gman1971

Yeah, DCDM is awesome, and ERDM is even more awesome, IMO, of course... Totally agree with you on SFRs... You can also make your own SFR (Single Frequency Repeater) with two radios operating in DCDM mode and a circular isolator (tuned to the frequency you want) Enable both radios as DCDM mode, then have one of the radios set as RX only for TS 1, make this radio ineligible for timing leader, and the other radio set normally but to TX on TS 2, make this radio preferred timing leader too. On your subscriber Gen2 XPR7550/SL7550, etc... radios you enable ERDM, which will listen to whatever time slot has the strongest incoming signal... so you get automatic talkaround switching for "free", as in: your radio will either listen directly to the TXing radio, talking on TS 1, or if the TS1 signal is too weak, or not there at all, it will automatically use the TS2 signal coming from the SFR. Can't beat that... The circular isolator can be replaced with a solid state T/R switch... but I yet have to find one of those switches that isn't worth an arm and a leg... mechanical T/R switches won't work, a relay won't last very long switching at DMR TDMA rates... G.

Not quite... DMR offers DCDM, which translates to: Dual Capacity Direct Mode, which allows for simplex two time slot operation without a repeater, as in: YES, you can have two conversations on the same channel without a repeater. The radios select a timing leader among the eligible radios, and you can also hint to have one as leader, etc... all when in DCDM mode. It works great, but it doesn't work very well on CCRs... as I've tried a bunch of them, and DCDM usually hangs the radios on most of the POS TYT's I've tried... Now, it works great on my EVX mobiles and portables, and of course it works great on the XPR gen2 radios too... (the 6550 doesn't have DCDM) If you want DMR with properly functioning DCDM you need to get something along the lines of an XPR7550, preferably an e model, just don't waste your money on Aliunce, Rexontec... et. all... CCR garbage... As for the Anytone AT-578... yeah, it has an SFR alright?, but its a piece of garbage: It freezes while operating in Single Frequency Repeater all the time. I have one, I've had one for almost a year now, its a dead weight piece of trash that will hang when you need it the most... its useless. Mine collecting dust in the parts bin... and yes, its been upgraded to latest FW, latest baseband etc. etc... still a piece of trash that will hang and freeze up. Again, if you want a real Single Frequency Repeater that won't check out when you might need it the most you're ( and I am ) gonna have to muster up for the SLR1000 Moto repeater, a 2 grand wonder... nothing else made in China will touch that thing... that is if long range and good reliability are your thing... otherwise, be prepared to deal with maintenance and upkeep when these CCR turds stop working... or when range is measured in tenths of a mile, rather than tens of miles, etc... yup... If you want professional results you need to buy professional equipment, how do I make such assessment? Well, I found this the hard way, after sinking a lot of money on garbage radios... stay away... but if you must, buy CCRs at your own peril, just don't expect miracles... G.

Its not above anyone's skill level: Get a 2nd hand XPR7550e... buy once, cry once. The cable can be found for dirt cheap on eBay, I own two cables, one OEM and one that was made by a ham guy who sells them on eBay... both appear to work just fine. Legacy CPS can be found on eBay as well. Make sure the radio has 2.09 or lower firmware, anything higher than 2.09 will require a 3 year MOL subscription to get the latest CPS. Setup all the GMRS freqs, the UHF itinerants, moto UHF radio channels, throw a few 70cm ham repeaters in case of emergency... load several of your area EMS, hospitals, public safety, etc, etc frequencies and you'll be a very happy camper. Try looking for one that has the RX Audio leveling feature, either free (enabled model) or has it already purchased. RX Audio Leveling is the best feature I've ever encountered on a radio. Radio is waterproof, MIL-SPEC to boot, has screen is probably the nicest screen I've seen on a talkie, and the receiver is certainly the best in its class. The 3.65" stubby antenna is great, looks awesome and beats all other radios I own with it, even if the other radios have a longer UHF antenna. The 5550e is another awesome radio, can be connected to your desktop so it can run as a control station (like mine) and can be remote controlled via desktop (so the 7550e btw). The codeplugs you use for the 7550e will mostly work on the 5550e. Will need some cut and paste, but it will transfer just fine. 5550e has the best effective sensitivity of any radio I've tested to date. G.

