Hi Chris,

Thank you for passing this along. I am getting 50M ohm between 2 and 3 and
nothing on the reverse. The other pins yield similar results. I get values
that are way off the mark or none at all.

I'll keep them around until I can get a good batch and I'll see how they
compare, for now, I'm marking them as being counterfeit.

Richard (VE9IT)

On Mon, Sep 24, 2018 at 1:52 PM Chris Smith <me@m0xte.uk> wrote:

Hi,

Quick update on this. I was contacted off list with measurements on
another NE602AN. If you swap the probes round on pin pairs 1,3 and 2,3
this drops to around 4.7M so clearly this is activating a semiconductor
junction inside the device.
7 -> 3 = 25k 1 -> 3 = 9.86M ohms 2 -> 3 = 9.73M ohms 6 -> 4 = 19.5k 6
-> 5 = 19.5k
That should be enough to do a simple red/green test on a 612/602 to see
if it is actually one or not.
Many thanks to the additional contributor :)

Best regards,

Chris Smith M0XTE

On Sun, 23 Sep 2018, at 20:56, Chris Smith wrote:

Sounds like they are hooky. This is happening very frequently with
popular parts. Get one out and measure the following with a DMM
on ohms.> From the datasheet there should be the following approximate
resistances> between the pins:
7 -> 3 = 25k
1 -> 3 = 1.5k
2 -> 3 = 1.5k
6 -> 4 = 19.5k
6 -> 5 = 19.5k

If all of these are vastly off then it's probably not a 612.

Finding out what it really is could be interesting :)

Best regards,

Chris Smith M0XTE


On Sun, 23 Sep 2018, at 20:51, Richard Seguin wrote:

Hello folks,

I'm experiencing a very fishy situation with a batch of NE612AN
double> balanced mixers that I got from China. When I apply power to>>

the correct> pin (I verified several times) they get really hot to

the touch.>> I created> a test circuit that is similar to what the

datasheet

specifies for an> unbalanced input, and I have also played around
with using a crystal>> oscillator instead of the DDS output that I

wanted to use.

I'm not looking for anyone to troubleshoot my circuit, I'm
more or less> curious if anyone else ran into symptoms like
this. I'm>> suspecting that> what I have may not be SA612AN mixers,

and that I am

applying>> power to the> incorrect pins.

If anyone has one of these laying around, what happens when you
apply VCC> (5V) to pin 8 and GND to pin 3? Does the IC heat up?

Richard (VE9IT)

Hi,

Quick update on this. I was contacted off list with measurements on
another NE602AN. If you swap the probes round on pin pairs 1,3 and 2,3
this drops to around 4.7M so clearly this is activating a semiconductor
junction inside the device.
7 -> 3 = 25k 1 -> 3 = 9.86M ohms 2 -> 3 = 9.73M ohms 6 -> 4 = 19.5k 6
-> 5 = 19.5k
That should be enough to do a simple red/green test on a 612/602 to see
if it is actually one or not.
Many thanks to the additional contributor :)

Best regards,

Chris Smith M0XTE

On Sun, 23 Sep 2018, at 20:56, Chris Smith wrote:

Sounds like they are hooky. This is happening very frequently with
popular parts. Get one out and measure the following with a DMM
on ohms.> From the datasheet there should be the following approximate
resistances> between the pins:
7 -> 3 = 25k
1 -> 3 = 1.5k
2 -> 3 = 1.5k
6 -> 4 = 19.5k
6 -> 5 = 19.5k

If all of these are vastly off then it's probably not a 612.

Finding out what it really is could be interesting :)

Best regards,

Chris Smith M0XTE


On Sun, 23 Sep 2018, at 20:51, Richard Seguin wrote:

Hello folks,

I'm experiencing a very fishy situation with a batch of NE612AN
double> balanced mixers that I got from China. When I apply power to>>

the correct> pin (I verified several times) they get really hot to

the touch.>> I created> a test circuit that is similar to what the

datasheet

specifies for an> unbalanced input, and I have also played around
with using a crystal>> oscillator instead of the DDS output that I

wanted to use.

I'm not looking for anyone to troubleshoot my circuit, I'm
more or less> curious if anyone else ran into symptoms like
this. I'm>> suspecting that> what I have may not be SA612AN mixers,

and that I am

applying>> power to the> incorrect pins.

If anyone has one of these laying around, what happens when you
apply VCC> (5V) to pin 8 and GND to pin 3? Does the IC heat up?

Richard (VE9IT)

Hi Graham,
Thanks for confirming the operation of the OCXO.
How critical is 5 volt precision in using the OCXO?

