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Posts posted by Lscott
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1 hour ago, WRYZ926 said:
You can roll up any extra coax at the antenna end which will act as a RFI choke, but it shouldn't be necessary.
For a J-Pole type antenna a coax line choke at the base of the antenna is HIGHLY recommended.
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Your comments about signal penetration is generally true.
The 2M band is popular for general communications. It’s other advantage is Hams are the primary users and enjoys worldwide allocation, typically 144 to 146 and 144 to 148, depending on country and zone.
The Ham 70cm band, at least in the US, is allocated frequencies from 420 to 450. There are some reductions in spectrum when close to the Canadian border. Due to the large spectrum allowed you find various experimental modes being used. Also most of the digital voice activity is on this band.
- SteveShannon, WSBB368 and WRUU653
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33 minutes ago, Guest IDontKnowAboutRadios said:
For the use case, our main job is working on and maintaining oil/gas wells
Oh-oh. The recommendations just changed. That’s an VERY important point. For safety reasons, fire and explosion, you would be well off to get what are called “intrinsically safe” radios. This might actually be a requirement for your work environment! They are specially fitted normal commercial grades radios but have been specifically sealed to prevent any arcing or sparking from the radio’s internals which can precipitate a gas explosion or fire. The same also applies to the battery packs, external speaker microphones etc.
If you look in the Kenwood catalog they do sell that type of radio for the models I recommend along with the safety rated battery packs.
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Kenwood offers some very good radios for a reasonable cost. For rugged outdoors use as you mentioned a public safety grade radio is a must. I would recommend the VHF models in the attached brochures. You will need the software and license for them.
To add some of the digital voice modes to the higher end models requires additional licenses.
The NX-5000 series is the only one that can do three digital voice modes, two at a time, NXDN, DMR and P25. The licenses for the first two are really cheap, about $42 each. The P25 license is very expensive and typically used by government agencies and first responders like police and fire.
If you don't need P25 then the somewhat cheaper NX-3000 series hand held might work for you.
The cheapest option is the NX-1000 series. They are good radios but aren't really public safety grade.
Encryption options are available for some of the digital modes if required.
The attached catalog has all of the options listed and the current "list" price. You may qualify for a discount if you're a local, state or federal government agency etc.
Kenwood Land Mobile Radio Guide 2024.pdf NX-5200_5300_5400.pdf NX-5700, 5800, 5900.pdf NX-3200_3300.pdf NX-1200_1300 Num 1.pdf NX-1700_1800.pdf
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1 hour ago, WSCA349 said:
Newbie question here. For example, I am monitoring on Channel 23 and someone is transmitting on that channel but yet I hear the responding person on say channel 21. I have a dual band handheld (UV-5G plus). Is that normal?
How have you got your radio programmed up?
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Despite the government's denials, a cell phone kill switch, I'm sure in the case of some "domestic disturbance" cell phone use would be restricted or disabled completely by their order. After J6 if it didn't exist then I'll bet it does now. That's when you're likely to need your radio the most to coordinate with others to get out of an area to a safe place.
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1 hour ago, WRYZ926 said:
Again use quality coax and quality connectors (if making your own cables).
I've tried installing my own connectors, wasn't easy, didn't turn out that well. Unless you've done a lot of it, and have the right tools, it's money well spent to just buy a cable with the connectors already installed. One less question mark if things don't work as planed.
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38 minutes ago, nokones said:
t's just 1 dB, not significant and you won't know the difference in the operating distance unless you buy your cable from Amazon.
For a db or two that's true for most people. With a modest gain antenna the coax loses can be compensated for. For people on the very fringe of a coverage zone every db counts.
- SteveShannon, WRYZ926 and WRXB215
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40 minutes ago, nokones said:
The Kenwood and Motorola portables and mobiles would be your best bet in order to be compliant with Part 95, Subparts A and E, and have the ability to program 70cm freqs. You will need to find the "R" model radio in the earlier models and the "Q" model radios for the later models in order to have the operating band range for programming the 70cm and GMRS freqs.
