Ian
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Posts posted by Ian
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Well, I can help answer some of your questions....
Thank you!
Lastly, please refrain from using non-appropriate language on this site.
Apologies. I'll be operating under "Art's Grammaw" vocabulary from now on.
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While reading regs, I noticed only mobiles seem to be allowed the full 50 watts. They indicate "fixed stations" have a 15 watt max. I am then assuming base stations and repeaters are fixed stations under the rules.
Thoughts?
Sent from my LG-D631 using Tapatalk
Fixed stations are also assumed to be those stations that only communicate with fixed stations; base stations are like fixed stations but intended to communicate with mobile units. It's assumed that fixed stations will be using tight-beam antennas, while base stations will be using omnidirectional antennae. The EIRP of the fixed station, even using only 15 watts, should probably be higher than the base station using an omni at the same range, so long as the beam antenna is pointed at you.
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I have a Midland MXT275 and it's in a temporary mount. Eventually, I hope to mount it behind the dash, with one of these bad boys or maybe one of these with a mudflap. That's a very popular mounting method in Australia, since a lot of the UHF-CBs use 8p8c jacks for their handheld control heads.
I'd like to mount it with one of their dual-band fender-mount antennas; the intent is a really factory look with no sacrifices involved, or hole-drilling required.
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The colocation fee and lease is more or less similar to the data center environment you're used to.
I'm in the same boat, as a newbie wanting a repeater, but that much I got out of a buddy who's building a repeater.
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No!
Now all I need is for Garmin to build a mobile GMRS/satnav combination, or to roll one myself.
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At some level, this is a "Why can't we have nice things?" question. (What nice things, you may ask? These nice things.)
But how hard would it be to find out who's using 452 and 472 MHz frequencies? Assigning them to GMRS, even on a secondary basis, gives us access to all-eight-channel-at-a-time, all-solid-state, no-oscilloscope-required repeaters.
I believe the semiconductor filters used here could be improved to do 5 MHz splits, but that is clearly beyond the current state of the art (though military tech may be capable of it, they have priority access to whatever spectrum they require to do their jobs, so alternately it may simply have never been developed, though their budgets are quite up to the R&D task involved.
https://en.wikipedia.org/wiki/Elliptic_filter
I think that the Elliptic filter is the best approach to building solid-state GMRS repeaters. Chebyshev and Butterworth filters have better ripple characteristics, but Elliptic filters offer the sharpest cutoff available, and if the location of the ripple can be controlled adequately, a circuit board with reliable, repeatable and temperature-insensitive performance could be a duplexer. If Butterworth filters are capable of acceptable performance, however… A circuit board with reliable, repeatable and temperature-insensitive performance could be a duplexer for every channel, simultaneously.
I've also looked into surface acoustic wave filters, which are doing the black magic in LTE base stations. They're almost certainly capable of the 5 MHz splits we need, but they also cost like black magic ought. A more compact repeater may be achievable, but a more affordable one? Not so much.
So, I ask you, the brain trust -- what's easier, the bureaucratic burden of finding an underutilized slice of spectrum at least 10 MHz away from our little chunk of the UHF, or the engineering burden of figuring out if this XXXXXXXX is possible, and then making it a product?
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They're marketed as "interference eliminator codes" in honest marketing. They offer no privacy, only solitude.
If you want privacy, you want encryption and or FHSS… both are illegal in GMRS, but available in 900 MHz unlicensed radios that can do up to 1 watt. Motorola markets them heavily for business use, as the licensing requirement is … well, "no requirement" is very easy to comply with.
They don't encrypt, but they do do FHSS, which makes them pretty low-probability-of-intercept.
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Has the Rino protocol been reverse-engineered yet?
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My reading - and I am neither doctor nor lawyer, and this does not constitute medical or legal advice, or the practice of medicine or law - of the FCC rules leads me to believe that only the exciter is the regulated component, so long as the rest of the mess doesn't cause it to radiate beyond your permissions.
So I guess have one more vote for no problemo so long as you keep it on channels 15-22, and especially keep it out of the interstitials.
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All good points. Leaning towards MotoTalk as my cross-band solution, 'cause it's as license-free as FRS and so much less congested.
