[K3] 1.0 Milliwatt Calibration

[Julian, G4ILO]

I was wondering why my 2m transverter was producing much less output than when I set it up, so I thought that perhaps I should do the 1 Milliwatt calibration procedure, which I never have done. I don't, unfortunately, have an accurate RF voltmeter, but I do have an Elecraft DL1 and a DVM.

At 1mW requested power I measured 36mV at the DL1 test point, which according to the formula (.036 x 1.414) + 0.15)^2 / 50 means I am only getting 0.8mW out. Is it OK to use the DL1 and this formula at this power level?

[Jon Kåre Hellan]

Julian, G4ILO wrote:

> I was wondering why my 2m transverter was producing much less output than
> when I set it up, so I thought that perhaps I should do the 1 Milliwatt
> calibration procedure, which I never have done. I don't, unfortunately, have
> an accurate RF voltmeter, but I do have an Elecraft DL1 and a DVM.
>
> At 1mW requested power I measured 36mV at the DL1 test point, which
> according to the formula (.036 x 1.414) + 0.15)^2 / 50 means I am only
> getting 0.8mW out. Is it OK to use the DL1 and this formula at this power
> level?
>

The formula assumes a constant 150 mV voltage drop across the diode, i.e. that it is conducting during
a half cycle. At the level you are measuring, things are more complicated. So I wouldn't rely
on the formula.

Things you could do:

1. Make an amplifier, and calibrate it.
2. Borrow a scope to make the measurement. You probably have to do this in order to do (1), as well.
3. Make a computer model in spice, and tweak until you get the the measured voltage. Spice wasn't
   around when I was studying circuits, but the DL1 looks simple enough to be a great case for
   learning it.

73
Jon LA4RT
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[Jon Kåre Hellan]

Does anything bad happen if you use lead based solder to service RoHS compliant boards, like
the K3?

Apart from turning the board into future toxic waste, that is :-)

73
Jon LA4RT
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[M0XDF]

The PC police come and take you away!
:-)
73 de M0XDF, K3 #174
--
Two things are infinite, the universe and human stupidity.
But I'm not so sure about the universe. -- Albert Einstein.



On 21 Apr 2010, at 12:17, Jon K Hellan wrote:

> Does anything bad happen if you use lead based solder to service RoHS compliant boards, like
> the K3?
>
> Apart from turning the board into future toxic waste, that is :-)
>
> 73
> Jon LA4RT

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[Gary Hvizdak]

On Wed Apr 21 at 0717 EDT Jon Hellan (LA4RT) wrote ...

Does anything bad happen if you use lead based solder to service RoHS
compliant boards, like the K3?

--

Jon,

    Unless you have the proper equipment (special tips for example) and
training to use lead-free solder, then leaded solder is actually preferred.
Most importantly the leaded solder will likely result in more reliable
joints/connections.

73,
Gary  KI4GGX

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[David Honey]

At 13:19 21/04/2010, David Ferrington, M0XDF wrote:
>The PC police come and take you away!
>:-)
>73 de M0XDF, K3 #174

Should that be the PCB police? :-)


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