K3 and Perseus SDR as a 2nd RX

[Bob DeHaney]

It looks very good, but the "Gotcha" is that it costs EURO 800 or $1040.00
including tax at the dealer here in Germany.  As near as I can tell that's
double the cost of the K3 2nd receiver.

Vy 73, Bob DJ0MBC/WU5T

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[Bill W4ZV]

Bob DeHaney wrote

It looks very good, but the "Gotcha" is that it costs EURO 800 or $1040.00
including tax at the dealer here in Germany.  As near as I can tell that's
double the cost of the K3 2nd receiver.

Also be aware that Blocking Dynamic Range (BDR) for the Perseus is relatively poor, as is true for all current SDRs.  BDR is 99 dB at 2 kHz and 117 dB at 20 kHz versus 139 dB for both 2 and 20 kHz, per ARRL Product Reviews.  If you have strong neighbors (either commercial or amateur stations), the Perseus will need additional filtering to prevent strong signals from overloading the front-end.

73,  Bill  W4ZV

[SSB Electronic USA]

On November 16 Bill W4ZV wrote:
>
> Also be aware that Blocking Dynamic Range (BDR) for the Perseus is
> relatively poor, as is true for all current SDRs.  BDR is 99 dB at 2 kHz
> and
> 117 dB at 20 kHz versus 139 dB for both 2 and 20 kHz, per ARRL Product
> Reviews.  If you have strong neighbors (either commercial or amateur
> stations), the Perseus will need additional filtering to prevent strong
> signals from overloading the front-end.

There is no need for additional filtering since the Perseus has 9 six pole
front-end bandpass filters (1.7 - 30 MHz.) plus a 3 pole low pass for 10
kHz. - 1.7 MHz.)

Today, SSB Electronic USA received an email from the ARRL acknowledging that
errors were made in the measurement of the Perseus SDR.

Over the past year, extensive measurements have been conducted not only by
Nico Palermo IV3NWV at Microtelecom but by Lief Asbrink SM5BSZ and Rob
Sherwood NC0B.
The Blocking Dynamic Range (BDR) numbers measured by all of the above were
much better (125 dB)  than the figures that were published by the League.
In addition, the IMD Dynamic Range figures published in QST reflect
differences at various spacings.  In an SDR such as the Perseus, the IMD
Dynamic Range will be the same at 2 kHz, 5 kHz. or 20 kHz.

The ARRL is currently in the process of taking another look and they should
be commended for doing so.  I am sure updated figures will be published in
the near future.

Please don't accuse me of being biased just because I am the US Perseus
distributor.  I also own a K3 s/n 1519 as well as a Perseus.   Both are
great radio's.

I would like to commend Eric and Wayne at Elecraft, Nico at Microtelecom as
well as Phil Covington for their contributions to receiver design and ham
radio and ..... last but not least the ARRL and Rob Sherwood for all the
reviews and measurements that give us something to think about and discuss
when we're not playing radio.

73's
Gerry Rodski K3MKZ
SSB Electronic USA




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[dj7mgq]

Hi Gerry,

> There is no need for additional filtering since the Perseus has 9 six
> pole front-end bandpass filters (1.7 - 30 MHz.) plus a 3 pole low pass
> for 10 kHz. - 1.7 MHz.)

I hope you don't mind my being at slightly sceptical that a low pass
filter is enough for serious LW/MW work. If one has a medium wave or
long wave broadcast stations in the vicinity, then additional filtering
will almost surely be needed.

Also it will be interesting to read how well the IMD behavior of the SW
front end filters themselves in such a small enclosure is. Small sized
toroids can, from what I know, be a weak point in a receiver with high
dynamic range.

 From what I've heard radios such as the Perseus appear indeed to be
very interesting but as always, a new technology, like good wine, needs
time to mature.

vy 73 de toby


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[SSB Electronic USA]

----- Original Message -----
Toby Deinhardt wrote:

>
> I hope you don't mind my being at slightly sceptical that a low pass
> filter is enough for serious LW/MW work. If one has a medium wave or long
> wave broadcast stations in the vicinity, then additional filtering will
> almost surely be needed.

Hi Toby,
My statement was meant as a general reply regarding the filtering on the
front end of the Perseus in view of the fact that the original post was
referring to erroneous Blocking Dynamic Range numbers and stating that
additional filtering would be required.  Since I knew for weeks that the
figures that were published were not correct, I was merely pointing out that
the Perseus does contain excellent preselector filters.

I have been monitoring the Perseus reflector for approximately 8 months and the Perseus has become the receiver of choice for serious LW/MW listeners.
I have not seen one comment  regarding additional filtering being required in any situation.  Believe me, the LW/MW DX'ers are just as passionate about their hobby as we are about Ham Radio.  With the Perseus's ability to display in real time and record 1600 kHz at one time and then play it back and tune through the recorded B/W as if it was happening in real time, I'm sure these guys have gained many hours of needed sleep.  You may want to check out the Perseus reflector on Yahoo to get a feel for what is happening in the Perseus world.
http://groups.yahoo.com/group/perseus_SDR/   as well as Guy Atkins site Five Below MW and Tropical band DXing with the Perseus
http://perseus-sdr.blogspot.com/.

> Also it will be interesting to read how well the IMD behavior of the SW
> front end filters themselves in such a small enclosure is. Small sized
> toroids can, from what I know, be a weak point in a receiver with high
> dynamic range.
I will let the above comment for the experts since I surely am not one of
them.
>
> >From what I've heard radios such as the Perseus appear indeed to be very
> interesting but as always, a new technology, like good wine, needs time to
> mature.
With over 1,000+ Perseus's now in use world wide, I think it has come along quite nicely.  Like the K3, the Perseus is an ever evolving work of art.

BTW since this originally started out as using a Perseus as a 2nd receiver.
I have used the Perseus as a 2nd receiver and also as an IF band scope with the K3.  For me, it's a good combination.

As I said previously, I own both a Perseus and a K3 and respect the great accomplishments that have been made by Elecraft, Nico at Microtelecom, Flex Radio, Phil Covington, Ten-Tec and the guys who started us over 11 years ago down a new path ......Kachina.    If I missed anyone, please accept my
apologies.

73
Gerry   K3MKZ

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