Re: [time-nuts] BNC Question
On 4/16/2011 2:59 PM, shali...@gmail.com wrote: As pointed out earlier (by Bruce and others), there is a vast quantity of 75 ohm BNC connectors which mate perfectly with 50 ohm BNC sockets (save for impedance mismatch). I have a set of 10 cables bought off the *bay with such connectors. These cables are 75 ohm, so there will be a mismatch in a 50 ohm system no matter what the connector is. No doubt, but I think you'll also find these are the Amphenol proprietary parts - which will damage the MIL-STD 75 ohm parts that HP and a lot of other vendors used for a long time, just damaged less frequently. I am not sure what would make those less *true* that anything else. Strictly speaking, BNC, TNC, and N are rooted in MIL-STDs from the fourties, the other stuff intermates and has improvements of varying nature. This gets into detailed semantics. Are the cheapie import connectors that can't sweep past 100 Mhz Ns or something else? They intermate, but they don't work so well. I am sure the mismatch of the connectors themselves, within the frequency range they are intended for will be well below the level where most would care. Right, but the issue was intermating and damaging one type with another and poor mating reliability. The fact is that there ARE BNC (and N and TNC) variants that will have this problem. There are a number of folks here who have flatly stated that this is not the case, but it really is. If you try to use BNC for precision RF measurements, be prepared to be surprised. BNCs can be as good as TNCs when properly applied, but the bayonet mechanism allows too much mechanical alignment play for reasonable reliability past a GHz or so. If they are properly installed and the cable is not allowed to put a radial or significant tensile load they perform as well as a TNC and close to an N. For all that, I won't use them in designs above 100 Mhz without a compelling reason. F's are cheaper, and SMAs are more reliable. If it's hard coded at 75 ohms and related to measuremnts - I use Ns. Unless the argument is about what they should be, what the standard says is irrelevant when you have a box of parts and wonder if you can used them. I think we're in 'violent agreement' here. My point is that you need to be aware of the many variations of connectors that have appeared in the last 50+ years and use care lest you end up with an undesired repair. Don't assume anything, just check before you plug. And this is the point. There *are* connectors that will not reliably intermate and will be damaged. This is true in BNC as well as N and TNC. Didier KO4BB -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ 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] BNC Question
HP made a point of telling users that the 75 ohm female BNC connectors used on HP equipment were fully and safely mate-able with standard male 50 ohm parts. This has been so certainly from the 1970's. Casual inspection of the part shows that it uses the identical center pin set as the 50 ohm parts. -Chuck Harris Oz-in-DFW wrote: On 4/16/2011 2:59 PM, shali...@gmail.com wrote: As pointed out earlier (by Bruce and others), there is a vast quantity of 75 ohm BNC connectors which mate perfectly with 50 ohm BNC sockets (save for impedance mismatch). I have a set of 10 cables bought off the *bay with such connectors. These cables are 75 ohm, so there will be a mismatch in a 50 ohm system no matter what the connector is. No doubt, but I think you'll also find these are the Amphenol proprietary parts - which will damage the MIL-STD 75 ohm parts that HP and a lot of other vendors used for a long time, just damaged less frequently. I am not sure what would make those less *true* that anything else. Strictly speaking, BNC, TNC, and N are rooted in MIL-STDs from the fourties, the other stuff intermates and has improvements of varying nature. This gets into detailed semantics. Are the cheapie import connectors that can't sweep past 100 Mhz Ns or something else? They intermate, but they don't work so well. I am sure the mismatch of the connectors themselves, within the frequency range they are intended for will be well below the level where most would care. Right, but the issue was intermating and damaging one type with another and poor mating reliability. The fact is that there ARE BNC (and N and TNC) variants that will have this problem. There are a number of folks here who have flatly stated that this is not the case, but it really is. If you try to use BNC for precision RF measurements, be prepared to be surprised. BNCs can be as good as TNCs when properly applied, but the bayonet mechanism allows too much mechanical