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Everything posted by Lscott
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Surecom SW-102: What it tests, how it tests
Lscott replied to Webslinger's question in Technical Discussion
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Mobile antennas and high gain = not always best?
Lscott replied to SvenMarbles's question in Technical Discussion
This is why some people keep a couple antennas in their vehicle. They use a low gain, 1/4 wave, in very hilly or mountainous area or a high gain antenna in nearly flat areas. -
Tidradio TD-H3 "Stun" and "Kill" functions?
Lscott replied to WSAA635's question in Technical Discussion
This is getting a bit off topic and into the weeds a bit. But the rule specifically mentions equipment certification. Anything after the cutoff date will not get certified if it has any kind of voice obscuring features. However it’s silent about equipment that was certified before that date and no mention the feature must not be used in that case. So, it’s very possible voice scrambling in OK, BUT only on radios certified before Dec 27, 2017. So, my favorite Kenwood radio, TK-3170, I use for GMRS, which by the way is certified Part 95 in 2004, has analog voice scrambling so it could be legal to use that feature. Interesting thought. -
https://3fs.net.au/tropospheric-propagation/
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Sargent Schultz, I see nothing.
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Manufactured by Gollum Radios I'm guessing.
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I'm not a conspiracy believer, but either the government has a secret "kill switch" or an understanding with the cell phone companies to turn off the service when asked/ordered to do so. If nothing else the FCC has the authority to license and control transmitters, which of course includes cell phone towers, and force the shut down. People forget that Ham radio was shut down during WWI and WWII by the FCC. It took a lot of lobbying to allow Ham radio to resume in a fashion like it was doing before the war. Not likely today, but that could change. https://bw.billl.net/wp-content/uploads/2019/11/Radio-History-03-Amateur-Radio-Before-and-During-WWII-By-Dan-Davis-W8LUX.pdf Then there is the question what happens to the Part 95 services? Is it also possible they too might be ordered to cease operations?
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Just think about what if the government wanted to pull the plug on purpose?
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Could also be some mixing products in the radio's front end. Take a frequency on 931.6MHz (public safety frequency) and mix it with 469MHz (business frequency) you get the difference of 462.6MHz right in the GMRS range. It could also be just the radio. My Kenwood dual band TH-G71A shows a full scale signal on channel 7. Take the antenna off, nothing. Then I tried several other radios on the same frequency. They show nothing there. So apparently it something weird with just the one radio.
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What kind of radio is being used? If it's a cheap Chinese radio they're not known for good receivers. Note that channel 3 is the Interstitial frequency, 462.6125, between the main channel 17, 462.6000, and main channel 18, 462.6250. For GMRS the channel bandwidth is 25KHz so there is considerable overlap on channel 3 with the adjacent channels 17 and 18. If the radio doesn't have extremely good selectivity you're likely to experience significant bleed over on 17 and 18 from a strong signal on channel 3. Also a strong signal on either channel 17 or 18 will bleed over on channel 3. FRS-GMRS Channels Layout.pdf
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Here is one idea used on an expensive Motorola XPR7550 radio. Allows the use of an external antenna by using a stud type adapter to BNC. The ground is made externally using a strip of sticky back copper foil tape over the back side of the case to the chassis for the ground connection to the adapter. Something like this could be use on the cheap radio. https://youtu.be/O3KEazVQ-RA?si=UV8kiC5HQjQ3gqMG
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At that price you can afford to destroy one or two and not feel too bad.
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What is the best commercial radio for GMRS use?
