Re: [Repeater-Builder] LMR feedline revisited and revised!
On 4/6/07, allan crites [EMAIL PROTECTED] wrote: Jeff DePolo, Gary Schafer, Nate Duehr, and Burt Lang, Thanks for the kind words, Allan -- but I really didn't add much to the topic other than to direct folks to information publicly available via Amphenol's website. It's been just as entertaining/educational for me to read along as anyone else, I'm sure... the folks here who've posted real RF engineering work on the topic shouldn't be weighed down with my name attached to them! (GRIN) I are just a ham here, but I do like to read and study the information from the folks who make a living doing this stuff... they've learned far more the hard way than I'll ever learn about the topic of repeaters! Nate WY0X
RE: [Repeater-Builder] LMR feedline revisited and revised!
contacts, leaving no air section, having improved power handling, high voltage breakdown, and VSWR, along with an improved quick connect / disconnect feature. One last item. I own an HP 8714A N/A and I'm sure I could make measurements of any parameters relating to the impedance and insertion loss of RF connectors. We did not have the equipment in 1955 to do the wondrous measurements available today. Allan Crites WA9ZZU Gary Schafer [EMAIL PROTECTED] wrote: Hi Allan, Coax line impedance is determined mainly by the size of the center conductor and its spacing to the outer shield of the cable and somewhat by the dielectric in the cable. The same is true for a connector. Any time you change the size of that center conductor or the spacing to the shell the impedance changes slightly. In a PL type connector the ratio of center conductor to shield changes from what the ratio of the cable to shield is so that gives an impedance change. A connector with a constant impedance may have different sizes of center conductors (center pin) than what the cable size is but that change in size maintains the same ratio of pin size to shield as the ratio of the cable center conductor to shield. That keeps the impedance the same through the connector as what the cable is. This is why a connector for a 75 ohm cable will be slightly different in size than one for 50 ohms. Note that 75 ohm cable has a smaller diameter center conductor than a 50 ohm cable that has the same outer shield size. 73 Gary K4FMX - From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of allan crites Sent: Thursday, March 22, 2007 10:57 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU Gary Schafer [EMAIL PROTECTED] wrote: -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, March 22, 2007 7:42 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 04:33 PM 3/22/2007, you wrote: doesn't make it right though considering the potentual losses. ---Pt...don't tell anyone but a PL259 ain't as horrible (loss wise at least) at VHF UHF as folklore would have you believe. The real issue is not of loss but rather that of a PL259 not being a constant impedance connector. This is where BNC's and N's shine. Ken Ken is exactly right! I would venture to say that there are probably few to none on this list that have any equipment that could measure the difference in loss between a PL259 and a good N connector. That loss thing is an old myth. Now as Ken said they are not a constant impedance and you will get a bump in the impedance with one that can give a mismatch in a fixed tuned circuit and you can have what is called mismatch loss which results from the circuit getting detuned slightly because of the impedance difference. There can also be swr losses caused by the impedance mismatch but a direct loss from the PL259 at VHF and UHF is almost non existent. At least not measurable. If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Case in point: The Motorola 2600 service monitor uses an N connector in order to meet the flatness spec over the entire range even though most people want a bnc for the rf connector on it. So they supply an N to bnc adaptor with each unit for those that insist on bnc connectors. 73 Gary K4FMX
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 3/22/2007 16:33, you wrote: From: Kevin Custer [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Date: Thu, 22 Mar 2007 18:03:43 -0400 Why would you even use pl259 connectors on uhf? Why not? Motorola and GE did? doesn't make it right though considering the potentual losses. PL259s are certainly not the ideal connector to use at 450 MHz, but if quality PL259s are used properly installed, they get the job done with negligible loss. Bob NO6B
RE: [Repeater-Builder] LMR feedline revisited and revised!
