Re: [time-nuts] HP 4193A 4815A probe compatibility?
In message 5045fb99932bb62b54dea2c4ec301...@sonic.net, Richard Karlquist writes: These days, you can buy a decent power detector chip from Analog Devices (possibly on an evaluation board) and maybe you don't need a power meter. I've played with one of those, and if you want to do anything but steer the amplification of a cell-phone tower, you need to build a two-dimensional calibration table to get usable precision. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility
There are many detector chip out there. The venerable AD8307 with greater than 80 db dynamic range goes from almost DC to 700 mhz. Linear Technology has several currently listed. Their LTC5508 covers 300 to greater than 7 GHz. Al On Oct 17, 2013, at 3:38 PM, Richard Karlquist rich...@karlquist.com wrote: If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Alas, the LT1088 is no longer made. http://www.linear.com/product/LT1088 Best regards, -Steve -- Steve Byan steveb...@me.com Littleton, MA 01460 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility
Hi The gotcha is that a true thermal converter takes care of a bunch of odd issues. Other approaches really don't cover all the bases. How any of this relates to TimeNuts is a bit beyond me ... Bob On Oct 18, 2013, at 1:12 PM, Al Wolfe alw.k...@gmail.com wrote: There are many detector chip out there. The venerable AD8307 with greater than 80 db dynamic range goes from almost DC to 700 mhz. Linear Technology has several currently listed. Their LTC5508 covers 300 to greater than 7 GHz. Al On Oct 17, 2013, at 3:38 PM, Richard Karlquist rich...@karlquist.com wrote: If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Alas, the LT1088 is no longer made. http://www.linear.com/product/LT1088 Best regards, -Steve -- Steve Byan steveb...@me.com Littleton, MA 01460 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility
Kenton A. Hoover liked your message with Boxer. On Fri, Oct 18, 2013 at 15:10, Bob Camp wrote:HiThe gotcha is that a true thermal converter takes care of a bunch of odd issues. Other approaches really don't cover all the bases.How any of this relates to TimeNuts is a bit beyond me ...BobOn Oct 18, 2013, at 1:12 PM, Al Wolfe wrote: There are many detector chip out there. The venerable AD8307 with greater than 80 db dynamic range goes from almost DC to 700 mhz. Linear Technology has several currently listed. Their LTC5508 covers 300 to greater than 7 GHz. Al On Oct 17, 2013, at 3:38 PM, Richard Karlquist wrote: If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Alas, the LT1088 is no longer made. http://www.linear.com/product/LT1088 Best regards, -Steve -- Steve Byan Littleton, MA 01460 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.___time-nuts mailing list -- time-nuts@febo.comTo unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nutsand follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
Except that if you blow the 54701A front-end, the IC is made of unobtanium. Likewise, buying an untested probe... As for the 4193A, if you know of an instrument without probe for $1, please let me know ASAP!!! The connector of the 4193A is the same awful connector as the 8411A so if you wanted to build your own, you could start from there. On Wed, Oct 16, 2013 at 4:42 PM, Tom Knox act...@hotmail.com wrote: I agree the 54701A is really a great product. Great point on attenuation, I always forget the 10x attn value changes when not being used on a O-Scope as a voltage probe. Thanks; Thomas Knox From: saidj...@aol.com Date: Wed, 16 Oct 2013 15:22:13 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility? Hi Rick, Tom, one little bit of knowledge I learned: I like the HP 54701A FET probes for frequency-domain stuff. Available for $300 on Ebay sometimes. I built a small power supply for one of mine, and use it as a probe for my Spectrum analyzer and scopes. Almost indestructable. It works really well up to about 3GHz and beyond, especially for relative measurements. The only disadvantage is that it has 100K resistance to ground which may affect sensitive capacitive circuits, and that it has 20dB attenuation. Otherwise it works really well for Spectrum analyzer and Network analyzer applications. bye, Said In a message dated 10/16/2013 11:33:11 Pacific Daylight Time, rich...@karlquist.com writes: The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