You have to be careful about which models to get. For example the Kenwood TK-3180's come in two different band splits. Both will cover GMRS, but only one has Part 95A certification. The 450-520 MHz band split can be "pushed", enter out of band frequencies with a warning message, down below 450 MHz to get into the repeater section of the Ham 70cm band.
https://forums.mygmrs.com/gallery/image/417-tk-2180jpg/?context=new
Some radios, like the Motorola's, the frequency range is locked to the official one and out of band frequencies can't be entered like with the Kenwood's. You have to buy the correct band split version. Also they may not have Part 95 certification either.
https://forums.mygmrs.com/gallery/image/261-motorola-xpr6550jpeg/
For example while the Motorola XPR6550 is a nice radio it's not FCC Part 95 certified.
TK-3180 FCC Grant-2.pdf TK-3180 FCC Grant-1.pdf TK-2180_3180 Brochure-2.pdf XPR6550 FCC Grant 4.pdf XPR6550 FCC Grant 3.pdf XPR6550 FCC Grant 2.pdf
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I think LMR600 has lower loses, a bit larger than LMR400, and I think it's not much more expensive either. The loss at 450MHz for LMR400 is 2.7db/100 feet. The loss at 450MHz for LMR600 is 1.7db/100 feet. For somebody who needs to run between 50 to 100 feed of coax stepping up to LMR600 would makes sense. The chart frequency of 450MHz is close enough to GMRS at 462/467 MHz the extra loss at the slightly higher frequency isn't that significant.
For 50 feet of LMR400 at 450 MHz the power loss would be about 27%.
For 50 feet of LMR600 at 450 MHz the power loss would be about 18%.
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On 3/8/2024 at 11:00 PM, WRYZ926 said:
And that is also why most of us will use LMR400 or equivalent coax for our base station antennas, it has the lowest loss per 100 feet for UHF.
At a reasonable cost. There is better cable, various types of "hard line", but gets expensive real fast.
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5 hours ago, nokones said:
Not the one on my racecar. Talley still has the ANXTRA4500N antenna. Surprisingly, they're still using the Antenex antenna part number. Unfortunately, the White Phantom is still the only single unit purchase and the Black is a minimum of 10 unit purchase and that is why I have a white Phantom non-ground plane NMO antenna instrad of the black non-ground plane NMO antenna.
I’ll have to check that one out. Every once in a while I get asked about it.
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5 hours ago, nokones said:
Low Profile. Please note the White Phantom antenna just under the rear window near the top and attached to the rollbar structure. This antenna is a non-ground plane designed antenna.
I was under the impression they all required a ground plane.
https://forums.mygmrs.com/gallery/image/428-stealth-dual-band-with-swr-scanjpg/
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Any updates on the mystery signal?
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I've seen this all before years ago on various CB Internet news groups. Same sort of logic. Always ends up in the same place.
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FCC database shows them licensed for VHF only and using DMR.
https://wireless2.fcc.gov/UlsApp/UlsSearch/license.jsp?licKey=1210947
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1 hour ago, WSBB368 said:
I’m sorry to bother but what do you mean by switching talk groups and everyone listening to the repeater is taken to the same talk group ?
Sent from my iPhone using TapatalkSome basic info to get you started.
https://www.brara.org/documents/presentations/The DMR Basics _ No Frills.pdf
- onemanparty, SteveShannon and WSBB368
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1 minute ago, WRXB215 said:
Current:
- 2x Baofeng MP31
- 1x Baofeng UV-5R GMRS
- 2x Baofeng UV-5R8W
- 1x AnyTone AT-778UV
- 1x Kenwood TH-75A
- 2x Abbree 771 antennas
- 2x Abbree 701 antennas
- 1x Nagoya UT-72 mag mount
Soon:
- 2x Baofeng GM-15 Pro 8W
- 2x Extra batteries
- 2x Abbree tactical 18.89 antennas
- 1x Big Blue 14W USB solar panel
You have a good start to your collection.
