to be done at that stage.
>
> 73,
> Don W3FPR
>
>
> Ken Alexander wrote:
> > 6713.95 with the K2 tuned to 1800 kHz, CW. Is
> that
> > considered close or do I have some work to do?
> >
> > 73 - Ken
> >
> >
> >
> > --- Ken Alexander <[hidden email]> wrote:
> >
> >
> >> Hi Don,
> >>
> >> It receives great on 160. The band was really
> >> hopping
> >> last night.
> >>
> >> I'll get back to you as soon as I figure out
> where
> >> this probe plugs in and where TP1 is.
> >>
> >> Thanks and 73,
> >>
> >> Ken
> >>
> >>
> >
>