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Trucker antenna
I like them two at a time--co-phased. Is there any gain to be had that way
or am I just skin pipe dreaming at the petro? |
Trucker antenna
Douglas W Adair wrote:
I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? Any time you double-illuminate the far field you are creating lobes and nulls. A single omnidirectional radiator is optimal for a moving station, unless you have means to steer the lobes whilst steering the vehicle. They do look bad-ass, but just connect one of them and you'll have better overall performance (theoretically). |
Trucker antenna
Dave wrote:
Douglas W Adair wrote: I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? Any time you double-illuminate the far field you are creating lobes and nulls. A single omnidirectional radiator is optimal for a moving station, unless you have means to steer the lobes whilst steering the vehicle. They do look bad-ass, but just connect one of them and you'll have better overall performance (theoretically). You could phase them for favoring the direction of travel, I suppose. That might be the idea. |
Trucker antenna
On Nov 30, 11:08*am, Dave wrote:
Dave wrote: Douglas W Adair wrote: I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? Any time you double-illuminate the far field you are creating lobes and nulls. *A single omnidirectional radiator is optimal for a moving station, unless you have means to steer the lobes whilst steering the vehicle. They do look bad-ass, but just connect one of them and you'll have better overall performance (theoretically). You could phase them for favoring the direction of travel, I suppose. That might be the idea. http://nimbusters.org/forum/read.php?board=8&id=647774 |
Trucker antenna
If fed in phase and spaced correctly, there could be gain to the front and
to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. "Douglas W Adair" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? |
Trucker antenna
On Nov 30, 4:40*pm, "Hal Rosser" wrote:
If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. "Douglas W Adair" wrote in ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro?- Hide quoted text - - Show quoted text - I figure this is for an 18 wheeler on CB. In that case the dual antennas make the patern more omni. Back in the 70s I belonged to a CB club and we did some test of the effects of auto body styles on radiation patterns. We discovered body stle and mounting location were as important if not more so than the antena you were using. An 18 wheeler with a single antenna mounted on a mirror has a really ragged radiation pattern. Two antennas makes it a lot less ragged, still a far way from being omni-directional. Jimmie |
Trucker antenna
I always wondered whether a short/loaded magbase antenna on the trailer
roof (so it doesnt hit bridges etc) would work better than a mirror mount... How much roof to bridge etc clearance is there normally? I would have a thought a DDRR would have been good too but I read something recently that mentioned performance has never been as good as expected. Thoughts? Cheers Bob JIMMIE wrote: An 18 wheeler with a single antenna mounted on a mirror has a really ragged radiation pattern. Two antennas makes it a lot less ragged, still a far way from being omni-directional. |
Trucker antenna
On Sun, 30 Nov 2008 08:05:31 -0500, "Douglas W Adair"
wrote: I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? Not much on a big truck. Since most of the usable cophased signal is blocked by the cab and trailer. I've found a single antenna works just as good. What hurts the system the most, is the factory installed crap. They generally use the smaller 75ohm cable and use splice after splice to make it work. I generally get my own cable, bypass their stuff. One thing to remember in cophasing, cable length DOES make a difference. If they are not equal, things will be out of whack. Unlike in a single antenna where length is not an issue. Oh and for all you loudmouths out there, the only reason they say you must have x amount of feet, is to sell the damn cable. In reality, the shorter the cable, the better off you are. Have you held an FCC license for radio work? I have. |
Trucker antenna
On Nov 30, 10:02*pm, richard wrote:
On Sun, 30 Nov 2008 08:05:31 -0500, "Douglas W Adair" wrote: I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? Not much on a big truck. Since most of the usable cophased signal is blocked by the cab and trailer. I've found a single antenna works just as good. What hurts the system the most, is the factory installed crap. They generally use the smaller 75ohm cable and use splice after splice to make it work. I generally get my own cable, bypass their stuff. Since the feed point impedance of most of those antennas is really way less than 50 ohms 75 ohm cable may not be the best choice to make a phaasing harness. Most of the time 50 ohm cable works better |
Trucker antenna
I like them two at a time--co-phased. Is there any gain to be had that way
or am I just skin pipe dreaming at the petro? If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. I believe you're correct. This is a "broadside array" configuration. Its gain over a single radiator rises roughly linearly (measured in dB over a single radiator) up to separations of around 5/8 wavelength. A separation of 1/2 wavelength gives around 4 dB gain over a single radiator and a very nice clean pattern (deep null to the sides) - this is the spacing most frequently described in the literature (e.g. Kraus, Terman) for broadside arrays. Gain maxes out at just under 5 dB at a 5/8-wavelength spacing (at the cost of a small side-lobe). [Figures are from the ARRL Antenna Book of a few years ago] Whether it's worth doing for a vehicle-mobile system is another question. You need more than .4 wavelengths of separation to get 3 dB of gain (half a nominal S-unit) - at 11-meter frequencies that's around 14 feet of