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5 hours ago, WRUI365 said:
Also have a Harris XG100pP which covers vhf/uhf and scan the 700/800 bands along with vhf/uhf trunk frequencies.
Drooling.
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1 hour ago, WRYD530 said:
Haven’t seen this topic really discussed. What radio(s) are everyone using. Home base station and mobile. Let’s include antenna and cable as well.
OK, you asked.
https://forums.mygmrs.com/gallery/image/249-934916052_radiocollectionjpg/?context=new
https://forums.mygmrs.com/gallery/image/259-ca-2x4mb-jeepjpg/?context=new
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25 minutes ago, WRYS709 said:
NOTE: How did such a discussion of ham radio dmr get into the GMRS subtopic?
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28 minutes ago, Guest larry said:
i know i am very late to this party.
but the yaesu VX6 is your radio,
they say good to 30 min under water down to 3 meters. unit is sealed up, has extras.
is a try band radio fits in your shirt pocket.
2meter, 1.25 cm, 70cm.
the battery is not so great do to the size of the radio so must have a second, but can be charged in your car or off any 12 V dc source. no cradle needed.
can be mars adjusted.
but the cost…. 3 - 4 US bills in 2024 new. and still in production.
Also NOT certified for GMRS.
For new users to GMRS the recommendation is to get a radio with Part 95A, under old rules, or Part 95E under the new rules certification. Some of the older commercial radios are certified under Part 95A and perfectly legal to use on GMRS. Plus, with some effort, they can be used outside of their official band split to allow operation into the upper half of the Ham 70cm band where the repeaters are typically located. Not all commercial radios allow this.
This is just one such example:
https://forums.mygmrs.com/gallery/image/263-tk-3170jpg/?context=new
The difference between a 4 watt verses a 5 watt radio isn't very significant. Some may recommend a higher power handheld radio. What you'll get is a much shorter battery life and a great hand warmer, burner, if the radios is used at high power for more than very brief transmissions. I've read where some people have destroyed their radio from heat, even at the 4 to 5 watt level, when used at high duty cycles.
Tell me about 1/4 waves
in Technical Discussion
Posted
They are. It depends are what point of view you take. The minimum length for a radiating element used as an antenna is 1/2 wavelength. Obviously a 1/4 wave alone won't work. That's where the ground plane come into play. The easiest way to understand how it functions is place your finger at a right angle against a mirror. You see a reflection of your finger so it looks twice as long. The same thing happens with a ground plane. It "reflects" the 1/4wave element making it look like a 1/2 wavelength long.
By bending the radials it changes the feed point impedance so it's closer to 50 ohms, a good match to the 50 ohm coax cable. A true 1/2 wavelength dipole antenna is closer to 70 to 75 ohms with the feed point at the center. That results in an SWR of about 1.5:1, which is perfectly acceptable by just about any radio out there.
A 1/2 wavelength antenna is used where a ground plane, or room for radials at the base of a 1/4 wavelength antenna, is not possible. The draw back is the antenna is now twice as tall and the bandwidth is reduced since a special matching section is required at the base of the antenna.
Also high gain antennas are multiple sections of 1/4 and 1/2 wave elements with a "phasing" section in between the sections. Those are the small bulges or tiny single loops you see spaced along the length. The down side to high gain antennas is the gain is HIGHLY concentrated in a direction perpendicular to the antenna. Works great for relatively flat open terrain. Not so good in hills or mountainous areas. People who like to hit the trails often carry two antennas. A high gain one, these antennas can be rather tall, used when on the highway and a low gain, usually a 1/4 wavelength, when hitting the trails.
https://forums.mygmrs.com/gallery/image/259-ca-2x4mb-jeepjpg/?context=new
https://forums.mygmrs.com/gallery/image/268-ca-2x4sr/?context=new
https://forums.mygmrs.com/gallery/image/338-cheap-14-wave-gmrs-antenna/?context=new