I've stayed out of the debate so far, but even Amphenol claims nominal 50 ohm impedance for their 50 ohm BNC connectors up to 4 GHz. On their N-connector they drop the nominal but they don't elaborate. BNC's are rated for a lower MUF because the mechanics of the bayonet lock aren't ideal. The inner portion of the connector can pivot somewhat depending on the angle the cable (or gravity) is pulling at. So, although the dielectric and the mating surfaces of the connector would likely work well above 4 GHz with creating a significant bump, the imperfections in bayonet causes it to be rated lower. In contrast, the TNC with its threaded attachment maintains the geometry better, and is thus rated for a higher frequency. The same issue exists between SMA and SMB connectors. Presumably SMA's are rated for higher MUF because the threaded coupling maintains a more consistent interface geometry as compared to SMB's which are push on connectors which leave more wiggle room (pun intended). N, BNC, TNC, LC, HN, SMA, et al were designed to maintain 50 ohms through the interface, though none are truly precision connectors. Not even an SMA is a precision connector. Precision connectors have virtually perfect mating repeatability. The most popular precision connectors are APC/GPC varients. They're more likely to be found on microwave test equipment. UHF connectors weren't designed for constant impedence. They were designed at a time when UHF was what we would now consider to be VHF-low, and the impedence bump was less of an issue. UHF connectors with Teflon dielectric have less of an impedence bump than cheaper (phenolic, bakelite, plastic, etc.) dielectric types. Some really cheezy UHF connectors have such high dielectric losses that they will get warm and, under very high power at VHF/UHF, actually melt. So stick with Teflon. I'll agree that maybe a BNC is not as good as an N-connector overall, but similar to your argument -- I'll bet no one here can measure the difference at VHF/UHF. Bet I can on my network analyzer :-) Seriously, with a good VNA, you'll be able to see changes in return loss at varying frequencies as you flex a BNC connection. Likewise, using TDR (or a VNA with time-domain analysis), you will be able to clearly see the bump in the line. Would you notice, or could you measure, the slight variation in Z of a BNC connection when it's flexed using a wattmeter or other gross measurement techniques at VHF or UHF? Probably not. But it's there. A UHF connector is tolerable on 70cm, providing it (and its mate) are Teflon dielectric. I will still try to avoid them whenever possible and stick with type N. Amp shows (much!) more RF leakage from a BNC than an N (which would be a detriment in some installations!) Again, due to the bayonet. One of the reasons you see UHF connectors on VHF and UHF mobile radios, including commercial radios, is because it is a lot harder to screw a UHF connector. You really have to work hard to bend a center pin on a PL-259, whereas a type N is a bit more delicate in that regard. Some may argue that a regular (solder-type) PL-259 is easier to install on a cable than a regular (mil clamp type) Type N, so that's why they were used (personally, I disagree, I always thought type N's were easier to put on). Nowadays, with the proliferation of crimp-type connectors, there is no advantage to one over the other. --- Jeff
RE: [Repeater-Builder] LMR feedline revisited and revised!
One of the reasons you see UHF connectors on VHF and UHF mobile radios, including commercial radios, is because it is a lot harder to screw a UHF connector. DOH! That should have said screw up a UHF connector. Blame Freud, and Ken with his Anna Nicole comment...
RE: [Repeater-Builder] LMR feedline revisited and revised!
Hi Allan, Coax line impedance is determined mainly by the size of the center conductor and its spacing to the outer shield of the cable and somewhat by the dielectric in the cable. The same is true for a connector. Any time you change the size of that center conductor or the spacing to the shell the impedance changes slightly. In a PL type connector the ratio of center conductor to shield changes from what the ratio of the cable to shield is so that gives an impedance change. A connector with a constant impedance may have different sizes of center conductors (center pin) than what the cable size is but that change in size maintains the same ratio of pin size to shield as the ratio of the cable center conductor to shield. That keeps the impedance the same through the connector as what the cable is. This is why a connector for a 75 ohm cable will be slightly different in size than one for 50 ohms. Note that 75 ohm cable has a smaller diameter center conductor than a 50 ohm cable that has the same outer shield size. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of allan crites Sent: Thursday, March 22, 2007 10:57 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU Gary Schafer [EMAIL PROTECTED] wrote: -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] mailto:Builder%40yahoogroups.com .com] On Behalf Of Ken Arck Sent: Thursday, March 22, 2007 7:42 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 04:33 PM 3/22/2007, you wrote: doesn't make it right though considering the potentual losses. ---Pt...don't tell anyone but a PL259 ain't as horrible (loss wise at least) at VHF UHF as folklore would have you believe. The real issue is not of loss but rather that of a PL259 not being a constant impedance connector. This is where BNC's and N's shine. Ken Ken is exactly right! I would venture to say that there are probably few to none on this list that have any equipment that could measure the difference in loss between a PL259 and a good N connector. That loss thing is an old myth. Now as Ken said they are not a constant impedance and you will get a bump in the impedance with one that can give a mismatch in a fixed tuned circuit and you can have what is called mismatch loss which results from the circuit getting detuned slightly because of the impedance difference. There can also be swr losses caused by the impedance mismatch but a direct loss from the PL259 at VHF and UHF is almost non existent. At least not measurable. If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Case in point: The Motorola 2600 service monitor uses an N connector in order to meet the flatness spec over the entire range even though most people want a bnc for the rf connector on it. So they supply an N to bnc adaptor with each unit for those that insist on bnc connectors. 73 Gary K4FMX
RE: [Repeater-Builder] LMR feedline revisited and revised!
-Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Thursday, March 22, 2007 11:04 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! On 3/22/07, Gary Schafer [EMAIL PROTECTED] wrote: If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Could you site a credible source that claims this? I can't find any references to impedance regarding BNC connectors. I've stayed out of the debate so far, but even Amphenol claims nominal 50 ohm impedance for their 50 ohm BNC connectors up to 4 GHz. On their N-connector they drop the nominal but they don't elaborate. They also say the BNC has low reflection below 4GHz... and their N connector specifications show nothing at all regarding that. The assumption here would be the N is slightly better again. And they show that you have to switch to a TNC for anything above 4GHz through 11GHz. Or the N again, of course. I'll agree that maybe a BNC is not as good as an N-connector overall, but similar to your argument -- I'll bet no one here can measure the difference at VHF/UHF. Amp shows (much!) more RF leakage from a BNC than an N (which would be a detriment in some installations!), insertion loss numbers that are within .05 dB of each other, and the center conductor also has a slightly higher resistance on the BNC vs. the N. If I missed anything there, here's their links: http://www.amphenolrf.com/products/bnc.asp http://www.amphenolrf.com/products/typen.asp But again, just like your comment about the PL259's... I would love to see a credible source on impedance measurements of BNC's that's available to the public. Don't worry, I'm not defending the BNC -- I'd rather not use them myself. Just playing devil's advocate on the statement, since it doesn't have any more credibility or science behind it than the PL259 comments did. I *can* find credible sources that show PL259's generally stink with real measurements at VHF/UHF... but I haven't been able to find such data for BNC's (yet). And judging by Amphenol's site, TNC's keep up pretty well with the N connector. Nate WY0X I don't know if I have seen this stuff in print either. I have gotten most of my info from engineers at Motorola and Wavetek. I used to sell their service monitors. Jeff pretty well sums up what the problems are with the bnc connectors. In most applications it doesn't matter much. But like I noted with the service monitors they could not maintain the output level and return loss spec with the bnc connectors and this was probably mostly due to the bnc not being a solid connector. Don't get me wrong, I am not saying that a bnc connector is junk. The comment was that if you want to worry about connectors then use an N rather than a bnc. This was for the benefit of those that worry about PL259's not being any good. The bnc is not too bad as HP used it on the front end of their older spectrum analyzers. They latter switched to a type N though. I guess they saw the light. :) A PL259 serves the purpose well in most cases and will have almost immeasurable loss but it will not have a constant impedance. Some places that matters and some places it does not. If you start sticking several PL type adaptors in line with your wattmeter you may see the wattmeter read different to what looks like loss but it is not loss in the adaptors or connectors. The change in impedance fools the wattmeter and it gives a different reading. If that change in impedance is reflected to a point where it upsets the tuning of a tuned circuit, like back to the output of a transmitter, then it can detune the transmitter slightly and actually cause it to put out less power. But the less output power is not due to connector loss. Jeff mentioned that non Teflon connectors get warm. I am not so sure that is due to poor dielectric or poor contact of the mating surfaces. Dielectric does not come into play much until you get into uhf. Coax cable dielectric makes little difference in cable loss thru vhf as most loss is attributed to resistive losses. 73 Gary K4FMX
Re: [Repeater-Builder] LMR feedline revisited and revised!
That is exactly what I am talking about. Aluminum braid on aluminum foil.. No more dissimilar metal problems right? Eric Lemmon wrote: Jay, You are referring to the blurb on the lower right corner of page 69 of the April, 2007, issue of QST. The notion of a lite version of any coaxial cable raises a red flag in my mind. Emotions aside, my take is that it will be LESS suitable for duplex work, and will enjoy the same low esteem earned by the new Belden 9913F cable. Inasmuch as the antenna and its feedline are usually the MOST critical components in any radio station, and usually are the MOST difficult to install, maintain, or troubleshoot (usually when freezing temperatures and high winds prevail), it hardly seems likely that anyone would even consider saving a few bucks to buy lite coaxial cable- but they are out there! 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Jay Urish Sent: Wednesday, March 21, 2007 9:01 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] LMR feedline revisited and revised! Did anybody see the ad for the 'new' LMR series feedline in this months league journal?(QST) They are going to an aluminum braid instead of the tinned copper. Its supposed to make it lighter and cheaper. Any opinions on whether this will make it more suitable for duplex work? -- Jay Urish W5GM ARRL Life Member Denton County ARRL VEC N5ERS VP/Trustee -- Jay Urish W5GM ARRL Life MemberDenton County ARRL VEC N5ERS VP/Trustee Monitoring 444.850 PL-88.5
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 06:16 AM 3/22/2007, you wrote: That is exactly what I am talking about. Aluminum braid on aluminum foil.. No more dissimilar metal problems right? You've still got a dissimilar issue with the connectors howevers Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
Re: [Repeater-Builder] LMR feedline revisited and revised!