Mark, Thats the big difference between the 54701A and most other fet probes, its virtually indestructible. They even designed it so it can drop directly on its tip without internal damage. Big difference to most other fet probes, HP even has a nice write up on their design efforts and how they made it almost bullet proof. It doesn't die by applying high AC or DC or RF levels like most other Spectrum Analyzer fet probes. Also, buying anything used obviously necessitates testing or trusting the seller. Why would this be any different here. Bye, Said Sent From iPhone On Oct 17, 2013, at 6:47, Mark Kahrs mark.ka...@gmail.com wrote: Except that if you blow the 54701A front-end, the IC is made of unobtanium. Likewise, buying an untested probe... As for the 4193A, if you know of an instrument without probe for $1, please let me know ASAP!!! The connector of the 4193A is the same awful connector as the 8411A so if you wanted to build your own, you could start from there. On Wed, Oct 16, 2013 at 4:42 PM, Tom Knox act...@hotmail.com wrote: I agree the 54701A is really a great product. Great point on attenuation, I always forget the 10x attn value changes when not being used on a O-Scope as a voltage probe. Thanks; Thomas Knox From: saidj...@aol.com Date: Wed, 16 Oct 2013 15:22:13 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility? Hi Rick, Tom, one little bit of knowledge I learned: I like the HP 54701A FET probes for frequency-domain stuff. Available for $300 on Ebay sometimes. I built a small power supply for one of mine, and use it as a probe for my Spectrum analyzer and scopes. Almost indestructable. It works really well up to about 3GHz and beyond, especially for relative measurements. The only disadvantage is that it has 100K resistance to ground which may affect sensitive capacitive circuits, and that it has 20dB attenuation. Otherwise it works really well for Spectrum analyzer and Network analyzer applications. bye, Said In a message dated 10/16/2013 11:33:11 Pacific Daylight Time, rich...@karlquist.com writes: The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions
Re: [time-nuts] HP 4193A 4815A probe compatibility?
OK I have really tried to stay clear of the discussion. My HP 8405 is in fine shape including probes and dividers. Though clearly not of the class of gear in discussion. However homebrewing replacements is of interest. My experience is with the HP power meters. I have a number of working units. But darned if the meters no probes or cables show up for a few dollars at fleas. So last fall I built home brew bolometers. By god they work! Though I would not make this a product. It was really hard to build under the microscope. What I learned however was significant in the construction and choice of materials. The real why of it. So these types of efforts are worth a try. Every time I have ever done them I walk away with one heck of an appreciation for those who figured it out long ago. Good luck if you make the effort. Suspect we are way out of line for time nuts. Paul WB8TSL On Thu, Oct 17, 2013 at 9:47 AM, Mark Kahrs mark.ka...@gmail.com wrote: Except that if you blow the 54701A front-end, the IC is made of unobtanium. Likewise, buying an untested probe... As for the 4193A, if you know of an instrument without probe for $1, please let me know ASAP!!! The connector of the 4193A is the same awful connector as the 8411A so if you wanted to build your own, you could start from there. On Wed, Oct 16, 2013 at 4:42 PM, Tom Knox act...@hotmail.com wrote: I agree the 54701A is really a great product. Great point on attenuation, I always forget the 10x attn value changes when not being used on a O-Scope as a voltage probe. Thanks; Thomas Knox From: saidj...@aol.com Date: Wed, 16 Oct 2013 15:22:13 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility? Hi Rick, Tom, one little bit of knowledge I learned: I like the HP 54701A FET probes for frequency-domain stuff. Available for $300 on Ebay sometimes. I built a small power supply for one of mine, and use it as a probe for my Spectrum analyzer and scopes. Almost indestructable. It works really well up to about 3GHz and beyond, especially for relative measurements. The only disadvantage is that it has 100K resistance to ground which may affect sensitive capacitive circuits, and that it has 20dB attenuation. Otherwise it works really well for Spectrum analyzer and Network analyzer applications. bye, Said In a message dated 10/16/2013 11:33:11 Pacific Daylight Time, rich...@karlquist.com writes: The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 4193A 4815A probe compatibility?
