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#22
posted to rec.boats
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VHF vs CB Antenna?
wrote:
On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) We get fog, and lots of ship traffic in SF Bay and slightly offshore. Would be nice to know what is coming. |
#23
posted to rec.boats
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VHF vs CB Antenna?
On Wed, 28 Nov 2018 07:17:33 -0500, "Mr. Luddite"
wrote: On 11/28/2018 7:04 AM, Keyser Soze wrote: On 11/28/18 7:02 AM, Mr. Luddite wrote: On 11/27/2018 11:15 PM, wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for.* There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz).* Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof.* That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio.** But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length.* At 27 MHz a full wavelength is about 103 inches.* A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF.* Have not used it in years.* Actually I am looking at a new radio for the boat.* One with AIS.* Maybe Santa Clause. My wife has her phone. That is all we need* ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat* ;-) Back in the CB craze (late 70's)* Radio Shack sold a base unit that could easily be modified if you knew what you were doing.* I bought one along and acquired a list of the required modifications. The modifications added an additional 40 channels (unauthorized) and increased the carrier power from 5 watts to 15 watts. It also increased the effective single sideband mode power to over 30 watts depending on how much you modulated it which was also another "tweak".** At the time we lived in a rented house near the shore and on Sunday mornings I could communicate via "skip" with people in much of eastern Europe, as far away as Italy.** In the evening I could easily talk to people west of the Mississippi using skip as far away as California, depending on the time as the sun set. Ended up doing the same mods for a couple of people who also bought the same Radio Shack radio. Don't know whatever happened to that radio.* I lost interest in CB after a while. Never understood the "CB culture." I don't even like to talk on the phone that much. For a while CB had two cultures, the "good buddy" road travel communications and people like me who were more interested in seeing how far you could communicate with others, similar to HAM radio and their custom of exchanging "QSL" cards by mail confirming successful contacts. Only time I was glad to have a CB radio in my vehicle was before cell phones came along. Was traveling up Rt. 95 from Long Island heading home at about one in the morning. It was raining hard and a car whizzed by me in the fast lane. Suddenly, all I saw were his headlights flashing back at me several times. As I approached him, his car was upside down on the side of the road. He had hit a large puddle of water and had hydroplaned, causing his car to hit the center guardrail and then flip several times. Got on the CB and after a few tries contacted someone who called the state police. I helped get the guy out of his car and he sat with me in mine until the police arrived. He was shaken up big time but didn't appear to have any serious injuries. === These days everyone has emergency communications via cell phone. It's much more reliable and easy to use. Ham radio is also experiencing a decline in popularity as the internet and sat phones have made it easy to communicate all over the world. --- This email has been checked for viruses by AVG. https://www.avg.com |
#24
posted to rec.boats
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VHF vs CB Antenna?
On Wed, 28 Nov 2018 17:40:39 -0000 (UTC), Bill
wrote: wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) We get fog, and lots of ship traffic in SF Bay and slightly offshore. Would be nice to know what is coming. === We use both AIS and radar in situations like that. Of course they're very useful at night also. --- This email has been checked for viruses by AVG. https://www.avg.com |
#25
posted to rec.boats
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VHF vs CB Antenna?
