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[S&DWS] Foundation Course Material in PDF Format
Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...in-pdf-format/ PDF File versions for the Foundation Course Fslide01-Introduction and Registration Fslide02-Nature-of-Amateur-Radio Fslide03-Safety Fslide04-Licence-Conditions Fslide05-Transmitters-and-Receivers Fslide06-Propagation Fslide07-Feeders-and-Antennas Fslide08-EMC Fslide09-Technical-Basics Fslide09-Technical-Basics Fslide10-Repeaters-and-CTCSS |
[S&DWS] Foundation Course Material in PDF Format
In message , S&DWS via
rec.radio.info Admin writes Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...in-pdf-format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are warned "Take care not to mix incompatible 50 and 75 Ohm versions which have different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both sexes). -- Ian |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 09:32, Ian Jackson wrote:
Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...in-pdf-format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are warned "Take care not to mix incompatible 50 and 75 Ohm versions which have different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both sexes). This is far too technical for a 'training scheme' that produces Fulls who have to ask the question "USB/LSB? I'm confused!". -- Spike |
[S&DWS] Foundation Course Material in PDF Format
In message , Spike
writes On 19/08/2017 09:32, Ian Jackson wrote: Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...aterial-in-pdf -format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are warned "Take care not to mix incompatible 50 and 75 Ohm versions which have different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both sexes). This is far too technical for a 'training scheme' that produces Fulls who have to ask the question "USB/LSB? I'm confused!". Don't worry - I can also confirm that both impedances of BNC connectors are totally compatible with both USB and LSB. -- Ian |
[S&DWS] Foundation Course Material in PDF Format
"Ian Jackson" wrote in message ... In message , S&DWS via rec.radio.info Admin writes Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...in-pdf-format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are warned "Take care not to mix incompatible 50 and 75 Ohm versions which have different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... |
[S&DWS] Foundation Course Material in PDF Format
In message , Jimbo
writes "Ian Jackson" wrote in message ... In message , S&DWS via rec.radio.info Admin writes Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...aterial-in-pdf -format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are warned "Take care not to mix incompatible 50 and 75 Ohm versions which have different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... For 43 years, my day job was cable TV - so I've rarely used anything other than 75 ohm coax! Some cable TV trunk coax used to be (as one of my bosses put it) "as thick as a horse's prick". Unfortunately, it was not too convenient for home use. But as for BNC connectors, they are essentially the same as the innards of 50 ohm N-connectors. You can mate a female BNC with a male 50 ohm N. However, note that you can't inter-mate 50 and 75 ohm N-connectors, as the 75 ohm has a much thinner pin. A 50 ohm female in a 75 ohm male won't make contact (unless you put a bit of wire inside the female receptacle). A 50 ohm male fully mated with a 75 ohm female will splay the receptacle, and cause usually permanent damage. -- Ian |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 09:32, Ian Jackson wrote:
This is NOT totally correct. While the profile of the pins are slightly different (the 50 ohm usually has a somewhat stubbier point), the diameters are the same. The difference in characteristic impedance is achieved by the amount of PTFE dielectric. An interesting snippet, Ian, thanks. Perhaps time to remind all that BNC is Bayonet-Neill-Concelman and not Bayonet Navy Connector, as M3s and M6s past and present and other similar CBers maintain. |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 09:52, Ian Jackson wrote:
Spike writes On 19/08/2017 09:32, Ian Jackson wrote: Sheffield & District Wireless Society /////////////////////////////////////////// Foundation Course Material in PDF Format Posted: 18 Aug 2017 04:04 AM PDT http://sheffieldwireless.org/2017/08...aterial-in-pdf -format/ PDF File versions for the Foundation Course Please may I offer one correction: In 'Antennas & Feeders', the information about BNC connectors, you are* warned "Take care not to mix incompatible 50 and 75 Ohm versions which have* different inner pin sizes". This is NOT totally correct. While the profile of the pins are slightly* different (the 50 ohm usually has a somewhat stubbier point), the* diameters are the same. The difference in characteristic impedance is* achieved by the amount of PTFE dielectric. As a result, you CAN physically mate 50 and 75 ohm BNC connectors (both* sexes). This is far too technical for a 'training scheme' that produces Fulls who have to ask the question "USB/LSB? I'm confused!". Don't worry - I can also confirm that both impedances of BNC connectors are totally compatible with both USB and LSB. I doubt knowing that would help the woodentop Full. -- Spike |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 10:34, Jimbo wrote:
sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) |
[S&DWS] Foundation Course Material in PDF Format
In message , Jeff writes
