Lscott
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Posts posted by Lscott
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2 hours ago, SteveShannon said:
Manufacturers could design mobile radios to put out half a watt, but because FRS regulations require handheld radios and because GMRS regulations limit 8-14 to handheld radios, mobile radios could not be certificates, even if they complied with the output power requirements.
That's correct.
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17 hours ago, CoffeeTime said:
Any ideas on a GMRS Mobile rig that has that 2 watt pwr. option for TX on FRS and is not locked out on FRS?
As pointed out FRS channels 8-14 are low power, 0.5 watts max. That's why mobile radios don't include them since they generally can't lower their power to the legal limit, otherwise GMRS and FRS radios use the same "simplex" frequencies. FRS does not have access to the repeater input frequencies whereas GMRS does.
Second if you have a GMRS license it's perfectly legal to communicate with FRS radios, even above 2 watts. On channels 1-7 you can use 5 watts max, and on channels 15-22 it's 50 watts max.
The point to remember is FRS radios use exclusively narrow-band FM while GMRS uses normal, wide-band, FM. If it's possible using a GMRS radio the bandwidth should be set to narrow-band when talking to FRS radio users. I use mainly commercial grade radios for GMRS. Those have the ability to use either bandwidth. For those radios I program in two banks of frequencies, one wide-band for GMRS, and the other narrow-band for FRS.
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On 6/15/2025 at 10:58 AM, WRDJ205 said:
I can't find a good explanation as to why the duplexers need to be tuned for a specific frequency pair. Why wouldn't a duplexer tuned for GMRS UHF bands be able to cover all pairs as long as the TX and RX radios had the proper offsets on them?
The simple explanation is one is used to isolate the transmitter from the receiver. Since the repeater is a full duplex operation, transmit and receives at the same time, any RF energy from the transmitter will get into the receiver. When this happens the receiver will trigger the transmitter. Now you have a feedback loop where the system will stay locked up on transmit until the power is yanked, destruction of the receiver's input at worse, or simply kills the sensitivity of the receiver then it becomes deaf to weak signals.
The typical notch/bandpass duplexer filter is setup such that the receive half of the filter is tuned to notch out the transmitter's frequency as much as possible. The bandpass filter on the transmitter side is tuned to eliminate as much of a spurious signals that are not on the exact transmitter's frequency, thus preventing them from entering the receiver's circuits.
For the above to work a certain frequency minimum difference between the transmit and receive frequencies are required. This minimum depends on the quality (design) of the duplexer.
https://horwin.info/en/pro-dupleksery/
https://www.repeater-builder.com/antenna/pdf/w6nbc-duplexer-book.pdf
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10 hours ago, WSHH887 said:
The north Vietnamese knew what frequency to monitor.
It was also known the NV had captured US man pack radios. These where used to monitor military communications. There were versions with encryption, but were extremely bulky.
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On 6/14/2025 at 11:49 PM, marcspaz said:
I may have mentioned this earlier in the thread... but I think the FCC is 40 years too late in approving FM on CB. I'm glad a manufacturer stepped up and got the change made, but it's just too late.
At least on the official side. My buddy has his "export" mobile radio for 12/11/10 meters. He's run FM on 11M with a few people, and that's before the FCC allowed it.
The question will it replace FRS. I think the answer is no. Why. The usage cases are different. People using FRS have short range communications requirements. The small size, radio plus antenna, fit in a shirt pocket or on a belt very easily. Anyone that's looked at some of the older "HT" style CB radio, well they're about the size of the old WWII walkies-talkies. The antennas for any reasonable radiation efficiency are ridiculously huge. These radios are not convenient to use.
The retired cop in my radio coffee group tells us stories how the older Motorola radios were not liked that well. They were large, bulky and the officers complained about the antennas poking them in the armpits all the time with the radio on their utility belt.
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10 hours ago, WSHH887 said:
Anytime someone asks about my antenna on my truck the think it's CB.
I've had the same experience with the monster sized dual band Ham antenna on my ride.
https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new
It doesn't look like any common "CB antenna", but I guess people just go with what the are familiar with.
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3 hours ago, nokones said:
I am thinking about the NX series. I kinda like the idea of having the ability of programming two of the three digital platforms at once and you can change it if you want to drop one and pick up the other.
The only model series that can do that so far is the NX-5K's. This allows the use of two out of three digital modes, DMR - NXDN - P25 Phase 1 and 2, to be active in the same code plug.
