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Everything posted by Lscott
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Intentional repeater jamming and how to deal with it
Lscott replied to WRAK968's question in Technical Discussion
Or they setup their own repeater and find repeater jamming isn’t so funny when they’re the ones suffering with the annoying behavior.- 48 replies
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Intentional repeater jamming and how to deal with it
Lscott replied to WRAK968's question in Technical Discussion
I see you're also a Ham so maybe the local club have a few guys that are into Fox Hunting with the required direction finding gear. Repeater jamming is something they take seriously since it does require a significant investment in time, money and equipment to put a repeater in operation. Some of the better equipped guys have Doppler direction finding equipment. The jammer only has to be on the air for a very short time to get a fix. I've seen a few using the system below. http://www.kn2c.us/ Also when you see police cars with those four short antennas in a square pattern they are using a similar system, LoJack, for locating stolen vehicles. The patent application covers the details. Starting at figure 6, sheet 5 of 7, you can see the 4-square antenna setup towards the bottom of the diagram. https://patentimages.storage.googleapis.com/5a/bb/67/410cde79598750/US4908629.pdf https://en.wikipedia.org/wiki/LoJack- 48 replies
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Intentional repeater jamming and how to deal with it
Lscott replied to WRAK968's question in Technical Discussion
Here are some suggestions from somebody who had similar problems. http://www.repeater-builder.com/k7pp/art005.html- 48 replies
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You can start looking at the site below for basic information on how to build a system. http://www.repeater-builder.com/rbtip/index.html
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Show me any legal GMRS radios,there are none.
Lscott replied to WRFS771's topic in Family Radio Service (FRS)
That won't go over so well is absolutely right. The Ham bands are ALWAYS being looked at by various groups to use. Hams already lost part of the 1.25 meter band due to UPS wanting it. At the site below look under the section heading "U.S. reallocation" for a brief history lesson. https://en.wikipedia.org/wiki/1.25-meter_band Hams have to constantly watch their bands for illegal CB'ers on the 12M and 10M bands, local TV stations on the old analog channel 2 made 6M almost unusable in those areas, fishing boats - high power Chinese cordless phones among other junk operating illegally on 2M, and on 70cm there is a low power commercial allocation at 433MHz, right in the middle of the band. Hams also had to deal with some companies using parts of 70cm for police drones etc. not to mention the band is shared with the US military. The later was an issue with the military Pave-Paws radars. http://www.arrl.org/news/air-force-pledges-continued-cooperation-with-radio-amateurs-during-cape-cod-radar-upgrades -
What radio do you have for your car / truck?
Lscott replied to TonyAldo's topic in General Discussion
Oh, one more thing. Look at the ID tag on the back of the radio. It has the manufacture’s model number on it. I’ve seen too many eBay sellers get the radio description wrong. The only way to not get stuck buying a model that won’t work on GMRS is to check that ID tag. Most sellers show it in one of the photos of the radio. If not contact the seller and ask for the exact model number that appears on the ID tag or request they add a photo showing it. -
What radio do you have for your car / truck?
Lscott replied to TonyAldo's topic in General Discussion
Be very careful which one you get. There are several different models of the TK-880 which covers different sections of the UHF band. The one you want is a Type-1. Look at the last page under specifications. The Type-1 is the only model that covers the GMRS frequencies and is Part 95 certified. https://criticalradio.com/Kenwood%20Spec%20Sheets/Data%20Sheets/TK780h_880h_ver2_k.pdf -
Maybe at some point they will issue a rule change which specifically requires it and end the debate. 8-) Until then there is some wiggle room. Even in the Ham world standard offsets are not always used. The following is for a 2M machine out where a Ham buddy lives. https://www.repeaterbook.com/repeaters/details.php?state_id=26&ID=10560 The "standard" for the 2M band is 0.6MHz. But not in the above case and it is a coordinated repeater, apparently, as you'll notice towards the bottom of the page. https://wiki.radioreference.com/index.php/Offset In the early days Hams used converted commercial VHF and UHF repeaters. On UHF the 5 MHz offset, I think, was mostly to do with the technical limitations on the cavity filters used. Here is some interesting reading on another forum. https://forums.qrz.com/index.php?threads/history-of-vhf-repeater-splits.26321/
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I'm sure there are like adding a DTMF decoder to unlock the repeater, which re-locks after a period of inactivity. Another is some of the 2-tone, 5-tone and digital ANI access systems supported by many of the commercial grade radios. I mentioned in another post where a Ham switched his Ham repeater to using Motorola MDC-1200 for access control too. Oh, I have a couple of Kenwood TK-2360 16 channel VHF radios that can do MDC-1200. I would like to find used some of the Kenwood TK-3360 UHF versions with the rare 400-470 MHz frequency range to add to my HT collection.
