On Thu, 12 Feb 2004 01:51:41 GMT, "Pete KE9OA"
wrote:

Hi Paul,
I just finished it this evening......................it is a
good piece of equipment, and worth the money. Tomorrow, I will do more
in-depth testing. It appears to have resolution to 6 digits, which is good.
It consists of a pair of 9851 DDS chips, with a 1496 being used as a direct
conversion detector. I think I am going to build another one, so I can use
one at home and one at work.

Thanks, Pete. Resolution is one thing, accuracy is another. Do you
have a proprietory instrument within calibration to compare it
against? I want to believe in this kit. If it works as advertised then
it's a significant breakthrough for those of us who feel reluctant to
part with 20,000 quid for a piece of relatively infrequently-needed
test equipment! Please report back here when you've had the chance to
check it out properly and let us know how it performs...
--

The BBC: Licensed at public expense to spread lies.

Thanks, Pete. Resolution is one thing, accuracy is another. Do you
have a proprietory instrument within calibration to compare it
against? I want to believe in this kit. If it works as advertised then
it's a significant breakthrough for those of us who feel reluctant to
part with 20,000 quid for a piece of relatively infrequently-needed
test equipment! Please report back here when you've had the chance to
check it out properly and let us know how it performs...

Paul, what part of the comparison between my Boonton and the N2PK VNA do you
have a difficult time with? Or for that matter, the comparisons with Chip
Owens HP 5783C? The accuracy is primarily limited by the quality of the OSL
standards used in setup, and the experience of the user in establishing
his/her reference plane.

W4ZCB

Agreed.....................a super good unit.

Pete

"Harold E. Johnson" wrote in message
news:bJRWb.300189$na.451700@attbi_s04...


Thanks, Pete. Resolution is one thing, accuracy is another. Do you
have a proprietory instrument within calibration to compare it
against? I want to believe in this kit. If it works as advertised then
it's a significant breakthrough for those of us who feel reluctant to
part with 20,000 quid for a piece of relatively infrequently-needed
test equipment! Please report back here when you've had the chance to
check it out properly and let us know how it performs...

Paul, what part of the comparison between my Boonton and the N2PK VNA do
you
have a difficult time with? Or for that matter, the comparisons with Chip
Owens HP 5783C? The accuracy is primarily limited by the quality of the
OSL
standards used in setup, and the experience of the user in establishing
his/her reference plane.

W4ZCB

Agreed.....................a super good unit.

Pete

"Harold E. Johnson" wrote in message
news:bJRWb.300189$na.451700@attbi_s04...


Thanks, Pete. Resolution is one thing, accuracy is another. Do you
have a proprietory instrument within calibration to compare it
against? I want to believe in this kit. If it works as advertised then
it's a significant breakthrough for those of us who feel reluctant to
part with 20,000 quid for a piece of relatively infrequently-needed
test equipment! Please report back here when you've had the chance to
check it out properly and let us know how it performs...

Paul, what part of the comparison between my Boonton and the N2PK VNA do
you
have a difficult time with? Or for that matter, the comparisons with Chip
Owens HP 5783C? The accuracy is primarily limited by the quality of the
OSL
standards used in setup, and the experience of the user in establishing
his/her reference plane.

W4ZCB

Paul Burridge wrote:
On Thu, 12 Feb 2004 01:51:41 GMT, "Pete KE9OA"
wrote:

Hi Paul,
I just finished it this evening......................it is a
good piece of equipment, and worth the money. Tomorrow, I will do more
in-depth testing. It appears to have resolution to 6 digits, which is good.
It consists of a pair of 9851 DDS chips, with a 1496 being used as a direct
conversion detector. I think I am going to build another one, so I can use
one at home and one at work.

Thanks, Pete. Resolution is one thing, accuracy is another. Do you
have a proprietory instrument within calibration to compare it
against? I want to believe in this kit.

N2PK's website (www.qsl.net/n2pk) gives exhaustive information about
measurement accuracy, standards and comparisons with professional VNAs.

When used correctly (a necessity for any VNA), N2PK's instrument is so
accurate that he had to go to extreme lengths to find any real
differences from commercial equipment. For example, the measured signal
magnitude tracks a 'standard' step attenuator to better than 0.1dB over
a 90dB range... but which is in error, the VNA or the attenuator? At
those levels of performance, it's almost impossible to tell.

Bottom line: you'll hardly ever need to worry about accuracy as such,
only about using the instrument correctly.

The only minor drawbacks are a small amount of thermal drift (because
this is a DC-coupled system) and the possibilities of responding to DDS
harmonics and spurs; all of these are very thoroughly documented.