The NX-3K's series you can use two different digital modes, DMR and NXDN no P25, but not in the same code plug. You have to load the mode specific code plug into the radio.
There is a member here, https://forums.mygmrs.com/profile/3159-tweiss3/, who has experience with both models and if you're really interested I would reach out and ask if he would contact you. There are software licensing and feature entitlement keys, mainly cost, to get the radios to the point where they would function in the manner you want.
NX-5000 NA.pdf NX-3200_3300.pdf NX-3220_3320.pdf
Oh, if you want to add the P25 option to the NX-5K series radios, well you're going to get RAPED on the price. The The radio comes with NXDN and the DMR option is super cheap, like around $60.
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35 minutes ago, nokones said:
but at least I do know how to spell radio.
With the state of education in the USA some of the young kids can't even do that. And they can't even figure out out how to turn on the spell checker feature on their computer software or smart devices. Sad.
When I can't spell something, at least I have an excuse, I explain "I'm and Engineer."
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32 minutes ago, LeoG said:
Probably to make sure the president doesn't get credit for quelling the riots.
Really?
Remember this?
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Using two-way radios may not be of a benefit when sophisticated DF gear is used. The local PD likely won't ave this kind of gear, but the US military, including the National Guard, might. Things get really crazy they will start looking for people.
One example is this brochure. The portable units can act together in a networked configuration for faster and higher accuracy location determination.
- PACNWComms and WSIK532
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On 5/29/2025 at 10:32 PM, LeoG said:
Sounds like it's related to the lipstick on the dipstick.
It's all the wicked Wick's fault.
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4 hours ago, WRYZ926 said:
That's a good price. And it is only 10-20 dollars more than the 2x4SR. The Antenna Farm has the best price I found for the 2x4SR at $62 and DX Engineering was $70
I paid close to $100 for mine at the Hamvention. Who knows, might have been due to the tariff crap then. R and L Electronics, which seemed to have the best price, was out of stock when I looked a while back. Plus they didn't have a booth at the Hamvention, which I though was sort of strange since they are one of the better known Ham gear vendors.
This is a link to a photo I just added to my album with the testing results and a photo of the antenna in it's protective sleeve. Note the antenna is clearly marked as a NR240CA. I've seen the NR240C being sold. Not sure if they are the same or not.
https://forums.mygmrs.com/gallery/image/613-nr240ca-roof-rack-mount-swr-and-photojpg/?context=new
- WRYZ926 and TrikeRadio
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43 minutes ago, dosw said:
Thanks. I'm going to order it.
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48 minutes ago, dosw said:
One antenna that is a no-ground-plane antenna that covers the range advertised for the NR240CA would be ideal.
The antenna is a 5/8 wave design, and really does need some kind of ground plane to work. For whatever reason it seems to work rather well on my roof rack mount. I suspect there is some coupling, capacitive, through the mounting strap to the rail plus the metal roof on the vehical.
A close up photo of what the mount looks like with an antenna installed on it. Note I use the UHF type mounts whereas most people like the NMO type. You can clearly see the electrical tape on the base of my old antenna since the fold over spring is worn out. I've been driving around like this for years. The mount is on the driver's side so I can reach it and unscrew the antenna when necessary.
https://forums.mygmrs.com/gallery/image/473-close-up-of-mobile-mount/?context=new
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46 minutes ago, dosw said:
I've been looking for days for a source for the NR240CA.
https://www2.randl.com/index.php?main_page=product_info&cPath=2_1240&products_id=76310
I got mine at the Hamvention last May from a vendor. I forget who it was, but the source in the above link has them.
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30 minutes ago, WRYZ926 said:
I know they fold. but as you mentioned, the fold over will wear out if used all of the time.
The Diamond antenna is a bit different. There is a locking collar you have to unscrew to lift up the antenna to fold over. No spring to wear out like on the Comet design. Another reason to go with the Diamond antenna for those interested in it.
- SteveShannon and WRYZ926
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13 hours ago, WRYZ926 said:
I did purchase the spring for my 2x4SR since the antenna is on my SxS.
