Re: Topband: Fsj4 series heliax around a rotor
More of a topic for a VHF/UHF forum where the question comes up often.. I use that coax on the mast and to power dividers and out to individual yagis but it certainly is not meant to survive long around a rotator. There I use LMR400UF and into a 50-75 Ohm coax line transformer into .75 to 1 75 Ohm CATV hardline for 144 MHz and higher. Another line transformer converts back to 50 Ohms in the house to keep the several Bird 43 line sections and elements happy. Carl KM1H - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: topband@contesting.com Sent: Saturday, June 07, 2014 11:09 PM Subject: Re: Topband: Fsj4 series heliax around a rotor This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
I turn 1/2 Cellflex cable which is similar to FSJ4 for more then 30 years and never had a problem. On one tower I turn a bunch of 5 cables at once. And yes, never damage by critters since using that kind of cable on all bands, also as feed lines for beverages. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Sonntag, 8. Juni 2014 15:33 To: j...@audiosystemsgroup.com; topband@contesting.com Subject: Re: Topband: Fsj4 series heliax around a rotor More of a topic for a VHF/UHF forum where the question comes up often.. I use that coax on the mast and to power dividers and out to individual yagis but it certainly is not meant to survive long around a rotator. There I use LMR400UF and into a 50-75 Ohm coax line transformer into .75 to 1 75 Ohm CATV hardline for 144 MHz and higher. Another line transformer converts back to 50 Ohms in the house to keep the several Bird 43 line sections and elements happy. Carl KM1H - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: topband@contesting.com Sent: Saturday, June 07, 2014 11:09 PM Subject: Re: Topband: Fsj4 series heliax around a rotor This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
What is this antenna, tower, rotator, and cable configuration? Im also using 5 cables and around a Tailtwister rotator. Carl KM1H - Original Message - From: Peter Voelpel dj...@t-online.de To: topband@contesting.com Sent: Sunday, June 08, 2014 10:45 AM Subject: Re: Topband: Fsj4 series heliax around a rotor I turn 1/2 Cellflex cable which is similar to FSJ4 for more then 30 years and never had a problem. On one tower I turn a bunch of 5 cables at once. And yes, never damage by critters since using that kind of cable on all bands, also as feed lines for beverages. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Sonntag, 8. Juni 2014 15:33 To: j...@audiosystemsgroup.com; topband@contesting.com Subject: Re: Topband: Fsj4 series heliax around a rotor More of a topic for a VHF/UHF forum where the question comes up often.. I use that coax on the mast and to power dividers and out to individual yagis but it certainly is not meant to survive long around a rotator. There I use LMR400UF and into a 50-75 Ohm coax line transformer into .75 to 1 75 Ohm CATV hardline for 144 MHz and higher. Another line transformer converts back to 50 Ohms in the house to keep the several Bird 43 line sections and elements happy. Carl KM1H - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: topband@contesting.com Sent: Saturday, June 07, 2014 11:09 PM Subject: Re: Topband: Fsj4 series heliax around a rotor This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
One option is to do what remote ENG trucks do and make at least a 540 deg or 720 deg (1.5 or 2.0 or more) loops rather than a 180 or 360. This will reduce some of the flexing action as it is more like changing the coil size instead of a lot of bending back and forth. You do need to be careful in prepping the ends for connectors. It is very easy to score the thin copper shield and it will fracture easily if scored. I recommend using some of the heat shrink with the glue inside on the back of the connector shell and down the cable three or four inches to act as a strain relief. tnx Mike / W5JR Alpharetta GA On Jun 8, 2014, at 1:17 PM, Carl k...@jeremy.mv.com wrote: What is this antenna, tower, rotator, and cable configuration? Im also using 5 cables and around a Tailtwister rotator. Carl KM1H - Original Message - From: Peter Voelpel dj...@t-online.de To: topband@contesting.com Sent: Sunday, June 08, 2014 10:45 AM Subject: Re: Topband: Fsj4 series heliax around a rotor I turn 1/2 Cellflex cable which is similar to FSJ4 for more then 30 years and never had a problem. On one tower I turn a bunch of 5 cables at once. And yes, never damage by critters since using that kind of cable on all bands, also as feed lines for beverages. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Sonntag, 8. Juni 2014 15:33 To: j...