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One Way Propagation ?
First off I don't really believe in one way propagaiton unless someone
can convince me otherwise ? However, I am curious about a phenomenon I've experienced with a number or radios and antennas over the years. I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm using now and lots of new transcievers. I work all CW and on occasion I'll get a 599 signal report from the other station yet he's barely copyable from my end. They all seem to be running the same 100 watts or more that I'm using now and are using a dipole cut for the frequency in use like I am or a G5RV etc. I wonder if anyone else has observed this and/or has an explanation ? This has occured on new transceivers too numerous to name over the years. So I know its not a problem with a particular radio. 73 and Thanks in Advance Gary K8IQ |
On Wed, 16 Feb 2005 02:19:31 -0500, Gary wrote:
First off I don't really believe in one way propagaiton unless someone can convince me otherwise ? However, I am curious about a phenomenon I've experienced with a number or radios and antennas over the years. I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm using now and lots of new transcievers. I work all CW and on occasion I'll get a 599 signal report from the other station yet he's barely copyable from my end. They all seem to be running the same 100 watts or more that I'm using now and are using a dipole cut for the frequency in use like I am or a G5RV etc. I wonder if anyone else has observed this and/or has an explanation ? This has occured on new transceivers too numerous to name over the years. So I know its not a problem with a particular radio. 73 and Thanks in Advance Gary K8IQ I have been thinking about that same thing. I hunt counties and therefore talk to lots of mobiles. Many times I talk to the same mobile in different locations. There are times I am received 59 and hear 22. Other times I hear 59 and get a 22. Since there are many mobiles throughout the country, I think I get a better picture of what propagation looks like than I would if I were just making random contacts. I live in the southeast and use a dipole, so for the most part, communications are in the same direction. Here is my theory, as unsound as it may be. Think of a station with 100 watts using a TV dish style antenna talking to a person using just a dipole with 100 watts. The dipole user will hear a much stronger signal. However, on HF, we don't use dishes. Or maybe we do... We know the ionosphere affects propagation. It is assumed that signals take the same path and therefore should have the same strength, but I don't think so. If the ionosphere is dense (relative to my frequency) behind and over my station, I may be using it as a 'dish' reflector. However, at your location, you may have a porous ionosphere so rather than your signal being reflected, it is being absorbed. The result is that I have an ERP of 200 watts and you reply to me with an ERP of 20. This is just my theory I have in my mind and it may be that it is more full of holes than the ionosphere I put over your station in the example. But, for what it's worth.... 73 for now. Buck N4PGW -- 73 for now Buck N4PGW |
On Wed, 16 Feb 2005 02:19:31 -0500, Gary wrote:
|First off I don't really believe in one way propagaiton unless someone |can convince me otherwise ? However, I am curious about a phenomenon |I've experienced with a number or radios and antennas over the years. |I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm |using now and lots of new transcievers. I work all CW and on occasion |I'll get a 599 signal report from the other station yet he's barely |copyable from my end. They all seem to be running the same 100 watts |or more that I'm using now and are using a dipole cut for the |frequency in use like I am or a G5RV etc. I wonder if anyone else has |observed this and/or has an explanation ? This has occured on new |transceivers too numerous to name over the years. So I know its not a |problem with a particular radio. It's just that big circulator in the sky. |
On 2005-02-16, Buck wrote:
We know the ionosphere affects propagation. It is assumed that signals take the same path and therefore should have the same strength, but I don't think so. If the ionosphere is dense (relative to my frequency) behind and over my station, I may be using it as a 'dish' reflector. However, at your location, you may have a porous ionosphere so rather than your signal being reflected, it is being absorbed. The result is that I have an ERP of 200 watts and you reply to me with an ERP of 20. takeoff angle also plays a big part in this. One station may have a lower angle and be making only 1 hop to the other station, while the other station may have a higher angle and be hitting the first station via 2 hops -- resulting in some signal loss. -- Alex / AB2RC Linux is user friendly, however it is not idiot friendly |
Buck wrote:
Many times I talk to the same mobile in different locations. There are times I am received 59 and hear 22. Other times I hear 59 and get a 22. Doesn't reciprocity assume similar antennas and similar power levels? Of course, someone running the legal power limit into a YAGI is going to be received well by almost everyone but someone replying with QRP into a short vertical whip is going to be at a disadvantage. Changes in polarization in the ionosphere can easily explain the above if one station is horizontally polarized and QSOing with mobiles. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Alex, I believe that the problem occuring here is that many are using words
