[Moon] EME Conference 2014 Pleumeur-Bodou

Edward R Cole kl7uw at acsalaska.net
Tue Sep 30 19:01:29 CEST 2014


Just reading the mail - no agenda!

But I am curious why Elecraft K3 is not included in this study?  As I 
have read from Sherwood Labs analysis the K3 transmitter comes out at 
top or near the top with clean output.  On VHF/UHF/mw of course the 
transverter LO must be considered for the output mix.  But having a 
good IF signal to start with certainly is an advantage.

I do not suffer the RF environmental density of central EU and have 
no other 144 eme stations to interfere with, at present.  On 1296 
there may be a couple stations within terrestrial range in some 
azimuth settings.

73, Ed - KL7UW
PS: the K3 is a dual conversion SDR.

At 05:56 AM 9/30/2014, Leif Asbrink wrote:
>Hello Matej,
>
>I have read your page about the meeting:
> > http://www.ok2kkw.com/00003016/eme2014/eme2014bodou_eng.htm
>
>Unfortunately your text in unclear on a couple of points.
>This is what you have published:
>"I had the opportunity to had talk with a well-known Leif, SM5BSZ
>and I must say that we liked it because both of us we agreed in
>opinions about some technical lectures - for example some aspects
>of HB9DRI's presentation of the usage of SDR for TX purposes.
>Due to my opinion Alex has little bit too much business look on
>this matter and some of his specific technical conclusions we found,
>let's say as a little bit too optimistic. Particularly VHF contest
>operation in Central EU has it's own specific technical categories
>and optimism are not in place. Then we talked about the problems
>with VHF contests in Central Europe, fighting with phase noise,
>IF crystal filtering in transverter and discussed contesting on
>VHF during 70's of last century."
>
>1) We both agree that commercially available ham transmitters do
>not have the spectral purity required for  VHF contest operation
>in Central EU, but I do not agree with you that Alex has little
>bit too much business look on this matter. You may have told me
>your opinion and I may not have told you I do not agree. Facts
>speak for themselves, here is measured sideband noise from a
>steady carrier on 144 MHz from unmodified transmitters:
>
>Model         Sideband noise            Reference
>            20kHz       100kHz
>           (dBc/Hz)    (dBc/Hz)
>R2-CW       -136        -139 
>http://www.sm5bsz.com/dynrange/annaboda/annaboda.htm
>TS780       -133        -140 
>http://www.sm5bsz.com/dynrange/annaboda/annaboda.htm
>TR9130      -132          ? 
>http://www.sm5bsz.com/dynrange/vhf2004/vhf2004.htm
>IC275       -130        -144 
>http://www.sm5bsz.com/dynrange/annaboda/annaboda.htm
>IQ+TX       -129        -132  Page 140 EME2014 proceedings
>FT736       -127          ? 
>http://www.sm5bsz.com/dynrange/eme2004/eme2004.htm
>TS711E      -126          ? 
>http://www.sm5bsz.com/dynrange/ssa2004/ssa2004.htm
>IC970H      -122        -132 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_IC970H
>TM255       -122        -125 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_TM255
>TS2000      -122          ? 
>http://www.sm5bsz.com/dynrange/eme2004/eme2004.htm
>IC7000      -122          ? 
>http://www.sm5bsz.com/dynrange/ssa2007/ssa2007.htm
>FT857       -120          ? 
>http://www.sm5bsz.com/dynrange/vhf2004/vhf2004.htm
>FT100       -119        -129 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_FT100
>IC746       -118          ?   http://www.sm5bsz.com/dynrange/rs05/rs05.htm
>IC706MKIIG  -117        -125 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_IC706MKIIG
>FT817       -117        -130 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_FT817
>FT847       -115        -130 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_FT847
>IC910       -114          ? 
>http://www.sm5bsz.com/dynrange/vhf2004/vhf2004.htm
>IC-821H     -113        -128 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_IC821H
>IC-706      -108        -125 
>http://www.sm5bsz.com/dynrange/rig_compare.htm#144_IC706
>
>Note that the IQ+TX is number 5 from the top on this list of 20 commercial
>transceivers. More importantly, most of the transceivers produce strong
>splatter and keying clicks when modulated. I am pretty sure the IQ+ 
>does not have
>any such problems. The IQ+TX has a bandwidth limiting filter after the D/A.
>
>Alex claims that the IQ+TX outperforms by 10 dB most of the commercial
>144 MHz transceivers. Correct would be to say  that the IQ+TX outperforms
>by 10 dB about 50% of the commercial 144 MHz transceivers on sideband
>noise on an unmodulated carrier and all of them in modulated modes.
>
>Dear Matej, please rephrase what you wrote in such a way that people
>do not get the opinion that I think like you on the bussines aspect
>of the presentation Alex did at the meeting. The fact that the IQ+TX
>is one of the better commercially available products does not (by far)
>make it good enough for VHF contest operation in Central EU. We agree
>on that - but not on what Alex presented which as far as I can judge
>was well motivated.
>
>I would also appreciate a link to information about IF crystal filtering
>in transverters. I would like to point people like ARRL Lab to that.
>They have measured horrible performance on Flex products without
>giving the appropriate information that those products have a serious
>design error. The situation in the US is quite different. They do
>not have the needs for dynamic range that we have in EU...
>
>73
>
>Leif
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73, Ed - KL7UW
http://www.kl7uw.com
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