Home |
Search |
Today's Posts |
#1
![]() |
|||
|
|||
![]()
For One and All,
Better Signal-to-Noise Ratio from a Combination of Improvements including . . . a Ground. http://groups.yahoo.com/group/Shortw...a/message/5961 What I generally 'see' as far as an "Improvement" of the quality of the RF Signal getting to the Receiver is from a combination of things. 1. The Wire Antenna Element is placed farther from the House. 2. A 'remote' Ground Rod is used : Again this Ground Rod is planted in the ground farther away from the House. 3. Use of a Matching Transformer between the Wire Antenna Element and the Coax Cable : Mounted the Matching Transformer on the Ground Rod - if possible. 4. Use of a Coax Cable Feed-in-Line : Laying-On -or- Buried-Under the Ground - if possible. 5. The Extra Mile - Use a well grounded Lightning Arrestor and/or an In-Line 1:1 Isolation Transformer where the Coax Cable leaves the Ground and enters the House. NOTE - All the above is no good if you do not have a very well Grounded Household Electrical System. Do This First ! RESULTS - Actually in most instances what I 'see' is a reduction in the S-Meter reading : But I also "Hear" a Greater Reduction of the Noise Level. Thus the Signal-to-Noise Radio 'improves' and the Listenability of the RF Signal (Audio) is much Better. BUT REMEMBER - YOUR PRIMARY USE OF A GROUND IS FOR IMPROVED ELECTRICAL SAFETY AND LIGHTNING PROTECTION - USE IT [.] i hope we are communicating - iane ~ RHF . . .. . = = = In , = = = "David G******" davidg******@c... wrote: JHR Wrote: "...... I do not mean to contradict you, but my personal experience with several radios yield the conclusion that grounding at any point has no effect on receiving....... .....I just don't get it." - - - - - - - - - - - - - - - - - - - - - - - - - - - - DAVE Wrote: Neither do I. My experience is the same. I have never witnessed a signal improvement from the use of a variety of different RF grounds. It think it's possible that once or twice I think I heard a small reduction in noise. I suspect that my house electrical system provides sufficient ground to yield the maximum differential between what's on my antenna and ground. ~ Dave . - - - - - - - - - - - - - - - - - - - - - - - - - - - - . Tous Sont Bienvenus ! - - - Groupe par Radio d'auditeur d'onde courte pour des Antennes de SWL http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . Alle Sind Willkommen ! - - - Shortwave Radiozuhörer Gruppe für SWL Antennen http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . Tutti Sono Benvenuti ! - - - Gruppo Radiofonico dell'ascoltatore di onda corta per le Antenne di SWL http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . Todos São Bem-vindos ! - - - Grupo de Rádio do ouvinte do Shortwave para Antenas de SWL http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . Все *адушны ! - - - Группа оператора на приеме коротковолнового диапазона Radio для Aнтенн SWL http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . ¡Todos Son Agradables! - - - Grupo de Radio del oyente de la onda corta para las Antenas de SWL http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ . . .. . |
#2
![]() |
|||
|
|||
![]()
For One and All,
For all and one... Better Signal-to-Noise Ratio from a Combination of Improvements including . . . a Ground. http://groups.yahoo.com/group/Shortw...a/message/5961 What I generally 'see' as far as an "Improvement" of the quality of the RF Signal getting to the Receiver is from a combination of things. 1. The Wire Antenna Element is placed farther from the House. This can help if needed. Most of my antennas are over the house. 2. A 'remote' Ground Rod is used : Again this Ground Rod is planted in the ground farther away from the House. But again, this is only due to the incomplete antenna that you are running in that case. "I assume the usual random wire of whatever config" 3. Use of a Matching Transformer between the Wire Antenna Element and the Coax Cable : Mounted the Matching Transformer on the Ground Rod - if possible. Again, this will almost always have zero effect on s/n ratio. There is usually no lack of signal without the transformer. 4. Use of a Coax Cable Feed-in-Line : Laying-On -or- Buried-Under the Ground - if possible. You do not have to use coax to have low noise reception. Ladder line can work just as well, if properly balanced. Coax is just often more convenient, and easier to work with. But ladder line can be just as quiet. If the coax is poorly decoupled, it will be as noisy as any unbalanced ladder line. 5. The Extra Mile - Use a well grounded Lightning Arrestor and/or an In-Line 1:1 Isolation Transformer where the Coax Cable leaves the Ground and enters the House. But what does this have to do with improving the s/n ratio? NOTE - All the above is no good if you do not have a very well Grounded Household Electrical System. Do This First ! I'm sorry, but this is pure hogwash. You *do not* need *any* kind of a ground to have a good low noise receiving system. RESULTS - Actually in most instances what I 'see' is a reduction in the S-Meter reading : But I also "Hear" a Greater Reduction of the Noise Level. Thus the Signal-to-Noise Radio 'improves' and the Listenability of the RF Signal (Audio) is