Lscott replied to TheNevilleKid's topic in General Discussion
If I have a choice I typical go for the 400MHz to 470MHz range since most of my usage is Ham so that covers the full band. It's also usable on GMRS, but as I mentioned before they're not certified for Part 95, but typically for Part 90 of course. When looking for used commercial grade radios there are several things I'll do before dropping my money on one. 1. Look up the manufacture's brochure to see what features the radio has, namely number of channels, display type, frequency ranges etc. You might decide at this point it doesn't look so appealing. 2. Look up the FCC ID's, usually on the manufactures brochures. Check to see what the certifications are for the radio, tested power levels, modulation types and frequency ranges. You need the FCC ID to verify what you're trying to buy or bid on. I frequently find sellers who get the model name wrong or frequency range wrong in the ad description. The FCC ID doesn't lie. 3. Check and see if the programming software is obtainable. This is a big one. Sometimes it almost impossible to find. If I can't get the software the idea is dead right there. It doesn't matter how good the radio is. Commercial radios are basically useless without the programming software, you REALLY need it. 4. Most commercial radios are firmware up-gradable. Chances are the one you're interested in will need a firmware update to make it compatible with the recent radio programming software release. 5. Are important accessories like battery packs, chargers, programming cables, microphones, power cables etc. easy and cheaply available? There are some nice used radios out there but battery packs are almost unobtainable as an example. 6. Then I go looking for the documentation for the radio. Important things like user manuals, service manuals, any programming tips etc. 7. Then it comes down to just how much you want to spend. Some sellers price the radios like they are gold plated. The worse offenders are sellers of digital radios with P25 being at the top of the list. In general it seems that the VHF gear sells for a premium compared to the UHF stuff. -
The miss match caused by the clips on the leads may eventually damage your radio. I would very seriously look for a good quality adapter for your radio. Unless it’s totally proprietary to the manufacturer you should find one. In the case of this cheap radio you could use it as is, or disassemble it and install the pigtail directly on the circuit board. I’ve seen this done in the past with FRS radios. There are some YouTube videos on the topic.
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It’s not a concern. You have to specifically enable it in a radio AND have to put in the particular code to do it. Leave the code out and “turn the feature off” NOBODY will have the ability to stun or kill your radio. That’s the case for every Kenwood radio I’ve programmed.
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Amateur radio maker getting into the GMRS market.
Lscott replied to WRUI365's topic in General Discussion
Looks like the text was written by a Chinese who is somewhat proficient with English, with poor spelling. -
Two possibilities. 1. You are using the wrong tone. 2. The repeater doesn't use a tone on the output. In that case no tone so your radio will never un-mute the audio. I almost NEVER use receive tones on my radios unless I need to REALLY block some interference from another repeater or simplex station. I just don't get the desire where people feel the need to use a receive tone when it's almost never required on their radio. It ends up leading to unnecessary problems like the above.
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What is the best commercial radio for GMRS use?
Lscott replied to TheNevilleKid's topic in General Discussion
My TK-3170's US versions will do the same. Might even go lower. The European versions start at 440MHz. -
People want to know why bother with a two way radio when the cell phone is so convenient in a STHF case? Here's one reason today. https://redstate.com/nick-arama/2024/02/22/major-cell-phone-outage-nationwide-at-and-t-t-mobile-verizon-some-911-down-n2170453
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Probably the dumbest question you’ve ever seen.
Lscott replied to WSAV277's question in Technical Discussion
Mostly true. There are older used commercial "LMR", Land Mobile Radio, radios that you can program with any frequency in the business band segment. Typical range is 450MHz to 490MHZ / 520MHz. Depending on manufacture some of those radios have have Part 95 certification, legal to use for GMRS. The caveat is they must be programmed to follow the GMRS rules for the allowed frequencies for the service. Many users on this forum use commercial hand held and mobile radios successfully. -
What is the best commercial radio for GMRS use?
Lscott replied to TheNevilleKid's topic in General Discussion
Most of the Kenwood radios are the 450 to 490 range, or the 450 to 520 range. Those might even have Part 95 certification on the older models. The 400 to 470 range is sort of rare. If you do find any it’s commonly on the digital radios, and occasionally on the analog only models. Also I’ve never seen the 400 to 470 range radios certified for Part 95. I’m also mainly a Kenwood guy too. https://forums.mygmrs.com/gallery/image/249-934916052_radiocollectionjpg/?context=new -
Prime example. https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
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Updated FCC rule 95.1749 now includes “or other networks” Jan 2024
Lscott replied to cozy659's topic in FCC Rules Discussion
Are all of them linked together on the same system? -
Updated FCC rule 95.1749 now includes “or other networks” Jan 2024
Lscott replied to cozy659's topic in FCC Rules Discussion
Anyway, back to the threads main topic.... -
Updated FCC rule 95.1749 now includes “or other networks” Jan 2024
Lscott replied to cozy659's topic in FCC Rules Discussion
Wow, that's in really great looking condition! People collect these and pay big bucks for them. To keep the slide on the metal types from sticking you use a VERY tiny dab of Vaseline on the slide edges as a lube.