[Elecraft] Fw: K3/K144XV/P3 Signal Strength Readings

[Geoffrey Downs]

Very interesting, Brett, and thank you for your comments and the research 
you have done. I *was* beginning to feel a little isolated by lack of 
comment from anyone hihi! Although I did receive one reply offlist reporting 
experience similiar to mine.

I was not aware of the 1990 Torremolinos recommendation as such but a recent 
thread here on the reflector 
http://mailman.qth.net/pipermail/elecraft/2011-January/143651.html noted the 
ambiguity about 6m and Alan Bloom of Elecraft concluded that it was 
generally accepted that it should be treated as in the -93dbm category like 
2m. However, you are correct to point out that it is a Region 1 (ie EU) 
recommendation and I have not been able find out whether or not there are 
similar or different recommendations for Regions 2 and 3.

Compared with my FT847 (another rig that straddles the -73/-93dbm boundary) 
the S meter on the K144XV/K3 reads low on 2m and there have been a number of 
postings on the reflector from at least two of the IARU regions, if not all 
three, by people who feel that at present it reads low compared with what 
they are used to on other rigs. This suggests to me that other commercial 
rigs for 2m do use the -93dbm standard - as the P3 now does. Unfortunately I 
do not have any test gear that will produce a known 50 microvolts or 5 
microvolts on 2m to do some checking. I accept that this doesn't seem to 
accord with your findings on your rig, Brett, if I properly understand them. 
As general comment, though, the rig doesn't seem to show enough difference 
in db between S1 and S9 on the bands you mention.

Things were not always how they are now. When the K144XV first came out the 
S meter registered too high and a firmware change reduced it, but perhaps 
the correction was overdone? I would certainly like the P3 and the K144XV/K3 
to agree on signal strength indication on 2m.

Elecraft or anyone care to comment?

73 to all

Geoff
G3UCK


----- Original Message ----- 
From: "VR2BrettGraham" <vr2bg at harts.org.hk>


>A lonely G3UCK said, seemingly talking to himself:
>
>
> I have wondered about this IARU R1 Recommendation about S-meters.  In
> order to comply, it means transverters have to be 20 dB hotter on the
> output for the same input signal level, as the transverter is usually
> used with a radio where S9 is -73 dBm & not -93 dBm.
> ...........
 A quick check of one
> such reasonably current product from one of The Big Three I own that I
> do not recall acting like it complies with the Recommendation shows that
> indeed, it does not.  It is has one of these new-fangled "light bulb"
> S-meters, where S1 is set to light up at different levels on 70cm, 2m,
> 6m, 10/20m & 80m (total spread between them: 9 dB).  S9 is set to 31,
> 31, 28, 25 & 22 dB above S1 on those bands, respectively.  From S9 to
> S9+60 is 60 dB.
>
..............
> > A good Recommendation would make sense on its own - not need a narrative
> & perhaps not one that says what this one does.  A good Recommendation
> would be followed & might also be something that we could look back at &
> see why it was we are told things should be done that way.  This was
> just a quick look, but my impression is that if S-meters are to work
> this way, it should be like an IARU bandplan & apply to just R1.
>
> 73, ex-VR2BG/p.