Home |
Search |
Today's Posts |
|
#1
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
On Mon, 16 Jan 2017 20:18:47 -0800 (PST), Tim
wrote: On Monday, January 16, 2017 at 9:48:58 PM UTC-6, wrote: On Mon, 16 Jan 2017 21:47:18 -0500, "Mr. Luddite" wrote: On 1/16/2017 9:45 PM, wrote: On Monday, September 25, 1995 at 3:00:00 AM UTC-4, MikeT1946 wrote: I just bought a boat that had been equipped with Loran, VHF, and Citizen's Band (CB). The former owner kept the CB. So I now have 3 antennas, and 2 things to hook them up to. The question is, can I hook the VHF up to what had been used as the CB antenna? They're both white plastic whip antennas, and I have no idea whether they're electronically different in any way or not. Radio experts? Thanks... -- Mike Wow. 1995. Back when rec.boats was about boats. Somebody been poking around in the google groups again? Not me but I will if you want. LOL That seems to be where these 22 year old posts come from Over on the home repair group the homeowner web seems to be famous for it. |
#2
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
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 |
#3
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
|
#4
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
On Tuesday, November 27, 2018 at 4:47:49 PM UTC-6, 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. I remember in the 'craze' the SWR meter was pretty popular, where you could tune a potentiometer to match the antennae to the radio for maximum efficiency. |
#5
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
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. ;-) |
#7
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
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. |
#8
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
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 ;-) |
#9
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
On Tue, 27 Nov 2018 21:42:22 -0500, "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 used to just buy what they had at Radio shack or something but my old 3d shift partner was a Ham/Navy ET so I got pretty good guidance. ;-) He was an RF wizard. He was the guy who left FE, went to IBM FSD, Lockheed, Loral and worked in Germany for a decade or two and now retired in Colorado. http://gfretwell.com/ftp/colorado/Greg%20and%20John.jpg Three old guys on the top of the hill behind John's house, next to the fence to Rocky Mountain Federal Park. Another Navy guy doing well! I hope "Dutch" (the dog) is still OK ;-) |
#10
posted to rec.boats
|
|||
|
|||
VHF vs CB Antenna?
|
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
TV antenna | Electronics | |||
FS ICOM AH-4 Auto Antenna Tuner with Long Wire Antenna Kit... | Cruising | |||
FS ICOM AH-4 Auto Antenna Tuner with Long Wire Antenna Kit | Electronics | |||
FS ICOM AH-4 Auto Antenna Tuner with Long Wire Antenna Kit | General | |||
vhf antenna | Electronics |