However, I'm backing off on the mobile repeater for the time being, and I'll figure something else out. Probably going to double down on the garage repeater; with a little luck I'll find a used Kenwood TKR840 or Ritron Responder in acceptable condition to tide me over until I can get to the advanced stuff.
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I recently contacted Midland to describe the need for a "plug-n-play" GMRS repeater. I listed all of the features that I desired, and added that making it "portable" and operable on 12VDC would be a big plus. I even suggested that they might spec-out an existing model being produced in the PRC. I even have a name for the dream machine....the Midland MXT-R50. Front-panel programmable, 50W, integral duplexer, RF circulator,etc (if necessary). If you would like to see such produced, contact Midland!Also feel free to add to the features that you would like to see.
While you are at it, ask Midland to produce a GMRS/repeater-capable HT that is type-accepted!
Both truly excellent ideas! I'll be hitting them up on Twitter and mentioning it in any relevant Facebook groups I can find…
Signal amplification for the win!
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Thank you, padre!
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You've done quite a bit of homework. It sounds much like my experiences over the years. That's how I ended up with MURS, GMRS, FRS, and amateur radio. I split my time mostly between GMRS and amateur radio; some FRS with a very minute smattering of MURS. The first two are most useful to me because of repeaters.
I certainly share in your frustration!
My condolences.
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On the Luiton LT-590, according the the manual that is "Data Terminal - reading/writing, cloning and theft alarm functions." i.e. It's the programming port... on the LT-590 at least.
If you haven't figured it out yet, that Midland price tag is for a locked down firmware and FCC certification. In other words, less radio and an FCC sticker for more money.
http://www.dovesandserpents.org/wp/wp-content/uploads/2012/04/facepalm.jpg
Edit: Holy crap, the Midland is TWICE THE PRICE!!! D:
Edit: I'm morbidly curious to see if the LT-590 programming software would work on the Midland…
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Hey, we can see individual repeaters' coverage circles on the map.
Is it possible, or at least reasonably feasible, to map all the repeaters' coverage circles simultaneously? Especially if some can be disabled (as a couple repeaters in the database seem to be down for the count, and a few others seem to be down for repair or upgrades, according to email exchanges I've had).
Penny for your thoughts?
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Hans, I'm going to slyly take what you're doing here and run with it.
Let's rationalize the entire Personal Radio Service.
MURS becomes part of FRS. They're both allowed two watts, business use, and no repeaters, yes?
GMRS gains the ability to listen to repeater inputs (a blindingly obvious solution, in hindsight, from my ham radio study guide) and … let's call it eight 50 watt VHF channels. Half will be repeater inputs, half will be repeater outputs. Preferentially taken from the color-dot pool, since the market has matured, and business radios aren't sold with all of the available channels programmed in any more.
All it would take is a ruling allowing cross-coupling of the part 95 services above 30 MHz. That would allow for GMRS to MURS links, or GMRS to the old 46/49 MHz band (is that still active?) while limiting it to above 30 MHz would eliminate CB. (I don't want to hear skip from channel 6 repeated on 462.500 all day.)
Allowing a 2-Watt VHF handheld to remote into a GMRS mobile would solve that guy's problem on that other thread - the guy who seems to want a wireless speaker-mic that works for 3 blocks from his mobile rig.
I doubt this will happen, but we can ask.
Yeah, actually, that'd be perfect. In the mean time, Uniden (may) have me covered.
Quarterwave: The hardware's the problem. What do you think about starting up group-buys on Massdrop for legal-but-unprofitable custom kit like better wireless mics?
If anything I said here would be done, merging FRS and MURS would be the golden ticket. It'd reduce the number of boxes I carry every day.
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I'm rocking the midland micromobile mxt105 - simplex only, but I'm quite fond of it. I was thinking about rolling an all-Midland repeater, but then I remembered that they don't have anything cheap (actually, they don't have anything AT ALL) that can listen on the repeater inputs.
Tangent: why does the mxt400 have a data terminal on the front panel, which the manual says isn't used?
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So much already written and available on this, yet every time we turn around there is a new post rehashing all of it. I think we all like helping others, but I can't frankly find the energy to do all that typing, bless you others for doing it. Some folks need to do a lot...a lot more reading before asking for the instant gratification answer. Not trying to offend anyone....just being direct.