like refraction, reflection as being interchangeable. I see a mountainside when operating close to as a reflector though it may well be an absorber too. Anything, both behind or in front of a driven element is a diffractor, thus its length alone with respect to the driver does not determine whether it reflects or not. If one solely focusses on the typical yagi then it is easy to talk in general terms which are not applicable to other arrays which leads to erroneous descriptions. It is quite easy to design an array where there are many elements behind the driven element and many would be of lengths both shorter and longer than the driven element but because they are closely coupled they can represent a single, longer element as coupled elements introduces quanlities other than simple physical length.. Regards Art "AB2RC" wrote in message ... On 2005-02-16, Buck wrote: We know the ionosphere affects propagation. It is assumed that signals take the same path and therefore should have the same strength, but I don't think so. If the ionosphere is dense (relative to my frequency) behind and over my station, I may be using it as a 'dish' reflector. However, at your location, you may have a porous ionosphere so rather than your signal being reflected, it is being absorbed. The result is that I have an ERP of 200 watts and you reply to me with an ERP of 20. takeoff angle also plays a big part in this. One station may have a lower angle and be making only 1 hop to the other station, while the other station may have a higher angle and be hitting the first station via 2 hops -- resulting in some signal loss. -- Alex / AB2RC Linux is user friendly, however it is not idiot friendly |
On Wed, 16 Feb 2005 02:19:31 -0500, Gary wrote:
First off I don't really believe in one way propagaiton unless someone can convince me otherwise ? However, I am curious about a phenomenon I've experienced with a number or radios and antennas over the years. I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm using now and lots of new transcievers. I work all CW and on occasion I'll get a 599 signal report from the other station yet he's barely copyable from my end. They all seem to be running the same 100 watts or more that I'm using now and are using a dipole cut for the frequency in use like I am or a G5RV etc. I wonder if anyone else has observed this and/or has an explanation ? This has occured on new transceivers too numerous to name over the years. So I know its not a problem with a particular radio. I run 9.5 Watts from a rare'ish grid square on 6m. Almost everybody else is running 100W or more. I get 5/9 reports from many, many S-3 to S-8 sigs. :-) If I give _my_ rpt first, I nearly always get the identical or better report from the other end. Seriously, tho'. I've seen One-Way-Is-FAR-MORE-Favorable-Than-The-Other propagation often -- on HF, and on 6M & 2M SSB. I don't really believe there is _no such thing as_ one-way propagation. 73 Jones -- | Marvin L Jones | jonz | W3DHJ | linux | Gunnison, Colorado | @ | Jonesy | OS/2 __ | 7,703' -- 2,345m | config.com | DM68mn SK |
"Cecil Moore" wrote in message ... Buck wrote: Many times I talk to the same mobile in different locations. There are times I am received 59 and hear 22. Other times I hear 59 and get a 22. Doesn't reciprocity assume similar antennas and similar power levels? Even more important is accuracy of both "meters" and truth in reporting Art Of course, someone running the legal power limit into a YAGI is going to be received well by almost everyone but someone replying with QRP into a short vertical whip is going to be at a disadvantage. Changes in polarization in the ionosphere can easily explain the above if one station is horizontally polarized and QSOing with mobiles. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
And enter in the operator and their station
Alligator -- big mouth --- little ears Elephant -- little mouth --- big ears Excessive noise on one end of the circuit can be a problem also -- they simply don't hear you thru the noise on their end, you hear them fine. No contact. -- Caveat Lector (Reader Beware) Help The New Hams Someone Helped You Or did You Forget That ? " wrote in message news:35QQd.9987$4q6.2993@attbi_s01... "Cecil Moore" wrote in message ... Buck wrote: Many times I talk to the same mobile in different locations. There are times I am received 59 and hear 22. Other times I hear 59 and get a 22. Doesn't reciprocity assume similar antennas and similar power levels? Even more important is accuracy of both "meters" and truth in reporting Art Of course, someone running the legal power limit into a YAGI is going to be received well by almost everyone but someone replying with QRP into a short vertical whip is going to be at a disadvantage. Changes in polarization in the ionosphere can easily explain the above if one station is horizontally polarized and QSOing with mobiles. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Doesn't reciprocity assume similar antennas and similar
power levels? Not both at once, I think. The explanation I've seen of it is that if you have two radios having identical transmitter power levels, then each radio's receiver will "see" the same input voltage from its peer's signal even if the two stations have wildly different antenna types (pattern, gain, takeoff angle, polarization, etc.). A change in one stations antenna which (e.g.) increases its gain in the direction of the other, will increase both stations' receiver-input voltage levels by the same amount... the changed station "hears" the other station better, and also "speaks" better to the other station by the same amount. Naturally, the two stations may report different signal qualities during the contact, depending on the sensitivities of their receivers, on the local noise-floor level, on the presence of nearby in-band RFI which desenses the receiver, on the meter calibration, on the operator's hearing, on QSB which comes and goes at about the same rate as the conversation changes directions, and so forth. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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