Re: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
On May 11, 2008, at 9:52 AM, n9wys wrote: Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually “unnoticed”… :-( Mark – N9WYS From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don’t have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP I noticed, and want to get my hands on some for a future project... (GRIN). Just had nothing to say about it... other than perhaps, Thanks for sharing! -- Nate Duehr, WY0X [EMAIL PROTECTED] 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] Re: Best coax for short jumpers in repeater cabinet?
At 04:50 PM 5/11/08 -, you wrote: Are you sure you don't mean 'RG-223' there, Skipper-doo? I use a lot of this on my bench and home equipment, for the same reasons the Skipp points out - it's cheap and effective. It's the same size (approximately) as RG-58, and uses mostly the same connectors (occasionally I'll get a crimp connector collar that's a little snug...) One doesn't have to go high dollar overkill spec all the time. I'm also a fairly big fan of RG-233 Coax for many repeater system/equipment applications. RG-233 seems to be the ignored step child of the coax family, which means it's not instant shark bait every time it pops up on Ebay and the surplus radio world market. I found a fairly decent price on some pre-made RG-233 Coax runs on Ebay: Cable Assembly RF Coax 7 ft RG-223/U N-Fe to SMA Male Ebay Item number: 190175957842 My offer to the seller for 2/3 the asking amount was accepted and I now have a fair number of those lines in my collection at a much better than the $3.10 (Tessco) list price per foot. Not a bad deal if you want to take the plunge... cheers, skipp skipp025 at yahoo.com www.radiowrench.com See you at Dayton! I'm the short chubby guy with red hair. [EMAIL PROTECTED] wrote: Hi Brent, I agree with Skipp, the LMR is not the cable i would recommend in a duplex repeater install. If you want jumper coax, I only use RG400 and it is a plenum rated silver plated with double shield braid silver. Both Motorola and Kenwood systems use this coax for there internal cableing inside the cabinet. I yet have seen them use LMR coax. Spend the little extra for good coax and you will find yourself much happier and not searching for weird site problems. For the main feed line, you can't get any better then Andrew's LDF coax for repeater installs. Yahoo! Groups Links - Adam -
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Nate, I first became enlightened when someone gave me several lengths of RG-393 with type-N connectors already on it. I used them in my first homebrew 900 machine, and then in my converted 900 MHz MSF5000 (although photos of the station show RG-400 - taken during testing). Once I did some research about the cable, I decided this was the stuff I wanted in all my applications. I'll spend the extra bucks to get the lengths I need made up for me. Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Nate Duehr On May 11, 2008, at 9:52 AM, n9wys wrote: Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually unnoticed. :-( Mark - N9WYS From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP I noticed, and want to get my hands on some for a future project... (GRIN). Just had nothing to say about it... other than perhaps, Thanks for sharing! -- Nate Duehr, WY0X [EMAIL PROTECTED]
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Sometimes skipper-don't type so well... yes I meant RG-223 and the Ebay Auction Example I listed in that post should clearly indicate the coax to be RG-223. Great and thanks for catching the typo. cheers, s. Adam T. Cately [EMAIL PROTECTED] wrote: At 04:50 PM 5/11/08 -, you wrote: Are you sure you don't mean 'RG-223' there, Skipper-doo? I use a lot of this on my bench and home equipment, for the same reasons the Skipp points out - it's cheap and effective. It's the same size (approximately) as RG-58, and uses mostly the same connectors (occasionally I'll get a crimp connector collar that's a little snug...) One doesn't have to go high dollar overkill spec all the time. I'm also a fairly big fan of RG-233 Coax for many repeater system/equipment applications. RG-233 seems to be the ignored step child of the coax family, which means it's not instant shark bait every time it pops up on Ebay and the surplus radio world market. I found a fairly decent price on some pre-made RG-233 Coax runs on Ebay: