[Elecraft] Bigger K3 S-meter

Joe Subich, W4TV lists at microham-usa.com
Fri Oct 31 18:31:52 EST 2008 

If you want a test instrument, purchase a test instrument 
and don't load up the cost of the K3 for all of the other 
users.  The K3 S-meter is one of the most accurate and 
linear meters of any transceiver - particularly if the 
K3 Smeter is configured for absolute mode.  Resolution 
better than 5/6 dB per step is better left to an SDR 
solution like SDR-IQ or LP-PAN.  

> Most people  would not buy any piece of test equipment 
> with 300% inaccuracy. 

Where is the 300% inaccuracy?  When calibrated according 
to the instructions, the K3 Smeter works out to about 
4.5 dB per unit (50 uV at S9, 1 uV at S2 => 34 dB/8). 
That makes the maximum "offset" in the middle of a step 
30% - not 300%. 

If you need better resolution than that - buy a spectrum 
analyzer. 

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Craig
> Sent: Friday, October 31, 2008 5:08 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Bigger K3 S-meter
> 
> 
> 
> Hi Guy
> 
> It seems that the consensus is that a pretty innacurate S-meter is ok.
> 
> I dont know why everything related to ham radio has to be 
> reduced to the bare minimum or  be in the totally useless 
> category. Not everyone's ham radio life revolves around  
> giving out cookie cutter signal reports. 
> 
> Most people  would not buy any piece of test equipment with  
> 300% inaccuracy. I could just imagine all the shouting if 
> power meters had   a tolerance of +- 200% or likewise VSWR 
> meter.  S meters should be no different. 
> 
> A calibrated S meter could be useful tool in many other ways.
> 
> - Measuring  field strength and patterns of antennas.
> 
> - Reporting on things like BPL and other radiated and 
> conducted measurements that seem to be a daily threat on HF. 
> Just knowing they close to  S9 plus plus minus 20 db is not a 
> professional way to build an argument against such pollution 
> in professional circles. Having a calibrated S meter  and 
> adding something a like calibrated loop with a known antenna 
> factor would make collecting and surveying potential RF 
> pollution data very easy. While we don't need 0.1 db accuracy 
> 1 db of accuracy is easily achieved in SDR radios.
> 
> http://www.vk1od.net/bpl/QueanbeyanBplTrial2.htm
> 
> - Using a good S-meter would also be a reliable  way of 
> surveying a potential new QTH. The data could be used to 
> compare signal noise levels to the thermal noise floor, or 
> even compare what you are measuring to the surveyed ITU noise 
> levels on HF.  It would be nice knowing that your potential 
> new QTH  is in a QRM silent location. It would also be good 
> comparing noise floors amongst hams for various locations.
> 
> - It would also be useful knowing how accurate and reliable 
> propagation programs are on a daily basis since they do 
> predict signal levels.  This might come in handy if one 
> wanted to build a DSP  based DF system which relies on 
> ionospheric data.
> 
> - As a general level meter around the shack, it could even be 
> used as an accurate power meter.
> 
> So to me a well calibrated S-meter can take  the place of 
> many expensive instruments that most hams dont have access to 
> on a daily basis. It is a very useful tool. When  we use some 
> sort of absolute reference our understanding of what we are  
> measuring on a daily basis  increases our understanding of 
> what we are doing in our hobby.
> 
> While we on this subject if further work is carried out on 
> the K3's s-meter  you might as  well follow the IARU's 
> recommendation for S-meters and make it quasi peak in nature.
> 
> Besides these days, with the  competition increasing in the 
> new radio market with radios like the Perseus, ADAT and the 
> newly released cheap Flexradio models, all which offer a very 
> accurate S-meters as a feature. It would do no harm to the 
> K3's reputation  having a feature that some consider 
> desirable, that's marketing not  rocket science.
> 
> 
> 73
> Craig
> 
> --- On Fri, 10/31/08, Guy, K2AV <olinger at bellsouth.net> wrote:
> 
> > From: Guy, K2AV <olinger at bellsouth.net>
> > Subject: Re: [Elecraft] Bigger K3 S-meter
> > To: elecraft at mailman.qth.net
> > Date: Friday, October 31, 2008, 12:05 PM
> > I would just like to see signal strength, including noise,
> > in absolute
> > reference levels. In particular when listening to a local while 
> > turning a beam kind of thing.  Although that can be done relatively
> > with the audio
> > voltage level, it wouldn't allow me to tell a local
> > that his ground wave
> > signal has gone down 3 db and is staying there, or be able
> > to create data
> > for studies over time.  
> > 
> > Since it is an SDW, such is possible.  dBuv is fine.  Might need 
> > linearity points as part of the package which could be calibrated
> > with a precision
> > attenuator. 
> > 
> > 
> > Changing the functionality of the BG or SM commands so they could 
> > provide greater resolution *would* break software, which is what I
> > was saying. But
> > while I can see that having software access to the dBm
> > reading could be
> > useful for antenna measurement purposes, given the vagaries
> > of propagation I
> > would have thought that a 1 S-unit resolution was perfectly
> > adequate for
> > normal purposes. I cannot see how it would be more useful
> > to be told I am
> > S6.5 rather than S6 or S7, or even S5 or S8! Whatever the
> > reading is it is
> > going to be different 20 seconds later anyway.
> > 
> > 
> > --
> > View this message in context:
> > http://n2.nabble.com/Bigger-K3-S-meter-tp1399030p1437492.html
> > Sent from the Elecraft mailing list archive at Nabble.com.
> > 
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