Re: Topband: Palomar R-X Noise Bridge
Absolutely and I had the pleasure of meeting him and hear him speak. Unfortunately his very public arguments with Warren Bruene in QEX and elsewhere over the "Conjugate Match" and then showing up on various forums to publicly push his last book as part of his legacy (which contains his final words on the subject with no further discussion) while the battle was still in progress was a bit dissapointing. Several tried to engage him in a discussion but he didnt want to be challenged and the subject was pulled out of respect for all the good he has done over his long career. Carl KM1H - Original Message - From: "Charlie Cunningham" To: "'Tom W8JI'" ; "'Top Band Contesting'" Sent: Saturday, February 15, 2014 4:35 PM Subject: Re: Topband: Palomar R-X Noise Bridge Walt surely did "know his stuff" and he published some great material!! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 15, 2014 4:31 PM To: Top Band Contesting Subject: Re: Topband: Palomar R-X Noise Bridge Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We "started" with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell "sort of stumbled" on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime "sort of stumbling" on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Walt surely did "know his stuff" and he published some great material!! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 15, 2014 4:31 PM To: Top Band Contesting Subject: Re: Topband: Palomar R-X Noise Bridge > Maxwell sort of stumbled on it in later years with those tiny beads that > seriously overheated with most amps. We "started" with the type that fit > over RG-213 and went from there to custom made, the big donuts, and sheet > products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell "sort of stumbled" on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime "sort of stumbling" on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Palomar R-X Noise Bridge
I just wanted to thank everyone who answered my question about coax impedance and how it would affect 1/4 wave stub length found and cut using a noise bridge. It won't. I though that was the way it worked, but I was not sure. I reasoned this group would have the answer. It did!! Another thing I love about this group is the way one simple question will be expanded on and applied to other similar subject. Always an education. 73 es DX Pat H. Armstrong KF5YZ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: "Tom W8JI" To: "'TopBand'" Sent: Saturday, February 15, 2014 12:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge 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 nothing at all to do with dielectric losses. N connectors have a tiny BNC size center pin. RG-213 have a woven braid and stranded center conductor making the small center conductor diameter heating and shield heating even worse. Jim is correct. Conductor losses significantly dominate dielectric losses at UHF and lower to the point where dielectric loss is meaningless. There are exceptions, of course, but not with normal parts. I didnt say that resistive losses dont dominate but dielectric losses do contribute. A N connector center pin is larger than the coax that goes into it so its loss is not an extra contributor. The mating point of M and F continues that size and with the dielectric do an excellent job of maintaining 50 Ohms well into the microwavesat low signal levels. OTOH an Amphenol or similar quality UHF connector pair will go up in smoke as I found out when first testing my HB 2M amp at 1800W into the Bird load. I used RG-213 only as a size example; others that are in the same genre including 9913 and LMR 400 contribute their own heat as those migrating from SSB to digital modes for EME and earthly propagation have been finding out. Im sure that those running tubes with handles even on 160 have had to migrate away from the UHF set. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We "started" with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell "sort of stumbled" on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime "sort of stumbling" on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: "Tom W8JI" To: "'TopBand'" Sent: Saturday, February 15, 2014 12:08 PM Subject: Re: Topband: Palomar R-X Noise Bridge 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. The lowest loss cables have large, smooth conductors that are the maximum possible size for the cable impedance. Dielectric is largely meaningless, except as it might affect conductor size. ** Which directly affects loss. While meaningless at 160 even in long runs the difference between the 1" Fused Disc and 1" solid foam Commscope is .5 vs .65dB/100' at 222 MHz which can add up to no contact in long lengths. We can argue this point endlessly, but it will always come back to the conductors. ** As close to an air dielectric as possible will have the largest diameter center conductor and lowest loss. Adding any other dielectric requires a smaller conductor to maintain the same impedance and with its own extra loss caused by the dielectric choice so it will always be a contributing factor since its dielectric constant and capacitance per foot varies and is not a lossless medium. It is also frequency sensitive. A nitrogen pressurized coax is about as good as it gets. The exception would be some horrible dielectric or operation way up above normal VHF/UHF with marginal dielectrics. It is the way it is. The confusion probably occurs because dielectrics with more air allow a larger conductor to be used for a given cable diameter and impedance, it is not because the dielectric has less loss. ** Im not confused but for the sake of the forum it is not exactly related to 160 so lets leave it for elsewhere. