This is certainly a novel approach to making UG21 connectors work with LMR400 cable. But, considering you can buy brand new N connectors with silver plated center pin for only $5.95 (at Texas Towers) it seems like a lot of work to maybe reuse an old connector. New UG21 connectors cost as much as one that fits properly so there is no cost savings going that route.
Regular L:MR400 uses a copper plated aluminum center conductor. Messing with the center conductor on that cable is going to damage the copper plating; making it impossible to solder.
73, Gerald Williamson K5GW General Manager/Texas Towers
In a message dated 5/21/2009 8:00:02 P.M. Central Daylight Time, [email protected] writes:
Glenn Little and others,
There is a neat way to use type N connectors on LMR400 and LMR400UF. I wrote an article for QST/QEX on the method and passed it to Ray Mack, W5IFS, who is an editor for QEX. He has not passed the article on as yet, though. Basically, the diameter of the inner conductor is too large for the typical N connector, therefore that diameter must be reduced to fit. The way to do that reduction effectively when you are making up a number of cables is to make a set of "Center Conductor Reduction Dies." Start with inch-long sections of 3/8-inch cold rolled steel and drill all the way through each piece with a series of numbered drills starting with the largest drill that is the diameter of the center conductor and ending with the drill that just enters the center pin of the N connector. This work is best done on a metal working lathe to get a concentric hole. Center drill the entry end to provide a starting chamfer. Using a thin cutoff wheel in your Dremel Moto-Tool, make two cross cuts on the centerline to about 1/8-inch below the chamfer on that end and once on the other end without a chamfer. Now, using the dies in descending sequence, chuck the die in an electric drill. Strip the end of the cable and expose a little more of the center conductor than is needed. Insert the cable into the reduction die and spin the drill motor until the end reaches the insulation (there will be a short section of unreduced center conductor). Reverse the die in the drill and finish the cut to the insulation. Move to the next die. Occasionally, trim the copper flash that develops. Stop when the center conductor enters the center pin of the N connector. For LMR400UF, you must make the center conductor a solid conductor by tinning the exposed center conductor. Again, inspect the face of the insulation and remove any copper flash to prevent a possible short. Now, you can assemble the cable to the N connector just as you would assemble it using RG8 cable. The cutting edges of the reduction die are those slots that you cut using the Dremel (you could do it with a hack saw as I did at first, but the Dremel is much faster). I have assembled about 40 N-M and N-F connectors to LMR400 cables using this method which really beats trying to reduce the center conductor with a file when you have many connectors to install.
73,
Lloyd Crawford, N5GDB, EM10bf [email protected] Roadrunners Microwave Group ----- Original Message ----- From: "D. McGarrett" [email protected] To: "Glenn Little WB4UIV" [email protected] Cc: "Microwave list" [email protected]; "'Amsat - BBs'" [email protected]; "Jim Sanford" [email protected] Sent: Thursday, May 21, 2009 6:41 PM Subject: Re: [Mw] [amsat-bb] Pre Fab Coax sections
Glenn Little WB4UIV wrote:
If you like throwing money at the problem, try Pasternack.
5 feet at $83.00 at S. M. Electronics. 5 feet at $78.25 at Pasternack.
I always build my own. That way I can only blame myself for bad cables.
73 Glenn WB4UIV
I don't have a solution for you, but when I was a working engineer, I found that Pasternack was one of the most expensive solutions (to anything!) there was. I never heard of S.M. Electronics. Google will give you a list of connector manufacturers and sales people. I'm with Glenn--build your own! LMR-xx cable is a product of Times Microwave. Excellent cable! (If you can use LMR-400, it will be a lot cheaper, but you _can't_ use regular type N connectors on it.) On the other hand, type N connectors are a lot easier to use than the GD UHF connectors, and work a heck of a lot better--but you probably know that already. _______________________________________________ Microwave mailing list [email protected] http://www.valinet.com/mailman/listinfo/microwave
_______________________________________________ Microwave mailing list [email protected] http://www.valinet.com/mailman/listinfo/microwave
**************Recession-proof vacation ideas. Find free things to do in the U.S. (http://travel.aol.com/travel-ideas/domestic/national-tourism-week?ncid=emlcn...)
On Thu, 21 May 2009 21:17:28 EDT, [email protected] said:
This is certainly a novel approach to making UG21 connectors work with LMR400 cable. But, considering you can buy brand new N connectors with silver plated center pin for only $5.95 (at Texas Towers) it seems like a lot of work to maybe reuse an old connector. New UG21 connectors cost as much as one that fits properly so there is no cost savings going that route.
I had a call from a ham at Dayton this year that said people in the flea market were (once again?) selling 7/8" hardline connectors for $35/ea OR MORE -- USED! These were still on chunks of 7/8" that were obviously removed by a tower crew. (Sawsall...)
I recently ordered some connectors from Hutton and got the wrong ones... 7/8" Andrews corrugated connectors came instead of the odd-ball CommScope smooth-wall stuff I was trying to get. $25 brand new from Hutton, and that was without any serious discount of any kind.