Al

On Mon, 24 Sep 2018 10:16:38 -0400, Graham <planophore@aei.ca> wrote:

Al,

Your brief description of the operation of your OCXO sounds like a
typical OCXO - higher current at start up til stabilization, then lower
current draw. Same goes for the frequency drift.

The adjustment only needs a potentiometer to be used as a voltage divider
and is not overly critical as far as value is concerned. I tend to use
something around 5k.

There is often a Vref output from OCXO that you would use on one side of
the pot rather than the VCC, the other side of the pot to ground, and
the wiper to the ADJ.

Don't expect a lot of adjustment range, on the order of single digit Hz
+/- of the nominal frequency

cheers, Graham ve3gtc


On 9/24/2018, "Alan Jones" <oalanjones@gmail.com> wrote:

I finally received a OCXO from the extremely slow boat from China.
How much resistance do I need in order to adjust "Vcont" on pin #3 ?

My initial hook up without Vcont, according to my eBay 8 digit frequency
counter showed a slow frequency drift from about 9.999.820 MHz up to
10.000.027 and stabilized after about 7 minutes. Current draw got up to
a
max of around 400 mA and then settled in around 198 mA and the
oscillator
can was warm to the touch.

The OCXO I received from eBay was used and has a calibration sticker on
it.

While looking for info on this OCXO I stumbled onto this document about
Precision Oscillator Overview.
http://freqelec.com/oscillators/osc_overview_4-07.pdf

I just ordered the GPSDO that Chuck referenced in an earlier email.
We will see how long it takes to get here!

Al, N8WQ

Sounds like they are hooky. This is happening very frequently with
popular parts. Get one out and measure the following with a DMM
on ohms.> From the datasheet there should be the following approximate
resistances> between the pins:
7 -> 3 = 25k
1 -> 3 = 1.5k
2 -> 3 = 1.5k
6 -> 4 = 19.5k
6 -> 5 = 19.5k

If all of these are vastly off then it's probably not a 612.

Finding out what it really is could be interesting :)

Best regards,

Chris Smith M0XTE


On Sun, 23 Sep 2018, at 20:51, Richard Seguin wrote:

Hello folks,

I'm experiencing a very fishy situation with a batch of NE612AN
double> balanced mixers that I got from China. When I apply power to>> the correct> pin (I verified several times) they get really hot to
the touch.>> I created> a test circuit that is similar to what the datasheet
specifies for an> unbalanced input, and I have also played around
with using a crystal>> oscillator instead of the DDS output that I wanted to use.

I'm not looking for anyone to troubleshoot my circuit, I'm
more or less> curious if anyone else ran into symptoms like
this. I'm>> suspecting that> what I have may not be SA612AN mixers, and that I am
applying>> power to the> incorrect pins.

If anyone has one of these laying around, what happens when you
apply VCC> (5V) to pin 8 and GND to pin 3? Does the IC heat up?

Richard (VE9IT)

Al,

Your brief description of the operation of your OCXO sounds like a
typical OCXO - higher current at start up til stabilization, then lower
current draw. Same goes for the frequency drift.

The adjustment only needs a potentiometer to be used as a voltage divider
and is not overly critical as far as value is concerned. I tend to use
something around 5k.

There is often a Vref output from OCXO that you would use on one side of
the pot rather than the VCC, the other side of the pot to ground, and
the wiper to the ADJ.

Don't expect a lot of adjustment range, on the order of single digit Hz
+/- of the nominal frequency

cheers, Graham ve3gtc


On 9/24/2018, "Alan Jones" <oalanjones@gmail.com> wrote:

I finally received a OCXO from the extremely slow boat from China.
How much resistance do I need in order to adjust "Vcont" on pin #3 ?

My initial hook up without Vcont, according to my eBay 8 digit frequency
counter showed a slow frequency drift from about 9.999.820 MHz up to
10.000.027 and stabilized after about 7 minutes. Current draw got up to a
max of around 400 mA and then settled in around 198 mA and the oscillator
can was warm to the touch.

The OCXO I received from eBay was used and has a calibration sticker on it.

While looking for info on this OCXO I stumbled onto this document about
Precision Oscillator Overview.
http://freqelec.com/oscillators/osc_overview_4-07.pdf

I just ordered the GPSDO that Chuck referenced in an earlier email.
We will see how long it takes to get here!

Al, N8WQ

Ed Nisley published an series of articles in Circuit Cellar Ink about
WWVB clocks. Feb 2010 was part 1 and detailed a WWVB simulator.

A quick search using Google will find a number of the WWVB simulator
results including some based on the ubiquitous Arduino.

