Meter readings jumping around

[David C Dawson-2]

Hi,
I have got to the stage where the physical construction of the RF board
on the K2 is complete and it is assembled except for the filter peaking.

I have noticed that the internal meter is jumping around somewhat at
times, although the analog meter I have in line with the dummy load does
not.

I noticed that when I applied power on 20 meters, and started tweaking
L8 and L9 the power went up and up to 8 watts, then when I did it again,
it was stable at around 2.0. Is that abnormal?

The S meter seems to jump around somewhat; that is, it jumps between two
adjacent bars (dot mode) on occasion.

I think that there may be a poor solder joint somewhere (historical
precedent ;-)).

Where should I start to look?
Thanks

--
David Dawson

The trouble with this country is that there are too many politicians
who believe, with a conviction based on experience, that you can fool
all of the people all of the time.
                -- Franklin Adams

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[Don Wilhelm-3]

David,

If the indication is only changing by 1 or 2 units on the last digit, that
is normal and is caused by the resolution available.

When peaking the filters, yes the output will increase.  If it climbs very
high, just exit TUNE and start enter it again to bring the power down.  Keep
the power low by exiting and re-entering TUNE) when peaking the filters -
you can see the peak more easily if you observe that rule.

Some degree of uncertainly in the S-meter indication is normal - if it
changes by only one bar, that is likely due to the resolution problem - the
real indication likely should be somewhere between the 2 bars, but that does
not exist, so it hits the lower one sometimes and the higher one other
times.  Such is the problem with many digital metering systems unless they
design for low order digit blanking.

OTOH, if the display is just showing random indications, then yes - look for
that elusive bad solder connection.

73,
Don W3FPR

> -----Original Message-----
> Hi,
> I have got to the stage where the physical construction of the RF board
> on the K2 is complete and it is assembled except for the filter peaking.
>
> I have noticed that the internal meter is jumping around somewhat at
> times, although the analog meter I have in line with the dummy load does
> not.
>
> I noticed that when I applied power on 20 meters, and started tweaking
> L8 and L9 the power went up and up to 8 watts, then when I did it again,
> it was stable at around 2.0. Is that abnormal?
>
> The S meter seems to jump around somewhat; that is, it jumps between two
> adjacent bars (dot mode) on occasion.
>
> I think that there may be a poor solder joint somewhere (historical
> precedent ;-)).
>
>

--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.22/590 - Release Date: 12/16/2006
5:39 PM

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[David C Dawson-2]

Thanks Don,
I've got the filters peaked now.

On Sun, Dec 17, 2006 at 09:33:03PM -0500, Don Wilhelm wrote:
> David,
>
> If the indication is only changing by 1 or 2 units on the last digit, that
> is normal and is caused by the resolution available.
That was about it.

>
> When peaking the filters, yes the output will increase.  If it climbs very
> high, just exit TUNE and start enter it again to bring the power down.  Keep
> the power low by exiting and re-entering TUNE) when peaking the filters -
> you can see the peak more easily if you observe that rule.
>
> Some degree of uncertainly in the S-meter indication is normal - if it
> changes by only one bar, that is likely due to the resolution problem - the
> real indication likely should be somewhere between the 2 bars, but that does
> not exist, so it hits the lower one sometimes and the higher one other
> times.  Such is the problem with many digital metering systems unless they
> design for low order digit blanking.

The S-meter was rapidly switching between the last 2 bars, so they
seemed both lit at the same time.
Was this what you are talking about?

As far as I can see, this doesn't happen in normal use.

>
> OTOH, if the display is just showing random indications, then yes - look for
> that elusive bad solder connection.
No, it was not like that.
>
> 73,
> Don W3FPR
>
A few other things:

-The speaker audio seems a tad low, not very low but not as loud as my
Icom 730 is.

-The speaker terminals were not at all like the manual, so I have only
hooked up the one connection; but I expect I can figure that out
eventually with no problem.

-the S meter is  about S5 with no signal, can I just go through the
previous set up for it as earlier in the manual? Any 'gotchas'?