Remember folks, you can't solder to aluminum. Anyone who says different and shows you the magic stick that can is a liar. I see demos of this crap at ham fests every now and then and every time I try to use it the joint looks good until you pick it up and the entire thing falls apart. That aluminum sloder paste doesn't work either and just makes a mess of your aluminum. The only real way to bond aluminum is with a TIG welder. And when you get the stuff hot enough to where it starts making a good bead it melts on you. So that would mean that only crimp on style connectors can be used with this type of coax. That would be fine for BNC and N, But most of the PL-259s wouldn't work. BTW leaving the braid on a PL-259 unsoldered is a good way to blow up the finals in your radio, so check your jumpers when you get a chance. It should be noted also that QST will usually post some kind of April fools joke in the April issue, so keep an eye out.
RE: [Repeater-Builder] LMR feedline revisited and revised!
FWIW - I used to weld aluminum with a gas torch (Oxy-Acetylene) a few years ago. And you are correct, it really took a bit to learn the touch needed to be able to do this. The rod melted at about 100 degrees lower than the work. (I repaired aluminum air conditioning condensers for cars...) Of course this process wont work with PL-259s, but I thought I'd add my 1.5¢ worth to the discussion... wink Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of DCFluX The only real way to bond aluminum is with a TIG welder. And when you get the stuff hot enough to where it starts making a good bead it melts on you. So that would mean that only crimp on style connectors can be used with this type of coax. That would be fine for BNC and N, But most of the PL-259s wouldn't work. BTW leaving the braid on a PL-259 unsoldered is a good way to blow up the finals in your radio, so check your jumpers when you get a chance. It should be noted also that QST will usually post some kind of April fools joke in the April issue, so keep an eye out.
Re: [Repeater-Builder] LMR feedline revisited and revised!
Yea, but dont you have that anyway? copper/zinc/tin/whatever pl259's and 2 piece N's are made of? Ken Arck wrote: At 06:16 AM 3/22/2007, you wrote: That is exactly what I am talking about. Aluminum braid on aluminum foil.. No more dissimilar metal problems right? You've still got a dissimilar issue with the connectors howevers Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net http://www.irlp.net
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 11:20 AM 3/22/2007, you wrote: Yea, but dont you have that anyway? copper/zinc/tin/whatever pl259's and 2 piece N's are made of? ---Let's see here. The braid is aluminum, the foil is aluminum but the connector is copper/zinc/tin or maybe silver. Sounds like dissimilar metal contact to me! Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
Re: [Repeater-Builder] LMR feedline revisited and revised!
I prefer to use 300 ohm twinlead and connect it right to the screw terminals on the back of the repeater. No connectors, no dissimilar metals- and the taller the tower the larger the radiator! BTW- Relax- That was a Joke. Tom W9SRV - Original Message From: Ken Arck [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Thursday, March 22, 2007 1:53:06 PM Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 11:20 AM 3/22/2007, you wrote: Yea, but dont you have that anyway? copper/zinc/tin/whatever pl259's and 2 piece N's are made of? ---Let's see here. The braid is aluminum, the foil is aluminum but the connector is copper/zinc/tin or maybe silver. Sounds like dissimilar metal contact to me! Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links Expecting? Get great news right away with email Auto-Check. Try the Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/newmail_tools.html
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 3/22/2007 11:58 AM, you wrote: I prefer to use 300 ohm twinlead and connect it right to the screw terminals on the back of the repeater. No connectors, no dissimilar metals- and the taller the tower the larger the radiator! Under ideal conditions twinlead doesn't radiate at all. However, anything that unbalances the line will cause it to radiate, including running it past another conductor in close proximity. Also, I'm not aware of any high-gain omni antenna designs that are balanced except possibly the vertically stacked dipole arrays. But then you'd have to design a corporate feed network out of twinlead too. Yikes!! Bob NO6B
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 11:58 AM 3/22/2007, you wrote: I prefer to use 300 ohm twinlead and connect it right to the screw terminals on the back of the repeater. No connectors, no dissimilar metals- and the taller the tower the larger the radiator! ---And here I thought balanced lines were only needed for SSB (balanced modulators and all that) Ken (wow, is it April already??) -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
RE: [Repeater-Builder] LMR feedline revisited and revised!
