On Nov 26, 1:01 pm, "Dale Parfitt" wrote:
wrote in message

... Receiver test data from
S = Sherwood
P = Passport
Q = ARRL QST mag

5 KHZ THIRD ORDER INTERCEPT DYNAMIC RANGE

This is one spec. That's like comparing cars soley on the transmission or
engine size. It tells you next to nothing about the receiver's overall
performance.
And for those of us with rotatable, directional antennas and no MW broadcast
stations in the same county, IP3 is probably the least important spec.
Dale W4OP

If you read the PDF file on Sherwood's site discussing the Performance
Chart, he concludes by stating, "You also have to like the operational
aspects of a radio, not just its numbers." I heartily agree. I've
had great performing receivers that were too much of a PITA to enjoy
using, so I ended up not using them, despite the great specs.

wrote in message
...

You are moving now from a superlative SDR-1000 to a much more modest
Perseus, the reason being that it can copy a huge 400 Khz of spectrum
at TOH for later playback, and however modest the specs of the Perseus
might be, this facility is going to get you lots more catches and
positive ID's.

Hi again John,

I would have to disagree that the Perseus is a "much more modest" receiver.
The SDR-IQ would fit that description, but Perseus has +31 dBm IP3 and 125
dBm blocking dynamic range (@ 14 MHz), assisted by a total of 9, 6-pole
bandpass filters and one 3-pole lowpass filter to help achieve this
performance. I know specs don't tell the whole story, but these are very
good to excellent numbers, not modest at all. In fact, the Perseus appears
to be roughly in the same league as the SDR-1000.

In my urban RF location I can use all the receive front end protection I can
get. Other than the SDR-1000, the best receiver here by far for this purpose
have been the two AR7030s I've owned. After some practice I didn't find the
ergonomics of the AORs to be an issue, and much of the time I operated them
via PC through ERGO control, which was even better.

More measurements and details of the Perseus are available he
http://www.microtelecom.it/perseus/ Granted, these are numbers from the
manufacturer himself. I'll be interested to read some independent tests in
the future, such as Sherwood Engineering.

Joe has concerns about outdated PC operating systems in the future, in
regard to SDR radios. I think this is a non-issue. All it means is that it
will be even less expensive to have a computer dedicated solely to operating
the radio down the road. I too am loathe to adopt Vista; fortunately Windows
XP is very usable. A few years down the road you'll be able to buy XP for
around $25-50 or so, just like you can get a Windows98 original disc for
that price now. The 1.0 GHz Pentium III machines selling at my local
computer surplus store for $50 now will be replaced with the likes of
Pentium 4 3.2 GHz PCs or maybe even 1.6 - 1.8 Ghz Core 2 Duos for $75.
Either of these setups will run SDRs OK. Today's "Cadillac" computers are
the old Chevys of tomorrow!

If you're concerned about parts availability, traditional radios from major
manufacturers have their share of orphaned and unavailable ICs and
transistors, too.

It took me a few years to embrace the SDR radio concept, as I've certainly
owned and enjoyed my share of traditional communications receivers.
Personally, I believe that receivers are way down the list of criteria
necessary for DXing success, but I like equipment and technology as much as
catching a new and distant station.

Here's my list of factors needed for hearing the DX, in descending order:

1. Antenna(s) - ya won't hear much without one! Perferably directional
and/or low noise designs.
2. A DXer with skill and experience
3. An RF-quiet environment
4. Luck!
5. The receiver

For me, the biggest advantage of SDRs are two main things: 1) fully
adjustable filters in any width desired, with performance better the
top-notch Collins filters I spent big bucks on over the years, and 2) a
detailed view of the DX being tuned, through spectrum displays or
panadapters. Once you "see" your DX at variable "zoom" levels, it's hard to
go back to a traditional radio! This is an especially neat feature for
split-frequency MW DXing, as you can keep an eye on very weak signals long
before they strengthen and break into audio.

73,

Guy

On Mon, 26 Nov 2007 23:06:39 -0800, Guy Atkins wrote:

wrote in message
...

You are moving now from a superlative SDR-1000 to a much more modest
Perseus, the reason being that it can copy a huge 400 Khz of spectrum
at TOH for later playback, and however modest the specs of the Perseus
might be, this facility is going to get you lots more catches and
positive ID's.