alignment play for reasonable reliability past a GHz or so. If they are properly installed and the cable is not allowed to put a radial or significant tensile load they perform as well as a TNC and close to an N. For all that, I won't use them in designs above 100 Mhz without a compelling reason. F's are cheaper, and SMAs are more reliable. If it's hard coded at 75 ohms and related to measuremnts - I use Ns. Unless the argument is about what they should be, what the standard says is irrelevant when you have a box of parts and wonder if you can used them. I think we're in 'violent agreement' here. My point is that you need to be aware of the many variations of connectors that have appeared in the last 50+ years and use care lest you end up with an undesired repair. Don't assume anything, just check before you plug. And this is the point. There *are* connectors that will not reliably intermate and will be damaged. This is true in BNC as well as N and TNC. Didier KO4BB ___ 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] BNC Question
An Amphenol document discussing the mating compatibility of their 50-ohm and 75-ohm BNC connectors can be found here _http://www.amphenolrf.com/products/bnc.asp?N=0sid=46B11E806D75617F_ (http://www.amphenolrf.com/products/bnc.asp?N=0sid=46B11E806D75617F) . Bruce, KG6OJI ___ 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] BNC Question
Oz-in-DFW wrote: BNCs can be as good as TNCs when properly applied, but the bayonet mechanism allows too much mechanical alignment play for reasonable reliability past a GHz or so. If they are properly installed and the cable is not allowed to put a radial or significant tensile load they perform as well as a TNC and close to an N. For all that, I won't use FWIW: The guts of a BNC/TNC is very similar if not identical to a type N, which is good for at least 12.4 GHz. The Agilent 13 GHz scopes have precision (IE tight fitting) BNC connectors on the probes. All of which of course doesn't mean the Asian BNC's you bought at the hamfest are any good. Rick 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] BNC Question
Rick Karlquist wrote: FWIW: The guts of a BNC/TNC is very similar if not identical to a type N, which is good for at least 12.4 GHz. The Agilent 13 GHz scopes have precision (IE tight fitting) BNC connectors on the probes. All of which of course doesn't mean the Asian BNC's you bought at the hamfest are any good. Rick N6RK There is a very significant difference between the N and the BNC construction with regards to what is the insulator in the transition section between the male and female connector: With the BNC (and TNC) connector(s), the space is filled with an interdigitated plastic dielectric. With the N, the space is filled with air. -Chuck Harris ___ 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] BNC question
On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. Risetime is the key aspect. If the impedance missmatch is sufficiently small compared to the rise-time, it has no significant effect. As I recall it ARCNET wasn't running at very high speeds and hence no need for short rise-times. Cheers, Magnus ___ 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] BNC question
Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. Risetime is the key aspect. If the impedance missmatch is sufficiently small compared to the rise-time, it has no significant effect. As I recall it ARCNET wasn't running at very high speeds and hence no need for short rise-times. Cheers, Magnus There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC variants. They do exist, I've seen hundreds of them. Bruce ___ 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] BNC question
On 04/10/2011 01:44 PM, Bruce Griffiths wrote: Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. Risetime is the key aspect. If the impedance missmatch is sufficiently small compared to the rise-time, it has no significant effect. As I recall it ARCNET wasn't running at very high speeds and hence no need for short rise-times. Cheers, Magnus There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC variants. They do exist, I've seen hundreds of them. These days there exists a standard variant of the BNC for 75 Ohm which is mechanical compatible with 50 Ohm. So that is what I recommend using. 75 Ohm BNC dominate with margin over 50 Ohm BNC at work. Our rise-times makes connector-choices more relevant. Cheers, Magnus ___ 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] BNC question