However, note that you can't inter-mate 50 and 75 ohm N-connectors, as the 75 ohm has a much* thinner pin. A 50 ohm female in a 75 ohm male won't make contact (unless you put a bit of wire inside the female receptacle). A 50 ohm male fully mated with a 75 ohm female will splay the receptacle, and cause usually permanent damage. The 50 & 75 ohm BNCs that I have in front of me at the moment have identical pin dimensions. Also the spec sheets on Amphenol's website show the pins as being the same dimension. Are there any drawings? If so, do they show the 50 ohm pin being somewhat 'bull-nosed', while the 75 is more pointed - and the differences in the PTFE dielectric 'sleeve'? -- Ian |
[S&DWS] Foundation Course Material in PDF Format
In message , Gareth's Downstairs Computer
writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! -- Ian |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 13:05, Ian Jackson wrote:
In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). Â*Â* when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. The N connector was designed by Neill, the C by Concelman, and they got together to create the BNC and TNC. But the _REAL_ reason that the N connector is so called is because there are N different ways to assemble it, and all of them wrong! :-) |
[S&DWS] Foundation Course Material in PDF Format
when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... For 43 years, my day job was cable TV - so I've rarely used anything other than 75 ohm coax! watch out brian will start slagging you off about digging holes now....tee hee |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/17 13:05, Ian Jackson wrote:
In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. |
[S&DWS] Foundation Course Material in PDF Format
"Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... |
[S&DWS] Foundation Course Material in PDF Format
In message , Brian Reay writes
On 19/08/17 13:05, Ian Jackson wrote: In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. As already mentioned about the N-connector, the B&L assembly is almost specifically designed to be botched. [Note: 'Botched' is the word, not 'bodged'!] The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. These days, because of the American use, the F-connector is the standard RF connector on all customer cable TV equipment (and also used a lot on headend and associated equipment). One technical virtue of the F male connector is that the 'pin' is simply the cable inner. That should not prevent it aligning with the female receptacle, unless whoever cut the cable bent it while doing so. It helps mating if the inner is cut to the correct length, ie protruding 1/16th inch. While the structural return loss of the F male connector is essentially perfect, it's the capacitance of the female that limits the top frequency. Like many connectors, it can be used at frequencies well above where it should be! These days, the cable TV industry uses various types of 'snap and seal' male connectors (the old crimp type are definitely verboten). However, for home use, for convenience I normally use the domestic screw-on type. Like the B&L, the secret is knowing what to do with the braid. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. The company once had a clear-out, and (among a lot of stuff) was going to dump several 1000' reels of RG11. Needless to say, I and another licensed co-worker tried to help them out with some of the cable. We offered it to three or four of the local clubs, but it was refused on the grounds that it was 75 ohms. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. -- Ian |
[S&DWS] Foundation Course Material in PDF Format
On Sat, 19 Aug 2017 15:35:41 +0100, "Jimbo"
wrote: "Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... Type 43 connector? |
[S&DWS] Foundation Course Material in PDF Format
On Sat, 19 Aug 2017 15:22:26 +0100, Brian Reay wrote:
On 19/08/17 13:05, Ian Jackson wrote: In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. Oh! has he finished? I dozed off for a moment there. |
[S&DWS] Foundation Course Material in PDF Format
The company once had a clear-out, and (among a lot of stuff) was going to dump several 1000' reels of RG11. Needless to say, I and another licensed co-worker tried to help them out with some of the cable. We offered it to three or four of the local clubs, but it was refused on the grounds that it was 75 ohms. I have an swr bridge that is switched 52/75 ohms ......... |
[S&DWS] Foundation Course Material in PDF Format
"Rambo" wrote in message ... On Sat, 19 Aug 2017 15:35:41 +0100, "Jimbo" wrote: "Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... Type 43 connector? no idea ... oh was that a submarine joke? .... |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/17 16:25, Rambo wrote:
On Sat, 19 Aug 2017 15:22:26 +0100, Brian Reay wrote: On 19/08/17 13:05, Ian Jackson wrote: In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. Oh! has he finished? I dozed off for a moment there. That short attention span probably contributes to your problems studying and acquiring technical knowledge. That accounts for your problems with the Advanced Exam and lack of other qualifications. You should really have tried to seek help earlier, you could perhaps have improved it and achieved at least some worthwhile qualifications. |
[S&DWS] Foundation Course Material in PDF Format
On 19/08/2017 16:25, Rambo wrote:
Brian Reay wrote: Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. Oh! has he finished? I dozed off for a moment there. It's the sledgehammer and nut syndrome, rather like using a VNA to set up an antenna when the distant station couldn't tell the difference between the results for that and using a 20p light bulb to do the same thing. -- Spike |
[S&DWS] Foundation Course Material in PDF Format
On Sat, 19 Aug 2017 16:53:49 +0100, "Jimbo"
