Lscott
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Posts posted by Lscott
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This is a technical question. The answer is a very qualified “maybe” and it will be specific to a particular model radio.
Now for the technical dive into why it might be an issue. Some of the more expensive radios, commercial grade, use a type of electronically tuned filter on the radio’s receiver section for better selectivity. That could be a variable capacitance diode fed with a variable DC voltage output by the microprocessor. That’s how the filter is tuned when the RX frequency is changed. That component would be OK. However I have spotted what appears to be a variable inductor, again using a variable voltage/current, to adjust the filter frequency. If it has a magnetic core the inductance could be affected by a very strong magnetic field in close proximity to the radio. That would bugger up the filter frequency and thus the receiver performance.
I think for the vast majority of radios people use a strong magnet isn’t an issue. It’s usually the high end commercial radios that use the tunable receiver input filters. And just about all of them typically use the variable capacitance diode in that circuit. Which are not affected.
- TrikeRadio and RIPPER238
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7 hours ago, Hoppyjr said:
A 2 hr 40 min drive and an insanely long line to get in…..
Yeah. The line was almost 1.5 miles long from the later news reports! The photo was looking ahead. We must have been at least 6 to 8 blocks away from the arena. It was a constant flow of people walking by the entire time we were in line.
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I have a buddy who wrote to the airline he was flying on. He got permission to use his Ham HT “on the plane!” Wow. I don’t know the particulars but he’s done it more than once.
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Before you start moving the antenna around and swapping it out for a different model I would do a simple experiment first. Have a buddy a mile or so distance monitor your transmission. Rotate you vehicle in a circle relative to your buddy. If the quality of the transmission, and watch the signal strength, doesn't vary too much then I would just leave it alone. The only really good reason for playing with a different antenna, or it's location, would be for a really poor SWR, something over 2:1. If it's under 2:1 I wouldn't worry about it much.
- WRXB215, SteveShannon and WRUU653
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On 10/13/2024 at 7:55 PM, WSEI687 said:
Is this violating any FCC rules
Absolutely.
On 10/13/2024 at 7:55 PM, WSEI687 said:potentially creating any problems?
Yes. There are other people using frequencies outside of the ones officially allocated for GMRS. That's why the FCC exists. It's their job to make sure various groups of users don't interfere with each other.
This should give you an idea just how packed the radio spectrum is. The FCC has to keep track of this mess.
https://www.ntia.doc.gov/files/ntia/publications/2003-allochrt.pdf
- amaff and SteveShannon
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8 hours ago, Blaise said:
I just ran across this Baofeng modification video. Brass tacks, just how bad an idea, from a technical standpoint, is the power mod in this vi
Generally not good.
1. Transistors are not great for linearity. As the amplitude increases for more power the waveform likely deviates further from the ideal sine wave shape. Any departure indicates harmonics of the base frequency are present. That's why there is a band pass filter on the output stage of the radio. The UV-5R's, particularly the older models, were known for having poor filtering on the output. If the radio meets FCC emission standards before the mod it might not afterwards.
2. All power transistors have a power dissipation rating, and thermal resistance from the transistor's junction to the heat sink. The power amp stage, transistor, in the radio is no exception. Whatever power is going into the final amplifier stage and not coming out as RF is turned into heat. It's not unusual for the efficiency to be around 50 percent. So if you get 10 watts out that means you're dumping 10 watts of heat into the radio's case. That can turn the radio in to an instant hand warmer. Maybe even too hot to hold and likely fail the output power transistor. The junction is going to be very significantly hotter than the case due to the thermal resistance. This is why I'm not a fan of tiny radios. Not enough case size to dissipate the waste heat generated during transmit.
3. In the case of number 2 above for lets say 10 watts out, 50 percent efficiency, the drain on the battery pack is 20 watts. Just how long do you think that tiny battery pack is going to last? You'll likely will need to carry around extra battery packs if you transmit at high power a lot, and don't manage to kill the radio from excessive heat before then.