separation, which I think not many vehicles will allow. Perhaps if you're driving a "wide load" transporter truck? At 6 feet of separation between antennas you'd have only around .2 wavelength, which yields less than 1 dB of gain over a single radiator. Hardly seems cost-effective. It might make more sense for 2-meter operation... but as most 2-meter mobile seems to be repeater-based, you really want omni rather than shaped-beam-down-the-road most of the time. There's also the matching issue. Each radiator in the array will have a feedpoint impedance different than what would have if used alone. You'll have to take this into account when designing the phasing harness, and you may need an impedance-matching network at the combining point to establish the 50-ohm load that your transceiver expects. If you don't match properly your transceiver won't see the load it expects, and may not deliver full rated power into the load - you could easily lose more signal strength this way than the array will gain back. If you do match properly, there will be some amount of loss in the matching network. There ain't no free lunch, alas. -- Dave Platt AE6EO Friends of 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! |
Trucker antenna
"Dave Platt" wrote in message
... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. I believe you're correct. This is a "broadside array" configuration. Its gain over a single radiator rises roughly linearly (measured in dB over a single radiator) up to separations of around 5/8 wavelength. A separation of 1/2 wavelength gives around 4 dB gain over a single radiator and a very nice clean pattern (deep null to the sides) - this is the spacing most frequently described in the literature (e.g. Kraus, Terman) for broadside arrays. Gain maxes out at just under 5 dB at a 5/8-wavelength spacing (at the cost of a small side-lobe). [Figures are from the ARRL Antenna Book of a few years ago] Whether it's worth doing for a vehicle-mobile system is another question. You need more than .4 wavelengths of separation to get 3 dB of gain (half a nominal S-unit) - at 11-meter frequencies that's around 14 feet of separation, which I think not many vehicles will allow. Perhaps if you're driving a "wide load" transporter truck? At 6 feet of separation between antennas you'd have only around .2 wavelength, which yields less than 1 dB of gain over a single radiator. Hardly seems cost-effective. It might make more sense for 2-meter operation... but as most 2-meter mobile seems to be repeater-based, you really want omni rather than shaped-beam-down-the-road most of the time. There's also the matching issue. Each radiator in the array will have a feedpoint impedance different than what would have if used alone. You'll have to take this into account when designing the phasing harness, and you may need an impedance-matching network at the combining point to establish the 50-ohm load that your transceiver expects. If you don't match properly your transceiver won't see the load it expects, and may not deliver full rated power into the load - you could easily lose more signal strength this way than the array will gain back. If you do match properly, there will be some amount of loss in the matching network. There ain't no free lunch, alas. Wow, Richard. This guy seems 7 ****loads smarter than you. Wonder if he ever "held an FCC license for radio work"? -- Dave Platt AE6EO Friends of 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! -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
"Douglas W. "Popeye" Frederick" wrote in message m... This guy seems 7 ****loads smarter than you. That coming from someone that lost the internet in his truck because he didn't know when to stop? ROTFLMAO "****in Sprint shut me down without warning" http://groups.google.com/group/misc....0ccb6f15cac165 |
Trucker antenna
"Douglas W Adair" wrote in
: I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? If you are going to co-phase get a comercially produced co-phase harness. Mount the anteneas 54" apart for cb band. |
Trucker antenna
On Mon, 1 Dec 2008 04:37:39 -0500, "Douglas W. \"Popeye\" Frederick"
wrote: "Dave Platt" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. I believe you're correct. This is a "broadside array" configuration. Its gain over a single radiator rises roughly linearly (measured in dB over a single radiator) up to separations of around 5/8 wavelength. A separation of 1/2 wavelength gives around 4 dB gain over a single radiator and a very nice clean pattern (deep null to the sides) - this is the spacing most frequently described in the literature (e.g. Kraus, Terman) for broadside arrays. Gain maxes out at just under 5 dB at a 5/8-wavelength spacing (at the cost of a small side-lobe). [Figures are from the ARRL Antenna Book of a few years ago] Whether it's worth doing for a vehicle-mobile system is another question. You need more than .4 wavelengths of separation to get 3 dB of gain (half a nominal S-unit) - at 11-meter frequencies that's around 14 feet of separation, which I think not many vehicles will allow. Perhaps if you're driving a "wide load" transporter truck? At 6 feet of separation between antennas you'd have only around .2 wavelength, which yields less than 1 dB of gain over a single radiator. Hardly seems cost-effective. It might make more sense for 2-meter operation... but as most 2-meter mobile seems to be repeater-based, you really want omni rather than shaped-beam-down-the-road most of the time. There's also the matching issue. Each radiator in the array will have a feedpoint impedance different than what would have if used alone. You'll have to take this into account when designing the phasing harness, and you may need an impedance-matching network at the combining point to establish the 50-ohm load that your transceiver expects. If you don't match properly your transceiver won't see the load it expects, and may not deliver full rated power into the load - you could easily lose more signal strength this way than the array will gain back. If you do match properly, there will be some amount of loss in the matching network. There ain't no free lunch, alas. Wow, Richard. This guy seems 7 ****loads smarter than you. Wonder if he ever "held an FCC license for radio work"? If i had said it, you would have a field day accusing me of all kinds of ****. Since the late 60's i've been working with CB and have done all kinds of experiments with antennas on a car. You name it, I had it. As he pointed out, the big problem with CB is, you need way much more space than a vehicle offers to truly get any usable gain from cophasing. Do you know the wavelength of 11 meters? if 27 feet, the normal height of base antenna, is equal to 5/8 or 1/4 wave, then what is 8/8 or 100%? Well over 100 feet. So to get the true proportion for proper cophasing, the road aint wide enough and neither is the vehicle. The only reason truckers run two antennas is because it looks cooler. The effectiveness of cophasing in a truck is screwed by the factory installed crap. |
Trucker antenna
"Top" wrote in message .. . If you are going to co-phase get a comercially produced co-phase harness. Mount the anteneas 54" apart for cb band. Please list your references |
Trucker antenna
"The Honorable Dr. Rocky Roads Presiding Judge" wrote in message ... "Douglas W. "Popeye" Frederick" wrote in message m... This guy seems 7 ****loads smarter than you. That coming from someone that lost the internet in his truck because he didn't know when to stop? ROTFLMAO And this from the coward who forgot to set her brakes and blamed it on someone who was not only NOT there, but was in a different state posting on here, and she calls everyone else and "idiot"?? That's funny as hell. |
Trucker antenna
richard wrote in
: On Mon, 1 Dec 2008 04:37:39 -0500, "Douglas W. \"Popeye\" Frederick" wrote: "Dave Platt" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. I believe you're correct. This is a "broadside array" configuration. Its gain over a single radiator rises roughly linearly (measured in dB over a single radiator) up to separations of around 5/8 wavelength. A separation of 1/2 wavelength gives around 4 dB gain over a single radiator and a very nice clean pattern (deep null to the sides) - this is the spacing most frequently described in the literature (e.g. Kraus, Terman) for broadside arrays. Gain maxes out at just under 5 dB at a 5/8-wavelength spacing (at the cost of a small side-lobe). [Figures are from the ARRL Antenna Book of a few years ago] Whether it's worth doing for a vehicle-mobile system is another question. You need more than .4 wavelengths of separation to get 3 dB of gain (half a nominal S-unit) - at 11-meter frequencies that's around 14 feet of separation, which I think not many vehicles will allow. Perhaps if you're driving a "wide load" transporter truck? At 6 feet of separation between antennas you'd have only around .2 wavelength, which yields less than 1 dB of gain over a single radiator. Hardly seems cost-effective. It might make more sense for 2-meter operation... but as most 2-meter mobile seems to be repeater-based, you really want omni rather than shaped-beam-down-the-road most of the time. There's also the matching issue. Each radiator in the array will have a feedpoint impedance different than what would have if used alone. You'll have to take this into account when designing the phasing harness, and you may need an impedance-matching network at the combining point to establish the 50-ohm load that your transceiver expects. If you don't match properly your transceiver won't see the load it expects, and may not deliver full rated power into the load - you could easily lose more signal strength this way than the array will gain back. If you do match properly, there will be some amount of loss in the matching network. There ain't no free lunch, alas. Wow, Richard. This guy seems 7 ****loads smarter than you. Wonder if he ever "held an FCC license for radio work"? If i had said it, you would have a field day accusing me of all kinds of ****. Since the late 60's i've been working with CB and have done all kinds of experiments with antennas on a car. You name it, I had it. As he pointed out, the big problem with CB is, you need way much more space than a vehicle offers to truly get any usable gain from cophasing. Do you know the wavelength of 11 meters? if 27 feet, the normal height of base antenna, is equal to 5/8 or 1/4 wave, then what is 8/8 or 100%? Well over 100 feet. So to get the true proportion for proper cophasing, the road aint wide enough and neither is the vehicle. The only reason truckers run two antennas is because it looks cooler. The effectiveness of cophasing in a truck is screwed by the factory installed crap. You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Toop |
Trucker antenna
"NightRogue" wrote in
news:_GUYk.404979$TT4.56720@attbi_s22: "The Honorable Dr. Rocky Roads Presiding Judge" wrote in message ... "Douglas W. "Popeye" Frederick" wrote in message m... This guy seems 7 ****loads smarter than you. That coming from someone that lost the internet in his truck because he didn't know when to stop? ROTFLMAO And this from the coward who forgot to set her brakes and blamed it on someone who was not only NOT there, but was in a different state posting on here, and she calls everyone else and "idiot"?? That's funny as hell. How many days has he been a rookie now? |
Trucker antenna
Top wrote:
"NightRogue" wrote in news:_GUYk.404979$TT4.56720@attbi_s22: "The Honorable Dr. Rocky Roads Presiding Judge" wrote in message ... "Douglas W. "Popeye" Frederick" wrote in message m... This guy seems 7 ****loads smarter than you. That coming from someone that lost the internet in his truck because he didn't know when to stop? ROTFLMAO And this from the coward who forgot to set her brakes and blamed it on someone who was not only NOT there, but was in a different state posting on here, and she calls everyone else and "idiot"?? That's funny as hell. How many days has he been a rookie now? trolls |