From: N9WYS [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! Date: Thu, 22 Mar 2007 12:10:58 -0500 FWIW - I used to weld aluminum with a gas torch (Oxy-Acetylene) a few years ago. And you are correct, it really took a bit to learn the touch needed to be able to do this. The rod melted at about 100 degrees lower than the work. (I repaired aluminum air conditioning condensers for cars...) Of course this process wont work with PL-259s, but I thought I'd add my 1.5¢ worth to the discussion... wink Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of DCFluX The only real way to bond aluminum is with a TIG welder. And when you get the stuff hot enough to where it starts making a good bead it melts on you. Not true , there are some special gas torches which make the job much easier The name escapes me as I use a tig for alloy but they are just a little hotter than a map gas unit . So that would mean that only crimp on style connectors can be used with this type of coax. That would be fine for BNC and N, But most of the PL-259s wouldn't work. Wby would you even use pl259 connectors on uhf ? BTW leaving the braid on a PL-259 unsoldered is a good way to blow up the finals in your radio, so check your jumpers when you get a chance. It should be noted also that QST will usually post some kind of April fools joke in the April issue, so keep an eye out. _ Advertisement: Its simple! Sell your car for just $20 at carsales.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fsecure%2Dau%2Eimrworldwide%2Ecom%2Fcgi%2Dbin%2Fa%2Fci%5F450304%2Fet%5F2%2Fcg%5F801577%2Fpi%5F1005244%2Fai%5F838588_t=754951090_r=tig_m=EXT Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] LMR feedline revisited and revised!
Why would you even use pl259 connectors on uhf? Why not? Motorola and GE did?
Re: [Repeater-Builder] LMR feedline revisited and revised!
Wby would you even use pl259 connectors on uhf ? Because 90% of the ham equipment (not including HT's) I have seen made for UHF does. The UHF MASTR-II series comes with SO-239s, N was common on the 800 stuff. About the only time I have seen N seriously used is on duplexers and circulators. People can also use this cable on HF and VHF where PL-259s are common. To date I have never seen a 'clamp' style PL-259. I have one for Heliax, but that doesn't count.
Re: [Repeater-Builder] LMR feedline revisited and revised!
Wby would you even use pl259 connectors on uhf ? Because a PL-259 is required for the best mobile UHF radio ever made. Motorola Syntor X W4DEX
Re: [Repeater-Builder] LMR feedline revisited and revised!
From: Dexter McIntyre W4DEX [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Date: Thu, 22 Mar 2007 18:39:25 -0400 Wby would you even use pl259 connectors on uhf ? Because a PL-259 is required for the best mobile UHF radio ever made. Motorola Syntor X W4DEX Not on either of mine , both have bnc fittings. _ Advertisement: Find new used iPods; designer clothing and more. Join free at http://www.ebay.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Frover%2Eebay%2Ecom%2Frover%2F1%2F705%2D10129%2D5668%2D323%2F4%2F%3Fid%3D3_t=760348364_r=Findnew_m=EXT
Re: [Repeater-Builder] LMR feedline revisited and revised!
From: Kevin Custer [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Date: Thu, 22 Mar 2007 18:03:43 -0400 Why would you even use pl259 connectors on uhf? Why not? Motorola and GE did? doesn't make it right though considering the potentual losses. _ Advertisement: Want FREE talk text to 5 Telstra numbers? Find out how http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fadsfac%2Enet%2Flink%2Easp%3Fcc%3DTEL243%2E40035%2E0%26clk%3D1%26creativeID%3D56076_t=761565722_r=Hotmail_email_tagline_1March07_m=EXT Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] LMR feedline revisited and revised!
From: DCFluX [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Date: Thu, 22 Mar 2007 15:05:09 -0700 Wby would you even use pl259 connectors on uhf ? Because 90% of the ham equipment (not including HT's) I have seen made for UHF does. Dosnt make it right though I have several Jap TX here and all the units with uhf use other fittings. The UHF MASTR-II series comes with SO-239s, N was common on the 800 stuff. About the only time I have seen N seriously used is on duplexers and circulators. People can also use this cable on HF and VHF where PL-259s are common. To date I have never seen a 'clamp' style PL-259. I have one for Heliax, but that doesn't count. _ Advertisement: Your Future Starts Here. Dream it? Then be it! Find it at www.seek.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fninemsn%2Eseek%2Ecom%2Eau%2F%3Ftracking%3Dsk%3Ahet%3Ask%3Anine%3A0%3Ahot%3Atext_t=754951090_r=seek_m=EXT
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 04:33 PM 3/22/2007, you wrote: doesn't make it right though considering the potentual losses. ---Pt...don't tell anyone but a PL259 ain't as horrible (loss wise at least) at VHF UHF as folklore would have you believe. The real issue is not of loss but rather that of a PL259 not being a constant impedance connector. This is where BNC's and N's shine. Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
Re: [Repeater-Builder] LMR feedline revisited and revised!
