- 1. Topband: Palomar R-X Noise Bridge (score: 1)
- Author: <mapa50@windstream.net>
- Date: Thu, 13 Feb 2014 23:18:07 -0600
- I have a question about using the noise bridge. I have used it cut stubs to 1/4 wavelength using 52 ohm cable with no problems. I now need some stubs using 75 ohm cable which I have on hand. Will the
- /archives//html/Topband/2014-02/msg00208.html (6,776 bytes)
- 2. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Carl" <km1h@jeremy.mv.com>
- Date: Fri, 14 Feb 2014 10:54:14 -0500
- I used a noise bridge to cut all the RG-11 stacked yagi and phased verticals phasing lines as well as harmonic stubs here when running a 2 station single op contest, before SO2R. Using the station re
- /archives//html/Topband/2014-02/msg00214.html (8,485 bytes)
- 3. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Fri, 14 Feb 2014 11:16:30 -0500
- I would expect it to work OK with 75 ohm cable. An open-circuited 1/4 wave line looks like a short at its sending end and you would be looking for a null as the line reaches a 1/4 wavelength, so I wo
- /archives//html/Topband/2014-02/msg00217.html (8,948 bytes)
- 4. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: donovanf@starpower.net
- Date: Fri, 14 Feb 2014 11:42:27 -0500 (EST)
- Null depth is a function of cable loss. Heliax produces the deepest null, small diameter coax (RG-59, RG-58) is quite poor 75 vs. 50 ohm should make no difference. 73 Frank W3LPL -- Original Message
- /archives//html/Topband/2014-02/msg00219.html (9,059 bytes)
- 5. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Carl" <km1h@jeremy.mv.com>
- Date: Fri, 14 Feb 2014 13:55:56 -0500
- Null depth is a function of cable loss. ** Yup Heliax produces the deepest null, small diameter coax (RG-59, RG-58) is quite poor ** The highest VF and lowest loss produces the deepest null but also
- /archives//html/Topband/2014-02/msg00224.html (10,612 bytes)
- 6. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: Jim Brown <jim@audiosystemsgroup.com>
- Date: Fri, 14 Feb 2014 13:16:40 -0800
- Not always -- stubs made with higher Vf cables are longer, so in my experience they come out about the same for attenuation and bandwidth. The only way to get a deeper null (with the reduction in ban
- /archives//html/Topband/2014-02/msg00229.html (8,428 bytes)
- 7. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Fri, 14 Feb 2014 16:36:19 -0500
- Makes sense. The lower the return-loss, the deeper the null! 73, Charlie, K4OTV Not always -- stubs made with higher Vf cables are longer, so in my experience they come out about the same for attenua
- /archives//html/Topband/2014-02/msg00230.html (8,756 bytes)
- 8. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Carl" <km1h@jeremy.mv.com>
- Date: Fri, 14 Feb 2014 17:17:40 -0500
- Not always -- stubs made with higher Vf cables are longer, so in my experience they come out about the same for attenuation and bandwidth. The only way to get a deeper null (with the reduction in ban
- /archives//html/Topband/2014-02/msg00231.html (9,030 bytes)
- 9. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: Jim Brown <jim@audiosystemsgroup.com>
- Date: Fri, 14 Feb 2014 18:42:14 -0800
- I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line),
- /archives//html/Topband/2014-02/msg00243.html (9,010 bytes)
- 10. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Fri, 14 Feb 2014 22:00:56 -0500
- All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect
- /archives//html/Topband/2014-02/msg00244.html (9,710 bytes)
- 11. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: Jim Brown <jim@audiosystemsgroup.com>
- Date: Fri, 14 Feb 2014 21:15:57 -0800
- On 2/14/2014 7:00 PM, Charlie Cunningham wrote: All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be fille
- /archives//html/Topband/2014-02/msg00247.html (9,714 bytes)
- 12. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Sat, 15 Feb 2014 00:28:01 -0500
- Thanks, Jim Well, I confess that most of my professional work has been near or above 1 GHz Thanks for tip about the Times datasheets! 73, Charlie,K4OTV If you run the equations, you find that below a
- /archives//html/Topband/2014-02/msg00249.html (10,055 bytes)
- 13. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Carl" <km1h@jeremy.mv.com>
- Date: Sat, 15 Feb 2014 11:05:15 -0500
- The lowest loss cable I have here is 75 Ohm 1" General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the
- /archives//html/Topband/2014-02/msg00251.html (12,074 bytes)
- 14. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "ZR" <zr@jeremy.mv.com>
- Date: Sat, 15 Feb 2014 11:05:25 -0500
- On 2/14/2014 7:00 PM, Charlie Cunningham wrote: All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be fill
- /archives//html/Topband/2014-02/msg00252.html (11,071 bytes)
- 15. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Sat, 15 Feb 2014 11:39:14 -0500
- I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance. 73, Charlie, K4OTV The lowest loss cable I have he
- /archives//html/Topband/2014-02/msg00254.html (12,690 bytes)
- 16. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Sat, 15 Feb 2014 11:41:09 -0500
- Do tell! Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. Ca
- /archives//html/Topband/2014-02/msg00255.html (11,401 bytes)
- 17. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: James Rodenkirch <rodenkirch_llc@msn.com>
- Date: Sat, 15 Feb 2014 09:45:11 -0700
- Carl: I've read, at several places, that sleeve baluns are effective at VHF and above but not at HF frequencies..thoughts?? 72/73, Jim Rodenkirch -- former Tempest inspector for the U.S. Navy..ahhhhh
- /archives//html/Topband/2014-02/msg00257.html (13,954 bytes)
- 18. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
- Date: Sat, 15 Feb 2014 11:53:16 -0500
- Hi, Jim Well, Maxwell's "W2DU" balu ns are ferrite sleeve baluns and you can get those that go down to 160m. It's a matter of choosine the right ferrite for the frequenc;y range of interest, and usin
- /archives//html/Topband/2014-02/msg00259.html (14,417 bytes)
- 19. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Tom W8JI" <w8ji@w8ji.com>
- Date: Sat, 15 Feb 2014 12:00:30 -0500
- Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. That has no
- /archives//html/Topband/2014-02/msg00260.html (10,340 bytes)
- 20. Re: Topband: Palomar R-X Noise Bridge (score: 1)
- Author: "Tom W8JI" <w8ji@w8ji.com>
- Date: Sat, 15 Feb 2014 12:08:19 -0500
- The lowest loss cable I have here is 75 Ohm 1" General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the
- /archives//html/Topband/2014-02/msg00261.html (10,203 bytes)
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