[Repeater-Builder] Re: Invar Rods
Don't know if they make an Invar flame suit, but I may need one :) What I have done in the past is obtained a piece of stainless redi-rod and short coupling nuts (female on both ends) with the same threading as the Sinclair. I then lengthen the rod by only the amount required by cutting the coupling nut and redi-rod studs to only lengthen the entire rod by 3/4 or so. This small amount when heated will only expand a fraction. It may be just what you need to counteract the contraction of Invar as it is heated. I have three duplexers in service (Q202 style) that have never had an issue. Although the temperature is pretty steady at my site. I even put them in a freezer and left them out in the sun, and there was no change in the notches or pass loss over about 50 degrees temperature difference... And yes I had a large deep freezer :) Dave Cameron VE7LTD --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: To expand on my comment, the invar rod is there to minimize the temperature lengthening and shortening the center probe. The original design with the invar to the bottom of the piston, keeps the overall length the same and allows temperature expansion to occur at the finger stock - thus not changing the overall length. If you rotate the piston, then the piston itself can expand and contract, and change the overall length. Not as much as if no invar was used, but it will be worse than if it were kept attached were it was designed. Chuck WB2EDV - Original Message - From: Chuck Kelsey wb2...@... To: Repeater-Builder@yahoogroups.com Sent: Sunday, July 18, 2010 8:55 AM Subject: Re: [Repeater-Builder] Re: Invar Rods Not a good idea. They are attached to the bottom to keep the expansion minimized. Turning them around will defeat the purpose of having the invar in the first place. Chuck WB2EDV - Original Message - From: IM Ashford imashf...@... To: Repeater-Builder@yahoogroups.com Sent: Sunday, July 18, 2010 8:54 AM Subject: Re: [Repeater-Builder] Re: Invar Rods Just a thought, Why dont you turn the pistons around to give you a longer reach? Ian G8PWE - Original Message - From: Burt Lang b...@... To: Repeater-Builder@yahoogroups.com Sent: Saturday, July 17, 2010 4:08 PM Subject: Re: [Repeater-Builder] Re: Invar Rods What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ Yahoo! Groups Links Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.839 / Virus Database: 271.1.1/3013 - Release Date: 07/18/10 02:35:00 Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.839 / Virus Database: 271.1.1/3013 - Release Date: 07/18/10 02:35:00
[Repeater-Builder] Re: Invar Rods
Hi Mike, No this was not one of Tommy's deals, but the guy had to have been to the Tommy Rea school of duplexer modification 101. Good to hear from you. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, k7...@... wrote: Hi Joe, Sounds like a Tommy Rea deal. He used to cut the rods off on all of the Sinclair resloc UHF duplexers. Mike Mullarkey K7PFJ 6886 Sage Ave Firestone, Co 80504 303-736-9693
Re: [Repeater-Builder] Re: Invar Rods
Just a thought, Why dont you turn the pistons around to give you a longer reach? Ian G8PWE - Original Message - From: Burt Lang b...@gorum.ca To: Repeater-Builder@yahoogroups.com Sent: Saturday, July 17, 2010 4:08 PM Subject: Re: [Repeater-Builder] Re: Invar Rods What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ Yahoo! Groups Links
Re: [Repeater-Builder] Re: Invar Rods
Not a good idea. They are attached to the bottom to keep the expansion minimized. Turning them around will defeat the purpose of having the invar in the first place. Chuck WB2EDV - Original Message - From: IM Ashford imashf...@btinternet.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, July 18, 2010 8:54 AM Subject: Re: [Repeater-Builder] Re: Invar Rods Just a thought, Why dont you turn the pistons around to give you a longer reach? Ian G8PWE - Original Message - From: Burt Lang b...@gorum.ca To: Repeater-Builder@yahoogroups.com Sent: Saturday, July 17, 2010 4:08 PM Subject: Re: [Repeater-Builder] Re: Invar Rods What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ Yahoo! Groups Links Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.839 / Virus Database: 271.1.1/3013 - Release Date: 07/18/10 02:35:00
Re: [Repeater-Builder] Re: Invar Rods