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What radio do you have for your car / truck?
Lscott replied to TonyAldo's topic in General Discussion
Never programmed a Motorola radio, but I have heard some complaints by others. I use a handheld radio for GMRS. The one I typically use is the Kenwood TK-370G-1, 128 channel, 4 watts, and part 95 certified. I also own the Kenwood TK-3170-1, 128 channel, 4 watts, and is also part 95 certified. The nice part about both is the ability to program frequencies down to around 440 MHz for the Ham band. The software gives a warning when trying to save the memory channel but takes the entry anyway. The simplex and repeater section of the US Ham 70cm band is between 440 and 450 so I'm not concerned about anything lower. With the above two radios I have access to GMRS and the Ham 70cm band in one radio. Both use easy to find speaker microphones, headsets, battery packs. The radios use the same accessories as the cheap Chinese radios, they cloned the Kenwood interface including the programming cable. When programming in repeaters I use just the access tone for transmit and nothing for the receive. I don't care if the repeater has a receive tone or not so worrying about split tone operation isn't an issue for me. Oh, about old radios with scratched up display glass, really plastic, tooth paste works great to get the scratches out with a lot of rubbing action. Its a VERY mild abrasive. After an hour or so the display glass on a number of my used radios looks almost new. -
Very interesting comments from everybody. The ones about "it's good practice" are well taken and valid. As mentioned sticking to the 5MHz offset is a good idea, but not required by the FCC rules. If and when a case arises where using a non-standard repeater offset is justified the current crop of GMRS specific radios can't handle it. A point that a potential buyer should be aware of if they have this situation.
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Splitting pairs would be an effective method to keep the majority of unauthorized users off a "private repeater", and most are - at least listed as such, given the current crop of GMRS specific radios can't handle this with the fixed 5MHz offset built into the firmware. Not publishing the access tones, or changing them, is a waste of time since some radios, particularly Ham, can automatically scan for them. And if the radio can't scan for the analog tone then trying one at a time Ker-chucking the repeater until they hear the squelch tail works too. The digital codes would take a bit more work. It wouldn't take long for somebody to figure out what they are and back to using the repeater. As I pointed out earlier any users of a non-standard repeater offset system would likely need to use old Part 90 radios, or dual Part 90/95 certified radios, to use it. If somebody has the technical skill to build a repeater they likely have the skills to program the old radios to work on it. Now the argument can be made that people can buy cheap radios, like the ubiquitous Baofangs and their derivatives, which can be programmed to work on such a system. However the majority of users simply want a radio they can turn on and communicate. They don't want to be radio tech geeks. I see enough posts on the forum from users who have problems just figuring out how to program the GMRS specific radios being sold where most of the technical settings are already set in the firmware.
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Perhaps. Given the recent rule changes GMRS repeaters have to tolerate possible interference on the adjacent interstitial frequencies between the main repeater input frequencies, if not on the frequencies used. There have been a few comments on the forum about this. If the offending person or business is not willing to change the repeater owner may have little choice. In my case a repeater, about the only one around in the area, has one or more local families sitting on the repeater output frequency. Fat chance getting them to move given the little kids are always screwing with the radios don't understand what is going on and the parents don't care. Several other channels are used by local businesses including, I suspect, by a nearby Chrysler assembly plant based on what I hear being discussed.
