Thanks, Don, you are great in explaining the figures in layman terms. While I
cannot control the other's transmitters' IMD / phase noise, I now at least know
what I will expect to be better off by using the KSYN3A especially under very
difficult RX conditions (assuming everything under the same conditions as the
current KSYN3).
TNX,
Johnny VR2XMC
寄件人︰ Don Wilhelm <w3...@embarqmail.com>
收件人︰ Johnny Siu <vr2...@yahoo.com.hk>; Elecraft Reflector
<elecraft@mailman.qth.net>
傳送日期︰ 2015年02月14日 (週六) 8:44 AM
主題︰ Re: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)
Johnny,
Hopefully I can simplify it a bit given your example.
That S9+60dB signal will have a weaker response in your receiver *if*
your receiver was the limiting factor. If the transmitter phase noise
(splatter and other 'bad stuff' was the original problem, then you may
or may not have any improvement for that example.
In other words, you will notice an improvement if other signals on the
band are relatively clean. The improvement when other signals on the
band are not clean will not be as obvious.
Actually if an S9+60dB signal 10 kHz away is going to give you problems,
then that signal is coming from a 'dirty transmitter'. I think a better
example would be -- If you can operate within 2 kHz of a strong signal
with the current KSYN3, then the KSYN3A may be able to allow you to
operate within 1.5 to 1.8 kHz of that same signal. In other words, you
will be able to "saddle up closer" to any signal unless the transmitter
is creating trash.
Note: All numbers are for relative comparison only. I pulled those
numbers out of my head for illustration purposes only and do not
represent any test data. I have not seen nor used the KSYN3A.
73,
Don W3FPR
On 2/13/2015 7:19 PM, Johnny Siu wrote:
> I must admit that understanding those figures are beyond my knowledge. In
> practical terms, if I can now hear a below S1 cw weak signal 10KHz away from
> a S9+60db station before upgrade, what will be the improvement after the
> installation of KSYN3A assuming operating under the same condition?
> Such a demonstation was given to me when I visited Icom HQ in Osaka last year
> in the announcement of the IC7850/IC7851. Again, IC7850 is known foir
> extremely low phase noise.
> Can any elecrafters interpret the improvements in an understandable layman
> terms?
> 73
> Johnny VR2XMCK-Line + KX3 + HR50
> 寄件人︰ Wayne Burdick <n...@elecraft.com>
> 收件人︰ Elecraft Reflector <elecraft@mailman.qth.net>
> 副本(CC)︰ "elecraft...@yahoogroups.com" <elecraft...@yahoogroups.com>
> 傳送日期︰ 2015年02月14日 (週六) 7:34 AM
> 主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)
>
> Hi all,
>
> I've updated the KSYN3A FAQ with the following information regarding testing
> of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.
>
> * * *
>
> Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using
> the new synthesizer?
>
> A: Our tests show in excess of 105 dB with the narrowest filters, though
> there are many factors, and this should be considered approximate. (A very
> robust test setup is required to make these measurements.) Rob Sherwood
> tested a K3 with a KSYN3A and obtained the following results:
>
> 2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
> 2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB
>
> Rob will be posting this information in his receiver performance chart
> (http://www.sherweng.com/table.html) after he completes his full suite of
> tests.
>
> * * *
>
> The above numbers were used with Rob's permission.
>
> 73,
> Wayne
> N6KR
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