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7 minutes ago, RIPPER238 said:
I have at best 6 repeaters around me and i'm very close to there max range. Never heard any traffic but i only have 2 open repeater options.
Remember people put up repeaters and the cost comes out of their own pockets. A few are more civic minded and operate open repeaters. However even if the repeater is listed as "closed" many times the owner will allow you to use if once they have your info and confirmation that you will adhere to whatever rules and restrictions they place on it's operation. All you need to do is try and contact the repeater owner and ask polity for permission to use it.
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20 hours ago, WRCZ387 said:
or separate frequencies mandated for analog & for digital for things to work with no interference
IF it ever comes to be that would be the most likely result. Also the one the FCC would be more inclined to consider. If you look back through the prior posts to this thread you'll find a file attached to one of mine that goes into a bit more detail on the subject.
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2 hours ago, WRCZ387 said:
or separate frequencies mandated for analog & for digital for things to work with no interference
I think that's the way it's likely to get done. The best idea I read was using the nearly unless FRS 0.5 watt interstitial channels. Using a digital voice mode narrow enough, there are a couple that would work, it would fit between the GMRS repeater channels without causing interference, and likely can be done at higher power like 5 watts. That would give GMRS effectively 7 more useful channels without begging the FCC to allocate more scarce UHF spectrum to the service. It also would keep the existing higher power frequencies free of digital so it won't disrupt FM operations there.
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28 minutes ago, WRYZ926 said:
This is true even with amateur radio. There is DMR, Yaesu Fusion and also D-Star used by Icom and Kenwood. People will argue which is better. And they are not compatible with each other.
The list is longer. There are more digital voice modes than the above if you count several more like NXDN, P25 and dPMR. Then there is the new one M17 too. Your waist line is going to look like Batman's utility belt with all the radios hanging on it for the various digital modes in use. The problem is finding a place to hang all the speaker mics.
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59 minutes ago, WSEM262 said:
Im curious why the existing GMRS frequencies cant be used as digital instead of analog? Would it create interference with the analog signal?
My repeater will do both... and it sure would be cool if it were legal to go digital.
That's a good question. I really don't know. There is a sizable group who are dead set against the idea. Those people have valid points why it shouldn't be allowed. IMHO I think many of the objections could be mitigated through careful rule changes. The fewer the better.
Unfortunately the GMRS community can't even agree to a common digital voice protocol. That would be the first major step one. Everyone has their favorite mode. However the favorite mode may not be the most appropriate. It has nothing to do with it's "technical" superiority. Whatever mode is chosen has to "fit" into the current usage of the service without causing widespread interference and chaos. That places some difficult restrictions on what could/should be used, and where. The end result could be a mode that might not be the majority's favorite, but would cause the least problems.
- SteveShannon and WSEM262
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7 hours ago, WSEL735 said:
I JUST set up my Kenwood NX-210G to our simple company voting reciever 4 site infrastructure....pretty straight forward but no ¿talk groups?. I would really like to understand THAT feature.???
This is a later version of that manual.
- BoxCar and onemanparty
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7 hours ago, WSEL735 said:
I JUST set up my Kenwood NX-210G to our simple company voting reciever 4 site infrastructure....pretty straight forward but no ¿talk groups?. I would really like to understand THAT feature.???
You might like a copy of this document. At times the Kenwood help file isn’t detailed enough.
NX-200_210_300_410_411_700_800_900_901 Function Reference.pdf
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5 minutes ago, MaxHeadroom said:
Digital Voice would not be within the rules either unless the point above with narrowbanding was able to be settled, and even then would only be one permitted modulation to prevent splintering of the service in a way that causes more issues than it solves. There's already super stringent regulation on data over the voice channels so I do not see a full digital modulation being easily accepted, never mind allowing multiple.