Trucker antenna
"Douglas W Adair" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? the real gain in that arrangement is in the thickness of the sales man's wallet. |
Trucker antenna
Dave wrote:
"Douglas W Adair" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? the real gain in that arrangement is in the thickness of the sales man's wallet. They certainly look better just like dual stacks look better than a single stack. |
Trucker antenna
"Top" wrote in message
.. . richard wrote in : On Mon, 1 Dec 2008 04:37:39 -0500, "Douglas W. \"Popeye\" Frederick" wrote: "Dave Platt" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? If fed in phase and spaced correctly, there could be gain to the front and to the back with a decreased propogation to the sides. This is usually desirable if traveling on a mostly straight stretch of highway. I think the spacing is a little too far apart for use on most cars. I believe you're correct. This is a "broadside array" configuration. Its gain over a single radiator rises roughly linearly (measured in dB over a single radiator) up to separations of around 5/8 wavelength. A separation of 1/2 wavelength gives around 4 dB gain over a single radiator and a very nice clean pattern (deep null to the sides) - this is the spacing most frequently described in the literature (e.g. Kraus, Terman) for broadside arrays. Gain maxes out at just under 5 dB at a 5/8-wavelength spacing (at the cost of a small side-lobe). [Figures are from the ARRL Antenna Book of a few years ago] Whether it's worth doing for a vehicle-mobile system is another question. You need more than .4 wavelengths of separation to get 3 dB of gain (half a nominal S-unit) - at 11-meter frequencies that's around 14 feet of separation, which I think not many vehicles will allow. Perhaps if you're driving a "wide load" transporter truck? At 6 feet of separation between antennas you'd have only around .2 wavelength, which yields less than 1 dB of gain over a single radiator. Hardly seems cost-effective. It might make more sense for 2-meter operation... but as most 2-meter mobile seems to be repeater-based, you really want omni rather than shaped-beam-down-the-road most of the time. There's also the matching issue. Each radiator in the array will have a feedpoint impedance different than what would have if used alone. You'll have to take this into account when designing the phasing harness, and you may need an impedance-matching network at the combining point to establish the 50-ohm load that your transceiver expects. If you don't match properly your transceiver won't see the load it expects, and may not deliver full rated power into the load - you could easily lose more signal strength this way than the array will gain back. If you do match properly, there will be some amount of loss in the matching network. There ain't no free lunch, alas. Wow, Richard. This guy seems 7 ****loads smarter than you. Wonder if he ever "held an FCC license for radio work"? If i had said it, you would have a field day accusing me of all kinds of ****. Since the late 60's i've been working with CB and have done all kinds of experiments with antennas on a car. You name it, I had it. As he pointed out, the big problem with CB is, you need way much more space than a vehicle offers to truly get any usable gain from cophasing. Do you know the wavelength of 11 meters? if 27 feet, the normal height of base antenna, is equal to 5/8 or 1/4 wave, then what is 8/8 or 100%? Well over 100 feet. So to get the true proportion for proper cophasing, the road aint wide enough and neither is the vehicle. The only reason truckers run two antennas is because it looks cooler. The effectiveness of cophasing in a truck is screwed by the factory installed crap. You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Top Thanks Top! -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
On Dec 1, 6:42*pm, "The Honorable Dr. Rocky Roads Presiding Judge"
wrote: Dave wrote: "Douglas W Adair" wrote in message ... I like them two at a time--co-phased. Is there any gain to be had that way or am I just skin pipe dreaming at the petro? the real gain in that arrangement is in the thickness of the sales man's wallet. - They certainly look better just like dual stacks - look better than a single stack. breaker, Breaker. BREAKER ! Ken I Gita Ray Di Oh Checka !?! |
Trucker antenna
Phuck off you scumbag loser. Nobody and I mean nobody is a better trucker
than I. |
Trucker antenna
In article ,
Douglas W. \"Popeye\" Frederick wrote: You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Top Thanks Top! I think that Top's calculations (and recommendations) are a bit off? CB has an 11-meter wavelength. There are just over 39 inches in a meter. Hence, the wavelength is around 430 inches. A 54-inch separation is only .12 wavelength. From the chart in the ARRL Antenna Book, it looks as if you'll get less than .5 dB of directional gain, compared with a single radiator of the same type and size. That's less than one tenth (!) of a nominal S-unit. You'd be very hard put to be able to detect this small of a difference in practice - it'll be less than the amount of signal variation you'll encounter due to reflections from nearby objects. In terms of getting yourself a directional-gain benefit, I think a co-phased two-radiator broadside array with a 54-inch separation is essentially useless on CB frequencies. There just isn't enough gain to matter. Now, as somebody else suggested, using such an array might get you a more consistent near-omnidirectional pattern than a single radiator would deliver, if your antennas are mounted less than optimally (e.g. on your sideview mirror post). Using two co-phase antennas might be worthwhile for this reason, even if you don't get a significant amount of directional gain. I suspect you'd get more bang for your buck by simply mounting a single antenna in a better location (e.g. roof mount) and paying attention to making the antenna's grounding to the chassis/groundplane as direct and solid as possible. -- Dave Platt AE6EO Friends of 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! |