Hi again John,

I would have to disagree that the Perseus is a "much more modest" receiver.
The SDR-IQ would fit that description, but Perseus has +31 dBm IP3 and 125
dBm blocking dynamic range (@ 14 MHz), assisted by a total of 9, 6-pole
bandpass filters and one 3-pole lowpass filter to help achieve this
performance. I know specs don't tell the whole story, but these are very
good to excellent numbers, not modest at all. In fact, the Perseus appears
to be roughly in the same league as the SDR-1000.


Wow!

I just looked at the Perseus, it looks incredible. I was thinking of
getting an SDR-IQ but since I'm in north London, UK, the extra DR of the
Perseus could be useful. However it's more than double the price and I
could pick up a preselector for under £100. So now I can't decide - and
the wife would go nuts if she ever found out I'd spent £600 on "just a
radio"!

Alex

Dear Guy,

Joe has concerns about outdated PC operating systems in the future, in
regard to SDR radios. I think this is a non-issue. All it means is that it
will be even less expensive to have a computer dedicated solely to operating
the radio down the road. I too am loathe to adopt Vista; fortunately Windows
XP is very usable. A few years down the road you'll be able to buy XP for
around $25-50 or so, just like you can get a Windows98 original disc for
that price now. The 1.0 GHz Pentium III machines selling at my local
computer surplus store for $50 now will be replaced with the likes of
Pentium 4 3.2 GHz PCs or maybe even 1.6 - 1.8 Ghz Core 2 Duos for $75.
Either of these setups will run SDRs OK. Today's "Cadillac" computers are
the old Chevys of tomorrow!

I was unaware that one could still buy old operating system discs new.
Do you know of places one can buy them? And can one buy a very
inexpensive (new) notebook computer with no operating system installed
so that one could install an older operating system if desired?

Do any of these SDRs operate with Linux?

I'm still not keen on an SDR (I like a "real" radio on which I can put
my hands, though I have no problems with radios with menu-driven
operating systems) mostly because, at the present time, I do not feel
these SDRs are good value for money. Some of these cost much more than
the computer to which they will be attached and which supplies most of
the processing power! The "guts" inside these SDRs do not, in my
opinion, justify their relatively high prices. But I'm sure that you
and many others here will disagree with me.

Perhaps one of these days someone is going to design an open-source
"radio program" which will do everything these current SDR models do
and, if history is any guide, he/she will put it out on the internet
for free. Maybe you'd just have to buy a USB-compatible connector for
an antenna.

Am I dreaming too much?

Best,

Joe

On Nov 27, 12:36 pm, Joe Analssandrini
wrote:
Dear Guy,

Joe has concerns about outdated PC operating systems in the future, in
regard to SDR radios. I think this is a non-issue. All it means is that it
will be even less expensive to have a computer dedicated solely to operating
the radio down the road. I too am loathe to adopt Vista; fortunately Windows
XP is very usable. A few years down the road you'll be able to buy XP for
around $25-50 or so, just like you can get a Windows98 original disc for
that price now. The 1.0 GHz Pentium III machines selling at my local
computer surplus store for $50 now will be replaced with the likes of
Pentium 4 3.2 GHz PCs or maybe even 1.6 - 1.8 Ghz Core 2 Duos for $75.
Either of these setups will run SDRs OK. Today's "Cadillac" computers are
the old Chevys of tomorrow!

I was unaware that one could still buy old operating system discs new.
Do you know of places one can buy them? And can one buy a very
inexpensive (new) notebook computer with no operating system installed
so that one could install an older operating system if desired?

Do any of these SDRs operate with Linux?

I'm still not keen on an SDR (I like a "real" radio on which I can put
my hands, though I have no problems with radios with menu-driven
operating systems) mostly because, at the present time, I do not feel
these SDRs are good value for money. Some of these cost much more than
the computer to which they will be attached and which supplies most of
the processing power! The "guts" inside these SDRs do not, in my
opinion, justify their relatively high prices. But I'm sure that you
and many others here will disagree with me.

Perhaps one of these days someone is going to design an open-source
"radio program" which will do everything these current SDR models do
and, if history is any guide, he/she will put it out on the internet
for free. Maybe you'd just have to buy a USB-compatible connector for
an antenna.

Am I dreaming too much?

