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#1
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I wouldn't normally advertise here, but I seen a post or two in recent times
looking for an antenna. Have 2 types available. A Discone and a Ground Plane. Both good for 25 - 1000 MHz. Both have a 1 year Factory Warranty. Both have a UHF Female Connector, the latter model having an 18" lead. The discone is an Antenna Specialist MON 64, the Ground Plane is a MONR-31 Should you wish more information, please feel free to write to Thanks, CL |
#2
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![]() CL schrieb: Have 2 types available. A Discone and a Ground Plane. Both good for 25 - 1000 MHz. On technical reason a ground plane antenna can NEVER work as a broadband antenna. It is limited to some frequencies or relatively small frequency ranges with acceptable gain. A discone has some gain above 0dBi on the wohle specified range up to 2 dBi. A groundplane has some gain up to 3 or 4 dBi on resonant frequencies and dramatic loss down to -(!)15dBi on nonresonant ranges. odo |
#3
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I'm not saying I "disagree" - though I've never fully gotten into the design
basics/performance, but "I" didn't "design" them - I only sell them! The last customer who bought a discone from me was very pleased with it - for whatever that is worth. I have the previous version of the ground plane I now handle, it didn't cover past 400 MHz, but it seemed to work well. I was just answering a need of sorts. Trying to be helpful. CL "Volker Tonn" wrote in message ... CL schrieb: Have 2 types available. A Discone and a Ground Plane. Both good for 25 - 1000 MHz. On technical reason a ground plane antenna can NEVER work as a broadband antenna. It is limited to some frequencies or relatively small frequency ranges with acceptable gain. A discone has some gain above 0dBi on the wohle specified range up to 2 dBi. A groundplane has some gain up to 3 or 4 dBi on resonant frequencies and dramatic loss down to -(!)15dBi on nonresonant ranges. odo |
#4
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![]() CL schrieb: I'm not saying I "disagree" - though I've never fully gotten into the design basics/performance, but "I" didn't "design" them - I only sell them! Bad enough that you believe in the sheet (=****) of the manufacturer. A professional seller you should know the technical basics on the products he sells. Never(!) believe in the "specs" a manufacturer gives, without some verification of plausibility on it. Name these "broadband groundplane" antennas JUNK and send them back to the manufacturer. Or keep them on 1/20 of the price and sell them as 'groundplane with gain some*where* between 25 and 1300Mhz' at 1/10 of the original price. This should satisfy everybody but the manufacturer :-) regards, Volker |
#5
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Eh, I did say I had tried a "previous" version of the ground plane. It did
"seem" to work ok. At that time, I didn't have 1/4 of the equipment I now have. I've not really had time or space to prove anything in or out. I'm preparing to move to a new location, then I can play all I want. More room for antennas and so on. Here, there hasn't been room for much of anything. No, I do "not" agree with all they write. There is always room for disagreement. I suppose it comes down to the point of IF that is the only product out there, and you need it, what choice do you have ESPECIALLY if you're not capable of building antennas like some of us are? Not much of a choice from that perspective. It's up to the individual. I'm not "pushing" anything. If they want to buy - they will, if not - so be it! That is their choice. CL. "Volker Tonn" wrote in message ... CL schrieb: I'm not saying I "disagree" - though I've never fully gotten into the design basics/performance, but "I" didn't "design" them - I only sell them! Bad enough that you believe in the sheet (=****) of the manufacturer. A professional seller you should know the technical basics on the products he sells. Never(!) believe in the "specs" a manufacturer gives, without some verification of plausibility on it. Name these "broadband groundplane" antennas JUNK and send them back to the manufacturer. Or keep them on 1/20 of the price and sell them as 'groundplane with gain some*where* between 25 and 1300Mhz' at 1/10 of the original price. This should satisfy everybody but the manufacturer :-) regards, Volker |
#6