This is an interesting topic on it's own.

cheers, Graham ve3gtc

On 9/24/2018, "Nick Kennedy" <kennnick@gmail.com> wrote:

That's a crazy enough idea to be a fun project. Be your own private NIST /
WWVB.

I did a PIC program a while ago to decode the data stream from a WWVB
module and have it update a clock, using a PIC.

Going the opposite way, you'd have to figure out how to do that
phase-shifty modulation scheme it uses.

72-

Nick, WA5BDU


On Sun, Sep 23, 2018 at 1:05 PM sigcom1 <sigcom@juno.com> wrote:

Funny, I was thinking almost exactly the same thing about a week ago

when

3 of my 4 WWVB-disciplined clocks refused to sync to NIST for
several days (only 1 remains recalcitrant at the moment).

With the future availability of those signals in question, it's 'time'
(ahem) to consider a GPS disciplined replacement, IMHO.

Faraday cage? I'll just call mine an Incidental Radiator. The trick is
to get my clocks to listen during daylight hours instead of
midnight as they do now ;-P .

73.......Steve Smith WB6TNL

On Sat, Sep 22, 2018 at 7:47 PM chuck adams <chuck.adams.k7qo@gmail.com

wrote:

Any one have the serial output data for the GPSDO? Might be interesting
to build a
1mW transmitter to emulate WWVB and feed my atomic clocks during the
daylight
hours from time to time. Of course, keeping it in a Faraday cage.

That's a crazy enough idea to be a fun project. Be your own private NIST /
WWVB.

I did a PIC program a while ago to decode the data stream from a WWVB
module and have it update a clock, using a PIC.

Going the opposite way, you'd have to figure out how to do that
phase-shifty modulation scheme it uses.

72-

Nick, WA5BDU


On Sun, Sep 23, 2018 at 1:05 PM sigcom1 <sigcom@juno.com> wrote:

Funny, I was thinking almost exactly the same thing about a week ago when
3 of my 4 WWVB-disciplined clocks refused to sync to NIST for
several days (only 1 remains recalcitrant at the moment).

With the future availability of those signals in question, it's 'time'
(ahem) to consider a GPS disciplined replacement, IMHO.

Faraday cage? I'll just call mine an Incidental Radiator. The trick is
to get my clocks to listen during daylight hours instead of
midnight as they do now ;-P .

73.......Steve Smith WB6TNL

On Sat, Sep 22, 2018 at 7:47 PM chuck adams <chuck.adams.k7qo@gmail.com>
wrote:

Any one have the serial output data for the GPSDO? Might be interesting
to build a
1mW transmitter to emulate WWVB and feed my atomic clocks during the
daylight
hours from time to time. Of course, keeping it in a Faraday cage.

I finally received a OCXO from the extremely slow boat from China.
How much resistance do I need in order to adjust "Vcont" on pin #3 ?

My initial hook up without Vcont, according to my eBay 8 digit frequency
counter showed a slow frequency drift from about 9.999.820 MHz up to
10.000.027 and stabilized after about 7 minutes. Current draw got up to a
max of around 400 mA and then settled in around 198 mA and the oscillator
can was warm to the touch.

The OCXO I received from eBay was used and has a calibration sticker on it.

While looking for info on this OCXO I stumbled onto this document about
Precision Oscillator Overview.
http://freqelec.com/oscillators/osc_overview_4-07.pdf

I just ordered the GPSDO that Chuck referenced in an earlier email.
We will see how long it takes to get here!

Al, N8WQ

I used to by from one seller.
as I searched now I get the ebay item 362255962960

please search
this guy is genuine


On Mon, Sep 24, 2018 at 3:11 PM Mvs Sarma <mvssarma@gmail.com> wrote:

I think it is 2.45 each at 10 lot and NOT a lot total price.



On Mon, Sep 24, 2018 at 2:13 PM Shirley Dulcey KE1L <mark@buttery.org>
wrote:

I don't think anybody has said that the surface mount SA602 and SA612
parts are scarce. They're still in production and readily available
from distributors.

What is getting scarce is the through-hole version. NXP (successor to
Signetics and Philips) stopped making them a while ago and supplies
are drying up. Diz still has them for now, as does the Switch and
Parts Store (WB9KZY). The Elecraft KX1 switched to using an SMD mixer
and an adapter board before it went out of production, and I suspect
the K2 has done that as well. Generic 8-SOIC to 8-PDIP adapter boards
are available from many sources. One example is the SparkFun
BOB-13655, which is $2.95 for a board that's actually four break-apart
adapters. Another example is the Adafruit 1212: $2.95 for a six pack
of boards. You also need headers; the inexpensive snap-apart ones will
work just fine. I have also seen adapters from Schmartboard and
generic ones for sale at hamfests.