Cable Assembly RF Coax 7 ft RG-223/U N-Fe to SMA Male Ebay Item number: 190175957842 My offer to the seller for 2/3 the asking amount was accepted and I now have a fair number of those lines in my collection at a much better than the $3.10 (Tessco) list price per foot. Not a bad deal if you want to take the plunge... cheers, skipp skipp025 at yahoo.com www.radiowrench.com See you at Dayton! I'm the short chubby guy with red hair. k7pfj@ wrote: Hi Brent, I agree with Skipp, the LMR is not the cable i would recommend in a duplex repeater install. If you want jumper coax, I only use RG400 and it is a plenum rated silver plated with double shield braid silver. Both Motorola and Kenwood systems use this coax for there internal cableing inside the cabinet. I yet have seen them use LMR coax. Spend the little extra for good coax and you will find yourself much happier and not searching for weird site problems. For the main feed line, you can't get any better then Andrew's LDF coax for repeater installs. Yahoo! Groups Links - Adam -
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Saturday, May 10, 2008 12:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
Re: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Hi Brent, I agree with Skipp, the LMR is not the cable i would recomend in a duplex preeater install. If you want jumper coax, i only use RG400 and it is a plenum rated silver plated with double shield brade silver. Both Motorola and Kenwood systems use this coax for there internal cableing inside the cabinet. I yet have seen them use LMR coax. Spend the little extra for good coax and you will find yourself much happier and not searching for weird site problems. For the main feed line, you cant get any better then Andrew's LDF coax for repeater installs. Mike Mullarkey K7PFJ -- Original message -- From: KF4TNP [EMAIL PROTECTED] RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I dont have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Saturday, May 10, 2008 12:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually unnoticed. :-( Mark - N9WYS From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP _ From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025 I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Re: Best coax for short jumpers in repeater cabinet? It's easy just to use some practical rule of thumb guidelines for coax runs. One doesn't have to use ultra over kill coax in every application. How long? - Length being enough to cause a loss, desired or otherwise (...and yes there is more than one case for a desired feed-line loss) Does the size matter? - Does the diameter of the cable make it practical to fit the application and are the connectors fairly easy to deal with in both size and price? Large RG-8 diameter size coax can become unwieldy in tight corner and space limited locations. Price? - Is the resultant purchase a good dollar to performance value and is the actual performance good enough for the application? One doesn't have to go high dollar overkill spec all the time. I'm also a fairly big fan of RG-233 Coax for many repeater system/equipment applications. RG-233 seems to be the ignored step child of the coax family, which means it's not instant shark bait every time it pops up on Ebay and the surplus radio world market. I found a fairly decent price on some pre-made RG-233 Coax runs on Ebay: Cable Assembly RF Coax 7 ft RG-223/U N-Fe to SMA Male Ebay Item number: 190175957842 My offer to the seller for 2/3 the asking amount was accepted and I now have a fair number of those lines in my collection at a much better than the $3.10 (Tessco) list price per foot. Not a bad deal if you want to take the plunge... cheers, skipp skipp025 at yahoo.com www.radiowrench.com See you at Dayton! I'm the short chubby guy with red hair. [EMAIL PROTECTED] wrote: Hi Brent, I agree with Skipp, the LMR is not the cable i would recommend in a duplex repeater install. If you want jumper coax, I only use RG400 and it is a plenum rated silver plated with double shield braid silver. Both Motorola and Kenwood systems use this coax for there internal cableing inside the cabinet. I yet have seen them use LMR coax. Spend the little extra for good coax and you will find yourself much happier and not searching for weird site problems. For the main feed line, you can't get any better then Andrew's LDF coax for repeater installs.