On 11/28/2018 1:47 PM, wrote:
On Wed, 28 Nov 2018 07:17:33 -0500, "Mr. Luddite" wrote: On 11/28/2018 7:04 AM, Keyser Soze wrote: On 11/28/18 7:02 AM, Mr. Luddite wrote: On 11/27/2018 11:15 PM, wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for.Â* There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz).Â* Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof.Â* That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio.Â*Â* But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length.Â* At 27 MHz a full wavelength is about 103 inches.Â* A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF.Â* Have not used it in years.Â* Actually I am looking at a new radio for the boat.Â* One with AIS.Â* Maybe Santa Clause. My wife has her phone. That is all we needÂ* ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boatÂ* ;-) Back in the CB craze (late 70's)Â* Radio Shack sold a base unit that could easily be modified if you knew what you were doing.Â* I bought one along and acquired a list of the required modifications. The modifications added an additional 40 channels (unauthorized) and increased the carrier power from 5 watts to 15 watts. It also increased the effective single sideband mode power to over 30 watts depending on how much you modulated it which was also another "tweak".Â*Â* At the time we lived in a rented house near the shore and on Sunday mornings I could communicate via "skip" with people in much of eastern Europe, as far away as Italy.Â*Â* In the evening I could easily talk to people west of the Mississippi using skip as far away as California, depending on the time as the sun set. Ended up doing the same mods for a couple of people who also bought the same Radio Shack radio. Don't know whatever happened to that radio.Â* I lost interest in CB after a while. Never understood the "CB culture." I don't even like to talk on the phone that much. For a while CB had two cultures, the "good buddy" road travel communications and people like me who were more interested in seeing how far you could communicate with others, similar to HAM radio and their custom of exchanging "QSL" cards by mail confirming successful contacts. Only time I was glad to have a CB radio in my vehicle was before cell phones came along. Was traveling up Rt. 95 from Long Island heading home at about one in the morning. It was raining hard and a car whizzed by me in the fast lane. Suddenly, all I saw were his headlights flashing back at me several times. As I approached him, his car was upside down on the side of the road. He had hit a large puddle of water and had hydroplaned, causing his car to hit the center guardrail and then flip several times. Got on the CB and after a few tries contacted someone who called the state police. I helped get the guy out of his car and he sat with me in mine until the police arrived. He was shaken up big time but didn't appear to have any serious injuries. === These days everyone has emergency communications via cell phone. It's much more reliable and easy to use. Ham radio is also experiencing a decline in popularity as the internet and sat phones have made it easy to communicate all over the world. That's too bad because it wasn't really all about continuous and reliable communications. The challenge was in frequency selection, antenna placement, etc. just to see how far you could establish communications. Kinda a nerdy hobby I guess. Even in the Navy on one of the ships I was assigned to and before it's homeport was changed from Newport, RI to Naples, Italy we used to try to maintain comms with another ship using the least amount of transmitter power as possible. Best we did was a two-way FSK teletype connection off the coast of RI to another ship transiting through the Straights of Gibraltar using less than 1,000 watts. |
#26
posted to rec.boats
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VHF vs CB Antenna?
On 11/28/2018 1:50 PM, wrote:
On Wed, 28 Nov 2018 17:40:39 -0000 (UTC), Bill wrote: wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) We get fog, and lots of ship traffic in SF Bay and slightly offshore. Would be nice to know what is coming. === We use both AIS and radar in situations like that. Of course they're very useful at night also. Wayne, BTW, my friends on the "Ring of Kerry" made it safely to Charleston, SC. and have set up for the winter. This is their first voyage after all the work they did on the boat and it looks like they are enjoying the adventure big time. They *did* stop at Coinjock to sample the fare and only ran aground once on the ICW on the way down. :-) |
#27
posted to rec.boats
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VHF vs CB Antenna?
On Wed, 28 Nov 2018 07:02:16 -0500, "Mr. Luddite"
wrote: On 11/27/2018 11:15 PM, wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) Back in the CB craze (late 70's) Radio Shack sold a base unit that could easily be modified if you knew what you were doing. I bought one along and acquired a list of the required modifications. The modifications added an additional 40 channels (unauthorized) and increased the carrier power from 5 watts to 15 watts. It also increased the effective single sideband mode power to over 30 watts depending on how much you modulated it which was also another "tweak". At the time we lived in a rented house near the shore and on Sunday mornings I could communicate via "skip" with people in much of eastern Europe, as far away as Italy. In the evening I could easily talk to people west of the Mississippi using skip as far away as California, depending on the time as the sun set. Ended up doing the same mods for a couple of people who also bought the same Radio Shack radio. Don't know whatever happened to that radio. I lost interest in CB after a while. CB was pretty big down in Southern Maryland because a decent base station with an illegal antenna (too tall) could reach 15-20 miles down the bay. If you had a decent marine antenna they could hear your answer. Most of my time was talking to truckers tho. I did make some pretty good friends over the years. |
#28
posted to rec.boats
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VHF vs CB Antenna?
