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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Ray<o:p></o:p></span></font></p>
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10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>By the way thanks for the updates to the
Wiki today.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Eric<o:p></o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> hpsdr-bounces@hpsdr.org
[mailto:hpsdr-bounces@hpsdr.org] <b><span style='font-weight:bold'>On Behalf Of
</span></b>Ray Anderson<br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, July 24, 2006 4:44
PM<br>
<b><span style='font-weight:bold'>To:</span></b> hpsdr@hpsdr.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [hpsdr] Proposal for
a 'low-end' RX/TX board for HPSDR</span></font><o:p></o:p></p>
</div>
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10.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>> I can see the argument for the front end LNA at 10 meters (or
maybe even<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>> 15 meters), but on the bands below that I think it may
actually be a<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>> liability unless you have an extraordinarily high IP3 for the
preamp.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>> While this can be done it comes at the expense of quite a
bit of DC<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>> current. This may not be a big deal but is something to be
considered.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>Typicaly the LNA will take 60-80mA. Compared to what will disappear
on tx<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>it pretty insignificant. One advantage of some amplification will
be to <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>lift rx noise floor compared to the spurs and sprogs from the LO
and DIG <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>inside the enclosure!<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>Ulrich suggested I think the BFG591 as a SMD alternative to the
2N5109 for<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>mixers and amp. Maybe the part would go well either in a Norton<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>configuration or the Mahkinson (N6NWP) MRF586 push pull pre-amp.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 face="Courier New"><span style='font-size:
10.0pt'>>Shel CT1IZU<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
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style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>Shel-<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>Good comments. Upon further consideration
I tend to agree with you. <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>The performance of a QSD can also be improved
by including a diplexer between the BPF and the QSD to properly terminate the
QSD input out of band. By utilizing the preamp the noise figure at higher
frequencies is improved and the QSD also sees a constant termination impedance
across a wide band since the amp exhibits 50 ohm input and output Z.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>I’ve recently placed a schematic of
a typical Norton amp on the Phoenix Wiki page. The schematic shows feedback
turn s ratios set up for about 9.5 dB gain. Can anyone comment on what
attributes the Makhinson (N6NWP) circuit (which is essentially a pair of Norton
amps in push-pull) brings to the table that would make it preferable over the
Norton amp in this application.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>Does anyone have some target figures
regarding performance that we should aspire to obtain? I think an IP3 of +40dBm
with a dynamic range of at least 100 dB and a noise floor in the vicinity of
-130 to -140 dbm are in the ballpark for state-of-the-art HF front ends these
days.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>I’m currently evaluating various options
as far as preamps, QSD circuits, filtering etc. are concerned. If anyone has
any favorite implementations that may be appropriate to <st1:place w:st="on"><st1:City
w:st="on">Phoenix</st1:City></st1:place> I’d like to see them during
this evaluation phase.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>73, Ray WB6TPU<o:p></o:p></span></font></p>
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