I think it is doable to a point. See the attached file for some slightly more in-depth comments on the topic. Also reference the following link since the radio is mentioned at the end of the attached file for a bit more information. Note there are a non-display and a limited keypad display model available.
https://forums.mygmrs.com/gallery/image/290-nx-1300duk5/?context=new
Also the same basic radio design is used for the Australian license free 5 watt UHF CB radio service too. It is sold under a different model number as well.
https://www.kenwood.com/au/com/lmr/tk-3710/pdf/TK-3710_CB_LMR Portable.pdf
6 minutes ago, MaxHeadroom said:Part 90 equipment on Part 95 - that is actually doable and I was working on in 2017 and 2019 but would need to be a separate effort from everything else considering what I mentioned above about all the other pieces. Add type acceptance onto frequency/spectrum management for a service and this would stall before it got any traction.
I agree. This has the best chance of action by the FCC. I'm guessing but a lot of people are running Part 90 only certified radios on GMRS now. The FCC by allowing this would just be officially acknowledging the current practice.
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18 minutes ago, WRUU653 said:
My point was not that someone shouldn’t care but that they are free to care and be interested in what they want. I’m not sure you understood where I was coming from. Perhaps I don’t understand your point.
My father is from Michigan for what it’s worth.
OK, I get it. It's just too easy to be disinterested in something you don't have a personal stake in was what I was trying to convey.
I was being a bit overboard in my comment.
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15 minutes ago, WRUU653 said:
I can’t help but see the irony of someone in Southern California who is reading a thread clearly
Same could be said about somebody here in Michigan, where I'm at, and don't give a crap about earthquakes, mud slides and forest fires there.
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23 minutes ago, tweiss3 said:
applaud the question and inquiry. It's always good to learn more. It took me a good 3 months after pouring though the Part 90 regs and all it's references, and coming up empty handed, before I found that agreement where it's pretty much buried that there is a 5W ERP limit before Canada gets a say.
I remember that. It was buried in a really obscure part of the regulations. That was why the FCC bounced your application for some of the business itinerant frequencies you wanted.
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6 minutes ago, WSEZ468 said:
I’m another new guy checking in! Looking forward to learning about GMRS and repeaters and of course radio programming! Glad to be here!
Welcome to the group. Lots of knowledgeable people here. Somebody is likely to have the answers you're looking for. Remember there are no dumb questions here, just a lack of knowledge that learning will soon correct.
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42 minutes ago, amaff said:
Ever watch a boomer try and drive a 1920s Ford? They think the ignition timing lever is their turn signal!!
No, but when I took driver's ED the instructor told us about a girl driving the car once. They were doing some real on the road practice. The instructor told her to make a left turn off the side street into the school's parking lot. She grabbed the shift lever on the right side of the steering column and flipped it all the way up. The transmission didn't like it much.
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1 hour ago, MarkInTampa said:
The fiber network runs in a redundant ring and is divided by 7 districts that run and maintain their own fiber within their district. Some of the districts even have redundant operation centers. For example district 1's primary operations center is in Ft Meyers and the backup is in Bartow 90 miles away. With additions of cameras, traffic detectors, EDMS (electronic digital message signs - and each one of those have a camera focused on them to confirm operation) and the like over the last 10 years that are all IP based and consume a ton of bandwidth fiber is the way to go.
Sounds like a fairly robust fault tolerant system. Has it been actually stress tested to verify it stays functional?
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29 minutes ago, MarkInTampa said:
I'm not sure how long SARNET will stay up or if DOT will allow them to run across the fiber - time will tell.
Wait till the system fails due to flooding since it's likely the critical lines are ground based. Then they'll start thinking about the microwave links again.
A buddy, whose a radio tech for a local city's transportation department, is working on installing a backup radio system on the city buses since they've had the cellar based communication system fail one too many times.
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Manually entering a frequency to assigned channel
in General Discussion
Posted
Just one more thing. There is nothing wrong programming in non GMRS frequencies if all you want to do is “monitor” them. You just need the correct license to transmit on those. Some specifically designed GMRS radios allow out of band frequencies, but those will only work on receiving.