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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..ah...Tempest comcerns - the good 'ol days hi Hi! Oh, the fun we had almost living in a screen room in order to get a product past those inspectors!! The effect of shielding and ferrites has been permanently imprinted on my brain. I sometimes have to laugh when reading that some consider a sleeve balun/choke to be a recent invention! Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We "started" with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Carl KM1H From: charlie-cunning...@nc.rr.com To: k...@jeremy.mv.com; topband@contesting.com Date: Sat, 15 Feb 2014 11:39:14 -0500 Subject: Re: Topband: Palomar R-X Noise Bridge 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 -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: "Charlie Cunningham" To: ; "'TopBand'" Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge > 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 those would likely > be > the lowest loss AND highest velocity factor cases. > > 73, > Charlie, K4OTV > > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > Brown > Sent: Friday, February 14, 2014 9:42 PM > To: 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > On 2/14/2014 2:17 PM, Carl wrote: >> Isnt that what "lowest loss" means? At least that was my intention. > > 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), but it's the fact that it's LARGER and has lower RF resistance, > NOT the higher Vf. > > Think of it this way -- The higher Vf cable has less attenuation per ft > because the higher Vf allows the center conductor to be larger. > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > one with with a solid dielectric and Vf =.66. If those coaxes are the > same diameter and of comparable quality, the stub attenuation and Q > will > be nearly the same. > > 73, Jim K9YC > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: > 02/15/14 > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
The proper ferrites work well down into any frequency you want, even LF. I use them into UHF as a way to keep 2 and 4 bay yagis from having distorted patterns that can kill a good F/B. Several A-B tests on the 20' test tower have confirmed their effectiveness. Common mode is a minor issue at those frequencies that is easilly buried into the noise. This hilltop is great BUT can get noisy so I design my yagis for high F/R and low frontal side lobes. Carl KM1H - Original Message - From: Charlie Cunningham To: 'James Rodenkirch' ; 'Carl' ; 'Top Band Contesting' Sent: Saturday, February 15, 2014 11:53 AM Subject: RE: Topband: Palomar R-X Noise Bridge 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 using enough ferrite to build p the common-mode impedance! 73, Charlie, K4OTV From: James Rodenkirch [mailto:rodenkirch_...@msn.com] Sent: Saturday, February 15, 2014 11:45 AM To: Charlie Cunningham; 'Carl'; Top Band Contesting Subject: RE: Topband: Palomar R-X Noise Bridge 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..ah...Tempest comcerns - the good 'ol days hi Hi! From: charlie-cunning...@nc.rr.com To: k...@jeremy.mv.com; topband@contesting.com Date: Sat, 15 Feb 2014 11:39:14 -0500 Subject: Re: Topband: Palomar R-X Noise Bridge 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 -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: "Charlie Cunningham" To: ; "'TopBand'" Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge > 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 those would likely > be > the lowest loss AND highest velocity factor cases. > > 73, > Charlie, K4OTV > > -Original Message----- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > Brown > Sent: Friday, February 14, 2014 9:42 PM > To: 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > On 2/14/2014 2:17 PM, Carl wrote: >> Isnt that what "lowest loss" means? At least that was my intention. > > 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), but it's the fact that it's LARGER and has lower RF resistance, > NOT the higher Vf. > > Think of it this way -- The higher Vf cable has less attenuation per ft > because the higher Vf allows the center conductor to be larger. > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > one with with a solid dielectric and Vf =.66. If those coaxes are the > same diameter and of comparable quality, the stub attenuation and Q will > be nearly the same. > > 73, Jim K9YC > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: > 02/15/14 > _ Topband Reflector Archives - http://www.contesting.com/_topband No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. The lowest loss cables have large, smooth conductors that are the maximum possible size for the cable impedance. Dielectric is largely meaningless, except as it might affect conductor size. We can argue this point endlessly, but it will always come back to the conductors. The exception would be some horrible dielectric or operation way up above normal VHF/UHF with marginal dielectrics. It is the way it is. The confusion probably occurs because dielectrics with more air allow a larger conductor to be used for a given cable diameter and impedance, it is not because the dielectric has less loss. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 nothing at all to do with dielectric losses. N connectors have a tiny BNC size center pin. RG-213 have a woven braid and stranded center conductor making the small center conductor diameter heating and shield heating even worse. Jim is correct. Conductor losses significantly dominate dielectric losses at UHF and lower to the point where dielectric loss is meaningless. There are exceptions, of course, but not with normal parts. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 using enough ferrite to build p the common-mode impedance! 73, Charlie, K4OTV From: James Rodenkirch [mailto:rodenkirch_...@msn.com] Sent: Saturday, February 15, 2014 11:45 AM To: Charlie Cunningham; 'Carl'; Top Band Contesting Subject: RE: Topband: Palomar R-X Noise Bridge 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..ah...Tempest comcerns - the good 'ol days hi Hi! > From: charlie-cunning...@nc.rr.com > To: k...@jeremy.mv.com; topband@contesting.com > Date: Sat, 15 Feb 2014 11:39:14 -0500 > Subject: Re: Topband: Palomar R-X Noise Bridge > > 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 > > -Original Message- > From: Carl [mailto:k...@jeremy.mv.com] > Sent: Saturday, February 15, 2014 11:05 AM > To: Charlie Cunningham; 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV > hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive > been using ferrite sleeve baluns since the mid 70's; I was introduced to > them by the company I worked for who was building equipment for the joint > CIA/DOD Tempest program. > > Carl > KM1H > > > - Original Message - > From: "Charlie Cunningham" > To: ; "'TopBand'" > Sent: Friday, February 14, 2014 10:00 PM > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > 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 those would likely be > > the lowest loss AND highest velocity factor cases. > > > > 73, > > Charlie, K4OTV > > > > -Original Message- > > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > > Brown > > Sent: Friday, February 14, 2014 9:42 PM > > To: 'TopBand' > > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > On 2/14/2014 2:17 PM, Carl wrote: > >> Isnt that what "lowest loss" means? At least that was my intention. > > > > 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), but it's the fact that it's LARGER and has lower RF resistance, > > NOT the higher Vf. > > > > Think of it this way -- The higher Vf cable has less attenuation per ft > > because the higher Vf allows the center conductor to be larger. > > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > > one with with a solid dielectric and Vf =.66. If those coaxes are the > > same diameter and of comparable quality, the stub attenuation and Q will > > be nearly the same. > > > > 73, Jim K9YC > > _ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > _ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > > > - > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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..ah...Tempest comcerns - the good 'ol days hi Hi! > From: charlie-cunning...@nc.rr.com > To: k...@jeremy.mv.com; topband@contesting.com > Date: Sat, 15 Feb 2014 11:39:14 -0500 > Subject: Re: Topband: Palomar R-X Noise Bridge > > 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 > > -Original Message- > From: Carl [mailto:k...@jeremy.mv.com] > Sent: Saturday, February 15, 2014 11:05 AM > To: Charlie Cunningham; 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV > hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive > been using ferrite sleeve baluns since the mid 70's; I was introduced to > them by the company I worked for who was building equipment for the joint > CIA/DOD Tempest program. > > Carl > KM1H > > > ----- Original Message - > From: "Charlie Cunningham" > To: ; "'TopBand'" > Sent: Friday, February 14, 2014 10:00 PM > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > 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 those would likely be > > the lowest loss AND highest velocity factor cases. > > > > 73, > > Charlie, K4OTV > > > > -Original Message- > > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > > Brown > > Sent: Friday, February 14, 2014 9:42 PM > > To: 'TopBand' > > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > On 2/14/2014 2:17 PM, Carl wrote: > >> Isnt that what "lowest loss" means? At least that was my intention. > > > > 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), but it's the fact that it's LARGER and has lower RF resistance, > > NOT the higher Vf. > > > > Think of it this way -- The higher Vf cable has less attenuation per ft > > because the higher Vf allows the center conductor to be larger. > > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > > one with with a solid dielectric and Vf =.66. If those coaxes are the > > same diameter and of comparable quality, the stub attenuation and Q will > > be nearly the same. > > > > 73, Jim K9YC > > _ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > _ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > > > - > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Do tell! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Saturday, February 15, 2014 11:05 AM To: j...@audiosystemsgroup.com; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge - Original Message - From: "Jim Brown" To: "'TopBand'" Sent: Saturday, February 15, 2014 12:15 AM Subject: Re: Topband: Palomar R-X Noise Bridge > 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 >> filled with air, dry nitrogen or evacuated. I expect those would likely >> be >> the lowest loss AND highest velocity factor cases. > > If you run the equations, you find that below about 1 GHz, the losses are > all copper losses. Dielectric loss is a few percent of the total loss in > the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that > it allows the center conductor to be larger for a given shield diameter. > But the improvement in loss of a foam dielectric coax below 1 GHz is > entirely due to the center conductor being larger. > > BTW -- the relevant equation is on each Times data sheet. > > 73, Jim K9YC 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. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge 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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: "Charlie Cunningham" To: ; "'TopBand'" Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge > 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 those would likely be > the lowest loss AND highest velocity factor cases. > > 73, > Charlie, K4OTV > > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > Brown > Sent: Friday, February 14, 2014 9:42 PM > To: 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > On 2/14/2014 2:17 PM, Carl wrote: >> Isnt that what "lowest loss" means? At least that was my intention. > > 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), but it's the fact that it's LARGER and has lower RF resistance, > NOT the higher Vf. > > Think of it this way -- The higher Vf cable has less attenuation per ft > because the higher Vf allows the center conductor to be larger. > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > one with with a solid dielectric and Vf =.66. If those coaxes are the > same diameter and of comparable quality, the stub attenuation and Q will > be nearly the same. > > 73, Jim K9YC > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: "Charlie Cunningham" To: ; "'TopBand'" Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge 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 those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what "lowest loss" means? At least that was my intention. 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), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: "Jim Brown" To: "'TopBand'" Sent: Saturday, February 15, 2014 12:15 AM Subject: Re: Topband: Palomar R-X Noise Bridge 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 filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. If you run the equations, you find that below about 1 GHz, the losses are all copper losses. Dielectric loss is a few percent of the total loss in the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that it allows the center conductor to be larger for a given shield diameter. But the improvement in loss of a foam dielectric coax below 1 GHz is entirely due to the center conductor being larger. BTW -- the relevant equation is on each Times data sheet. 73, Jim K9YC 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. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Saturday, February 15, 2014 12:16 AM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge 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 filled with air, dry nitrogen or evacuated. I expect > those would likely be the lowest loss AND highest velocity factor cases. If you run the equations, you find that below about 1 GHz, the losses are all copper losses. Dielectric loss is a few percent of the total loss in the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that it allows the center conductor to be larger for a given shield diameter. But the improvement in loss of a foam dielectric coax below 1 GHz is entirely due to the center conductor being larger. BTW -- the relevant equation is on each Times data sheet. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. If you run the equations, you find that below about 1 GHz, the losses are all copper losses. Dielectric loss is a few percent of the total loss in the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that it allows the center conductor to be larger for a given shield diameter. But the improvement in loss of a foam dielectric coax below 1 GHz is entirely due to the center conductor being larger. BTW -- the relevant equation is on each Times data sheet. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: > Isnt that what "lowest loss" means? At least that was my intention. 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), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
On 2/14/2014 2:17 PM, Carl wrote: Isnt that what "lowest loss" means? At least that was my intention. 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), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: "Jim Brown" To: Sent: Friday, February 14, 2014 4:16 PM Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 10:55 AM, Carl wrote: The highest VF and lowest loss produces the deepest null but also the least deep null bandwidth due to the higher Q. 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 bandwidth you have noted), is to reduce the RF resistance -- this means larger diameter coax and a more robust shield, like hard line. 73, Jim K9YC Isnt that what "lowest loss" means? At least that was my intention. On 6M Ive used a 7/8" Heliax stub to kill harmonics getting into the police system 200' away. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Makes sense. The lower the return-loss, the deeper the null! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 4:17 PM To: topband@contesting.com Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 10:55 AM, Carl wrote: > The highest VF and lowest loss produces the deepest null but also the > least deep null bandwidth due to the higher Q. 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 bandwidth you have noted), is to reduce the RF resistance -- this means larger diameter coax and a more robust shield, like hard line. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