wrote: "Rambo" wrote in message .. . On Sat, 19 Aug 2017 15:35:41 +0100, "Jimbo" wrote: "Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... Type 43 connector? no idea ... oh was that a submarine joke? .... No it's a coax connector http://www.servicepower.co.uk/catego...43-connectors/ |
[S&DWS] Foundation Course Material in PDF Format
On Sat, 19 Aug 2017 18:06:12 +0100, Brian Reay wrote:
On 19/08/17 16:25, Rambo wrote: On Sat, 19 Aug 2017 15:22:26 +0100, Brian Reay wrote: On 19/08/17 13:05, Ian Jackson wrote: In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. Oh! has he finished? I dozed off for a moment there. That short attention span probably contributes to your problems studying and acquiring technical knowledge. That accounts for your problems with the Advanced Exam and lack of other qualifications. You should really have tried to seek help earlier, you could perhaps have improved it and achieved at least some worthwhile qualifications. Perhaps if you should refrain from your self indulgent monologues and also take a break from fretting about others, and actually post something of interest, you wouldn't come across as such a dull crushing repetitive bore. |
[S&DWS] Foundation Course Material in PDF Format
"Rambo" wrote in message ... On Sat, 19 Aug 2017 18:06:12 +0100, Brian Reay wrote: On 19/08/17 16:25, Rambo wrote: On Sat, 19 Aug 2017 15:22:26 +0100, Brian Reay wrote: On 19/08/17 13:05, Ian Jackson wrote: In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! Well, the B&L connectors are used for TV which covers well into the 100s of MHz. There is also the F connector, another 'cheap and cheerful' beast, used beyond 1GHz. I've not done any measurements but it obviously performs were enough for the task demanded of it. Both the B&L and F connector suffer (as do all connectors) problems if not fitted correctly but they are more prone to being 'bodged'. The B&L is, for example. prone to issues with poor braid bonding while the F connector, which uses the centre conductor as the pin, tend to be prone to the 'pin' not aligning etc. I believe the F connector is used in the US where we would, generally, expect to see a B&L connector. I believe the B&L is virtually unknown in the US. I was contacted by a US amateur some time back who had acquired a bit of UK kit (KW?) which had B&L sockets. He'd not seen them before. I sent him some plugs etc. Of course, there is nothing 'magic' about 50 ohm coax or the connectors we 'normally' use on our radios. If we were to stick to using 75 ohm coax and B&L connectors the world wouldn't end. Likewise, if you mixed 50 ohm and 75 ohm, while you may be able to measure a slight difference, chances are, in real terms, it wouldn't make much difference to the overall set up performance- at least unless you were doing something 'exotic'. You'd be more likely to notice the impact of a poorly fitted 'correct' connector in an all 50 ohm system. I tend to favour N types but I've not change all the connectors on my radios. The 'first' patch lead as whatever the radio needs on one end and required N type to connect to rest on the station on the other. The same for my mobile set ups. I also have a good collect of, quality, interseries, adaptors etc and a set of the correct connectors for my Bird power meters and dummy load etc. Through in a few home brew special adaptor leads for things I don't have adaptors for and I can interconnect virtually anything. Oh! has he finished? I dozed off for a moment there. That short attention span probably contributes to your problems studying and acquiring technical knowledge. That accounts for your problems with the Advanced Exam and lack of other qualifications. You should really have tried to seek help earlier, you could perhaps have improved it and achieved at least some worthwhile qualifications. Perhaps if you should refrain from your self indulgent monologues and also take a break from fretting about others, and actually post something of interest, you wouldn't come across as such a dull crushing repetitive bore. he is isn't he ...... |
[S&DWS] Foundation Course Material in PDF Format
"Rambo" wrote in message ... On Sat, 19 Aug 2017 16:53:49 +0100, "Jimbo" wrote: "Rambo" wrote in message . .. On Sat, 19 Aug 2017 15:35:41 +0100, "Jimbo" wrote: "Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... Type 43 connector? no idea ... oh was that a submarine joke? .... No it's a coax connector http://www.servicepower.co.uk/catego...43-connectors/ no don't think I have any of those ...... |
[S&DWS] Foundation Course Material in PDF Format
On Sat, 19 Aug 2017 20:33:52 +0100, "Jimbo"
wrote: "Rambo" wrote in message .. . On Sat, 19 Aug 2017 16:53:49 +0100, "Jimbo" wrote: "Rambo" wrote in message ... On Sat, 19 Aug 2017 15:35:41 +0100, "Jimbo" wrote: "Ian Jackson" wrote in message ... In message , Gareth's Downstairs Computer writes On 19/08/2017 10:34, Jimbo wrote: sexes). when I was newly licensed and poor I used 75 ohm TV coax and belling lee connectors on HF and got away with it ....... And it was standard on 145MHz. (QQV03-10 anyone?) Actually, the original B&L connector is a pretty good 75 ohm match up to 1GHz and more. If I remember correctly, many 50 ohm BNCs are not so hot 500MHz. With 75 ohms, the problem is maintaining the structural return loss constant while having enough PTFE insulation to hold the pin in place. Some are only really good to around 200Mhz. Of course, for most purposes, both are usable to much higher frequencies. And mixable! I got a load of weird connectors and adaptors from a guy that worked at the sub base at New London in 1979 ...still using them ...... Type 43 connector? no idea ... oh was that a submarine joke? .... No it's a coax connector http://www.servicepower.co.uk/catego...43-connectors/ no don't think I have any of those ...... I've seen too bloody many !!!! |
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