> > -----Original Message-----
> > Hi,
> > I have got to the stage where the physical construction of the RF board
> > on the K2 is complete and it is assembled except for the filter peaking.
> >
> > I have noticed that the internal meter is jumping around somewhat at
> > times, although the analog meter I have in line with the dummy load does
> > not.
> >
> > I noticed that when I applied power on 20 meters, and started tweaking
> > L8 and L9 the power went up and up to 8 watts, then when I did it again,
> > it was stable at around 2.0. Is that abnormal?
> >
> > The S meter seems to jump around somewhat; that is, it jumps between two
> > adjacent bars (dot mode) on occasion.
> >
> > I think that there may be a poor solder joint somewhere (historical
> > precedent ;-)).
> >
> >
> --
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.5.432 / Virus Database: 268.15.22/590 - Release Date: 12/16/2006
> 5:39 PM
>

--
David Dawson

The trouble with this country is that there are too many politicians
who believe, with a conviction based on experience, that you can fool
all of the people all of the time.
                -- Franklin Adams

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[David C Dawson-2]

Thanks again, Don,
On Mon, Dec 18, 2006 at 08:36:25AM -0500, Don Wilhelm wrote:
> David,
>
> Fine on getting the K2 peaked.
Yep!!
>
> Yes, if you have the LED display set to DOT - you will see the resolution
> uncertainty region as two adjacent bars alternately flickering - nothing
> worng, just the logic can't make up its mind about which one is the more
> 'average'.  If you set to BAR display, the effect is not as noticable, in
> that case, just the highest bar will appear a bit more dim than the others.
FB!
>
> The K2 does not have a powerful audio amplifier - that was done by intent to
> reduce the current draw when operating QRP on battery power.  As a result,
> it is not as loud as many other transceivers.  The volume should be more
> than adequate for normal environments although in high ambient noise
> situations (like mobile operation) it may require a external audio
> amplifier.
This is true, the audio was adequate, but not very loud; I could hear it
fine, but with the Icom beside it, it appeared not so loud.
>
> I don't understand about your speaker connections, you will have to be more
> descriptive about it.
Well, there is not a specific ground tab in the triangle formation as
illustrated in the manual. Instead, there are two terminals in line with
a central rivet. If one was just a tie point, then I could use the
rivet, I suppose. I was probably a tad tired to figure it out.
>
> You should do the AGC Threshold and CAL S Lo and CAL S Hi after all the
> peaking alignment - it is OK to do it just the same way you did it before.
>
OK!





There is one teensie little problem left, and that is the paddle modes
behave exactly the same. I had been using an MFJ keyer on my Icom, with
the Curtis chip; I set it up to be able to switch between A and B mode,
so I'm quite familiar with that.

I am wondering if there could be a solder bridge between 2 IC pins
somewhere, thus preventing switching between A and B modes?

--
David Dawson

The trouble with this country is that there are too many politicians
who believe, with a conviction based on experience, that you can fool
all of the people all of the time.
                -- Franklin Adams

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[David C Dawson-2]

Thanks Tom,
I think the right word I should have used is 'dithering' instead of
'jumping'. I can handle that.

On Mon, Dec 18, 2006 at 10:15:30AM -0600, Tom Hammond wrote:

> Hi David:
>
> >I have noticed that the internal meter is jumping around somewhat at
> >times, although the analog meter I have in line with the dummy load does
> >not.
> >
> >I noticed that when I applied power on 20 meters, and started tweaking
> >L8 and L9 the power went up and up to 8 watts, then when I did it again,
> >it was stable at around 2.0. Is that abnormal?
> >
> >The S meter seems to jump around somewhat; that is, it jumps between two
> >adjacent bars (dot mode) on occasion.
> >
> >I think that there may be a poor solder joint somewhere (historical
> >precedent ;-)).
>
> It's not all that normal for readings to 'JUMP' around, but during
> tune-up, it IS normal for readings to increase well past the preset
> POWER level. This is due to the fact that the ALC is being disabled
> during this part of the tune-up process, so as you peak things up,
> you will normally see power appear to run kinda wild.
>
> When you see this phenomenon, just EXIT from TUNE mode and re-enter
> TUNE again. When you re-enter TUNE mode, the power level will be
> reestablished and you'll be returned to the specified power lever so
> you can continue to peak things up... and see the power again rise
> UNTIL you hit the point where there's no further increase!!!  You may
> have to exit/re-enter TUNE 2-3 times during the alignment session!!!
> If you have POWER set to 1W or 2W during tuning, DO NOT allow the
> displayed power to exceed 6W-7W while tuning before you exit and
> re-enter TUNE mode... just for safety.

That's understood, I got the hang of it pretty quickly.
>
> 73,
>
> Tom Hammond   N0SS
>

--
David Dawson

The trouble with this country is that there are too many politicians
who believe, with a conviction based on experience, that you can fool
all of the people all of the time.
                -- Franklin Adams

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