From what I recall from our candle lit lab, the 75 ohm BNCs had a slightly larger pin and would open up the 50 ohm females just a skoosh so when you put a 50 ohm, into a 50 ohm that had been tweaked by a 75 ohm, they were noisy or intermittent. Greg On 4/10/2011 5:30 AM, Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. Risetime is the key aspect. If the impedance missmatch is sufficiently small compared to the rise-time, it has no significant effect. As I recall it ARCNET wasn't running at very high speeds and hence no need for short rise-times. Cheers, Magnus ___ 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] BNC question
Types BNC connectors exist in 50 and 75ohm http://en.wikipedia.org/wiki/Ohmversions, matched for use with cables of the samecharacteristic impedance http://en.wikipedia.org/wiki/Characteristic_impedance. The 75 ohm types can sometimes be recognized by the reduced or absentdielectric http://en.wikipedia.org/wiki/Dielectricin the mating ends. The 50 and 75 ohm connectors are typically specified for use at frequencies up to 4 and 2 GHz respectively. 75 ohm BNC Connectors are primarily used for video andDS3 http://en.wikipedia.org/wiki/Digital_Signal_3Telco central office applications^[/clarification needed http://en.wikipedia.org/wiki/Wikipedia:Please_clarify/] , whereas 50 ohm are used for data and RF. TheBBC http://en.wikipedia.org/wiki/British_Broadcasting_Corporationhad a convention that BNC connectors used for video were always 50 ohm, maybe because an accidentally connected 50 ohm plug would damage a 75 ohm socket.^[/dubious http://en.wikipedia.org/wiki/Wikipedia:Disputed_statement--discuss http://en.wikipedia.org/wiki/Talk:BNC_connector#Video/] Many VHF receivers used 75 ohmantenna http://en.wikipedia.org/wiki/Antenna_%28radio%29inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg On 4/10/2011 9:25 AM, Greg Broburg wrote: From what I recall from our candle lit lab, the 75 ohm BNCs had a slightly larger pin and would open up the 50 ohm females just a skoosh so when you put a 50 ohm, into a 50 ohm that had been tweaked by a 75 ohm, they were noisy or intermittent. Greg On 4/10/2011 5:30 AM, Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. Risetime is the key aspect. If the impedance missmatch is sufficiently small compared to the rise-time, it has no significant effect. As I recall it ARCNET wasn't running at very high speeds and hence no need for short rise-times. Cheers, Magnus ___ 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] BNC question
I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg Indeed, the 75-ohm will have the smaller inner, and hence may be damaged by the larger pin on the 50-ohm connector. David GM8ARV -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] BNC question
Greg Broburg wrote: receivers used 75 ohmantenna http://en.wikipedia.org/wiki/Antenna_%28radio%29inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg Sadly, you remembered incorrectly. Both 75 ohm, and 50 ohm BNC parts use the same center pin assemblies. The only difference is the 75 ohm part has the teflon shroud removed from around the female pin. They mate in all combinations without any risk of damage. The N style connector is a different story, however. It is a higher performance connector, and as a result they needed to make the center conductor of a 75 ohm connector smaller in diameter all the way through, so the 75 ohm center male pin is slender, as is the 75 ohm center female pin. If you jam a thicker 50 ohm center pin into the slender 75 ohm female pin, it will bend the socket leafs out and probably break it. -Chuck Harris ___ 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] BNC question
Chuck Harris wrote: Greg Broburg wrote: receivers used 75 ohmantenna http://en.wikipedia.org/wiki/Antenna_%28radio%29inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg Sadly, you remembered incorrectly. Both 75 ohm, and 50 ohm BNC parts use the same center pin assemblies. The only difference is the 75 ohm part has the teflon shroud removed from around the female pin. They mate in all combinations without any risk of damage. Not necessarily true, BNCs intended for use with RG59 cable with either a 0.7mm diameter pin or a 0.9mm diameter pin are readily available. Whilst one of these may now be non standard they are nevertheless they are still available from Chinese manufacturers at least. The N style connector is a different story, however. It is a higher performance connector, and as a result they needed to make the center conductor of a 75 ohm connector smaller in diameter all the way through, so the 75 ohm center male pin is slender, as is the 75 ohm center female pin. If you jam a thicker 50 ohm center pin into the slender 75 ohm female pin, it will bend the socket leafs out and probably break it. -Chuck Harris ___ 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] BNC question