On 2013-10-17 08:34, paul swed wrote: However homebrewing replacements is of interest. My experience is with the HP power meters. I have a number of working units. But darned if the meters no probes or cables show up for a few dollars at fleas. So last fall I built home brew bolometers. By god they This is similar to my previous comment about the vector impedance meter market. At flea markets, it seems paradoxically like a cable is worth more than a power sensor which in turn is worth more than a power meter. The opposite order of the original list prices. These days, you can buy a decent power detector chip from Analog Devices (possibly on an evaluation board) and maybe you don't need a power meter. If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
On Oct 17, 2013, at 3:38 PM, Richard Karlquist rich...@karlquist.com wrote: If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Alas, the LT1088 is no longer made. http://www.linear.com/product/LT1088 Best regards, -Steve -- Steve Byan steveb...@me.com Littleton, MA 01460 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
On 10/17/13 4:46 PM, Steve Byan wrote: On Oct 17, 2013, at 3:38 PM, Richard Karlquist rich...@karlquist.com wrote: If you are below 80 MHz, Linear Technologies makes a thermal power meter on a chip. Alas, the LT1088 is no longer made. http://www.linear.com/product/LT1088 Rochester Electronics.. The leaders in the trailing edge of electronics... You'll probably pay for it, but they have a lot of older parts (they even go so far as to run a 3 and 4 fab, I think) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 4193A 4815A probe compatibility?
I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
Hi Rick, Tom, one little bit of knowledge I learned: I like the HP 54701A FET probes for frequency-domain stuff. Available for $300 on Ebay sometimes. I built a small power supply for one of mine, and use it as a probe for my Spectrum analyzer and scopes. Almost indestructable. It works really well up to about 3GHz and beyond, especially for relative measurements. The only disadvantage is that it has 100K resistance to ground which may affect sensitive capacitive circuits, and that it has 20dB attenuation. Otherwise it works really well for Spectrum analyzer and Network analyzer applications. bye, Said In a message dated 10/16/2013 11:33:11 Pacific Daylight Time, rich...@karlquist.com writes: The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
Thanks Rick; There is so much conflicting information I do not know what to believe anymore. George sounds like the person to talk to. It sounds like an aftermarket probe would be a great way for someone to make a few extra dollars. I like the Tomco option, it looks like a nice instrument. Thanks Again. Thomas Knox Date: Wed, 16 Oct 2013 11:16:27 -0700 From: rich...@karlquist.com To: time-nuts@febo.com Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility? The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 4193A 4815A probe compatibility?
I agree the 54701A is really a great product. Great point on attenuation, I always forget the 10x attn value changes when not being used on a O-Scope as a voltage probe. Thanks; Thomas Knox From: saidj...@aol.com Date: Wed, 16 Oct 2013 15:22:13 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility? Hi Rick, Tom, one little bit of knowledge I learned: I like the HP 54701A FET probes for frequency-domain stuff. Available for $300 on Ebay sometimes. I built a small power supply for one of mine, and use it as a probe for my Spectrum analyzer and scopes. Almost indestructable. It works really well up to about 3GHz and beyond, especially for relative measurements. The only disadvantage is that it has 100K resistance to ground which may affect sensitive capacitive circuits, and that it has 20dB attenuation. Otherwise it works really well for Spectrum analyzer and Network analyzer applications. bye, Said In a message dated 10/16/2013 11:33:11 Pacific Daylight Time, rich...@karlquist.com writes: The 4815A used P channel FETs which were available 50 years ago and are now unobtainium. The 4193A used N channel FETs which were available 10 to 30 years ago and may even be currently available. They are DEFINITELY NOT INTERCHANGEABLE. This is according to ex-HP'er George Standford, who used to support vector impedance meters with HP's blessing. He held the worlds remaining supply of P channel FETs for fixing probes. He was in New Jersey, but my contact info for him is no longer valid. I don't know how to identify them, but in principle an ohmmeter might be able to identify the polarity of the FETs. While we are on the topic, it turns out that the market is such that a 4193A with probe might sell for $5000, but if you break up the set, the probe is worth $4999 and the instrument is worth $1. Well, maybe I exaggerated that a little, but not much :-) I actually know someone who paid $5000 for just a 4193 probe. He made the mistake of purchasing an instrument without a probe, and paid way too much. It is also worth noting that now you can buy a very nice vector impedance meter from Tomco in Austrailia for only $3000 new. I A/B'ed one of these with an HP one, and I will have to admit that the Tomco is the real deal, not a cheap knockoff. Rick Karlquist N6RK On 2013-10-16 09:15, Tom Knox wrote: I hope this is not to far off topic. Does any one know if the 4193A and 4815A probe are physically interchangeable and electronically compatible? If not does anyone know the differences and how to identify which is which? If you feel this is to far off topic please contact me directly. Thanks very much. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
