<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV id=yiv1429317426>Preamp is on because my RX does not function with it off. <BR><BR>--- On <B>Sat, 12/27/08, Richard Stasiak <I><rstasiak@sympatico.ca></I></B> wrote:<BR>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(16,16,255) 2px solid">From: Richard Stasiak <rstasiak@sympatico.ca><BR>Subject: Re: [hpsdr] MERCURY<BR>To: carcia@sbcglobal.net<BR>Date: Saturday, December 27, 2008, 9:16 PM<BR><BR>
<DIV id=yiv1521593757>Hi Francis
<DIV><BR></DIV>
<DIV>I only have one signal generator so I can't test the 20 khz test. Did you have the preamp on?</DIV>
<DIV><BR></DIV>
<DIV>Rick</DIV>
<DIV><BR>
<DIV>
<DIV>On 27-Dec-08, at 9:08 PM, FRANCIS CARCIA wrote:</DIV><BR class=Apple-interchange-newline>
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<DIV>well pretty quiet on 160 so far tonight so ran some quick numbers. First I don't trust my numbers unless they are the same three times. Also rough readings may be off a couple dB. </DIV>
<DIV>1. MDS on 75M about -136 with 500 Hz filter iin CW mode. Noise floor about -140 dBM.</DIV>
<DIV>2. Two tone dynamic range two signals 3.870 and 3.890 MHz.</DIV>
<DIV> Spur comes out of the noise floor when both signals hit -80 dBM so pretty crappy</DIV>
<DIV> around 60 db dynamic range. I notice weird effect so run levels higher. When both </DIV>
<DIV> Run up to -27 dBM spur at -121 dBM (approx 94 dB)</DIV>
<DIV>3. Then I selected "dither enabled" Spur now comes out of the noise floor at about -65 dBM</DIV>
<DIV> so about 70 dB dynamic range. At -30 dBM signals spur is at -120 dBM </DIV>
<DIV> (about 90 dB dynamic range)</DIV>
<DIV>4. Now I also turn on "random enabled" With both signals at -40 dBM the spur is in the </DIV>
<DIV> noise. I then increased the signals to -25 dBM bringing the spur up to -130 dBM.</DIV>
<DIV> (dynamic range 105 dB)</DIV>
<DIV>Test configuration 2 HP8640B generators with the same HB combiner I've been using for 30</DIV>
<DIV>years. 6 db pads on all three ports. </DIV>
<DIV>Yup, this looks interesting guys. </DIV>
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<DIV> </DIV>
<DIV> </DIV>
<DIV>--- On <B>Sat, 12/27/08, Richard Stasiak <I><<A href="mailto:rstasiak@sympatico.ca" target=_blank rel=nofollow>rstasiak@sympatico.ca</A>></I></B> wrote:<BR></DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(16,16,255) 2px solid">From: Richard Stasiak <<A href="mailto:rstasiak@sympatico.ca" target=_blank rel=nofollow>rstasiak@sympatico.ca</A>><BR>Subject: Re: [hpsdr] MERCURY<BR>To: "Graham / KE9H" <<A href="mailto:KE9H@austin.rr.com" target=_blank rel=nofollow>KE9H@austin.rr.com</A>><BR>Cc: "Jerry Flanders" <<A href="mailto:jeflanders@comcast.net" target=_blank rel=nofollow>jeflanders@comcast.net</A>>, <A href="mailto:hpsdr@lists.hpsdr.org" target=_blank rel=nofollow>hpsdr@lists.hpsdr.org</A>, <A href="mailto:carcia@sbcglobal.net" target=_blank rel=nofollow>carcia@sbcglobal.net</A><BR>Date: Saturday, December 27, 2008, 7:16 PM<BR><BR><PRE>>>
>> Do we need filters on Mercury to attenuate unwanted
>> "subharmonic" (or whatever it is called) responses?
> It depends what your antenna system is feeding to Mercury. I am
> running it
> without input filter on a low multi-band dipole, and it generally
> works just fine.
> It is a pretty robust receiver, barefoot.
> If you are close to a broadcast transmitter location, or you have a
> high
> wideband antenna, your results might be different.
I have had just a few hours with Mercury now (barebones card, no input
filters) with various antennas. I am amazed at its capabilities. On
160m it blows the socks off my SDR1000....... don't even need to
switch on the bci filter.
Mercury is a keeper!
Need to interface that 100w amp I have been saving, to get this rig on
the air.
73
Rick ve3mm
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