Barry C' wrote: Why would you even use pl259 connectors on uhf? Why not? Motorola and GE did? doesn't make it right though considering the potentual losses. Yea, what the heck do they know about radio anyway? Kevin
RE: [Repeater-Builder] LMR feedline revisited and revised!
-Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, March 22, 2007 7:42 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 04:33 PM 3/22/2007, you wrote: doesn't make it right though considering the potentual losses. ---Pt...don't tell anyone but a PL259 ain't as horrible (loss wise at least) at VHF UHF as folklore would have you believe. The real issue is not of loss but rather that of a PL259 not being a constant impedance connector. This is where BNC's and N's shine. Ken Ken is exactly right! I would venture to say that there are probably few to none on this list that have any equipment that could measure the difference in loss between a PL259 and a good N connector. That loss thing is an old myth. Now as Ken said they are not a constant impedance and you will get a bump in the impedance with one that can give a mismatch in a fixed tuned circuit and you can have what is called mismatch loss which results from the circuit getting detuned slightly because of the impedance difference. There can also be swr losses caused by the impedance mismatch but a direct loss from the PL259 at VHF and UHF is almost non existent. At least not measurable. If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Case in point: The Motorola 2600 service monitor uses an N connector in order to meet the flatness spec over the entire range even though most people want a bnc for the rf connector on it. So they supply an N to bnc adaptor with each unit for those that insist on bnc connectors. 73 Gary K4FMX
Re: [Repeater-Builder] LMR feedline revisited and revised!
Gary wrote: Yes I know you can plug an N connector into a bnc. Yes you can but I believe you will find the pin on a N male is larger than a BNC female is designed to take. A 75 ohm N pin is probably close to the same as a BNC. Years ago after finding broken BNC jacks on some high dollar test equipment I learned to use an adapter if needed. W4DEX BTW, has anyone other than Barry ever seen a BNC antenna connector on a Syntor X?
Re: [Repeater-Builder] LMR feedline revisited and revised!
At 07:47 PM 3/22/2007, you wrote: Yes you can but I believe you will find the pin on a N male is larger than a BNC female is designed to take. Hey! Keep the Anna Nicole Smith talk down to a low whisper, ok? Ken (sometimes you just can't pass one by) -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
RE: [Repeater-Builder] LMR feedline revisited and revised!
I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU Gary Schafer [EMAIL PROTECTED] wrote: -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, March 22, 2007 7:42 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 04:33 PM 3/22/2007, you wrote: doesn't make it right though considering the potentual losses. ---Pt...don't tell anyone but a PL259 ain't as horrible (loss wise at least) at VHF UHF as folklore would have you believe. The real issue is not of loss but rather that of a PL259 not being a constant impedance connector. This is where BNC's and N's shine. Ken Ken is exactly right! I would venture to say that there are probably few to none on this list that have any equipment that could measure the difference in loss between a PL259 and a good N connector. That loss thing is an old myth. Now as Ken said they are not a constant impedance and you will get a bump in the impedance with one that can give a mismatch in a fixed tuned circuit and you can have what is called mismatch loss which results from the circuit getting detuned slightly because of the impedance difference. There can also be swr losses caused by the impedance mismatch but a direct loss from the PL259 at VHF and UHF is almost non existent. At least not measurable. If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Case in point: The Motorola 2600 service monitor uses an N connector in order to meet the flatness spec over the entire range even though most people want a bnc for the rf connector on it. So they supply an N to bnc adaptor with each unit for those that insist on bnc connectors. 73 Gary K4FMX
Re: [Repeater-Builder] LMR feedline revisited and revised!
On 3/22/07, Gary Schafer [EMAIL PROTECTED] wrote: If you really want to get picky use only N connectors and not even bnc. A bnc is not a constant impedance connector either although somewhat better than a PL259. Yes I know you can plug an N connector into a bnc but the bnc still is not a constant impedance device. Could you site a credible source that claims this? I can't find any references to impedance regarding BNC connectors. I've stayed out of the debate so far, but even Amphenol claims nominal 50 ohm impedance for their 50 ohm BNC connectors up to 4 GHz. On their N-connector they drop the nominal but they don't elaborate. They also say the BNC has low reflection below 4GHz... and their N connector specifications show nothing at all regarding that. The assumption here would be the N is slightly better again. And they show that you have to switch to a TNC for anything above 4GHz through 11GHz. Or the N again, of course. I'll agree that maybe a BNC is not as good as an N-connector overall, but similar to your argument -- I'll bet no one here can measure the difference at VHF/UHF. Amp shows (much!) more RF leakage from a BNC than an N (which would be a detriment in some installations!), insertion loss numbers that are within .05 dB of each other, and the center conductor also has a slightly higher resistance on the BNC vs. the N. If I missed anything there, here's their links: http://www.amphenolrf.com/products/bnc.asp http://www.amphenolrf.com/products/typen.asp But again, just like your comment about the PL259's... I would love to see a credible source on impedance measurements of BNC's that's available to the public. Don't worry, I'm not defending the BNC -- I'd rather not use them myself. Just playing devil's advocate on the statement, since it doesn't have any more credibility or science behind it than the PL259 comments did. I *can* find credible sources that show PL259's generally stink with real measurements at VHF/UHF... but I haven't been able to find such data for BNC's (yet). And judging by Amphenol's site, TNC's keep up pretty well with the N connector. Nate WY0X
RE: [Repeater-Builder] LMR feedline revisited and revised!