The chip on many of the 8-SOIC adapters is rotated 90 degrees from the
position of the adapter. Make sure to point everything the right way.

One downside of using adapters is that the bypass capacitors are
farther away from the chip. If that turns out to be a problem you can
try putting an SMD bypass cap on the adapter board.

If you get desperate, the NTE7164 is an SA602-compatible part. But you
won't enjoy the price tag.

Although MSOP adapters also exist, don't try to use one with an
Si5351A. That chip is fussy about the lead lengths of its bypass
capacitor and crystal. A much better idea is to use an Si5351A
breakout board; they are available from Adafruit, QRP Labs, and
Etherkit.

It appears that some opportunists are selling counterfeit parts. Be
wary of SA602 and SA612 DIPs (or the older NE602 and NE612 if anybody
offers those) from eBay and Ali Express.
On Mon, Sep 24, 2018 at 1:03 AM Michael <pixelwaster@gmail.com> wrote:

Arrow.com has smd SA612 for $1.66 each. Minimum of 1 ordered with free
overnight shipping. They do ship overnight on a few parts! The next
break points are at 10/1.4988, 100/1.3005, 1000/1.008
The date code is 1708 from Thailand and they have 1900 in stock.
If you are willing to wait three day you can get the parts form the
Netherlands dated 1827. Still free shipping.

Michael
N9XYP

On 9/23/2018 10:17 PM, na5n_qrp wrote:

Kits and Parts (Diz) also has the thru-hole versions shown on his
website ... the NE602AN and NE612AN, as well as the SA602AD SMT

part.

5 for $10, or $2 each. Mouser also has the SMD versions for $2.88/1
and $2.45/10 with 11,000 in stock. DigiKey has them as well for

$2.36

each with 1,000 in stock. Search for SA602 or SA612 ... NE602/612
produces no results and seldom shown in their catalogs, but they

have

them. They're not as rare as some have claimed.

I think it is 2.45 each at 10 lot and NOT a lot total price.



On Mon, Sep 24, 2018 at 2:13 PM Shirley Dulcey KE1L <mark@buttery.org>
wrote:

I don't think anybody has said that the surface mount SA602 and SA612
parts are scarce. They're still in production and readily available
from distributors.

What is getting scarce is the through-hole version. NXP (successor to
Signetics and Philips) stopped making them a while ago and supplies
are drying up. Diz still has them for now, as does the Switch and
Parts Store (WB9KZY). The Elecraft KX1 switched to using an SMD mixer
and an adapter board before it went out of production, and I suspect
the K2 has done that as well. Generic 8-SOIC to 8-PDIP adapter boards
are available from many sources. One example is the SparkFun
BOB-13655, which is $2.95 for a board that's actually four break-apart
adapters. Another example is the Adafruit 1212: $2.95 for a six pack
of boards. You also need headers; the inexpensive snap-apart ones will
work just fine. I have also seen adapters from Schmartboard and
generic ones for sale at hamfests.

The chip on many of the 8-SOIC adapters is rotated 90 degrees from the
position of the adapter. Make sure to point everything the right way.

One downside of using adapters is that the bypass capacitors are
farther away from the chip. If that turns out to be a problem you can
try putting an SMD bypass cap on the adapter board.

If you get desperate, the NTE7164 is an SA602-compatible part. But you
won't enjoy the price tag.

Although MSOP adapters also exist, don't try to use one with an
Si5351A. That chip is fussy about the lead lengths of its bypass
capacitor and crystal. A much better idea is to use an Si5351A
breakout board; they are available from Adafruit, QRP Labs, and
Etherkit.

It appears that some opportunists are selling counterfeit parts. Be
wary of SA602 and SA612 DIPs (or the older NE602 and NE612 if anybody
offers those) from eBay and Ali Express.
On Mon, Sep 24, 2018 at 1:03 AM Michael <pixelwaster@gmail.com> wrote:

Arrow.com has smd SA612 for $1.66 each. Minimum of 1 ordered with free
overnight shipping. They do ship overnight on a few parts! The next
break points are at 10/1.4988, 100/1.3005, 1000/1.008
The date code is 1708 from Thailand and they have 1900 in stock.
If you are willing to wait three day you can get the parts form the
Netherlands dated 1827. Still free shipping.

