Thank you for posting this, Wally. Have fun with your new radio!
Just to clear up some confusion, if there were stations at 7.033 and 7.037 (4
kHz apart) they would have generated third-order products at 7.029 and 7.041,
not at 7.035 where you were listening. So yours was a test of the *blocking*
(not IM) dynamic range.
Assuming S9 = [50 uV in 50 ohms] = -73 dBm, if the two blockers were each at S9
+ 60 dB that is (very roughly) -13 dBm each. Two such blockers would be double
that power or -10 dBm.
The S5 signal you were listening to was very roughly at -97 dBm ( 4 S-Units or
24 dB below S9). So it would only take about 87 dB of blocking dynamic range to
handle the situation which is well within the capabilities of most modern
receivers.
Regards,
Al W6LX
-----Original Message-----
From: cq-contest-bounces@contesting.com
[mailto:cq-contest-bounces@contesting.com] On Behalf Of wally
Sent: Saturday, November 13, 2010 2:02 AM
To: cq-contest@contesting.com
Subject: [CQ-Contest] TS590S from contesting point of view
Here is the info abt the test I have made this morning with my new TS590S :
I had my neighbours LZ2CF and LZ2TW transmitting 2 Khz apart on both sides (
7.033 and 7.037 ) from 7.035 where LZ1PM was emitting a CW sig with S5
strenght (559 ) LZ1PM is app. 250 km away from my QTH. Both LZ2CF and LZ2TW
were 599 + 60 db.
With Preamp. off, AGC off and DSP filter at 500 Hz I was able to copy LZ1PM
just fine with negligible IMD from CF and TW. Turned DSP to 300Hz and I was
able to copy LZ1PM with NO ANY interference from two 599+60db signals just 2
Khz apart on both sides of 7.035 !!! ( signals strenght was measured with AGC
set to "fast")
Hope that info helps contesters with relatively limited budget.
73, de Wally LZ2CJ
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