Trucker antenna
|
Trucker antenna
In article ,
Top wrote: Cophase being omindirectional? You need to do some more reading before you try to correct anything. The directionality of a broadside array (with the two radiators fed exactly in phase) depends very strongly on the separation between the two antennas. For separations of 1/4 wavelength or less, there's very little directionality - the pattern is very close to omnidirectional. Every dual-antenna truck setup I've seen has been a side-by-side mounting (e.g. one on the left mirror and one on the right), and the harness feeds them both in-phase. I've been assuming that this was what was being meant by "co-phase". If so, I stand by my statement that two CB antennas, fed in phase through a co-phase harness (i.e. no phase difference between the two), and separated by only 54 inches, produces a nearly-omnidirectional signal. The two antennas need to be further apart, before the pattern becomes significantly directional. Take a look at the NEC plots at http://www.cosjwt.com/index.php?a=20 to see... the 4.5-foot separation model produces a pattern which is almost circular. There is little gain towards the front and back, and very little loss off to the sides. These plots seem to jibe well with other references I've read (Terman, Kraus, and the graphs in the ARRL Antenna Book). The other alternative is an end-fire array, with the antennas fed signals of opposite phase - with these then there can be significant directionality even with close spacing of the antennas. In a truck-antenna system, this would require placing the antennas one in front of the other, separating them by several feet, and inverting the phase of the signal sent to one of the two antennas (perhaps by having the feed coax to one antenna be 1/2-wavelength longer than the other). You could get several dB of gain this way... but the close spacing will cause the antenna feedpoint impedance to drop a lot, and some form of matching network will certainly be required to keep the radio happy and develop maximum power from the transmitter. The two bottom plots on the site I mentioned above, show the effect of feeding the antennas with signals of different phase. In these examples, the pattern is being skewed off to one side - the difference in feedline length is converting the antenna from a broadside array to an end-fire array. With the right amount of phase shift, you end up with a cardioid pattern, with a broad lobe in one direction and a very deep null in the other. -- Dave Platt AE6EO Friends of 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! |
Trucker antenna
"Dave Platt" wrote in message
... In article , Douglas W. \"Popeye\" Frederick wrote: You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Top Thanks Top! I think that Top's calculations (and recommendations) are a bit off? I'm a "single antenna" guy myself. I think, in a truck, at least, that "big radio" is synonymous with "big wris****ch". :-) We can't mount the antennae high or center, because the 13', 6" height of the truck is where the low bridges start. Also, most tractors have this horrific system that intergrates AM/FM with the CB coax. A CB stick on the left mirror and an AM/FM on the right, and a splitter in the coax, so I always run my own coax seperately. And I have a cellular antenna on one side, any way, for dual plane signal boost, and it has to be 8" (I think) away from other sticks. But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? CB has an 11-meter wavelength. There are just over 39 inches in a meter. Hence, the wavelength is around 430 inches. A 54-inch separation is only .12 wavelength. From the chart in the ARRL Antenna Book, it looks as if you'll get less than .5 dB of directional gain, compared with a single radiator of the same type and size. That's less than one tenth (!) of a nominal S-unit. You'd be very hard put to be able to detect this small of a difference in practice - it'll be less than the amount of signal variation you'll encounter due to reflections from nearby objects. In terms of getting yourself a directional-gain benefit, I think a co-phased two-radiator broadside array with a 54-inch separation is essentially useless on CB frequencies. There just isn't enough gain to matter. Now, as somebody else suggested, using such an array might get you a more consistent near-omnidirectional pattern than a single radiator would deliver, if your antennas are mounted less than optimally (e.g. on your sideview mirror post). Using two co-phase antennas might be worthwhile for this reason, even if you don't get a significant amount of directional gain. I suspect you'd get more bang for your buck by simply mounting a single antenna in a better location (e.g. roof mount) and paying attention to making the antenna's grounding to the chassis/groundplane as direct and solid as possible. -- Dave Platt AE6EO Friends of 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! -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
On 2 Dec 2008 06:15:20 GMT, Top wrote:
(Dave Platt) wrote in : In article , Douglas W. \"Popeye\" Frederick wrote: I suspect you'd get more bang for your buck by simply mounting a single antenna in a better location (e.g. roof mount) and paying attention to making the antenna's grounding to the chassis/groundplane as direct and solid as possible. Cophase being omindirectional? You need to do some more reading before you try to correct anything. IF the cophased antennas are less than 1/4 wave apart, there is virtually no change. |
Trucker antenna
On Mon, 1 Dec 2008 23:55:02 -0800, (Dave Platt)