@audiosystemsgroup.com; topband@contesting.com Subject: Re: Topband: Fsj4 series heliax around a rotor More of a topic for a VHF/UHF forum where the question comes up often.. I use that coax on the mast and to power dividers and out to individual yagis but it certainly is not meant to survive long around a rotator. There I use LMR400UF and into a 50-75 Ohm coax line transformer into .75 to 1 75 Ohm CATV hardline for 144 MHz and higher. Another line transformer converts back to 50 Ohms in the house to keep the several Bird 43 line sections and elements happy. Carl KM1H - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: topband@contesting.com Sent: Saturday, June 07, 2014 11:09 PM Subject: Re: Topband: Fsj4 series heliax around a rotor This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
That's what I was thinking all along. If you put enough large loops in it, you could even get away with using 3/4 aluminum hardline. :-) Of course, that doesn't mean it should be done. 73, Mike www.w0btu.com On Sun, Jun 8, 2014 at 2:44 PM, Mike/W5JR w5jr.li...@att.net wrote: One option is to do what remote ENG trucks do and make at least a 540 deg or 720 deg (1.5 or 2.0 or more) loops rather than a 180 or 360. This will reduce some of the flexing action as it is more like changing the coil size instead of a lot of bending back and forth. You do need to be careful in prepping the ends for connectors. It is very easy to score the thin copper shield and it will fracture easily if scored. I recommend using some of the heat shrink with the glue inside on the back of the connector shell and down the cable three or four inches to act as a strain relief. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
I have used Andrew FSJ4 cables for years as rotor loops. Andrew does not recommend it outdoors, but I have come up with a good technique for its use. When you put the connectors on each end, be sure to remove about 1/2” or more of the outer plastic sheath behind the connector body so the copper is exposed. Then knead some butyl rubber sealing goop in there to provide a strong vapor barrier just behind the connector body. Cover that with some wraps of good vinyl tape. Superflex is very prone to getting nicks in the outer jacket and allowing water to get in under the jacket. This has migrated to inside the connectors many times for me, causing no end of trouble on 1296 and 2304 MHz. (One drop of water will kill 2304 signals by 30-40 dB...hard to believe!) I think the water pressure can build up and the hydrostatic head is enough to push through the simple O ring inside the connector. Since employing this technique, my water entry problems have largely disappeared with Superflex. I have yet to have a cable break with flexing. All my failures were water related. I cover each connector with a layer or two of good tape, then use butyl rubber and follow that with more tape and some wx seal like Scotch kote or some form of oil based varnish to make sure there are no air pockets open where water can enter. 73 Dave K1WHS _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
Rotator is home brew with a slew drive of 76cm diameter and turns from north +/- 270°, tower is free standing and face width is 50cm at the top section. The 5 Cellflex cables are tied together with ty-raps. Antennas can be seen on http://www.qrz.com/db/DJ7WW. On my old location I also turned three length of RG218 with its solid inner conductor around the rotator for many years until I moved. 73 Peter -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Sonntag, 8. Juni 2014 19:18 To: Peter Voelpel; topband@contesting.com Subject: Re: Topband: Fsj4 series heliax around a rotor What is this antenna, tower, rotator, and cable configuration? Im also using 5 cables and around a Tailtwister rotator. Carl KM1H - Original Message - From: Peter Voelpel dj...@t-online.de To: topband@contesting.com Sent: Sunday, June 08, 2014 10:45 AM Subject: Re: Topband: Fsj4 series heliax around a rotor I turn 1/2 Cellflex cable which is similar to FSJ4 for more then 30 years and never had a problem. On one tower I turn a bunch of 5 cables at once. And yes, never damage by critters since using that kind of cable on all bands, also as feed lines for beverages. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Sonntag, 8. Juni 2014 15:33 To: j...@audiosystemsgroup.com; topband@contesting.com Subject: Re: Topband: Fsj4 series heliax around a rotor More of a topic for a VHF/UHF forum where the question comes up often.. I use that coax on the mast and to power dividers and out to individual yagis but it certainly is not meant to survive long around a rotator. There I use LMR400UF and into a 50-75 Ohm coax line transformer into .75 to 1 75 Ohm CATV hardline for 144 MHz and higher. Another line transformer converts back to 50 Ohms in the house to keep the several Bird 43 line sections and elements happy. Carl KM1H - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: topband@contesting.com Sent: Saturday, June 07, 2014 11:09 PM Subject: Re: Topband: Fsj4 series heliax around a rotor This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