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Hi Mark, Probably not ignored or unnoticed... but more related to how easy it is to find and of course the cost before applying at least some portions of the rules of thumb check list mentioned in my last post. Much of what many surplus equipment builders use is directly related to what we find cheap, easy and good enough to make the application properly play. cheers, skipp n9wys [EMAIL PROTECTED] wrote: Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually unnoticed. :-( Mark - N9WYS On Behalf Of KF4TNP RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
That's true too, Skipp. Hope to bump into you at Dayton, since we've talked on the phone and via e-mail! It'll be nice to put a face to the keyboard/phone voice! ;-) I'll look hard around the Brat vendor for sure!! BTW - I'll at least be wearing a tag with my callsign. Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025 Hi Mark, Probably not ignored or unnoticed... but more related to how easy it is to find and of course the cost before applying at least some portions of the rules of thumb check list mentioned in my last post. Much of what many surplus equipment builders use is directly related to what we find cheap, easy and good enough to make the application properly play. cheers, skipp n9wys [EMAIL PROTECTED] wrote: Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually unnoticed. :-( Mark - N9WYS On Behalf Of KF4TNP RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Brent, RG-393 cable is definitely good stuff. The Mil-Spec can be downloaded here: www.dscc.dla.mil/Downloads/MilSpec/Docs/MIL-DTL-17/mil17ss127.pdf Looking in the TESSCO catalog, I don't see any connectors listed for RG-393, which is a little bit smaller in diameter than RG-213. I suppose connectors intended for RG-213 could be used in a pinch, but I'd be concerned about the impedance bump caused by using a mismatched connector. I'm not saying there are no connectors made for RG-393, only that they may be hard to find. Where did you find connectors made for your cable? 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of KF4TNP Sent: Sunday, May 11, 2008 6:14 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Saturday, May 10, 2008 12:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
At 5/11/2008 08:52, you wrote: Looks like you and I are in the minority, Brent. I mentioned this same cable about a week ago, and it went virtually unnoticed :-( Mark N9WYS From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP RG-393/U I have a hardline to antenna jumper that's RG-393. It's good stuff, just don't see it often at the swap meets. RG-214 RG-223 are the usual finds. yes stay away from the TYPE stuff at all costs for duplexed lines. I think every RG-214 jumper bought that says that is either copper or tinned braid. OK for radio to duplexer connections but no good for duplexed connections (on or after the duplexer T). Bob NO6B
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Eric, The connectors I have for the 393 are from Times Microwave. Times Recommended the use of the below LMR4oo connectors. TC-400-716MC and the TC-400-716FC 7/16 Din male and female TheType N connectors are Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 Male Time TC-400-NMC-RA Brent KF4TNP _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Sunday, May 11, 2008 1:09 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? Brent, RG-393 cable is definitely good stuff. The Mil-Spec can be downloaded here: www.dscc.dla.mil/Downloads/MilSpec/Docs/MIL-DTL-17/mil17ss127.pdf Looking in the TESSCO catalog, I don't see any connectors listed for RG-393, which is a little bit smaller in diameter than RG-213. I suppose connectors intended for RG-213 could be used in a pinch, but I'd be concerned about the impedance bump caused by using a mismatched connector. I'm not saying there are no connectors made for RG-393, only that they may be hard to find. Where did you find connectors made for your cable? 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of KF4TNP Sent: Sunday, May 11, 2008 6:14 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? RG-393/U M17/127 I use this cable in most runs in the transmitter buildings to and from each station since it has the dual silver shields, I don't have dissimilar metals to worry about. And can handle 1.8kw @950Mhz it works out great. Brent KF4TNP From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of skipp025 Sent: Saturday, May 10, 2008 12:10 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Brent, Thanks for the feedback. I found that RF Industries does have connectors for RG-393/U, which they call Cable Group I. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of KF4TNP Sent: Sunday, May 11, 2008 12:58 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? Eric, The connectors I have for the 393 are from Times Microwave. Times Recommended the use of the below LMR4oo connectors. TC-400-716MC and the TC-400-716FC 7/16 Din male and female TheType N connectors are Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 Male Time TC-400-NMC-RA Brent KF4TNP