Thanks for all the input. I looked closely at the connectors and they seem to match some 50 Ohm connectors that I have. I have removed them from the board and now have eight isolated BNC connectors for my project. Joe Gray W5JG ___ 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] BNC question
I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. I want to use these isolated BNC connectors for a frequency distribution amp. What do you think? I'm still trying to find some old Ethernet cards for the transformers. I know the cards will have BNC connectors, but the hub has eight matched BNC connectors, so using them would be preferrable. Joe Gray W5JG ___ 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] BNC question
Hi Stan this one has been covered before the pins are the same size the difference is in the amount of dielectric round the socket in the femalethe 75 ohm one hase the socket poking free of the ptfe and on the 50 ohm it is flush with the end. The the centre connectors mate correctly together. Alan G3NYK - Original Message - From: Stan, W1LE stanw...@verizon.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, April 10, 2011 12:32 AM Subject: Re: [time-nuts] BNC question Hello Joe, It probably is a 50 ohm BNC female connector. Check out a male loose connector with a known 50 ohm center pin. Does the male pin fit the female nicely ? I have rarely seen a 75 ohm BNC center pin, but they are out there. I have never seen a 93 ohm BNC center pin. (never looked for them.) If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it may not mate properly with a low resistance joint. ie. poor mechanical fit. If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will probably destroy the female center pin. Cost wise, the 50 ohm BNC connectors are the least expensive, so that is what manufacturers use. For most applications the electrical length of the center pin is a very small part of a wavelength, so there is only a very small impact on the impedance, on the rare occasion impedance is of concern. Stan, W1LE On 4/9/2011 6:53 PM, Joseph Gray wrote: I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. I want to use these isolated BNC connectors for a frequency distribution amp. What do you think? I'm still trying to find some old Ethernet cards for the transformers. I know the cards will have BNC connectors, but the hub has eight matched BNC connectors, so using them would be preferrable. Joe Gray W5JG ___ 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] BNC question
At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a 50 Ohm BNC to me. The ARCNET spec states: The MIC for use with coaxial cable is a conventional BNC per MIL-STD-348A. If you look at that spec, it's for 50 Ohm connectors. 75 Ohm ones don't have the insulator around the center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't matter. ___ 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] BNC Question
Interestingly, 50 and 75-ohm BNC connectors have the same pin/shell dimensions and properly couple together. For more information go to _http://www.cliftonlaboratories.com/august_2007.htm_ (http://www.cliftonlaboratories.com/august_2007.htm) and scroll down to the 02 August 2007 entry. There is a link to the Amphenol site for specifics about the connectors. I am planning to use an Extron video distribution amplifier for standard frequency distribution. The 75-ohm connectors will be OK. These amplifiers feed multiple 75-ohm outputs from a zero-impedance source by inserting a 75-ohm resistor in each leg. Some folks using these for standard frequency distribution change the resistors to 50-ohms. Bruce, KG6OJI ___ 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] BNC Question
Sorri, I must have been thinking type N connectors. Stan, W1LE On 4/9/2011 8:18 PM, brucekar...@aol.com wrote: Interestingly, 50 and 75-ohm BNC connectors have the same pin/shell dimensions and properly couple together. For more information go to _http://www.cliftonlaboratories.com/august_2007.htm_ (http://www.cliftonlaboratories.com/august_2007.htm) and scroll down to the 02 August 2007 entry. There is a link to the Amphenol site for specifics about the connectors. I am planning to use an Extron video distribution amplifier for standard frequency distribution. The 75-ohm connectors will be OK. These amplifiers feed multiple 75-ohm outputs from a zero-impedance source by inserting a 75-ohm resistor in each leg. Some folks using these for standard frequency distribution change the resistors to 50-ohms. Bruce, KG6OJI ___ 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.