That's what I was thinking all along. If you put enough large loops in it, you could even get away with using 3/4 aluminum hardline. :-) Of course, that doesn't mean it should be done. Even the CB operator down the road does this. He has regular 7/8th inch and, as far as I know, it has been like that at least ten years without an issue. That antenna flip flops in the wind all the time. If a CB operator who has a ground system consisting of wires stuck in a jug of saltwater (he actually has that) can figure out to use a couple large circles in the heliax to his Joe Gun beam to stop breakage, I expect Hams could figure it out. :) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
I have used Andrew FSJ4 cables for years as rotor loops. Andrew does not recommend it outdoors, but I have come up with a good technique for its use. When you put the connectors on each end, be sure to remove about 1/2” or more of the outer plastic sheath behind the connector body so the copper is exposed. Then knead some butyl rubber sealing goop in there to provide a strong vapor barrier just behind the connector body. Cover that with some wraps of good vinyl tape. Superflex is very prone to getting nicks in the outer jacket and allowing water to get in under the jacket. This has migrated to inside the connectors many times for me, causing no end of trouble on 1296 and 2304 MHz. (One drop of water will kill 2304 signals by 30-40 dB...hard to believe!) I think the water pressure can build up and the hydrostatic head is enough to push through the simple O ring inside the connector. Since employing this technique, my water entry problems have largely disappeared with Superflex. I have yet to have a cable break with flexing. All my failures were water related. I cover each connector with a layer or two of good tape, then use butyl rubber and follow that with more tape and some wx seal like Scotch kote or some form of oil based varnish to make sure there are no air pockets open where water can enter. 73 Dave K1WHS Thanks for that info Dave and I can see where the FSJ may offer a slight edge heading into the microwaves over LMR-400UF. But assuming a rotor loop of 5' the difference at 432 is a whopping .04dB and I would think that the loop would be a bit longer or even double as in 2 turns for the FSJ. Suddenly there is either no difference or even a loss for the FSJ. The original poster was planning to make the complete run from the FSJ for protection from critters and no frequency was mentioned; but at HF to low UHF there is no loss benefit worth mentioning for a rotator loop. Maybe for a CB operator or a ham running tubes with handles the extra power handling might be important. I'll stick to the LMR-400UF, cable cost and connectors are reasonable, and there is no danger of copper breakage and water ingress Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Fsj4 series heliax around a rotor
Sorry for this not being entirely topband-related, but I'm hoping some people here have tried this. I have a beam on a rotor than has lmr400 feeding it now. The cable has been damaged by critters that like snacking on polyethylene. I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. Has anyone had any issues with fsj4 series heliax in rotor loops? I'm interested to know if the flexing causes any fracturing issues with the corrugated copper shield in the cable. I'm thinking it will be ok if I make the loop big enough and I'd rather not splice in a piece of lmr ultraflex if I don't have to. Anyone out there have some experience they can share? -Bill Sent from my iPhone _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fsj4 series heliax around a rotor
This would be a natural topic for Tower Talk. Access via contesting.com 73, Jim K9YC On 6/7/2014 7:03 PM, Bill Wichers wrote: I'm thinking about replacing the lmr400 with fsj4-50b heliax since I have several thousand feet of that on a reel. I'm also thinking that the corrugated copper shield will resist critter damage better than the braid in the lmr400 cable. _ Topband Reflector Archives - http://www.contesting.com/_topband