wrote: In article , Top wrote: Cophase being omindirectional? You need to do some more reading before you try to correct anything. The directionality of a broadside array (with the two radiators fed exactly in phase) depends very strongly on the separation between the two antennas. For separations of 1/4 wavelength or less, there's very little directionality - the pattern is very close to omnidirectional. Every dual-antenna truck setup I've seen has been a side-by-side mounting (e.g. one on the left mirror and one on the right), and the harness feeds them both in-phase. I've been assuming that this was what was being meant by "co-phase". If so, I stand by my statement that two CB antennas, fed in phase through a co-phase harness (i.e. no phase difference between the two), and separated by only 54 inches, produces a nearly-omnidirectional signal. The two antennas need to be further apart, before the pattern becomes significantly directional. Take a look at the NEC plots at http://www.cosjwt.com/index.php?a=20 to see... the 4.5-foot separation model produces a pattern which is almost circular. There is little gain towards the front and back, and very little loss off to the sides. These plots seem to jibe well with other references I've read (Terman, Kraus, and the graphs in the ARRL Antenna Book). The other alternative is an end-fire array, with the antennas fed signals of opposite phase - with these then there can be significant directionality even with close spacing of the antennas. In a truck-antenna system, this would require placing the antennas one in front of the other, separating them by several feet, and inverting the phase of the signal sent to one of the two antennas (perhaps by having the feed coax to one antenna be 1/2-wavelength longer than the other). You could get several dB of gain this way... but the close spacing will cause the antenna feedpoint impedance to drop a lot, and some form of matching network will certainly be required to keep the radio happy and develop maximum power from the transmitter. The two bottom plots on the site I mentioned above, show the effect of feeding the antennas with signals of different phase. In these examples, the pattern is being skewed off to one side - the difference in feedline length is converting the antenna from a broadside array to an end-fire array. With the right amount of phase shift, you end up with a cardioid pattern, with a broad lobe in one direction and a very deep null in the other. Ya gots to understand with whom you are trying to communicate. "Top" is the master know it all who has absolutely no background in electronics. He just drives a truck and thinks that gives him the knowledge. You've heard of "Billy Big Rigger"? You just met the dude. Top just goes along with what other truckers have said over the years. I have the actual working experience to back me up with. The only thing Top knows about CB is how to yack on it. |
Trucker antenna
On Tue, 2 Dec 2008 03:17:22 -0500, "Douglas W. \"Popeye\" Frederick"
wrote: "Dave Platt" wrote in message ... In article , Douglas W. \"Popeye\" Frederick wrote: You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Top Thanks Top! I think that Top's calculations (and recommendations) are a bit off? I'm a "single antenna" guy myself. I think, in a truck, at least, that "big radio" is synonymous with "big wris****ch". :-) We can't mount the antennae high or center, because the 13', 6" height of the truck is where the low bridges start. Also, most tractors have this horrific system that intergrates AM/FM with the CB coax. A CB stick on the left mirror and an AM/FM on the right, and a splitter in the coax, so I always run my own coax seperately. And I have a cellular antenna on one side, any way, for dual plane signal boost, and it has to be 8" (I think) away from other sticks. But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? No dumb****. As I have tried to explain to you once before, DO NOT buy one of those radios. If you get caught with it in the USA alone, and are transmitting on it, no license? Bye bye. Pay the $10,000 fine lose the radio. Every trucking company in Canada that uses them has a Canadian license to operate them with. They are not like CB's. They are commercial business radios. I trust maybe now you'll listen to one of the radio experts for a change. Would one of you in the radio groups who knows Canadian radios please explain this to the jerk? He thinks that because he's a trucker, he can have any damn radio he wants in his truck. |
Trucker antenna
In article ,
Douglas W. \"Popeye\" Frederick wrote: But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? In principle, you could combine the CB output (27 MHz) with the VHF radio output (up above the 2-meter band) using a diplexer, and feed the result down a single coax. At the antenna end, you'd have a couple of choices. You can use another diplexer to split out the HF and VHF signals, and feed them to two separate antennas. Or, you might be able to find a single CB-type antenna which is also capable of matching up well enough on these VHF frequencies to work tolerably well. The chances are very poor that a randomly-selected CB antenna would give you a tolerable SWR on the 160-or-so-MHz VHF band... and if it did, there's no telling what its vertical radiation pattern would look like. An antenna intended for these two bands would probably have to be custom designed - I can think of a couple of possible ways to do it. Such a dualband antenna would almost certainly be a compromise antenna on both bands - it wouldn't work as well as separate antennas designed for best operation on a single band each. Commercial HF/VHF diplexers run somewhere around $80, last time I looked. You'd probably find it less expensive in the end to just run a second coax and put up a second (VHF-only) whip antenna. -- Dave Platt AE6EO Friends of 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! |
Trucker antenna
uuuuhhhh..... you're wrong as usual Bulli****.