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
No Problem Eric, _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Sunday, May 11, 2008 5:40 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? Brent, Thanks for the feedback. I found that RF Industries does have connectors for RG-393/U, which they call Cable Group I. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of KF4TNP Sent: Sunday, May 11, 2008 12:58 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? Eric, The connectors I have for the 393 are from Times Microwave. Times Recommended the use of the below LMR4oo connectors. TC-400-716MC and the TC-400-716FC 7/16 Din male and female TheType N connectors are Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 Male Time TC-400-NMC-RA Brent KF4TNP
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Jeff, I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. I recommend at least 1/2 heliax. Know cost, but well worth the cost. 7/8 even better, but with your 150 ft or so run 1/2 would be ok. At 122 ft HAAT you can get 30 miles to a mobile, but this is assuming flat terrain. To an HT not unless one is on a mountain or air plane, hi. However, your 3 db gain antenna is room for improvement. If possible put up commercial grade 6 db like the DB224. Might find one used. They go for about $450 new. 3 db gain antenna for repeater is low. Would improve tx and rx. Some say only 3 db, but you will see notable difference. With you running 100 W on TX I am sure the portables can hear the repeater, but trying to get back with 5 W 14 miles is pretty good. Installing the pre-amp will help, but only if the tx does not cause desense. Might try turn power down to say 40 W. Not necessary to run 100 W when listening to 5 W HT. However, if see little change with 100/40 W then leave at 100 W. You may be to the limit of your system and it may be working well and as good as one might expect. The changes I recommend is improve antenna, 1/2 or larger heliax and install pre-amp. Start with pre-amp. If tx don't over power it you will see improvement and is easy addition. Otherwise I think the equipment on the ground is good as is. 73, ron, n9ee/r Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. On Thu, May 8, 2008 at 9:07 PM, jstechnicalservice wrote: Thanks, Ron Here is more information on what we have. The HAAT is 122ft., we currently have a Maxrad MFB-1503 3db antenna and LMR400 coax. We are using a ST2 Midland at 110W and there is some type of older pre-amp installed with no tag, but has 6db hand written on it. Any suggestions for improvement will be appreciated but we do have a limited budget, especially with the impending rebanding. We want the high-band repeater in place for backup when this happens and also as our primary for the time being. Jeff, To really give advice here what HAAT is your antenna. At 100 ft AGL 14 miles is about the expected range. Still depends on your terrain. As for feedline I think the LMR400 is a double shielded coax with 2 different shield materials. It has been found these generate noise on the tx side from the high RF. This would affect rcv. Probably good for rcv, but my standard is have nothing in a repeater that causes problems. I use either RG214 double shielded RG8 size and also 1/4 heliax. Both give good shielding and with short pieces little loss. Also RG142 which is a double shielded RG58 size cable often silver shield. Motorola and others use this inside their equipment. Never use double shielded cable with the 2 shields of different material like 9913 or some of the LMR stuff. Again the tx high RF will generate noise. 73, ron, n9ee/r From: jstechnicalservice [EMAIL PROTECTED] Date: 2008/05/08 Thu PM 12:30:30 CDT To: Repeater-Builder@ yahoogroups. com mailto:Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Best coax for short jumpers in repeater cabinet? I was hoping to get some opinions on the best coax to make jumpers for internal connections on a 152 Mhz public safety repeater. I'm currently using LMR400 and we can hit the repeater consistantly with a 5 watt handheld at 14 miles. The problem is we sometimes need around 15 to 16. I was hoping to improve performance as much as possible. Thanks Jeff Skaggs Concord-Greene FD Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. mailto:Repeater-Builder@yahoogroups.com