Best,

Joe

JA,

-IF- SDR Radios become like PCs expect that within
4 Years you will be able to buy one at Half-the-Price
with Twice-the-Power. Then within 2 Years you will be
able to buy one at Half-the-Price with Twice-the-Power.

But the 'key' is like "PC"s with a high enough Interest
in them {Consumer Demand for more Freatures} and a large
enough Sales Volume to bring the price down, Down. DOWN !

~ RHF

On Nov 27, 12:36 pm, Joe Analssandrini
wrote:
Dear Guy,

Joe has concerns about outdated PC operating systems in the future, in
regard to SDR radios. I think this is a non-issue. All it means is that it
will be even less expensive to have a computer dedicated solely to operating
the radio down the road. I too am loathe to adopt Vista; fortunately Windows
XP is very usable. A few years down the road you'll be able to buy XP for
around $25-50 or so, just like you can get a Windows98 original disc for
that price now. The 1.0 GHz Pentium III machines selling at my local
computer surplus store for $50 now will be replaced with the likes of
Pentium 4 3.2 GHz PCs or maybe even 1.6 - 1.8 Ghz Core 2 Duos for $75.
Either of these setups will run SDRs OK. Today's "Cadillac" computers are
the old Chevys of tomorrow!

I was unaware that one could still buy old operating system discs new.
Do you know of places one can buy them? And can one buy a very
inexpensive (new) notebook computer with no operating system installed
so that one could install an older operating system if desired?

Do any of these SDRs operate with Linux?

I'm still not keen on an SDR (I like a "real" radio on which I can put
my hands, though I have no problems with radios with menu-driven
operating systems) mostly because, at the present time, I do not feel
these SDRs are good value for money. Some of these cost much more than
the computer to which they will be attached and which supplies most of
the processing power! The "guts" inside these SDRs do not, in my
opinion, justify their relatively high prices. But I'm sure that you
and many others here will disagree with me.

Perhaps one of these days someone is going to design an open-source
"radio program" which will do everything these current SDR models do
and, if history is any guide, he/she will put it out on the internet
for free. Maybe you'd just have to buy a USB-compatible connector for
an antenna.

Am I dreaming too much?

Best,

Joe

My understanding is you can use the SDRs as panadapters. Granted, an
expensive panadpter.

There is a home brew group that makes a board or kit sdr. Google
SoftRock-40

On Tue, 27 Nov 2007 12:36:29 -0800, Joe Analssandrini wrote:

I was unaware that one could still buy old operating system discs new.
Do you know of places one can buy them? And can one buy a very
inexpensive (new) notebook computer with no operating system installed
so that one could install an older operating system if desired?

Do any of these SDRs operate with Linux?


Yes, the SDR-1000, SDR-5000, SDR-14 and SDR-IQ are all supported by
Linrad.

http://www.nitehawk.com/sm5bsz/linuxdsp/linrad.htm

Anything that outputs I/Q audio will able to be used with Linrad in fact,
eg the Softrock.

Leif also produces his own hardware for Linrad, specialising in EME and
very weak signal.



I'm still not keen on an SDR (I like a "real" radio on which I can put
my hands, though I have no problems with radios with menu-driven
operating systems) mostly because, at the present time, I do not feel
these SDRs are good value for money. Some of these cost much more than
the computer to which they will be attached and which supplies most of
the processing power! The "guts" inside these SDRs do not, in my
opinion, justify their relatively high prices. But I'm sure that you and
many others here will disagree with me.

Perhaps one of these days someone is going to design an open-source
"radio program" which will do everything these current SDR models do
and, if history is any guide, he/she will put it out on the internet for
free. Maybe you'd just have to buy a USB-compatible connector for an
antenna.

Linrad is open-source.


Am I dreaming too much?


A little - you can't just connect an antenna to a USB port or the like -
you either need something to downconvert the RF to audio frequencies so it
can be sampled by your sound card (like the SDR-1000/5000/Softrock), in
which case you can see a band segment equal to the sampling rate of your
soundcard, or instead sample the whole band with an A-D convertor. The
latter approach is used by the SDR-14/IQ/Perseus.