I think she could take any size pin. Fred Sorry couldn't resist. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, March 22, 2007 9:53 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! At 07:47 PM 3/22/2007, you wrote: Yes you can but I believe you will find the pin on a N male is larger than a BNC female is designed to take. Hey! Keep the Anna Nicole Smith talk down to a low whisper, ok? Ken (sometimes you just can't pass one by) -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.arcomcontrollers.com/ Coming soon - the most advanced repeater controller EVER. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links
RE: [Repeater-Builder] LMR feedline revisited and revised!
Allan, That's a good question! Both N and BNC connectors vary the dielectric thickness, and the spacing and diameter of the center and shield elements, so that the swept impedance seen by a Time-Domain Spectrometer (TDR Test Set) shows no variation in characteristic impedance through the connector. When a Constant-Impedance connector is installed CORRECTLY in a transmission line, its presence will not be revealed when swept with a TDR Test Set. The infamous PL-259 plug, when mated with the matching SO-239 jack, is far from constant impedance. Even the most basic TDR Test Set can detect the impedance bump where UHF connectors are used. Where the impedance is not constant, unwanted parasitic oscillations can occur, which means that intermodulation and spurious signals have a fertile breeding ground. Moreover, the ideal RF transmission system comprises cable and connectors that present a uniform 50-ohm impedance, without any significant bumps or dips. This cannot be achieved with RF connectors that do not have constant impedance. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of allan crites Sent: Thursday, March 22, 2007 7:57 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU
RE: [Repeater-Builder] LMR feedline revisited and revised!
Roger that. They will plug in but will destroy the bnc side. 73 Gary K4FMX -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Dexter McIntyre W4DEX Sent: Thursday, March 22, 2007 10:47 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Gary wrote: Yes I know you can plug an N connector into a bnc. Yes you can but I believe you will find the pin on a N male is larger than a BNC female is designed to take. A 75 ohm N pin is probably close to the same as a BNC. Years ago after finding broken BNC jacks on some high dollar test equipment I learned to use an adapter if needed. W4DEX BTW, has anyone other than Barry ever seen a BNC antenna connector on a Syntor X? Yahoo! Groups Links
Re: [Repeater-Builder] LMR feedline revisited and revised!
Hi folks I have heard that the military will not allow BNCs on RF connections because the bayonet connection on the outside shell allows the ground side of the cable to vary (wiggle) and be noisy. BNCs appear to be used for data and low freq but TNCs are specified for RF use. Some years ago a local club was having trouble with their homebuilt duplexor that used BNC connectors on the cable connections. The duplexor became noisy intermittantly. Move the cables and it would quiet down for a few days but would always return. I suppled them with equivalent TNC connectors for the duplexor and they never had trouble again from that source. The standard PL259/SO239 combo has an impedance of approximately 35 ohms. If the insulation is removed from the SO239, the impedance is close to 50 ohms. I did see a Japanese wattmeter (I think it was Yaesu) that had insulatorless SO239s on it. One problem with the PL259 that I have not seen mentioned is that it is not weatherproof and the ground connection is problematic at best. It is very easy to tighten the shell and then find it loose because the teeth on the PL259 were not bottomed into the notches in the SO-239. Just my 2c for what it is worth. Burt VE2BMQ Eric Lemmon wrote: Allan, That's a good question! Both N and BNC connectors vary the dielectric thickness, and the spacing and diameter of the center and shield elements, so that the swept impedance seen by a Time-Domain Spectrometer (TDR Test Set) shows no variation in characteristic impedance through the connector. When a Constant-Impedance connector is installed CORRECTLY in a transmission line, its presence will not be revealed when swept with a TDR Test Set. The infamous PL-259 plug, when mated with the matching SO-239 jack, is far from constant impedance. Even the most basic TDR Test Set can detect the impedance bump where UHF connectors are used. Where the impedance is not constant, unwanted parasitic oscillations can occur, which means that intermodulation and spurious signals have a fertile breeding ground. Moreover, the ideal RF transmission system comprises cable and connectors that present a uniform 50-ohm impedance, without any significant bumps or dips. This cannot be achieved with RF connectors that do not have constant impedance. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of allan crites Sent: Thursday, March 22, 2007 7:57 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU
RE: [Repeater-Builder] LMR feedline revisited and revised!