much Better. Well, sure, you are decoupling the feedline in a better manner. Ground wouldn't have anything to do with it, except you are using ground as a method to decouple the feedline. You can decouple the feedline just as well using other "non grounded" methods. You are confusing a technique with the actual cure. The actual cure is the decoupling of the line, not the ground. The ground is just a method you are using to decouple the line. BUT REMEMBER - YOUR PRIMARY USE OF A GROUND IS FOR IMPROVED ELECTRICAL SAFETY AND LIGHTNING PROTECTION - USE IT [.] I have no argument with this if those concerns are actual. IE: My battery run IC-706 needs no safety ground. In that case, it can be ignored. But my older tube rigs do need to be safety grounded. In that case, ignoring can be painful... ![]() Most of my antennas are elevated, and my mast does take strikes from time to time. I *do* have a well grounded mast for a lightning return, and I have a ground bulkhead outside my window to ground lines to in bad wx... But still....Has nothing to do with improving s/n ratio.. :/ i hope we are communicating - iane ~ RHF Your lips move, but I can't hear what you're sayin.... "optional Pink Floyd content" added as a bonus... |
#3
![]() |
|||
|
|||
![]()
MK - After all this is a NewsGroup
and 'your' Opinion is Welcome ![]() "With my best Elvis impersonation" Thank ya, vury vury much... MK - Hey I guess you are right, 'we' should all pack-up our long wire antennas and sell our radios. Oops That's a - no, No. NO ! No. Nothing wrong with using any type of antenna. What is getting you into trouble is applying the technique used with one particular type of antenna, and imply that it applies to all. And also you are giving credit to the wrong thing that improves the antenna you are using. It ain't the ground in itself, or the transformer, which is almost never actually needed. It's the decoupling of the feedline. The only reason ground is mentioned is cuz it's the method used to help decouple the feedline. But still in the big picture, the random is fairly lame vs other choices. It's just how far you want to go with it. If I had to transmit using random wires, "which I have tried", I would be miserable. Poor overall performance in general, and a nightmare as far as rf problems in the shack, etc. Being I already have full size dipoles for most of the HF bands, it would be silly for me to use random wires for SWL. And once you compare the two types, it's not too likely you would want to use the random wire if you have room for dipoles. I've also used full size HF ground planes. I often run one for 40m, 36 ft at the base on a mast. The antenna is nearly 70 ft tall. It is killer for long haul on the lower -mid HF bands late at night. On a path to Australia, that GP would beat my dipole at 36 ft by appx 4 s units. Using that ground plane, and 1 KW of power I would always be over S 9 in Australia. Once got a report of 20 db over 9 in Tokyo. That antenna browns the food. And my dipole would probably beat the average random wire by 4 s units. Then on the upper HF bands, I have a yagi. Will hear stuff that wouldn't exist on many random wires due to the forward gain, and f/b ratio. And it's steerable from the shack. Use a random wire instead? Thanks, but no thanks.. :/ But I realize, not everyone is me... BTW, a random wire must be at least one wavelength long on the band in use to qualify as a "long wire". Pretty easy on the upper bands, but will need a pretty long wire on the low bands. IE: 4 mhz will need appx 230-240 ft... MK |
#4
![]() |
|||
|
|||
![]() From: Organization: http://groups.google.com Newsgroups: rec.radio.shortwave Date: 22 Oct 2005 23:46:25 -0700 Subject: Better Signal-to-Noise Ratio from a Combination of Improvements including . . . a Ground MK - After all this is a NewsGroup and 'your' Opinion is Welcome ![]() "With my best Elvis impersonation" Thank ya, vury vury much... MK - Hey I guess you are right, 'we' should all pack-up our long wire antennas and sell our radios. Oops That's a - no, No. NO ! No. Nothing wrong with using any type of antenna. What is getting you into trouble is applying the technique used with one particular type of antenna, and imply that it applies to all. And also you are giving credit to the wrong thing that improves the antenna you are using. It ain't the ground in itself, or the transformer, which is almost never actually needed. It's the decoupling of the feedline. The only reason ground is mentioned is cuz it's the method used to help decouple the feedline. (snip) MK- Please elaborate. I am under the impression that: 1. A random-length "inverted L" wire antenna with coax lead-in is a good choice for a simple, effective receive antenna for 1.8 to 30mHz listening. 2. That the matching transformer, with proper ground, is a simple, practical, easy way to mitigate extraneous RF noise. Is there a better single antenna that covers the HF spectrum? And what are other ways to decouple the feedline? Thanks, Greg |
#5
![]() |
|||
|
|||
![]()
MK- Please elaborate. I am under the impression that:
1. A random-length "inverted L" wire antenna with coax lead-in is a good choice for a simple, effective receive antenna for 1.8 to 30mHz listening. It's ok for general use. I'm not against random wires. Just RHF's description of why or how they work... 2. That the matching transformer, with proper ground, is a simple, practical, easy way to mitigate extraneous RF noise. The matching transformer has nothing to do with it. The ground is used as a method to help decouple the feedline. It's the decoupling of the line that mitigates common mode currents. All the matching transformer does is change impedance. But impedance/ SWR, etc, have *nothing* at all to do with common mode currents flowing on the shield. Nada. Zilch. The only reason people use the transformer is to provide a better transfer of power. But it's almost always overkill. The use of one can pump up the S meter, but it rarely improves the s/n ratio. In some cases, the transformer can actually degrade the signal if the original match was better than the new one. Is there a better single antenna that covers the HF spectrum? And what are other ways to decouple the feedline? Dunno. Just depends on the needs, path, time of day, freq, etc, etc. No one antenna is best for everything. Thats why I have several. For general multiband use, I like paralleled dipoles fed with a single coax. A 1:1 balun or a coax choke at the feedpoint is used to decouple the line. Some like a dipole fed with ladder line and tuner. The dipole would be cut for the lowest band to be used. Some like a large loop fed in the same manner. There are a zillion antennas that can be used. It depends on the antenna, etc, but with most systems, baluns or chokes are the most common decoupling devices. With elevated ground planes, the radials help decouple the line, and extra "decoupling radials, cones, sleeves, etc can be used. With the random wires, grounding the shield, or chokes are commonly used. But the use of ground as a decoupling aid is only used on incomplete antennas like coax fed random wires, ground mount verticals, etc.. You won't see that used on many "complete" antenna systems. MK |
#6
![]() |
|||
|
|||
![]() From: Organization: http://groups.google.com Newsgroups: rec.radio.shortwave Date: 23 Oct 2005 12:19:53 -0700 Subject: Better Signal-to-Noise Ratio from a Combination of Improvements including . . . a Ground MK- Please elaborate. I am under the impression that: 1. A random-length "inverted L" wire antenna with coax lead-in is a good choice for a simple, effective receive antenna for 1.8 to 30mHz listening. It's ok for general use. I'm not against random wires. Just RHF's description of why or how they work... 2. That the matching transformer, with proper ground, is a simple, practical, easy way to mitigate extraneous RF noise. The matching transformer has nothing to do with it. The ground is used as a method to help decouple the feedline. It's the decoupling of the line that mitigates common mode currents. All the matching transformer does is change impedance. But impedance/ SWR, etc, have *nothing* at all to do with common mode currents flowing on the shield. Nada. Zilch. The only reason people use the transformer is to provide a better transfer of power. But it's almost always overkill. The use of one can pump up the S meter, but it rarely improves the s/n ratio. In some cases, the transformer can actually degrade the signal if the original match was better than the new one. Is there a better single antenna that covers the HF spectrum? And what are other ways to decouple the feedline? Dunno. Just depends on the needs, path, time of day, freq, etc, etc. No one antenna is best for everything. Thats why I have several. For general multiband use, I like paralleled dipoles fed with a single coax. A 1:1 balun or a coax choke at the feedpoint is used to decouple the line. Some like a dipole fed with ladder line and tuner. The dipole would be cut for the lowest band to be used. Some like a large loop fed in the same manner. There are a zillion antennas that can be used. It depends on the antenna, etc, but with most systems, baluns or chokes are the most common decoupling devices. With elevated ground planes, the radials help decouple the line, and extra "decoupling radials, cones, sleeves, etc can be used. With the random wires, grounding the shield, or chokes are commonly used. But the use of ground as a decoupling aid is only used on incomplete antennas like coax fed random wires, ground mount verticals, etc.. You won't see that used on many "complete" antenna systems. MK Okay, thanks. I'm starting to get the picture, though I'm not familiar with the coax choke. I guess I'll do a little more googling. Greg |
#7
![]() |
|||
|
|||
![]()
"N" - and so what do you recommend to a Shortwave Listener
(SWL) who simply has a 25-30 Foot Square Backyard ? ? ? This same Broadcast Program SWL, who only can get their Antenna Wire up about about 15-20 Feet High; and wants to hear everything from 500 kHz thru 30 MHz ? ? ? ~ RHF |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Inverted ground plane antenna: compared with normal GP and low dipole. | Antenna | |||
The Apollo Hoax FAQ | General | |||
Poor quality low + High TV channels? How much dB in Preamp? | Antenna | |||
QST Article: An Easy to Build, Dual-Band Collinear Antenna | Antenna | |||
Ten-tec vee beam | Antenna |