On Wednesday, November 28, 2018 at 2:18:19 PM UTC-5, Mr. Luddite wrote:
On 11/28/2018 1:47 PM, wrote: On Wed, 28 Nov 2018 07:17:33 -0500, "Mr. Luddite" wrote: On 11/28/2018 7:04 AM, Keyser Soze wrote: On 11/28/18 7:02 AM, Mr. Luddite wrote: On 11/27/2018 11:15 PM, wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for.Â* There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz).Â* Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof.Â* That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio.Â*Â* But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length.Â* At 27 MHz a full wavelength is about 103 inches.Â* A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF.Â* Have not used it in years.Â* Actually I am looking at a new radio for the boat.Â* One with AIS.Â* Maybe Santa Clause. My wife has her phone. That is all we needÂ* ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boatÂ* ;-) Back in the CB craze (late 70's)Â* Radio Shack sold a base unit that could easily be modified if you knew what you were doing.Â* I bought one along and acquired a list of the required modifications. The modifications added an additional 40 channels (unauthorized) and increased the carrier power from 5 watts to 15 watts. It also increased the effective single sideband mode power to over 30 watts depending on how much you modulated it which was also another "tweak".Â*Â* At the time we lived in a rented house near the shore and on Sunday mornings I could communicate via "skip" with people in much of eastern Europe, as far away as Italy.Â*Â* In the evening I could easily talk to people west of the Mississippi using skip as far away as California, depending on the time as the sun set.. Ended up doing the same mods for a couple of people who also bought the same Radio Shack radio. Don't know whatever happened to that radio.Â* I lost interest in CB after a while. Never understood the "CB culture." I don't even like to talk on the phone that much. For a while CB had two cultures, the "good buddy" road travel communications and people like me who were more interested in seeing how far you could communicate with others, similar to HAM radio and their custom of exchanging "QSL" cards by mail confirming successful contacts. Only time I was glad to have a CB radio in my vehicle was before cell phones came along. Was traveling up Rt. 95 from Long Island heading home at about one in the morning. It was raining hard and a car whizzed by me in the fast lane. Suddenly, all I saw were his headlights flashing back at me several times. As I approached him, his car was upside down on the side of the road. He had hit a large puddle of water and had hydroplaned, causing his car to hit the center guardrail and then flip several times. Got on the CB and after a few tries contacted someone who called the state police. I helped get the guy out of his car and he sat with me in mine until the police arrived. He was shaken up big time but didn't appear to have any serious injuries. === These days everyone has emergency communications via cell phone. It's much more reliable and easy to use. Ham radio is also experiencing a decline in popularity as the internet and sat phones have made it easy to communicate all over the world. That's too bad because it wasn't really all about continuous and reliable communications. The challenge was in frequency selection, antenna placement, etc. just to see how far you could establish communications. Kinda a nerdy hobby I guess. Even in the Navy on one of the ships I was assigned to and before it's homeport was changed from Newport, RI to Naples, Italy we used to try to maintain comms with another ship using the least amount of transmitter power as possible. Best we did was a two-way FSK teletype connection off the coast of RI to another ship transiting through the Straights of Gibraltar using less than 1,000 watts. I'm not a ham but I know a couple. There's a challenge some of them participate in to see who can get a QSL card from 100 countries using only 1 watt.. One of the guys had cards from 60-70. The atmospheric conditions have to be just right to form a transmission line from you to that country. They call it "skip". Ham operators are still pretty useful in certain situations, especially when the cellular system is down. Fo example, there's a privately owned (by ham clubs) radio network that covers the Carolina's, and up into Virginia and part of Georgia. With a ham license and a $400 handheld, you can talk to another ham anywhere in that area. That's not an unusual thing. |
#29
posted to rec.boats
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VHF vs CB Antenna?