True, but I don't think she was constant impedance, either... Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Fred Flowers I think she could take any size pin. Fred Sorry couldn't resist. -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Ken Arck At 07:47 PM 3/22/2007, you wrote: Yes you can but I believe you will find the pin on a N male is larger than a BNC female is designed to take. Hey! Keep the Anna Nicole Smith talk down to a low whisper, ok? Ken (sometimes you just can't pass one by)
Re: [Repeater-Builder] LMR feedline revisited and revised!
I think I will continue to use crimps and proper rubber seal wrap . From: Burt Lang [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR feedline revisited and revised! Date: Fri, 23 Mar 2007 01:12:41 -0400 Hi folks I have heard that the military will not allow BNCs on RF connections because the bayonet connection on the outside shell allows the ground side of the cable to vary (wiggle) and be noisy. BNCs appear to be used for data and low freq but TNCs are specified for RF use. Some years ago a local club was having trouble with their homebuilt duplexor that used BNC connectors on the cable connections. The duplexor became noisy intermittantly. Move the cables and it would quiet down for a few days but would always return. I suppled them with equivalent TNC connectors for the duplexor and they never had trouble again from that source. The standard PL259/SO239 combo has an impedance of approximately 35 ohms. If the insulation is removed from the SO239, the impedance is close to 50 ohms. I did see a Japanese wattmeter (I think it was Yaesu) that had insulatorless SO239s on it. One problem with the PL259 that I have not seen mentioned is that it is not weatherproof and the ground connection is problematic at best. It is very easy to tighten the shell and then find it loose because the teeth on the PL259 were not bottomed into the notches in the SO-239. Just my 2c for what it is worth. Burt VE2BMQ Eric Lemmon wrote: Allan, That's a good question! Both N and BNC connectors vary the dielectric thickness, and the spacing and diameter of the center and shield elements, so that the swept impedance seen by a Time-Domain Spectrometer (TDR Test Set) shows no variation in characteristic impedance through the connector. When a Constant-Impedance connector is installed CORRECTLY in a transmission line, its presence will not be revealed when swept with a TDR Test Set. The infamous PL-259 plug, when mated with the matching SO-239 jack, is far from constant impedance. Even the most basic TDR Test Set can detect the impedance bump where UHF connectors are used. Where the impedance is not constant, unwanted parasitic oscillations can occur, which means that intermodulation and spurious signals have a fertile breeding ground. Moreover, the ideal RF transmission system comprises cable and connectors that present a uniform 50-ohm impedance, without any significant bumps or dips. This cannot be achieved with RF connectors that do not have constant impedance. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of allan crites Sent: Thursday, March 22, 2007 7:57 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] LMR feedline revisited and revised! I sure would like to hear what you all mean by constant impedance . Allan Crites, WA9ZZU _ Advertisement: Its simple! Sell your car for just $20 at carsales.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fsecure%2Dau%2Eimrworldwide%2Ecom%2Fcgi%2Dbin%2Fa%2Fci%5F450304%2Fet%5F2%2Fcg%5F801577%2Fpi%5F1005244%2Fai%5F838588_t=754951090_r=tig_m=EXT
RE: [Repeater-Builder] LMR feedline revisited and revised!
Jay, You are referring to the blurb on the lower right corner of page 69 of the April, 2007, issue of QST. The notion of a lite version of any coaxial cable raises a red flag in my mind. Emotions aside, my take is that it will be LESS suitable for duplex work, and will enjoy the same low esteem earned by the new Belden 9913F cable. Inasmuch as the antenna and its feedline are usually the MOST critical components in any radio station, and usually are the MOST difficult to install, maintain, or troubleshoot (usually when freezing temperatures and high winds prevail), it hardly seems likely that anyone would even consider saving a few bucks to buy lite coaxial cable- but they are out there! 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jay Urish Sent: Wednesday, March 21, 2007 9:01 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] LMR feedline revisited and revised! Did anybody see the ad for the 'new' LMR series feedline in this months league journal?(QST) They are going to an aluminum braid instead of the tinned copper. Its supposed to make it lighter and cheaper. Any opinions on whether this will make it more suitable for duplex work? -- Jay Urish W5GM ARRL Life Member Denton County ARRL VEC N5ERS VP/Trustee
