[Elecraft] 6M Preamp

[Joe Subich, W4TV]

> I'm not saying that performance on six meters should have 
> been higher than the performance on the HF bands. I'm saying 
> that it should not be worse than an IC-756 PRO III, a TS-2000 
> or an FT-2000 would be, considering the claims made about the 
> K3's performance.

No, you are asking for a lower MDS than on HF without regard to 
the overall performance of the radio in terms of dynamic range. 
There are many K3 users who rely on dynamic range and freedom 
from interference on HF that blows away any of the radios you 
list.  Even on six meters they K3 dynamic range far exceeds that 
of the YaeComWood radios you cite.  

Above all, your information concerning sensitivity is just plain 
wrong.  The ARRL Lab data shows the FT-2000 sensitivity (MDS) on 
50 MHz (preamp off) at -122 dBm ... and measures the K3 MDS at 
-128 dBm (preamp off).  Similarly, with "preamp 1" the FT-2000 
measured at -131 dBm vs. -135 dBm for the K3 (internal preamp). 
If you want to compare the TS-2000, its MDS (preamp off) is -127 
dBm rising to -142 dBm with preamp on but with a dynamic range 
of only 66dB (worse than a 30 year old FT-101!).  To complete 
your comparisons, the Icom has the same -136 dBm MDS with 
"preamp 1" and a dynamic range of only 74 dB.  I would say 
that Eric and Wayne made exactly the right design decisions 
with a -136 dBm MDS and 100 dB dynamic range. 

Yes, the K3's MDS is slightly worse on 50 MHz than on 14 MHz 
due to the additional filtering in the front end.  However, even 
with a lousy vertical antenna, my receiver noise always increases 
by at least 2 dB when switching from a dummy load to the antenna. 
A second higher gain, preamplifier would be of no value to the 
vast majority of K3 users ... in fact it would likely be counter-
productive as it would harm the excellent dynamic range of the 
radio.  Why should those who have no need for the ultra high 
sensitivity on a band they rarely use subsidize performance that 
benefits only a limited few?  




> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Julian, G4ILO
> Sent: Thursday, October 23, 2008 2:52 PM
> To: elecraft at mailman.qth.net
> Subject: RE: [Elecraft] 6M Preamp
> 
> 
> 
> 
> 
> Joe Subich, W4TV-3 wrote:
> > 
> > I don't know that you can say performance on six meters should
> > have been higher than the performance on the HF bands.  There 
> > are probably more K3 users who will never use six meters in any 
> > serious way than those who will.  However, the Elecraft preamp 
> > does represent a substantial premium for RX Loop pass-through and 
> > ease of integration.  Whether the premium is justified is a 
> > decision for the user and the option allows those who need it 
> > to get the performance without taxing those who will never benefit 
> > from it. 
> > 
> I'm not saying that performance on six meters should have 
> been higher than the performance on the HF bands. I'm saying 
> that it should not be worse than an IC-756 PRO III, a TS-2000 
> or an FT-2000 would be, considering the claims made about the 
> K3's performance.
> 
> I have no idea of the proportion of K3 users who will never 
> use 6 meters in any serious way. However I think there are 
> quite a few, such as myself, who will have some fun on the 
> band from time to time simply because modern HF transceivers 
> now include it. I'm certainly not serious enough about 6m to 
> spend money on a preamp for it, so I'm feeling a little 
> short-changed after receiving information that the K3 is so 
> deaf on 6m that you need one. The other radios mentioned 
> above certainly are usable on 6m without a preamp by all but 
> the most diehard enthusiast who would probably want it at the 
> masthead anyway.
> 
> -----
> Julian, G4ILO. K2 #392  K3 #222.
> http://www.g4ilo.com/ G4ILO's Shack   
> http://www.ham-directory.com/ Ham
> Directory    http://www.g4ilo.com/kcomm.html KComm for 
> Elecraft K2 and K3 
> -- 
> View this message in context: 
> http://n2.nabble.com/6M-Preamp-tp1366337p1369367.html
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> 
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