I did hundreds of hours of reading before asking for help. The most important result of that reading was finding out what was possible, and how out of my depth I was. The second most important result was to become angry and confused, as I realized that it's basically not possible to use new-production radios on GMRS beyond two watts, or with repeaters, with a few important (but non-overlapping) exceptions.
I explored going business band, but I'm not entitled to buy a business license without using the radios to earn a profit, or at least performing activities tangential to or in support of it.
I started off with cell phones, but holes in their coverage usually lead to me being screamed at. A social solution is impossible, so a technical solution, no matter how difficult or expensive, must be pursued.
I explored ISM radios, but the TriSquare eXRS - my first choice - is long discontinued and absent from the secondary market.
I tried MotoTALK, but it doesn't have the range to cover my entire block, and is therefore not fit for purpose.
I saw Motorola's DLR series, but they're a NXDN derived system, and are technically only incompatible with MotoTALK due to deliberate changes to the FHSS hopping order, in order to impose market segmentation; like MotoTALK, they're limited to one watt, and by the propagation characteristics of 900 MHz.
Even before the cell phones, I bought some early FRS radios, nice single-channel Radio Shack units, but the audio quality was unacceptable. Allegedly. (I blame reluctance from the neophobe who yells at me.)
I bought some more FRS radios, and they failed within a week. (Motorola Talkabout T4300, to name-n-shame)
I bought those last ones for some volunteer work, and the returns process took the entire period they would have been useful.
Bought a bunch of Motorola Spirit MURS radios, which were the first really useful things I laid hands on, and I love them.
But good luck finding a mobile MURS radio…. There was one certified under 95J for rally-car communication, but it was $600 new and it's been discontinued in favor of an intra-car intercom without a transceiver.
I went back to the ISM band with the EnGenius cordless SN-920 cordless phone system from the pawn shop, which does one watt of 900 MHz, full duplex, with some attempt at encryption and FHSS. The system had been out of production for a decade, new batteries are not a thing, and their customer service told me to buy a new system. The Durafon 1x goes for about $550 on Amazon with one handset, but the base that supports their good handsets is $1200, and each handset is $500-550. Not happening soon.
I'm running out of subparts now, and I've failed miserably at getting anyone else I know to get a ham license, citing either not-giving-a-shit, or in one case, the toxic community of fudds, and in another case "that's great I'll do it" turned into "I never said that. What's ham radio, anyway?"
I have given myself panic attacks trying to read and understand case law and parse the federal register. I am now confident that the real motivation is to destroy the personal radio services so that the frequency can be leased to the highest bidder (but let's be honest, probably Verizon).
Meanwhile, in Australia, home of the UHF-CB, repeater capable hardware is more-or-less Walmart grade and fairly cheap. Wireless microphones and headsets are not exotic. UHF use (for "UHF" is all you have to say to express that you're talking about unlicensed personal radios) is relatively mainstream, and they have 80 channels to our 22 (though a few are blocked off for future inventions).
I find it profoundly frustrating and unfair - though I recognize nothing about the universe is intrinsically fair - that there is nothing really fitting into the niche of "prosumer" gear in the United States other than used gear of questionable reliability. (Which is to say I've had poor experiences with used radios' reliability, and new radios as well! Until my recent GMRS buying spree, I was at like one-for-seventeen UHF radios still working. I've joked that "this is where UHF gear comes to die" with serious justification.)
TL;DR: I'm tired, frustrated, and anxious about this. I've done my homework, and I'm sick of owning inevitable failures. I want some successes to be proud of, dammit! I'm also aware that I wrote four pages of refutation to the accusation of "instant gratification" and that's not normal, but you discovered one of the psychological land mines I wasn't aware I had. I'm sorry this came out pointed in your general direction, but I simply can't bring myself to delete it now. May it instead illustrate some of the things I've tried that brought me to this place in my attempt to create elegant technical solutions to problems.
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Breaking this out for tl;dr -
With multiple requests for more clarity in my needs, my "minimum viable product" is: I want a garage repeater that'll cover the neighborhood and those stores I use the most 'cause they're closest. I'm leaning towards using an Ed Fong J-pole attached to the chimney as a my antenna, and a cheap Chinese duplexer tuned so I can change channels on the repeater without visiting a radio dealer. -
Yeah, I'm well aware. The wireless mic/repeater comparison was yours.