Michael
N9XYP

On 9/23/2018 10:17 PM, na5n_qrp wrote:

Kits and Parts (Diz) also has the thru-hole versions shown on his
website ... the NE602AN and NE612AN, as well as the SA602AD SMT part.
5 for $10, or $2 each. Mouser also has the SMD versions for $2.88/1
and $2.45/10 with 11,000 in stock. DigiKey has them as well for $2.36
each with 1,000 in stock. Search for SA602 or SA612 ... NE602/612
produces no results and seldom shown in their catalogs, but they have
them. They're not as rare as some have claimed.

I don't think anybody has said that the surface mount SA602 and SA612> parts are scarce. They're still in production and readily available
from distributors.

What is getting scarce is the through-hole version. NXP (successor to> Signetics and Philips) stopped making them a while ago and supplies
are drying up. Diz still has them for now, as does the Switch and
Parts Store (WB9KZY). The Elecraft KX1 switched to using an SMD mixer> and an adapter board before it went out of production, and I suspect
the K2 has done that as well. Generic 8-SOIC to 8-PDIP adapter boards> are available from many sources. One example is the SparkFun
BOB-13655, which is $2.95 for a board that's actually four break-apart> adapters. Another example is the Adafruit 1212: $2.95 for a six pack
of boards. You also need headers; the inexpensive snap-apart ones will> work just fine. I have also seen adapters from Schmartboard and
generic ones for sale at hamfests.

The chip on many of the 8-SOIC adapters is rotated 90 degrees from the> position of the adapter. Make sure to point everything the right way.>
One downside of using adapters is that the bypass capacitors are
farther away from the chip. If that turns out to be a problem you can> try putting an SMD bypass cap on the adapter board.

If you get desperate, the NTE7164 is an SA602-compatible part. But you> won't enjoy the price tag.

Although MSOP adapters also exist, don't try to use one with an
Si5351A. That chip is fussy about the lead lengths of its bypass
capacitor and crystal. A much better idea is to use an Si5351A
breakout board; they are available from Adafruit, QRP Labs, and
Etherkit.

It appears that some opportunists are selling counterfeit parts. Be
wary of SA602 and SA612 DIPs (or the older NE602 and NE612 if anybody> offers those) from eBay and Ali Express.
On Mon, Sep 24, 2018 at 1:03 AM Michael <pixelwaster@gmail.com> wrote:>>

Arrow.com has smd SA612 for $1.66 each. Minimum of 1 ordered
with free>> overnight shipping. They do ship overnight on a few parts! The next
break points are at 10/1.4988, 100/1.3005, 1000/1.008
The date code is 1708 from Thailand and they have 1900 in stock.
If you are willing to wait three day you can get the parts form the
Netherlands dated 1827. Still free shipping.

Michael
N9XYP

On 9/23/2018 10:17 PM, na5n_qrp wrote:

Kits and Parts (Diz) also has the thru-hole versions shown on his
website ... the NE602AN and NE612AN, as well as the SA602AD
SMT part.>>> 5 for $10, or $2 each. Mouser also has the SMD versions for $2.88/1>>> and $2.45/10 with 11,000 in stock. DigiKey has them as well
for $2.36>>> each with 1,000 in stock. Search for SA602 or SA612 ... NE602/612
produces no results and seldom shown in their catalogs, but
they have>>> them. They're not as rare as some have claimed.

Arrow.com has smd SA612 for $1.66 each. Minimum of 1 ordered with free
overnight shipping. They do ship overnight on a few parts! The next
break points are at 10/1.4988, 100/1.3005, 1000/1.008
The date code is 1708 from Thailand and they have 1900 in stock.
If you are willing to wait three day you can get the parts form the
Netherlands dated 1827. Still free shipping.

Michael
N9XYP

On 9/23/2018 10:17 PM, na5n_qrp wrote:

Kits and Parts (Diz) also has the thru-hole versions shown on his
website ... the NE602AN and NE612AN, as well as the SA602AD SMT part.
5 for $10, or $2 each. Mouser also has the SMD versions for $2.88/1
and $2.45/10 with 11,000 in stock. DigiKey has them as well for $2.36
each with 1,000 in stock. Search for SA602 or SA612 ... NE602/612
produces no results and seldom shown in their catalogs, but they have
them. They're not as rare as some have claimed.

Kits and Parts (Diz) also has the thru-hole versions shown on his website ... the NE602AN and NE612AN, as well as the SA602AD SMT part.  5 for $10, or $2 each.  Mouser also has the SMD versions for $2.88/1 and $2.45/10 with 11,000 in stock.  DigiKey has them as well for $2.36 each with 1,000 in stock.  Search for SA602 or SA612 ... NE602/612 produces no results and seldom shown in their catalogs, but they have them.  They're not as rare as some have claimed.