On Wed, 28 Nov 2018 14:51:15 -0500, wrote:
On Wed, 28 Nov 2018 07:02:16 -0500, "Mr. Luddite" wrote: On 11/27/2018 11:15 PM, wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) Back in the CB craze (late 70's) Radio Shack sold a base unit that could easily be modified if you knew what you were doing. I bought one along and acquired a list of the required modifications. The modifications added an additional 40 channels (unauthorized) and increased the carrier power from 5 watts to 15 watts. It also increased the effective single sideband mode power to over 30 watts depending on how much you modulated it which was also another "tweak". At the time we lived in a rented house near the shore and on Sunday mornings I could communicate via "skip" with people in much of eastern Europe, as far away as Italy. In the evening I could easily talk to people west of the Mississippi using skip as far away as California, depending on the time as the sun set. Ended up doing the same mods for a couple of people who also bought the same Radio Shack radio. Don't know whatever happened to that radio. I lost interest in CB after a while. CB was pretty big down in Southern Maryland because a decent base station with an illegal antenna (too tall) could reach 15-20 miles down the bay. If you had a decent marine antenna they could hear your answer. Most of my time was talking to truckers tho. I did make some pretty good friends over the years. My longest distance conversation was with a trucker on the west side of El Paso, TX, while I was approaching from the east side on I-10. We were both on high ground with the valley between us and were over 30 miles apart. |
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VHF vs CB Antenna?
On Wed, 28 Nov 2018 14:22:12 -0500, "Mr. Luddite"
wrote: On 11/28/2018 1:50 PM, wrote: On Wed, 28 Nov 2018 17:40:39 -0000 (UTC), Bill wrote: wrote: On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill wrote: Mr. Luddite wrote: On 11/27/2018 7:36 PM, wrote: On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite" wrote: On 11/27/2018 5:22 PM, wrote: I have a uniden CB radio (new) and have an existing larsen wb vhf radio already on my truck. Will this antenna work with my new radio. Derek Can't determine without knowing what freq range the truck antenna is "cut" for. There are two VHF bands, low-band VHF (49-108 MHz), high-band VHF (169-216 MHz). Marine radios operate in the high band. Generally it will receive ok but transmit range may be limited due to high standing wave ratio (SWR). Even a marine VHF antenna should be tweaked in terms of length to minimize SWR in the middle of the radio's freq range. He is talking about CB (27mz) so that is over twice the wavelength of the lowest frequency VHF. SWR is really going to be ugly but since they are capped at 5w, (usually more like 4.5) I doubt the magic smoke comes out but he won't be "getting out" far either. If his "truck" is a real one (breaker good buddy size) and he has 8-9' from mirror to mirror the best antenna is the co phasers you see on big rigs. Otherwise it is hard to beat a bottom coil loaded ~48" antenna right in the center of the roof. That is what I had on my van but you had to remember to take off the vertical when you went into a parking garage. ;-) I completely missed that it was a CB radio he was talking about. Thought he was talking about a new VHF Marine radio. But the antenna issues remain the same. For max range whatever antenna he uses needs to be of the proper length. At 27 MHz a full wavelength is about 103 inches. A half wave antenna would be about 51.5 inches long and aquarter wave length antenna would therefore be about 25.75 inches. If really anal about these things, an SWR meter should then used to trim the antenna length to the lowest SWR on channel 20 (mid-range). I have an old SWR meter from the CB craze years that I never use anymore but for some reason it's one of those things I just can't throw away. I have one for my marine VHF. Have not used it in years. Actually I am looking at a new radio for the boat. One with AIS. Maybe Santa Clause. My wife has her phone. That is all we need ;-) Worst case I call a tow pirate but I have plenty of neighbors who owe me a tow. Sinking is not an issue, we will just wade ashore, I will plot a course through the mangroves with my aerial photos and boy scout compass and we will walk home. I do have loppers on the boat ;-) We get fog, and lots of ship traffic in SF Bay and slightly offshore. Would be nice to know what is coming. === We use both AIS and radar in situations like that. Of course they're very useful at night also. Wayne, BTW, my friends on the "Ring of Kerry" made it safely to Charleston, SC. and have set up for the winter. This is their first voyage after all the work they did on the boat and it looks like they are enjoying the adventure big time. They *did* stop at Coinjock to sample the fare and only ran aground once on the ICW on the way down. :-) === Good for them. If you've never touched bottom on the ICW, then you just haven't been at it long enough. There are some real problem areas that are only negotiable at half tide or better, other places that have missing navigation marks, and a few spots that are badly charted. We are fortunate to have a full length keel with a metal shoe on it so the props and shafts are well protected. Charleston is not nearly far enough south for a comfortable winter on a boat however. We have neighbors down the street that just brought their 58 footer down here from the Charleston area. --- This email has been checked for viruses by AVG. https://www.avg.com |
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