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Looking through the FCC rules there doesn't seem to be any requirements that repeater offsets must be 5MHz. ----------------------------------------------------------------------------------------------------------------------------------------------------------------- §95.1763 GMRS channels. The GMRS is allotted 30 channels—16 main channels and 14 interstitial channels. GMRS stations may transmit on any of the channels as indicated below. (a) 462 MHz main channels. Only mobile, hand-held portable, repeater, base and fixed stations may transmit on these 8 channels. The channel center frequencies are: 462.5500, 462.5750, 462.6000, 462.6250, 462.6500, 462.6750, 462.7000, and 462.7250 MHz. ( 462 MHz interstitial channels. Only mobile, hand-held portable and base stations may transmit on these 7 channels. The channel center frequencies are: 462.5625, 462.5875, 462.6125, 462.6375, 462.6625, 462.6875, and 462.7125 MHz. © 467 MHz main channels. Only mobile, hand-held portable, control and fixed stations may transmit on these 8 channels. Mobile, hand-held portable and control stations may transmit on these channels only when communicating through a repeater station or making brief test transmissions in accordance with §95.319©. The channel center frequencies are: 467.5500, 467.5750, 467.6000, 467.6250, 467.6500, 467.6750, 467.7000, and 467.7250 MHz. (d) 467 MHz interstitial channels. Only hand-held portable units may transmit on these 7 channels. The channel center frequencies are: 467.5675, 467.5875, 467.6125, 467.6375, 467.6625, 467.6875, and 467.7125 MHz. --------------------------------------------------------------------------------------------------------------------------------------------------------------------- I see a lot of newbie questions about repeaters where the "typical" reply states the repeater input frequency is 5MHz higher than the output frequency. However the rules don't require that. Read sections §95.1763 A and C. No mention about a required offset when going through a repeater. It seems so long as the repeater output frequency is one of the 462MHz main channels and the input frequency is one of the 467MHz main channels the FCC is fine with that. Why does that matter? Many people are buying GMRS specific radios that have the repeater frequencies per-programmed into them, with the "common" 5MHz offset assumed by the manufacture and hard coded by the firmware. However if a repeater owner sets up his system to use an input frequency and output frequency that is NOT a 5MHz offset anyone unfortunate enough to own a radio with the repeater frequencies hard coded by the firmware is out of luck. There is noway to make it work short of changing the frequencies. For somebody who wants to keep his repeater "private" with reduced chances of being abused by non authorized users could employ a nonstandard frequency offset. Of course anyone who wishes to use the repeater must have a radio that allows the "non-standard" 5MHz offset to be programmed into it. That leaves for the most part old commercial radios. For a really flexible GMRS specific radio a manufacture should provide a repeater memory channel where the input and output frequencies are selected from a list along with the access tone(s) required. I see enough comments about the Midland radios concerning the tone and bandwidth issues, but nothing about the repeater offsets. If the radios are targeted to be "fully" GMRS rule compliant, sooner or later, the above issue should be addressed as well. This likely also applies to the other GMRS specific radios I see mentioned on the forum.
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Whats with repeater users needing permission on GMRS?
Lscott replied to w4thm's topic in General Discussion
As a side note there is a story about a Ham who really disliked people using cheap Chinese radios on his repeater. His “solution” was switching to Motorola MDC for access, which they don’t have. Predictably he got a lot of negative comments over the switch, mostly along the lines of being a Motorola radio snob. But it was his repeater if I remember right. https://en.wikipedia.org/wiki/MDC-1200 -
My Range Experience Using Baofeng handhelds
Lscott replied to OffRoaderX's topic in General Discussion
Some years back I heard a Ham talking to his buddy at Dayton Hamvention one year. He went into the porta-potty. Well his expensive HT slipped off the belt into the big round hole. No guessing what he was shopping for later. -
You should key up the repeater, state your call sign, then say something along the lines of "testing...testing". Some people instead of saying "testing" ask for a radio check. Whatever you do the FCC requires you to identify with your call sign. Just keying up the repeater to hear the squelch tail and not ID is called "ker-chucking" the repeater and is bad practice, yet you hear people doing it. Some repeaters have anti ker-chucking protection where the transmitter doesn't key up right away, there is a slight time delay. Others need to detect some real audio before going into transmit mode.