Top was Military and got his commo expertise there. IIRC he's not a truck driver at all. |
Trucker antenna
"Zeke" wrote in message ...
uuuuhhhh..... you're wrong as usual Bulli****. Top was career Military and got his commo expertise there. IIRC he's not a truck driver at all. Exactly, a matter of public record here that Richard has seen several times previously, and just forgot. Here's Richard's esteemed military career (and how he was caught lying about it): http://bolo_bullis.tripod.com/ What's amazing is that Richard and I were just discussing what a total, absolute and complete asshole he makes himself look like every time he tries to make himself look tough or smart at anyone's expense. Of course he can't hear a word of that, and immediately starts this. Richard, who is also a career pedophile and damn proud of it, has had, and will always have, the same problem, and that's that he just can't keep his festering gob shut. What amazes me is that he's skunked a dozen usenet groups over the years, is internationally know as a scumbag, but still sees the world through his own rose colored glasses, like we might have forgotten his previous and extensive bombast and flummery. Funny, or sad? -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
"richard" wrote in message
... On Tue, 2 Dec 2008 03:17:22 -0500, "Douglas W. \"Popeye\" Frederick" wrote: "Dave Platt" wrote in message ... In article , Douglas W. \"Popeye\" Frederick wrote: You still didn't give any useful information. No surpise since you have none. For an average of the cb band running 1/4 wave the antennas should be spaced 54 inches apart. Use a commercially produced cophase harness if you can find it. Make sure you match the SWR and you will out do any other mobile off the front or rear. Top Thanks Top! I think that Top's calculations (and recommendations) are a bit off? I'm a "single antenna" guy myself. I think, in a truck, at least, that "big radio" is synonymous with "big wris****ch". :-) We can't mount the antennae high or center, because the 13', 6" height of the truck is where the low bridges start. Also, most tractors have this horrific system that intergrates AM/FM with the CB coax. A CB stick on the left mirror and an AM/FM on the right, and a splitter in the coax, so I always run my own coax seperately. And I have a cellular antenna on one side, any way, for dual plane signal boost, and it has to be 8" (I think) away from other sticks. But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? No dumb****. As I have tried to explain to you once before, DO NOT buy one of those radios. **** you, dickhead. If you get caught with it in the USA alone, and are transmitting on it, no license? Bye bye. Pay the $10,000 fine lose the radio. Sure. What's the fine for my 250 watt kicker? Don't forget to add that in. Every trucking company in Canada that uses them has a Canadian license to operate them with. They are not like CB's. They are commercial business radios. I trust maybe now you'll listen to one of the radio experts for a change. I am. They said the radios were available, the private frequencies, not the radios, are licensed, and the freqs I'm interested are available to the public. And the license, if you want one, is easy and cheap. Were your mother and father related -before- the wedding? Inquiring minds want to know. Because you have an uncanny resemblence to the Deliverance banjo boy. Would one of you in the radio groups who knows Canadian radios please explain this to the jerk? He thinks that because he's a trucker, he can have any damn radio he wants in his truck. Jesus, are you stupid. Try reading the thread that I cited, that flatly proves you wrong. And as I already stated, and you apparently forgot, the radio would be for emergencies only, and that I would have no reason to use it in the states. Your memory is just shot, ****head, have you ever met a guy named John Francis? Or been to Australia? I find it amazing that you'd be afraid of an FCC fine, that I have a one-in-ten-million chance of -ever- receiving, while you publically brag about being in possession of 45,000 child pornography pictures. Amazing. Simply amazing. -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
"Dave Platt" wrote in message
... In article , Douglas W. \"Popeye\" Frederick wrote: But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? In principle, you could combine the CB output (27 MHz) with the VHF radio output (up above the 2-meter band) using a diplexer, and feed the result down a single coax. At the antenna end, you'd have a couple of choices. You can use another diplexer to split out the HF and VHF signals, and feed them to two separate antennas. Or, you might be able to find a single CB-type antenna which is also capable of matching up well enough on these VHF frequencies to work tolerably well. The chances are very poor that a randomly-selected CB antenna would give you a tolerable SWR on the 160-or-so-MHz VHF band... and if it did, there's no telling what its vertical radiation pattern would look like. An antenna intended for these two bands would probably have to be custom designed - I can think of a couple of possible ways to do it. Such a dualband antenna would almost certainly be a compromise antenna on both bands - it wouldn't work as well as separate antennas designed for best operation on a single band each. Commercial HF/VHF diplexers run somewhere around $80, last time I looked. You'd probably find it less expensive in the end to just run a second coax and put up a second (VHF-only) whip antenna. Thanks! That's the kind of helpful and intelligent response I was looking for. The radio would be for emergency communications anyway, to trucks in the -immediate- vicinity. The 4 "LADD" frequencies are used by the scale houses up there, as well. -- Dave Platt AE6EO Friends of 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! -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