Again, the closest and cheapest thing I can think of would be dump GMRS and rely on 100% networking; like the Inrico network radio products. https://network-radi...-network-radio/ They also produce handheld models.
Good luck.
Edit: If you are relying on email notifications to reply to messages then you are missing edits. There is more to these messages than to which you appear to be reading or replying.
Oh, crap. I'll be doing this the manual way for the foreseeable future, then. Thank you!
Simply put, a mobile repeater would do this part. Two used mobile radios from eBay that are part 95 accepted and a repeater controller. If I remember correctly, the Motorola M1225 radios are part 95 (verify first). They would only require a cable to connect them (dirt cheap or roll your own), programming, a duplexer, and an antenna. Easy peasy. Not particularly rocket surgery.
We have a repeater like that sitting in our radio room. You can purchase the two radios with cable, programming, and a microphone; often for under $200. We used the seller "mineforyours" on eBay for our initial look-see into this type of repeater. The cheap China duplexers are under $100 tuned on eBay. Add feedline and a mobile antenna. Consider solutions to battery drain on the vehicle.
You could also purchase two Motorola or similarly suited part 95 radios and a repeater controller (there are a few out there new production on the cheap). It doesn't have to be pre-made.
Does this not satisfy this part of your project?
That's definitely the solution I'm leaning towards, if the $100 crystal-controlled Ebay special (it includes a tuned duplexer, sometimes!) doesn't happen to me soon. I'll probably use Midland -- wait. They can't listen to repeater inputs.
I'll probably find the cheapest receiver I can, since unless contradicted, the best information I've found yet says that only the exciter has to be 95 certified. (Read as a component of the transmitter, when used with an amplifier, or the whole transmitter, when used without.)And no, it doesn't have to be pre-made. I'm sorry if I gave that impression, as I'm well aware that borders on impossibility. I just really want all the components to be replaceable on short notice if something goes belly-up on me.
This is one of those extraneous bits of information that throws me off in these posts. Getting into the mobile repeater takes whatever watts it takes to get in. If you are relatively close enough and the propagation is good enough, it might only take a few milliwatts. BUT, in everyday use, it is merely the settings on the handheld used; low, medium, or high if ya got em. Low might be more than a few milliwatts but it's what you have at the time. Too much minutuae in some of this description is muddying the waters, IMHO.
Again, cross-band repeat would be simplest but we don't have that option in GMRS. So, a basic mobile repeater is the way to go. There is no need to reinvent the wheel. There is affordable used gear available right now to do it.
It should only take a few mW from inside the car. If this was Australia, I'd just get a Uniden UHF-CB, and the first party wireless mics, but they aren't even trying to make that available in the US, even though it's explicitly legal. Wait, that's not true - they're only making them available with connectors for three high-dollar CB radios.
Cross-band repeat would be simplest, but we __do__ have the option in GMRS, as I realized last night just before bed. MotoTALK does about 0.7 watts of 900 MHz FHSS in the ISM band there, so with a custom cable and turning on vox on both the GMRS transmitter and the cellphone I'm using as a base for the "wireless mic", I really could have a cop-a-like system.
Having said that, and with requests for more clarity in my needs, my "minimum viable product" is: I want a garage repeater that'll cover the neighborhood and those stores I use the most 'cause they're closest. I'm leaning towards using an Ed Fong J-pole attached to the chimney as a my antenna, and a cheap Chinese duplexer tuned so I can change channels on the repeater without visiting a radio dealer.
The first enhancement to this minimum viable product shall be a battery backup, for I live in Florida.
Ian. You titled this topic “A Beginners Repeater.” But, then you describe a very complex system that nobody here seems to fully comprehend. Then, when people suggest you simplify things, you respond that each suggestion offered won’t meet your beginner needs. Finally, you seem to misunderstand or misinterpret parts of Part-95 and in so doing, you seem to go in unsupportable directions and avoid other, much simpler, potential solutions.
At this point, I too will join the growing crowd watching from the bleachers, at least until you can provide a simple use case example that does not involve any discussion of how it should be done. Something like: “4 people are hunting in the woods and a 5th person is coordinating their a actions from a fixed location and they need to share their ideas for lunch.” Really, something that basic would be a good way to start getting the help you have requested.