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![]() CL schrieb: Eh, I did say I had tried a "previous" version of the ground plane. It did "seem" to work ok. At that time, I didn't have 1/4 of the equipment I now have. Your initial posting implied (to me) that you are a professional seller of this antennas (and maybe other equipment). Sorry when I was wrong. As a "normal user" you may have trusted the manufacturers "promises". regards, Volker |
#7
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"Volker Tonn" wrote:
On technical reason a ground plane antenna can NEVER work as a broadband antenna. It is limited to some frequencies or relatively small frequency ranges with acceptable gain. A discone has some gain above 0dBi on the wohle specified range up to 2 dBi. A groundplane has some gain up to 3 or 4 dBi on resonant frequencies and dramatic loss down to -(!)15dBi on nonresonant ranges. You set an unreachable standard, Volker. There is no antenna made that is not more resonant on some frequencies and less resonant on others. Certainly some do perform better than either the ground plane or discone, but these antennas have their place also. Few antennas can beat the utter bandwidth of a discone and the ground plane is ideal where an even less intrusive antenna is desired. Indeed, I've had success with a simple wire that is probably not directly resonant on any desired frequency. In other words, any antenna is clearly better than nothing. Dwight Stewart (W5NET) http://www.qsl.net/w5net/ |
#8
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![]() Dwight Stewart schrieb: ... Few antennas can beat the utter bandwidth of a discone and the ground plane is ideal where an even less intrusive antenna is desired. Giving a specification(!) on a groundplane from 25-100Mhz is taking a customer for a ride. An antenna specified(!) for a frequency *range* implies at least that it has gain over an isotropic radiator wich is simply not true for a groundplane "25-1000Mhz". It would be a different thing in konjunktion with some active elctronics -wich is not the case-. And yes, you can have very much success on a simple antenna design. A CB-whip with top loading coil (in europe known as DV27S -length of 1.4mtr-) is known to be a good performer on _some_ "interesting" frequency ranges. It works on the same principle like the mentioned groundplane when installed on a metal sheet ...at a fraction of cost (less than 10EUR/ 13US$). Volker |
#9
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As "I" had stated, if those antennas are the only game in town and people
are wanting to buy them, not knowing how to make one, what choice is left? Though I can build one myself and have, most people won't want a "homemade" antenna. SO...... No antenna is "perfect". Antennas for the most part are tested in a set of conditions usually fixed, whereas their use out side those conditions can vary greatly. Type of cable, length, height of installation, surroundings, etc... NO antenna can work "as" the factory suggests, even if there are good points to the antenna. You're setting the bar way too high. If you've got ideas for better antennas, I'm sure they'd love to hear from you. CL. "Volker Tonn" wrote in message ... Dwight Stewart schrieb: ... Few antennas can beat the utter bandwidth of a discone and the ground plane is ideal where an even less intrusive antenna is desired. Giving a specification(!) on a groundplane from 25-100Mhz is taking a customer for a ride. An antenna specified(!) for a frequency *range* implies at least that it has gain over an isotropic radiator wich is simply not true for a groundplane "25-1000Mhz". It would be a different thing in konjunktion with some active elctronics -wich is not the case-. And yes, you can have very much success on a simple antenna design. A CB-whip with top loading coil (in europe known as DV27S -length of 1.4mtr-) is known to be a good performer on _some_ "interesting" frequency ranges. It works on the same principle like the mentioned groundplane when installed on a metal sheet ...at a fraction of cost (less than 10EUR/ 13US$). Volker |
#10
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![]() CL schrieb: You're setting the bar way too high. No. But of course it is not _your_ fault that the 'Antenna Specialist MONR-31' CAN not meet the specs. If you've got ideas for better antennas, I'm sure they'd love to hear from you. CL. As I already stated. This Antenna is good for _some_ frequency *ranges*. Bad enough, the manufacturer(!) does not tell it in the specs. There are _very_ few designs for passive omnidirectional broadband antennas. But all of theem need relatively much of space. Physics can not be cheated. Not better in performance the CB-antenna I mentioned works nearly equal for a much better value. Volker |
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