The advantage of the latter system is that you can have a Panadaptor
covering as much of the HF spectrum as you like. The disadvantage is that
when you want to select a particular "band" to listen to, you need a
digital downconvertor to get rid of the extraneous data (so you don't
exceed the bandwidth of your USB port.) The DDCs tend to be quite
expensive - eg in the case of the Perseus they use Altera FPGAs, which are
not cheap by any means and require very specialised knowledge to program.

However, since SDR is rapidly becoming "de facto" in commercial situations
(especially mobile phones) there will be more and more devices and ICs
coming onto the market, which will keep driving prices down.

Cheers

Alex

Wow! - Guy I certainly got the wrong idea about that Perseus, I should
have known if you are committing yourself to one it would be top end
cutting edge technology. Enjoy it when it comes and good DX with it.
Am I right in saying that you need a fairly top end computer/laptop
with Intel Duocore plus a good soundcard to run it? And then there is
the fact that if you want to enjoy the full benefits of it's enormous
capabilities you are going to need something like a 1 Terabyte
outboard hardisk to record the vast amount of info it generates?
That's all going to add up to quite a lot of moolla! Anyway, I can see
that's the way the MW DX hobby is going and the lads with Perseus are
going to outperform us old dodderers with our single catch sets by
quite a way in both volume and quality of exotic catches.

Guy wrote:
Here's my list of factors needed for hearing the DX, in descending
order:

1. Antenna(s) - ya won't hear much without one! Perferably directional
and/or low noise designs.
2. A DXer with skill and experience
3. An RF-quiet environment
4. Luck!
5. The receiver

Guy, thanks for publishing that again, it's always a good issue to
debate. I agree with you on all except for item 4: LUCK. Our famous
South African golfer Gary Player once replied to a reporter at the
Masters who said to him "That was a lucky shot!", to which Gary
replied: "The more I practise the luckier I get". I think this applies
to radio as well, as I find some of the best DXer's use their vast
experience and aquired skill to pull out signals from nowhere that
lesser mortals don't find or see. I learnt quite a lot from an amazing
DXer years ago who had that uncanny knack of finding rare and exotic
catches that no one else seemed to find until he pointed them out to
us. I like to think that with years more experience behind me and some
familiarity with the MW band that I too can now unerringly dig out
that exotic DX. But the real fun of this hobby is that you never get
tired of it, as just when you are getting bored with the same old
thing, conditions will change and a whole new lot of catches will pop
up and enthuse you again to go on far a few more years. I can see from
the MW logs that are coming in this year from all over the world that
it will go down as a vintage year, one of the best ever. That's the
fun of it, but you have to have the patience to hope for those good
years.

Alex wrote:
[and the wife would go nuts if she ever found out I'd spent £600 on
"just a radio"!]

I know the feeling very well - in my household my old ball and chain
insists that for every penny I spend on radio she gets one as well.
That makes buying even a modest MP3 recorder painful, let alone when I
got my big ticket Icom. Paying double for everything is a pain in the
ass and very limiting.............

Have fun and good DX

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx

On Nov 27, 9:06 am, "Guy Atkins" wrote:
wrote in message

...

You are moving now from a superlative SDR-1000 to a much more modest
Perseus, the reason being that it can copy a huge 400 Khz of spectrum
at TOH for later playback, and however modest the specs of the Perseus
might be, this facility is going to get you lots more catches and
positive ID's.

Hi again John,

I would have to disagree that the Perseus is a "much more modest" receiver..
The SDR-IQ would fit that description, but Perseus has +31 dBm IP3 and 125
dBm blocking dynamic range (@ 14 MHz), assisted by a total of 9, 6-pole
bandpass filters and one 3-pole lowpass filter to help achieve this
performance. I know specs don't tell the whole story, but these are very
good to excellent numbers, not modest at all. In fact, the Perseus appears
to be roughly in the same league as the SDR-1000.

In my urban RF location I can use all the receive front end protection I can
get. Other than the SDR-1000, the best receiver here by far for this purpose
have been the two AR7030s I've owned. After some practice I didn't find the
ergonomics of the AORs to be an issue, and much of the time I operated them
via PC through ERGO control, which was even better.

More measurements and details of the Perseus are available hehttp://www..microtelecom.it/perseus/ Granted, these are numbers from the
manufacturer himself. I'll be interested to read some independent tests in
the future, such as Sherwood Engineering.