Understood and I apologize - I really muddied the waters by not clearly breaking this up into more sane chunks. IE, garage repeater, car repeater, fun projects to add later. Only thing I'm worried about is the ready availability of repair parts, thus the requirement that all components are still in production, though I suppose a sufficiently large supply of old stock might soothe my nerves.
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Oh, one problem that we are going to run into is that APRS has a fixed limit of six characters for the call sign. All GMRS calls are seven characters. That might cause compatibility issues with existing software, many of such is woefully outdated and unmaintained, even if the standard itself is updated to allow seven.
And the wind is taken out of my sails. :|
In the mean time, anyone got any ideas about how to get a radio to use a callsign as a Roger beep, using either fast Morse or ASCII? Neither sounds particularly rough to listen to...
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Corey, I want a beginner's repeater that can grow with me as I go from trying to manage in big box marts with no cell coverage, to dealing with those shit weeks when hurricanes take down the everything. Mostly the goal of mobile repeaters is going to be a repeater pretending to be a mobile, with a few mW of input -- if I can find gear like that. If not, I'm looking at other options, but they price is just unbelievably unaffordable.
Hans, wireless mics are better for really short ranges between the user and the radio, but you can't be arsed to find a wired mic. Repeaters are better for when you're at least a block away or more from the repeater and you still want to use your big 'ol transmitter.
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For a couple hundred bucks, I can get a crystal-controlled repeater and an amplifier to bring it up to fifty-ish watts.
Yes I do want champagne on a beer budget. But I think you miss my point.
Mobile repeaters won't be talking to another fixed repeater. They'll be more or less pretending to be powerful simplex radios with wireless microphones. I'm still trying to figure out how to make the linked repeater thing work, legally, so I need to ignore the whole thing and figure out how to make it work without networking.
However, if I can figure out how to make repeater networking work, then the cost of the X10 gear will justify itself, as I'll be able to bill myself as a consultant and build other people's radio networks as my day job.
10 MHz Split vs. Filter Technology
in FCC Rules Discussion
Posted
Corey, the reason I'd like to play with solid-state filters is to push the state of the art forward. Cavities are perfectly serviceable, and I intend to use them in my first repeater. However, at some point I'd like to build a truck-mounted transportable repeater, and it doesn't have room for a 19" equipment rack. That means compromises in order to achieve acceptable performance and flexibility. Complexity gets me great performance - imagine a hydrogen balloon carrying the antenna, tethered to the truck bed by some G-line - but drives up the cost something fierce. It'd be a fun project, though, when I'm independently wealthy. In the meanwhile, I shall content myself with only a modest improvement in antenna height.
Also, if I ever ended up with a lunchbox repeater like that, I'd be using an external linear amp to give it some respectable power output... ideally also a lunchbox form factor with an internal backup power supply.
Berkinet, I've looked at tiny fifty-watt duplexers on Amazon (about fifty bucks) that would easily fit in a single-DIN car mounting. I suspect that's what the lunchbox repeater is using. Alas, cars these days don't tend to have any DIN mounts, let alone extras. I just can't afford the equipment to tune them myself, and I'm not sanguine about what I've heard about thermal drift on these things' calibration. In a perfect world, there'd be community repeaters I could borrow everywhere I go, but most of the time I'm somewhere where I can't reach 'em, though at home I can sometimes barely hear the two in the region.
Jones, I do want an eight-channel repeater, and I want it cheap. Not for me, but for the future of our hobby and the service as a whole. If everybody could drop no more than $500 on a repeater and a cute little chimney-top tower, suburbia will be blanketed in community repeaters, and the utility and value of having a radio increases exponentially. Cost, complexity, and colocation will kill budding hobbyists' ambitions, and in the same way you say "just use simplex" hams tell me "just use a cellphone". I'd prefer not to be beholden to people whose business model includes AI-driven ad tracking and selling personal information; the competition will ultimately limit their options for screwing their customers over. If people put wi-fi on those community repeaters' cute little towers, many people could get by without any cell plan at all. I don't want to be the underutilized slice of UHF that gets sold to AT&T next... best way to avoid that, in my opinion, is to increase traffic and use until cell phone companies will look at the spectrum, sigh, and realize that even if they did buy it they'd never in their wildest dreams of enforcement success be able to stop all the people with walkie talkies from causing constant 5G blackouts, and won't be tempted to lobby for this.
That's why I want an eight-channel repeater. Not for me, but for everybody.