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
I think the LMR400 is a double shielded with each shield different metals. One braid and one foil. This is a no-no for duplexed repeaters for the higher TX RF will generate noise getting into receiver. Just to be clear... The dissimilar shield metals is the potential problem source, not the braid - foil combination. And notice I used the term potential problem source. It's not always automatic gremlin 101 right out of the starting gate... Some years back I used a fairly large amount of LMR-400 feed line in various new radio repeater system (applications) until I sourced more than an unacceptable number of antenna system train wrecks specific back to the LM-400 (and LMR-600) cable. Sometimes the problem took months and even years to develop... but from memory I've never had an installation of conventional antenna hard-line or coax feed sabotage a radio system like the many examples I've had to ferret out from or back to LMR-400. No more LMR-400 for me or any antenna system I'm involved with. The other cute dissimilar metal shielded coax problem is how physical cable movement can easily be a noise generator. There is a potential for LMR-400 coax moving in the wind to be noisy... and I have seen that demonstrated in an actual installation. cheers, skipp skipp025 at yahoo.com www.radiowrench.com
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
At 05:11 5/10/2008, Ron Wright wrote: At 122 ft HAAT you can get 30 miles to a mobile, but this is assuming flat terrain. To an HT not unless one is on a mountain or air plane, hi. I routinely hit the Mt Vaca repeater (2m, 2900ASL) from a hilltop (780ASL) 50 miles away. Most of the intervening terrain is relatively low. Using 5w and a rubber duck on an Icom T7H. So all you need is a good line of sight, even for a pretty long distance. -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
If you're hitting the 195 Vaca Repeater it probably has a number of active voting receivers in operation. If you're talking about the 147.000 Vaca Repeater... it normally has a single mountain top receiver. The 145.470 Vacaville Repeater can be operational using various combinations of single and multiple voting receivers. All the mentioned repeaters use quite different antennas for quite different reasons. Sometimes repeater users might not know what we are doing up on the various mountain tops. And of course you're always welcome to ask and participate... cheers, skipp skipp025 at yahoo.com Dave Gomberg [EMAIL PROTECTED] wrote: At 05:11 5/10/2008, Ron Wright wrote: At 122 ft HAAT you can get 30 miles to a mobile, but this is assuming flat terrain. To an HT not unless one is on a mountain or air plane, hi. I routinely hit the Mt Vaca repeater (2m, 2900ASL) from a hilltop (780ASL) 50 miles away. Most of the intervening terrain is relatively low. Using 5w and a rubber duck on an Icom T7H. So all you need is a good line of sight, even for a pretty long distance.
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Thanks, Ron Here is more information on what we have. The HAAT is 122ft., we currently have a Maxrad MFB-1503 3db antenna and LMR400 coax. We are using a ST2 Midland at 110W and there is some type of older pre-amp installed with no tag, but has 6db hand written on it. Any suggestions for improvement will be appreciated but we do have a limited budget, especially with the impending rebanding. We want the high-band repeater in place for backup when this happens and also as our primary for the time being. Jeff, To really give advice here what HAAT is your antenna. At 100 ft AGL 14 miles is about the expected range. Still depends on your terrain. As for feedline I think the LMR400 is a double shielded coax with 2 different shield materials. It has been found these generate noise on the tx side from the high RF. This would affect rcv. Probably good for rcv, but my standard is have nothing in a repeater that causes problems. I use either RG214 double shielded RG8 size and also 1/4 heliax. Both give good shielding and with short pieces little loss. Also RG142 which is a double shielded RG58 size cable often silver shield. Motorola and others use this inside their equipment. Never use double shielded cable with the 2 shields of different material like 9913 or some of the LMR stuff. Again the tx high RF will generate noise. 