I'm always amazed that hams don't shop before going to hamfests... P.T. Barnum said "There's a sucker born every minute", and he was right. $25 may still be high, but $35 for old used junk that will likely need a new o-ring and other repairs... is ridiculous.
Connector prices have really fallen in the down economy and low commodities prices... stock up now... they'll go sky high again in a few years. As usual...
Nate WY0X -- Nate Duehr [email protected]
I wasn't going to say anything but now that Gerald brings it up, N Connectors for LMR400 and similar cables are available from several sources (including Texas Towers). Given that, it seemed like a lot of work to me also.
73 Jim, W4KXY
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. Richard P. Feynman -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, May 21, 2009 9:17 PM To: [email protected]; [email protected]; [email protected] Cc: [email protected]; [email protected]; [email protected]; [email protected] Subject: Re: [Mw] [amsat-bb] Pre Fab Coax sections
This is certainly a novel approach to making UG21 connectors work with LMR400 cable. But, considering you can buy brand new N connectors with silver plated center pin for only $5.95 (at Texas Towers) it seems like a lot of work to maybe reuse an old connector. New UG21 connectors cost as much as one that fits properly so there is no cost savings going that route.
Regular L:MR400 uses a copper plated aluminum center conductor. Messing with the center conductor on that cable is going to damage the copper plating; making it impossible to solder.
73, Gerald Williamson K5GW General Manager/Texas Towers
In a message dated 5/21/2009 8:00:02 P.M. Central Daylight Time, [email protected] writes:
Glenn Little and others,
There is a neat way to use type N connectors on LMR400 and LMR400UF. I wrote an article for QST/QEX on the method and passed it to Ray Mack, W5IFS, who is an editor for QEX. He has not passed the article on as yet, though. Basically, the diameter of the inner conductor is too large for the typical N connector, therefore that diameter must be reduced to fit. The way to do that reduction effectively when you are making up a number of cables is to make a set of "Center Conductor Reduction Dies." Start with inch-long sections of 3/8-inch cold rolled steel and drill all the way through each piece with a series of numbered drills starting with the largest drill that is the diameter of the center conductor and ending with the drill that just enters the center pin of the N connector. This work is best done on a metal working lathe to get a concentric hole. Center drill the entry end to provide a starting chamfer. Using a thin cutoff wheel in your Dremel Moto-Tool, make two cross cuts on the centerline to about 1/8-inch below the chamfer on that end and once on the other end without a chamfer. Now, using the dies in descending sequence, chuck the die in an electric drill. Strip the end of the cable and expose a little more of the center conductor than is needed. Insert the cable into the reduction die and spin the drill motor until the end reaches the insulation (there will be a short section of unreduced center conductor). Reverse the die in the drill and finish the cut to the insulation. Move to the next die. Occasionally, trim the copper flash that develops. Stop when the center conductor enters the center pin of the N connector. For LMR400UF, you must make the center conductor a solid conductor by tinning the exposed center conductor. Again, inspect the face of the insulation and remove any copper flash to prevent a possible short. Now, you can assemble the cable to the N connector just as you would assemble it using RG8 cable. The cutting edges of the reduction die are those slots that you cut using the Dremel (you could do it with a hack saw as I did at first, but the Dremel is much faster). I have assembled about 40 N-M and N-F connectors to LMR400 cables using this method which really beats trying to reduce the center conductor with a file when you have many connectors to install.
73,
Lloyd Crawford, N5GDB, EM10bf [email protected] Roadrunners Microwave Group ----- Original Message ----- From: "D. McGarrett" [email protected] To: "Glenn Little WB4UIV" [email protected] Cc: "Microwave list" [email protected]; "'Amsat - BBs'" [email protected]; "Jim Sanford" [email protected] Sent: Thursday, May 21, 2009 6:41 PM Subject: Re: [Mw] [amsat-bb] Pre Fab Coax sections
Glenn Little WB4UIV wrote:
If you like throwing money at the problem, try Pasternack.
5 feet at $83.00 at S. M. Electronics. 5 feet at $78.25 at Pasternack.
I always build my own. That way I can only blame myself for bad cables.
73 Glenn WB4UIV
I don't have a solution for you, but when I was a working engineer, I found that Pasternack was one of the most expensive solutions (to anything!) there was. I never heard of S.M. Electronics. Google will give you a list of connector manufacturers and sales people. I'm with Glenn--build your own! LMR-xx cable is a product of Times Microwave. Excellent cable! (If you can use LMR-400, it will be a lot cheaper, but you _can't_ use regular type N connectors on it.) On the other hand, type N connectors are a lot easier to use than the GD UHF connectors, and work a heck of a lot better--but you probably know that already. _______________________________________________ Microwave mailing list [email protected] http://www.valinet.com/mailman/listinfo/microwave
_______________________________________________ Microwave mailing list [email protected] http://www.valinet.com/mailman/listinfo/microwave
**************Recession-proof vacation ideas. Find free things to do in the U.S. (http://travel.aol.com/travel-ideas/domestic/national-tourism-week?ncid=emlc ntustrav00000002) _______________________________________________ Microwave mailing list [email protected] http://www.valinet.com/mailman/listinfo/microwave
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