"richard" wrote in message
... Ya gots to understand with whom you are trying to communicate. "Top" is the master know it all who has absolutely no background in electronics. He just drives a truck and thinks that gives him the knowledge. You've heard of "Billy Big Rigger"? You just met the dude. Top just goes along with what other truckers have said over the years. I have the actual working experience to back me up with. The only thing Top knows about CB is how to yack on it. Wow. Acer laptop: $600 20" monitor: $225 Verizon data card: $50 Watching Richtard stick his pecker in the outlet, -again-, Priceless. -- Popeye "Best thing for him, really. His therapy was going nowhere," -Hannibal Lector. www.finalprotectivefire.com http://picasaweb.google.com/Popeye8762 |
Trucker antenna
On Tue, 2 Dec 2008 14:51:28 -0500, "Douglas W. \"Popeye\" Frederick"
wrote: "Zeke" wrote in message ... uuuuhhhh..... you're wrong as usual Bulli****. Top was career Military and got his commo expertise there. IIRC he's not a truck driver at all. Exactly, a matter of public record here that Richard has seen several times previously, and just forgot. Since this thread is going to groups who do not know me, I will try to clairify the lies here. Here's Richard's esteemed military career (and how he was caught lying about it): http://bolo_bullis.tripod.com/ First, that is an exact copy of my dd214 acquired under the FOIA. It states I served. Unlike the lies that promulgate from it that says I did not. 2nd, why is the word before "discharge" blacked out? That was not done by the US goverment. It was done to make it look more damning. I never claimed to be anything I was not. I said I never got beyond boot camp and my highest rank was E1. The dd214 confirms that. I said I had enlisted for the ASA but never got involved with it. While others claimed I had claimed to be super secret spy or in special forces. Most of those lies were all created by "Just Taylor". What's amazing is that Richard and I were just discussing what a total, absolute and complete asshole he makes himself look like every time he tries to make himself look tough or smart at anyone's expense. I'm not saying I am smarter than many, in this thread I have been trying to point out that a lot of information given in this thread is totally wrong. As have others. Why don't you pick on them, asshole. Of course he can't hear a word of that, and immediately starts this. Richard, who is also a career pedophile and damn proud of it, has had, and will always have, the same problem, and that's that he just can't keep his festering gob shut. Pedophile being defined here as a person who others claim is a pedophile because the damning word sticks to more feeble brains than any other word. No one has ever proven, in 10 years, that I am, have been, or currently am, a true pedophile. It's nothing more than ill words on a screen. What amazes me is that he's skunked a dozen usenet groups over the years, is internationally know as a scumbag, but still sees the world through his own rose colored glasses, like we might have forgotten his previous and extensive bombast and flummery. While ****heads like you keep wanting to let the world know about the past anyway they can. No proof, just a lot of hot air. Funny, or sad? Sad boy you are and you wore a uniform? God help us all. |
Trucker antenna
On Tue, 2 Dec 2008 10:29:49 -0800, (Dave Platt)
wrote: In article , Douglas W. \"Popeye\" Frederick wrote: But hhhhhere's a question for the braintrust: I'm after a (mobile) VHF radio that's common to northern (i.e., the Yukon, and Northwest Territories) Canadian truckers- who don't monitor CB bands. (info:) http://forums.qrz.com/showthread.php?t=171741 I'm sure, as a sine wave challenged layman, that I can't use the same antenna and coax as my CB? In principle, you could combine the CB output (27 MHz) with the VHF radio output (up above the 2-meter band) using a diplexer, and feed the result down a single coax. At the antenna end, you'd have a couple of choices. You can use another diplexer to split out the HF and VHF signals, and feed them to two separate antennas. Or, you might be able to find a single CB-type antenna which is also capable of matching up well enough on these VHF frequencies to work tolerably well. The chances are very poor that a randomly-selected CB antenna would give you a tolerable SWR on the 160-or-so-MHz VHF band... and if it did, there's no telling what its vertical radiation pattern would look like. An antenna intended for these two bands would probably have to be custom designed - I can think of a couple of possible ways to do it. Such a dualband antenna would almost certainly be a compromise antenna on both bands - it wouldn't work as well as separate antennas designed for best operation on a single band each. Commercial HF/VHF diplexers run somewhere around $80, last time I looked. You'd probably find it less expensive in the end to just run a second coax and put up a second (VHF-only) whip antenna. Trust me. he has no clues as to what you just said. This fool wants to run a vhf radio in Canada just to talk to Canadian truckers. He thinks those radios can be bought and used just like a CB. As I have operated radios on 47mhz, held a 2nd class fcc license, I think I know a lot more than he does. |
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