Good idea for anybody who is going to routinely use this antenna mounted up high. I picked one up at the Hamvention last May for mine for future use. I would install it if I planed on using the antenna at some point. Right now I have my old CA-2x4MB on the ride. That monster is about 60 inches tall.
https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new
The match on it is something else. This was done when I had it on my old Jeep. It looked better than the newer CA-2x4SR. The one on the ride the fold over string is shot, that's the black electrical tape you see, the antenna is at least 20 years old. I do have a new one still in the green plastic sleeve, never been outside of the house. I purchased both at the same time.
https://forums.mygmrs.com/gallery/image/223-ca-2x4mb-jeep/?context=new
https://forums.mygmrs.com/gallery/image/282-ca-2x4mb-scansjpg/?context=new
I've been looking around for a possible replacement for it. After testing the CA-2x4SR and N240CA, on my roof rack mount, either one might be a good replacement, and they are only 40 inches tall. I might go for the NR240CA, yeah it's more expensive, but the SWR match looks a bit better over the ranges I'm interested in.
One thing people don't talk about here, or elsewhere for that matter, what the match looks like in crummy weather, like moderate to heavy rain or fog. It's going to get worse to some degree. If you start out with a really low SWR it likely won't deteriorate nearly as bad in less than ideal weather. Modern radios are designed to tolerate SWR's up to 2:1 at full power. After that the radios, with SWR protection circuits, will start to fold back power to protect the output power stage.
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22 hours ago, Majik said:
I’m running the MXTA25 ghost on a hood-hinge mount on the passenger side. Absolutely not the best location for it RF-wise, but it was the best spot for me since I wasn’t prepared to drill the cab roof.
I picked up a no-name one at a local swap a long while back just for fun, it was really cheap. Tested it and I wasn't impressed with this sample. Likely better ones out there.
https://forums.mygmrs.com/gallery/image/428-stealth-dual-band-with-swr-scanjpg/?context=new
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Just now, WRYZ926 said:
The 2x4SR is hard to beat.
Yup. The price is very reasonable too.
- SteveShannon and WRYZ926
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Well I got around to doing an SWR scan of both the Comet CA-2x4SR and the Diamond NR240CA wide-band antennas the past few days. Both were tested on the UHF type roof rack mount I have on my Mazda. Both antennas are 5/8 wave design, thus they need a decent ground plane to work. I expected crummy results. However I'm absolutely shocked how well they matched up on the VHF and UHF bands!!! I guess there is enough "ground plane" under the mount, plus whatever capacitive coupling between the mounting strap and roof rack rail for a better coupling to the rack rail. The installation looks like this photo, but I have a different antenna on the mount at the time.
https://forums.mygmrs.com/gallery/image/471-mobile-mount-with-antenna-rear-view/?context=new
The attached photos show the match on the VHF and UHF bands. The results are very similar. Not uprising since both designs look about the same except the center loading coil. subjectively I think the Diamond antenna match is a bit better.
- GrouserPad and WRYZ926
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17 minutes ago, SteveShannon said:
Chirp does remarkably well for being non-commercial software. If it was available for all of my radios I might never have switched to RT Systems. And I will not say that RT Systems has worked perfectly. I’ve run across a few problems with RT Systems when programming DMR code plugs, which admittedly is an order of magnitude more complicated than typical analog radios. But their DMR calculator makes it much easier and when I have had a problem I have been very impressed by RT Systems willingness to thoroughly discuss and understand every issue that I have reported. Having RT Systems available for my db20g radios really made the difference for me though. I really like this radio and Chirp isn’t available for this radio.
My personal preference is to use the official factory software where possible. That's really important for commercial radios. CHIRP is nice, but for every radio it supports the developers have to reverse engineer the code plug layout and communications protocol with the radio. When it works, great. The one issue with Chirp is it may not always give you access to all of the radio's features. For that the only choice is the factory software.
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30 minutes ago, Majik said:
I’ve been able to get into repeaters with low watts at distance so it’s working for me, despite the non-optimal config.
You can always change it later. Once you drill a hole, well that's not going away if you change your mind. I had a buddy who messed up his measurement when he drilled a hole for his NMO mount in the roof of his old van. It got into one of the support beams on the underside. He ended up putting a plug in the hole he couldn't use and drilled a new hole over a bit. We kidded him for a while asking to see the Band-Aid on his Boo-Boo.
Oh, if you do end up at some point drilling a hole. Be absolutely sure you use the right hole saw. The wrong one will really mess up the roof.
- Majik, WRYZ926 and SteveShannon
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1 hour ago, Davichko5650 said:
KAUO6363, Sent in a form that was in the Kraco box to Uncle Charlie when I was at Ft. Campbell in '76.
Kraco CB's were the equivalent of GMRS CCR's today. They were the cheapest POS radio's you could buy.
GMRS for LA Riots.
in General Discussion
Posted
It might be a secret credit card number to use, billed direct to the government, when ordering out a pizza for deliver.