[Elecraft] K3S Initial setup calibration problem

[Tom Norris]

Hi Alan,

That's good news! Glad you went for a walk and had a revelation, I think I
need a little longer walk perhaps! I'm still having problems but gathering
good data for help I hope. I have enabled my modules and filters but still
no received broadcast, WWV time signal or Ham traffic. Hence I have not
done the Reference Oscillator Calibration and not able to do the Wattmeter
adjustment although I do get a 14.050 Mhz 15mv RF signal (and a 7.050 Mhz
signal at 60mv-only a 20 Mhz 'scope) at the proper respective frequencies
when TUNE is pressed but VFO A has no effect on the output signal according
to the oscilloscope. Am emailing K3support at elecraft.com and hope they find,
as you say, that they can cure my 'Stupid' :-)

I'm confused as to getting these messages on the Elecraft Reflector, I hope
this one makes it.
73,
Tom NB5Q

On Sat, Dec 16, 2017 at 6:56 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:

> Tom,
>
> The K3 wattmeter calibration is different than the K3 Utility TX gain
> calibration.
>
> Do the wattmeter calibration as indicated in the manual, and then you can
> do the TX Gain calibration from K3 Utility.
>
> 73,
> Don W3FPR
>
> On 12/16/2017 8:33 PM, Tom Norris wrote:
>
>> OK on the scope frequency response, I will use that info when I look at
>> that tomorrow (too late now, in the house with XYL) ​Just C
>> urious
>> ​​
>> if the K3 Utility Transmitter Gain
>> ​Calibration​
>> (pg
>> ​52)
>>  rel
>> ​ies​
>> on the K3 power
>> ​watt​
>> meter reading responding correctly (after manual Wattmeter
>> ​calibration on pg 52)​. Could this explain the failure of the K3 Utility
>> Transmitter Gain Calibration try earlier.
>>
>> Thanks, Tom NB5Q
>>
>> On Dec 16, 2017 5:55 PM, "Don Wilhelm" <donwilh at embarqmail.com <mailto:
>> donwilh at embarqmail.com>> wrote:
>>
>>     Tom,
>>
>>     If your 'scope is rated at 20 MHz, that is the 3dB point for the
>>     vertical amplifier.  It will show only 1/2 of the actual amplitude
>>     at 20 MHz.  Use a frequency that is 1/3 or less of the 'scope
>>     rating to get an accurate vertical voltage response - i.e. use 7
>>     MHz or below.
>>
>>     I trust a 100MHz scope only to 30MHz for correct vertical
>>     amplitude, and the 10X probes must be rated for 100 MHz and above
>>     for that situation to be accurate.  A 1X probe or a piece of coax
>>     used as a probe may not produce an accurate indication of the RF
>>     voltage.
>>
>>     73,
>>     Don W3FPR
>>
>>     On 12/16/2017 7:38 PM, Tom Norris wrote:
>>
>>         Thanks Don, I will look at the signal with a 20 Mhz scope and
>>         see what the voltage is during xmt. Since I did not see any
>>         K3S display change while making adjustment with VFO A knob or
>>         hear any signal increase in the Omni D I was thinking I'm not
>>         affecting the power adjustment of the K3S.
>>         Thanks, Tom NB5Q
>>
>>         On Dec 16, 2017 5:29 PM, "Don Wilhelm" <donwilh at embarqmail.com
>>         <mailto:donwilh at embarqmail.com> <mailto:donwilh at embarqmail.com
>>
>>         <mailto:donwilh at embarqmail.com>>> wrote:
>>
>>             Tom,
>>
>>             Have you checked that external wattmeter at 5 watts?
>>             Many wattmeters when on the 200 watt range may not show any
>>             significant output until you get to 10 or 20 watts.
>>
>>             Use the 20 watt range on the wattmeter - and do not really
>>         trust
>>             it at the 5 watt level.  The diodes in many wattmeters are a
>>             potential problem and may not register anything unless the
>>         power
>>             is 10 watts and above. The exception is QRP wattmeters with op
>>             amps and compensating diodes.
>>
>>             If you have access to a 'scope with a 10X probe, that is more
>>             accurate.
>>             Set the scope to read the RF voltage and connect it across the
>>             dummy load.  If your dummy load does not allow access to
>>         the coax
>>             center conductor, use a Tee adapter to access the center
>>         conductor.
>>             The RF peak to peak voltage for 5 watts is 44.7 volts.
>>
>>             Bottom line - do not trust your instruments (wattmeter in this
>>             case) until it is proven trustworthy  at the power level
>>         involved.
>>
>>             73,
>>             Don W3FPR
>>
>>
>>             On 12/16/2017 6:20 PM, Tom Norris wrote:
>>
>>                 Newly assembled working great so far.
>>                 At the Owners Manual Calibration Procedures pg 52
>>         (Fred Cady
>>                 book Elecraft
>>                 K3S and P3 referred me to Owners Manual for some
>>         Calibrations
>>                 after going
>>                 through Configuring the K3S pg 26...)
>>                 Wattmeter:
>>                 Both CONFIG:TUN PWR and PWR SET to NOR (KPA3A not
>>         installed
>>                 yet, all covers
>>                 on.
>>                 Low-Power (5 W) W mtr calibration
>>                 On 20 meter band at 14.050
>>                 On a 1kw Cantenna 50 ohm dummy load (ch'd w/ Ohm meter)
>>                 Set power to 5.0 watts on K3S with Pwr knob
>>                 Go to CONFIG WMTR LP showing
>>                 Press TUNE (hear signal on Omni D) but does not
>>         register on
>>                 ext W Mtr and
>>                 cannot vary output with VFO A knob (which is the
>>         instructed
>>                 'Parameter'
>>                 adjustment knob I assume?)
>>                 Ext W Mtr is working ok with Omni D output
>>
>>
>>
>>
>