73, ron, n9ee/r From: jstechnicalservice [EMAIL PROTECTED] Date: 2008/05/08 Thu PM 12:30:30 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Best coax for short jumpers in repeater cabinet? I was hoping to get some opinions on the best coax to make jumpers for internal connections on a 152 Mhz public safety repeater. I'm currently using LMR400 and we can hit the repeater consistantly with a 5 watt handheld at 14 miles. The problem is we sometimes need around 15 to 16. I was hoping to improve performance as much as possible. Thanks Jeff Skaggs Concord-Greene FD Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Get rid of the LMR400 and replace it with some kind of hardline. Vern KI4ONW From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of jstechnicalservice Sent: Thursday, May 08, 2008 9:08 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet? Thanks, Ron Here is more information on what we have. The HAAT is 122ft., we currently have a Maxrad MFB-1503 3db antenna and LMR400 coax. We are using a ST2 Midland at 110W and there is some type of older pre-amp installed with no tag, but has 6db hand written on it. Any suggestions for improvement will be appreciated but we do have a limited budget, especially with the impending rebanding. We want the high-band repeater in place for backup when this happens and also as our primary for the time being. Jeff, To really give advice here what HAAT is your antenna. At 100 ft AGL 14 miles is about the expected range. Still depends on your terrain. As for feedline I think the LMR400 is a double shielded coax with 2 different shield materials. It has been found these generate noise on the tx side from the high RF. This would affect rcv. Probably good for rcv, but my standard is have nothing in a repeater that causes problems. I use either RG214 double shielded RG8 size and also 1/4 heliax. Both give good shielding and with short pieces little loss. Also RG142 which is a double shielded RG58 size cable often silver shield. Motorola and others use this inside their equipment. Never use double shielded cable with the 2 shields of different material like 9913 or some of the LMR stuff. Again the tx high RF will generate noise. 73, ron, n9ee/r From: jstechnicalservice [EMAIL PROTECTED] Date: 2008/05/08 Thu PM 12:30:30 CDT To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Best coax for short jumpers in repeater cabinet? I was hoping to get some opinions on the best coax to make jumpers for internal connections on a 152 Mhz public safety repeater. I'm currently using LMR400 and we can hit the repeater consistantly with a 5 watt handheld at 14 miles. The problem is we sometimes need around 15 to 16. I was hoping to improve performance as much as possible. Thanks Jeff Skaggs Concord-Greene FD Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?
Without looking at the rest of the replies, I will comment here on the cable you have. replace that LMR400 with heliax. LDF4050A or better, LDF5-50A or equivalent You can get a good eal on Heliax and connectors from: http://www.surpluscoax.com/index.html The LDF5-50A is $2.55 per foot, less than 1/2 of the usual price for this cable, and their shipping charges are reasonable. Buy cable and connectors at the same time, and buy the correct connectors for the cable you buy. This alone will actually help on the receive, not to mention the transmit. Add a better antenna as well. I have not heard from them yet, but I may wind up helping the local VFD here get their system on the air. Not sure what they have in the vehicles, but the main base unit is an MTR2000 Motorla, and the tower is about 85 feet high (27 meters according to the information on the FCC web site). But not sure about the antennas or coax being used yet either. I will not look too deep till I know more. the use of cables like LMR400 is frowned on for repeater use, and may not do as well as even 1/2 Heliax can do. the 7/8 Heliax would be far better. I have 7/8 Heliax for use with my 440 repeater, and figure it will help me to have decent range, even though I won't have the antenna very high for the time being. in the cabinet, as others have mentioned, use a good double shieleded coax like RG142, RG214 or similar. Even tyhere, avoid the stuff with foil and braid mixed. YMMV Wayne WA2YNE --- In Repeater-Builder@yahoogroups.com, jstechnicalservice [EMAIL PROTECTED] wrote: Thanks, Ron Here is more information on what we have. The HAAT is 122ft., we currently have a Maxrad MFB-1503 3db antenna and LMR400 coax. We are using a ST2 Midland at 110W and there is some type of older pre-amp installed with no tag, but has 6db hand written on it. Any suggestions for improvement will be appreciated but we do have a limited budget, especially with the impending rebanding. We want the high-band repeater in place for backup when this happens and also as our primary for the time being.