If it works as advertised then
it's a significant breakthrough for those of us who feel reluctant to
part with 20,000 quid for a piece of relatively infrequently-needed
test equipment! Please report back here when you've had the chance to
check it out properly and let us know how it performs...

Having had one running for about six months, I can confirm it's
excellent. Far from being infrequently-needed, it has become one of
those instruments I couldn't possibly manage without!

Read the documentation and you'll see exactly why.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)

http://www.ifwtech.co.uk/g3sek

On Thu, 12 Feb 2004 19:52:26 +0000, "Ian White, G3SEK"
wrote:

Having had one running for about six months, I can confirm it's
excellent. Far from being infrequently-needed, it has become one of
those instruments I couldn't possibly manage without!

Read the documentation and you'll see exactly why.

I shall. And thanks for the info!
I didn't realise you'd bought the kit. Did you have to have it shipped
over from the States? I assume there's no outlet for them here, as yet
at any rate. What's the UK price inc.shipping? (Just in case I can't
find those details on the site).

--

The BBC: Licensed at public expense to spread lies.

Paul Burridge wrote:
On Thu, 12 Feb 2004 19:52:26 +0000, "Ian White, G3SEK"
wrote:

Having had one running for about six months, I can confirm it's
excellent. Far from being infrequently-needed, it has become one of
those instruments I couldn't possibly manage without!

Read the documentation and you'll see exactly why.

I shall. And thanks for the info!
I didn't realise you'd bought the kit. Did you have to have it shipped
over from the States? I assume there's no outlet for them here, as yet
at any rate. What's the UK price inc.shipping? (Just in case I can't
find those details on the site).

At the time, there wasn't a kit as such, but the parts cost about £100
in total (not including the DDS ICs, which Analog Devices generously
supply free to amateurs as 'samples').

However, certain parts are only obtainable in the USA, so people in
Europe are getting together to buy in bulk. I don't have any specific
information about that, but a mailing-list is to be started shortly
(wait for the announcement) so that will be a focal point for people to
co-ordinate their buying.



--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)

http://www.ifwtech.co.uk/g3sek

Paul Burridge wrote:
On Thu, 12 Feb 2004 19:52:26 +0000, "Ian White, G3SEK"
wrote:

Having had one running for about six months, I can confirm it's
excellent. Far from being infrequently-needed, it has become one of
those instruments I couldn't possibly manage without!

Read the documentation and you'll see exactly why.

I shall. And thanks for the info!
I didn't realise you'd bought the kit. Did you have to have it shipped
over from the States? I assume there's no outlet for them here, as yet
at any rate. What's the UK price inc.shipping? (Just in case I can't
find those details on the site).

At the time, there wasn't a kit as such, but the parts cost about £100
in total (not including the DDS ICs, which Analog Devices generously
supply free to amateurs as 'samples').

However, certain parts are only obtainable in the USA, so people in
Europe are getting together to buy in bulk. I don't have any specific
information about that, but a mailing-list is to be started shortly
(wait for the announcement) so that will be a focal point for people to
co-ordinate their buying.



--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)

http://www.ifwtech.co.uk/g3sek

On Thu, 12 Feb 2004 19:52:26 +0000, "Ian White, G3SEK"
wrote:

Having had one running for about six months, I can confirm it's
excellent. Far from being infrequently-needed, it has become one of
those instruments I couldn't possibly manage without!

Read the documentation and you'll see exactly why.

Okay, I've read the dox but am still in the dark as to what *you* use
yours for. What makes it so indispensible?

--

The BBC: Licensed at public expense to spread lies.

Okay, I've read the dox but am still in the dark as to what *you* use
yours for. What makes it so indispensible?

When was the last time you needed to know a capacitor value AT the
frequency you're going to use it at? (the "C" minus the "L" of the leads)
Or the passband of a filter and it's IL and it's skirts and it's blowby and
it's group delay and it's terminating impedances?
Or needed dual high level isolated oscillators to make Ip3 measurements on a
receiver or transmitter?
Or have a precision sweep generator and trigger for a Spectrum Analyzer?
Or needed the inductance of an inductor AT the operating frequency? (The "L"
less the "C")
Or needed the series and parallel resonant frquencies of a crystal and the
Rs of same and it's "Q"?
Or needed the "S" parameters of a small signal transistor?
Or wanted to know the impedance of your antenna at the shack end of the
coax. Or, if you were smart enough to log the length of coax when you
installed it, the impedance AT the antenna?
Or needed the Zo of a length of coax?
Or the gain of an amplifier over it's frequency range and it's 3 dB corners
to the 0.01 dB?
Or needed a quadrature signal source to be the LO of that new I-Q receiver?

Or-or-or

It's a lab in a box.

W4ZCB