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Just weird and look at the price tag
Lscott replied to GuySagi's topic in Family Radio Service (FRS)
Hummm.... 2x Kenwood TK-3180 3x Kenwood TK-380 Motorola HT750 Kenwood TK-3700 3x Kenwood TK-350G Kenwood TK-353G A whole slew of BaoFeng BF-888S and GT1 radios Kenwood TK-880 Kenwood TK-890 Kenwood TK-8360 Here's my list of just HT's, they all work and are programmed: Tri Band: 1 x TH-D74A VHF/UHF tri-band analog/D-Star Digital (MARS/CAP mod) 1 x UV-5X3 VHF/UHF tri-band 128 channel 1 x TH-350 VHF/UHF tri-band 128 channel Dual Band: 1 x TH-G71A VHF/UHF 200 channel 1 x UV-5R VHF/UHF 128 channel 1 x D878UV VHF/UHF analog/DMR Digital Multi Band: 1 x FT817 HF/VHF/UHF (MARS/CAP mod) VHF: 5 x TK-270G-1 VHF 128 channel 1 x TK-2000 VHF 16 channel (International Version) 2 x TK-2170-K VHF 128 channel 1 x TK-2140-1 250 channel (European Version) 2 x TK-2140 US version 250 channel 2 x TK-2160 VHF 16 channel 1x TK-2360 VHF 16 channel UHF: 2 x TK-370-1 UHF 32 channel 4 x TK-370G-1 UHF 128 channel 1 x BF-888S UHF 16 channel 2 x TK-3170-K UHF 128 channel 4 x TK-3160-1 UHF 16 channel 1 x T5720 (Motorola FRS Radio) I have a few dead ones in a junk draw that I may try to fix at some point or use for spare parts. Charger Collection: 5 x KSC-25 1 x KSC-25 (Chinese Clone mod'ed with Anderson Power Pole Input) 4 x KSC-16 1 x KSC-23 1 x KSC-35S Various chargers for specific Chinese and non Chinese Ham radios. Then there are the battery packs, antennas, mobile and base radios too..... -
It just proves that if your LOS is obstruction free the distance can be very large. Ham's have been sending signals through their LEO, low earth orbit satellites, and the ISS, international space station, for years using nothing more than a 5 watt HT connected to a small handheld Yagi antenna. I made a few contacts years back using my mobile VHF/UHF radio with nothing more that a high gain vertical on the roof. http://www.arrowantennas.com/arrowii/146-437.html https://www.amsat.org/wordpress/wp-content/uploads/2014/01/Work_FM_Sats-20131010.pdf
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The best I can suggest is just simply ask why recommend a different tone from the one you wanted. At least per your post they want to discuss it with you. They may have a very good reason. https://wiki.radioreference.com/index.php/Continuous_Tone-Coded_Squelch_System https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
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State Laws - Operation Of Mobile Two-way Radios
Lscott replied to marcspaz's topic in General Discussion
Well not for everyone. The law specificity exempts Amateur Radio, those holding a valid FCC license. However what about others that hold a valid FCC license such as GMRS? I guess Hams have better lobbyists and a well organized group, ARRL, to represent their interests. -
State Laws - Operation Of Mobile Two-way Radios
Lscott replied to marcspaz's topic in General Discussion
I assure you the following is true. I've had a few Hams say they do CW while driving. They have a Morse Code key strapped to their thigh. One hand on the steering wheel while the other is sending code. I can't imagine how this can be done without the driver's attention being split between the Morse Key and paying attention to the road. Some people can't even drive and chew gum at the same time. I wonder just how this would be classified? There is no microphone. -
State Laws - Operation Of Mobile Two-way Radios
Lscott replied to marcspaz's topic in General Discussion
"Please note: Use of an HT would still be a violation. The radio must be mounted and the microphone be corded to the radio. Please remember that not all law enforcement officers will be aware of these documents, and may not follow them. Amateurs may still be cited." So what is really the difference between holding a corded microphone or your HT with a pig-tail on it to the roof mounted antenna? These kind of laws are just pain silly. -
Yeah, until the local PD shows up because you look "suspicious" and won't believe you're just doing a radio range check. Even a few Hams get hassled by the local PD for having a "scanner" in a vehicle and or hearing police radio dispatch calls coming from their VHF/UHF mobile. The recommendation is keeping a copy of the local/state law showing the exception for Hams handy along with your license just in case in the glove box.
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Nice radio but it appears not to be certified for FCC Part 95 GMRS use. https://fccid.io/AFJIC-F221S