To expand on my comment, the invar rod is there to minimize the temperature lengthening and shortening the center probe. The original design with the invar to the bottom of the piston, keeps the overall length the same and allows temperature expansion to occur at the finger stock - thus not changing the overall length. If you rotate the piston, then the piston itself can expand and contract, and change the overall length. Not as much as if no invar was used, but it will be worse than if it were kept attached were it was designed. Chuck WB2EDV - Original Message - From: Chuck Kelsey wb2...@roadrunner.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, July 18, 2010 8:55 AM Subject: Re: [Repeater-Builder] Re: Invar Rods Not a good idea. They are attached to the bottom to keep the expansion minimized. Turning them around will defeat the purpose of having the invar in the first place. Chuck WB2EDV - Original Message - From: IM Ashford imashf...@btinternet.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, July 18, 2010 8:54 AM Subject: Re: [Repeater-Builder] Re: Invar Rods Just a thought, Why dont you turn the pistons around to give you a longer reach? Ian G8PWE - Original Message - From: Burt Lang b...@gorum.ca To: Repeater-Builder@yahoogroups.com Sent: Saturday, July 17, 2010 4:08 PM Subject: Re: [Repeater-Builder] Re: Invar Rods What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ Yahoo! Groups Links Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.839 / Virus Database: 271.1.1/3013 - Release Date: 07/18/10 02:35:00 Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.839 / Virus Database: 271.1.1/3013 - Release Date: 07/18/10 02:35:00
[Repeater-Builder] Re: Invar Rods
Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Glenn Little WB4UIV glennmaill...@... wrote: Does anyone need INVAR rods? I salvaged some from a TV audio / video RF combiner. 73 Glenn WB4UIV
RE: [Repeater-Builder] Re: Invar Rods
Hi Joe, Sounds like a Tommy Rea deal. He used to cut the rods off on all of the Sinclair resloc UHF duplexers. Mike Mullarkey K7PFJ 6886 Sage Ave Firestone, Co 80504 303-736-9693 _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of burkleoj Sent: Saturday, July 17, 2010 12:57 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Invar Rods Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com , Glenn Little WB4UIV glennmaill...@... wrote: Does anyone need INVAR rods? I salvaged some from a TV audio / video RF combiner. 73 Glenn WB4UIV
Re: [Repeater-Builder] Re: Invar Rods
What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ
RE: [Repeater-Builder] Re: Invar Rods
You might save on Invar if you can get away with using coupling nuts to reuse your short rods, and don't forget the jam nuts. I've done it with no measurable degradation. Ross Kc7rjk -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of burkleoj Sent: Friday, July 16, 2010 11:57 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Invar Rods Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com , Glenn Little WB4UIV glennmaill...@... wrote: Does anyone need INVAR rods? I salvaged some from a TV audio / video RF combiner. 73 Glenn WB4UIV
[Repeater-Builder] Re: Invar Rods
Burt, I have not had a chance to measure them yet, but I am pretty sure they are the 1/4 diameter ones as they are from a fairly new Sinclair Resloc VHF 6 cavity duplexer. I will get a measurement tomorrow and report back. Thanks, Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Burt Lang b...@... wrote: What diameter are the rods? The older Sinclair VHF Hi cans used 5/16in diameter whereas the newer cans used 1/4 in daiameter. burkleoj wrote: Glenn, I need 6 of them for a Sinclair duplexer that I have. Someone cut the rods off when it was originally on a commercial frequency. The rods in my duplexer are so short that it will not tune below 147 MHz before they disappear inside the top of the cavity. Very common when the frequencies are in the high 160s I can get some dimensions for you to see if the ones you have may work. Thanks, Joe - WA7JAW You can buy invar rod material from some metal suppliers but you won't like the price. It normally comes in 12ft lengths but the dealers will cut it in half in order to ship UPS. The last time I bought some (around 1990) the price was $30/lb. The dealer was Diezel (or Diesel) Metals on Long Island somewhere. I still have some left from that order. FYI Invar is an allow consisting of exactly 35.16% nickel with the remainder iron. It is magnetic and will corrode in a damp environment leaving a green rust on the surface. Burt VE2BMQ
