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Everything posted by BoxCar
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And I'm certain that the first device you used to check an antenna's efficiency was an antenna analyzer. People usually learn to crawl before they do handsprings with advanced level equipment such as the Vector Network Analyzer.
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GMRS preference over HAM ? (for those holding both licenses)
BoxCar replied to a topic in Guest Forum
There are two primary ways to get license totals. I'll lay odds Berkinet filtered the list by asking for active licenses onlt. -
The 6.1 meter or 20 foot rule means the structure is not subject to registration. Towers and poles greater than 20 feet in height are usually listed on the license as the transmitter location. This primarily applies to services where individual frequencies are required to be coordinated which isn't needed for personal or amateur communications. There are other rules that apply such as being near an airport or lighting for antennas more than 20 feet in height.
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Start with a search on the license type specifying your state, county. If it's not there, try looking for the frequency using a B/ILT license type. If you don't find it there, contact the FCC and file an interference complaint from an unlicensed station and give them all the details you can.
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L bracket. Here's one but there are a great many others. Larsen TMB34B GigaParts.com
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Here's a better one. B4505CS Chrome Base Coil Half Wave Antenna - NMO Spring - 450-470 MHz – Arcadian - ArcAntenna.com
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Output power isn't the biggest factor in calculating range, It's antenna height and obstructions. Power does play a good part but it's all about location, location, location. Granted 45W will transmit further than 5W but not that much more than 25W through the same antenna.
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The license holder is required to be in control of the station. How would that control be exercised if the two people where in different locations?
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Usually an unlicensed person can use a GMRS radio if they are in the presence of a license holder being responsible for the operation. That can best be visualized as standing next to the unlicensed person.
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New GMRS Application Fee Reduced to $35 (from $70)
BoxCar replied to intermod's topic in General Discussion
KEN9116 -
power supply to use and set up my 50X1 with chirp
BoxCar replied to cbrown038's question in Technical Discussion
You'll need a power supply outputting at least 15 amps at 13.8VDC. Lots of inexpensive ones on all the online sites. Even the cheap chinese ones work well. -
One thing I think many would like is an ignore feature where posts from ignored users would not show. The ability to edit your personal ignore list would be required so names could be taken off the list as well as being added.
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It's not much more difficult to pass the Genera class exam which also covers everything the Tech class can use plus even more frequencies.
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The key question is your budget and the number of units (radios) needed. CCRs or Cheap Chinese Radios vary greatly from model to model. The Woxuns have a better user rating than a great many of the Baofengs but again, they do have some good units as well. Flea Bay is a good source for used high grade radios from manufacturers like Motorola, ICOM. Vertex-Standard, Kenwood and others. Many of these are not certified under Part 95 of the FCC regulations but are certified under Part 90 which has tighter specifications. That doesn't make it all right to use them on GMRS but many do. Amateur or Ham radios are also not certified for GMRS, but again, many do use them. The best of the bunch will be a commercial or public safety grade unit, but those are typically limited in the number of channels available and require some expertise in setting up the channels for use. Many are best programmed by a radio shop for a fee but you also need to know before hand exactly what you need for each channel. BTech offers a good GMRS handheld that can be programmed from the front panel or through a PC/MAC using a free program. The Midland units are fair but both they and the BTech along with the Woxuns work better with upgrade antennas. The best advice is to do your homework first, build a needs list and the search for radios that come closest to meeting all your needs along with the nice-to-have features.
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Measure twice, cut once. A lot of antennas have a little slop at the base which allows the antenna to be made longer. Take a reading with the antenna fully seated in the base then another as you raise the antenna about a 1/4 inch in the base. see which way the SWR changes. That will tell you if you need to lengthen or shorten the antenna. If shortening, cut off about 1/4inch increments and work from there.
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Can GMRS Be Used in Disaster Response Service?
BoxCar replied to edgeready's topic in General Discussion
In the event of a disaster the FCC won't be actively searching for individuals using radios improperly except those in the public safety bands or federal/military channels. That "grace period" will be short, probably less than 72 hours before they would begin active enforcement. GMRS, MURS and CB radios are too plentiful for much active enforcement unless the user was actively interfering with disaster response units. -
Depends. What do you have? I bought a Surecom digital from everyone's favorite online store.
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Most of the radios used by members are purchased online. What you end up with will depend on how you intend to use it. For a mobile installation (vehicle) you will probably end up with either a 25W or 45W unit. As far as efficiency, there isn't that much difference between 25 and 45W. It's in the antenna. The same can be said for a home or base unit which is usually a mobile attached to a power supply for the needed DC power. Base station antennas are different than those used for handheld or mobile stations. The Ed Fong antenna from edsantennas.com is a good inexpensive unit. Base station antennas also need to be as high up as you can get them as this affects the range more than power.
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Well, I don't have an MXT400 or the desire to get one so I can't speak to the channels installed. However, the issues with repeaters is fairly well documented. First, the wideband and narrowband point. Radios having one bandwidth can, and do, talk to each other over the same channels. Radios on wideband hear the narrowband radio with lower volume while the opposite is true for narrow band radios listening to wide band radios. This has to do with the amount of signal carrying the intelligence. Narrowband radios carry their intelligence or speech using 11.3 kilohertz of bandwidth and wide band radios use 20 kilohertz for speech. More bandwidth, the stronger the received speech volume. Also, the wideband radio will be more intelligible at the farthest range for both. The second issue for the Midlands has to do with the signaling tones used by most repeaters. Some repeaters need a specific tone to "wake up" and process the incoming signal. If the output from the repeater does not carry a tone or uses the same tone the MXT works. It's when the output signal uses a different tone than the input, split tones, that the Midland fails, This is because the Midland cannot assign one tone for transmit and another to receive without modification.
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You also need to remember the coverage area shown in those maps is theoretical in they assume certain parameters that may be incorrect. The coverage for a radio signal depends on three things, location, height and radiated power. Location can best be described as where the antenna is physically located and the terrain surrounding the antenna. The second factor, height is how far above the ground at that physical location is the radiating portion of the antenna. Power takes into effect the type of emission, bandwidth the signal occupies and the amount of radiated signal. All the coverage areas shown on myGMRS are circular ignoring the actual terrain at and near the repeater. It is unknown what antenna height is used and the radiated power. I know if I were to put up a site at my location the coverage would be shown as a circle but in all actuality it would be a wedge toward the WSW due to hills higher than my antenna surrounding my location.
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Either antenna will work on your top. The addition of an extra thickness of metal as a brace may be difficult because of the NMO mount the antennas use. Often there just isn't enough length on the mount to go through two thicknesses of material. I would shorten the coax just for a neater installation but that's your call.