On 2/14/2014 10:55 AM, Carl wrote: The highest VF and lowest loss produces the deepest null but also the least deep null bandwidth due to the higher Q. 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 bandwidth you have noted), is to reduce the RF resistance -- this means larger diameter coax and a more robust shield, like hard line. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: To: Sent: Friday, February 14, 2014 11:42 AM Subject: Re: Topband: Palomar R-X Noise Bridge 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 the least deep null bandwidth due to the higher Q. I used CATV RG-11 for my stubs and could get a good 25 dB+ null compared to about 12dB for RG-58. I had to add pieces for CW contests on some bands. The 25dB was sufficient to operate on any other band and put the TX phase noise in the noise. Carl KM1H 75 vs. 50 ohm should make no difference. 73 Frank W3LPL - Original Message - From: "Charlie Cunningham" To: map...@windstream.net, topband@contesting.com Sent: Friday, February 14, 2014 4:16:30 PM Subject: Re: Topband: Palomar R-X Noise Bridge 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 would expect the method to work fine with 75 ohm line. In fact, the 50 or 75 ohm line, if we consider it to be lossless would be operating at infinite VSWR so I wouldn't think the modest difference in characteristic impedance would make any real difference. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of map...@windstream.net Sent: Friday, February 14, 2014 12:18 AM To: topband@contesting.com Subject: Topband: Palomar R-X Noise Bridge 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 same procedure work for 75 ohm that works for 52 ohm cable, or will the different impedance need to be accounted for. I started to cut cable and this question came to me. My first thought is that it will work fine, but I am not sure. I did some searches on the web but found nothing about it. Any help would be appreciated. Thanks, Pat Armstrong KF5YZ _ 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: Palomar R-X Noise Bridge
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 - From: "Charlie Cunningham" To: map...@windstream.net, topband@contesting.com Sent: Friday, February 14, 2014 4:16:30 PM Subject: Re: Topband: Palomar R-X Noise Bridge 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 would expect the method to work fine with 75 ohm line. In fact, the 50 or 75 ohm line, if we consider it to be lossless would be operating at infinite VSWR so I wouldn't think the modest difference in characteristic impedance would make any real difference. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of map...@windstream.net Sent: Friday, February 14, 2014 12:18 AM To: topband@contesting.com Subject: Topband: Palomar R-X Noise Bridge 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 same procedure work for 75 ohm that works for 52 ohm cable, or will the different impedance need to be accounted for. I started to cut cable and this question came to me. My first thought is that it will work fine, but I am not sure. I did some searches on the web but found nothing about it. Any help would be appreciated. Thanks, Pat Armstrong KF5YZ _ 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: Palomar R-X Noise Bridge
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 would expect the method to work fine with 75 ohm line. In fact, the 50 or 75 ohm line, if we consider it to be lossless would be operating at infinite VSWR so I wouldn't think the modest difference in characteristic impedance would make any real difference. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of map...@windstream.net Sent: Friday, February 14, 2014 12:18 AM To: topband@contesting.com Subject: Topband: Palomar R-X Noise Bridge 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 same procedure work for 75 ohm that works for 52 ohm cable, or will the different impedance need to be accounted for. I started to cut cable and this question came to me. My first thought is that it will work fine, but I am not sure. I did some searches on the web but found nothing about it. Any help would be appreciated. Thanks, Pat Armstrong KF5YZ _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
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 receiver also works well as the backround noise null is easily heard. I did that several times when a 9V battery was dead and compared results later, they were right on. Carl KM1H - Original Message - From: To: Sent: Friday, February 14, 2014 12:18 AM Subject: Topband: Palomar R-X Noise Bridge 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 same procedure work for 75 ohm that works for 52 ohm cable, or will the different impedance need to be accounted for. I started to cut cable and this question came to me. My first thought is that it will work fine, but I am not sure. I did some searches on the web but found nothing about it. Any help would be appreciated. Thanks, Pat Armstrong KF5YZ _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Palomar R-X Noise Bridge
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 same procedure work for 75 ohm that works for 52 ohm cable, or will the different impedance need to be accounted for. I started to cut cable and this question came to me. My first thought is that it will work fine, but I am not sure. I did some searches on the web but found nothing about it. Any help would be appreciated. Thanks, Pat Armstrong KF5YZ _ Topband Reflector Archives - http://www.contesting.com/_topband