Joe has concerns about outdated PC operating systems in the future, in
regard to SDR radios. I think this is a non-issue. All it means is that it
will be even less expensive to have a computer dedicated solely to operating
the radio down the road. I too am loathe to adopt Vista; fortunately Windows
XP is very usable. A few years down the road you'll be able to buy XP for
around $25-50 or so, just like you can get a Windows98 original disc for
that price now. The 1.0 GHz Pentium III machines selling at my local
computer surplus store for $50 now will be replaced with the likes of
Pentium 4 3.2 GHz PCs or maybe even 1.6 - 1.8 Ghz Core 2 Duos for $75.
Either of these setups will run SDRs OK. Today's "Cadillac" computers are
the old Chevys of tomorrow!

If you're concerned about parts availability, traditional radios from major
manufacturers have their share of orphaned and unavailable ICs and
transistors, too.

It took me a few years to embrace the SDR radio concept, as I've certainly
owned and enjoyed my share of traditional communications receivers.
Personally, I believe that receivers are way down the list of criteria
necessary for DXing success, but I like equipment and technology as much as
catching a new and distant station.

Here's my list of factors needed for hearing the DX, in descending order:

1. Antenna(s) - ya won't hear much without one! Perferably directional
and/or low noise designs.
2. A DXer with skill and experience
3. An RF-quiet environment
4. Luck!
5. The receiver

For me, the biggest advantage of SDRs are two main things: 1) fully
adjustable filters in any width desired, with performance better the
top-notch Collins filters I spent big bucks on over the years, and 2) a
detailed view of the DX being tuned, through spectrum displays or
panadapters. Once you "see" your DX at variable "zoom" levels, it's hard to
go back to a traditional radio! This is an especially neat feature for
split-frequency MW DXing, as you can keep an eye on very weak signals long
before they strengthen and break into audio.

73,

Guy

Hi John,

I think you are spot-on with your comments on "luck". Most of the time, good
DXers "make their luck" based on their wealth of experience.

I've watch my friend John Bryant on many DXpeditions, pass by *common*
trans-Pacific MW signals of amazing strength during excellent propagation
conditions. Despite the allure and fun of enjoying a "near-local" quality
signal of regularly heard DX, he goes right to frequencies with interesting
jumbles of low-level audio to see what might rise above the din, or he
chases his personal "hitlist" of highly sought-after stations. John knows
not to waste his time on the common stuff during the excellent openings. In
this way, John makes his own luck. In the same way, on his Easter Island
DXpedition he didn't spend much time tuning Chinese MW stations which are
common at our Grayland DXpedition location. He went after DX that would be
more exotic for his interests, and more distant from Easter Island. He was
rewarded with catches like Radio Farda-UAE and BBC-Oman on medium wave.

You asked about the PC requirements of Perseus. I have not seen anything
published specifically listing the minimum requirements, but I've upgraded
to a laptop with a T7200 Core 2 Duo Processor and 2 Gb of PC-5300 SDRAM
memory. Based on what others have been using successfully, this will be more
than enough processing power. I'm hoping it will also handle recording
bandwidths 400 kHz when the Perseus designer implements this capability. My
500gb hard drive has an eSata interface, as well as my laptop. I plan to get
another large HD, and I am hoping the eSata format's faster data transfer
will handle the 400 kHz requirements when it comes to speed to/from the
buffers.

Guy

On Nov 28, 10:16 am, wrote:


I know the feeling very well - in my household my old ball and chain
insists that for every penny I spend on radio she gets one as well.
That makes buying even a modest MP3 recorder painful, let alone when I
got my big ticket Icom. Paying double for everything is a pain in the
ass and very limiting.............

Have fun and good DX

John Plimmer, Montagu, Western Cape Province, South Africa

Try to find a Creative Labs Zen V Plus, it is a 4GB MP3 player/
recorder with
mic and stereo !!line!! input. LithION battery that is recharged by
the USB
data transfer port and super, and I mean silent, RF quiet!
Flash drive or flash RAM, no hard drive to fail.

USA prices:
$100 for a 4GB
$69 0r $79 for 2GB.

128 or 168? encoding. Since I use mine for HF I haven't even tested
the higher
datarate. I would love a firmware patch to lower the capture rate to
64K. It will
run for at least 15 hours and, to me this is worthless, will also play
videos.

Best trade of the year.
Got one for my wife and me.
She will fight to keep hers!


Terry