Well, just to put it out there, the UV-82 and most low tier Anytones will desense really bad when other radios are TXing nearby.

What are the other radios involved? G.

Totally free to just open the account. The 3 year CPS subscription is where the $$$$ is at. G.

Great video. That is why I ditched every SO-239/259... it wasn't cheap, but well worth it. Motorola Mini UHF isn't that great either. Moto users don't really have much of a choice although some of those seem to be silver plated... which is better than chrome, but on several of my non-moto radios I've resoldered the UHF with an N tri-metal.

That 299 thing is a waste of money, as I've been told in numerous occasions by other Commsupport members, who have tried it, and told me precisely to avoid it at all costs. Quoting some of those people here: "its utter garbage" So I would personally stay away from it, and trusting those people has made my radio range grow tens of miles, and I am no longer stuck at <2 miles on 50W mobile anymore. Again, you are better off with an XiR radio that has a Motorola designed FPP. With that said, I honestly think you won't need it, I could be wrong, but in my experience I haven't had a need to have a VFO or any sort of FPP... even before starting carrying LMR gear, I don't recall ever using VFO or FPP on my GD77, MD5 nor TH-F6a.... The handful of times I've used VFO on the TH-F6a was to listen to HF and AM airband, b/c these days everything is all digital, so you need to buy a digital scanner, with multimode capabilities... Also, the scan speed on all CCRs is pathetic at best... and the XPR7550 and the 6550 can only do 16 channel scan lists, so either way, you are screwed..., you'll be better off buying a dedicated digital scanner. IMO, just program all the Itinerants, Moto LMR radio channels, EMS, Fire Dept, Hospitals, Marine, A large set of Ham repeaters, GMRS, etc etc. basically anything that might come in handy, and you're set. Again, If I wanted to just listen to traffic I'll just encourage you to buy a dedicated Scanner, or an HF rig. If plugging 200 channels by hand is not your thing then there are codeplugs already made for the XPR radios that will have a ton of repeaters already programmed in them, just download and flash. G.

Hey, congrats!! 5550 is a phenomenal radio. I have mine right in front of my mouse and keyboard, with the RMN5127C mic... works great. Oh, no worries, its just another feedline... you can manage, right? heh. G.

Or a radio with a better receiver. No amount of power you can safely pump on that thing will make up for a 25 dBm desense. G.

I was prey to the cable loss BS scam, apparently the low loss cable myth seems to be targeted towards beginners just to sell them low performance LMR400, misleading them into believing that a .3 dB loss is going to render your radio useless. Not so. FYI, I currently have a 2.3 dB insertion loss between my preselector and the 3 TX/RX bandpass cavities combined on my house base setup, even with a 2.3 dB I can easily reach 20 miles on 25W base to mobile... again, don't fall for the cable loss BS. A 1 dB loss is not going to hurt anything. Go with Heliax, and not b/c of the lower loss, but for the lower noise, which means better signal to noise ratio, since with LMR400 chances are the noise floor will increase by a few dB, which will certainly hurt things a lot more than losing a 0.3 dB of your signal. Again, don't use UHF chrome connectors, use N trimetal. Impedance mismatch and PIM will also ruin your range too... and will be an absolute witch hunt to find them. G.

Oh well, about the TYT schematics... that is kinda what we suspected anyways.... I just find the beater radio argument less and less convincing every day that goes by... much the same way some people carry a 1000 dollar cellphone Galaxy S20 or whatever it happens to be the latest toy at the phone store... people don't carry a 1998 bar phone b/c they are afraid/worried their super duper Galaxy S20 is going to break on concrete, or go down the ocean like the Titanic... well, I've carried an EVX-539 and now a 6550, and yes, it will suck if they break, but these radios are just meant to take abuse, can be submerged... and yes, if my XPR goes down in the ocean like the Titanic I am SOL, but so am I if my 1 grand Galaxy S20 (I don't own that phone btw, haha) goes down the ocean too... in the end, it is what it is. Comparing the Japanese radios from the 70s, 80s to the CCR turds is kinda irrelevant, but if we must pick on it, then its worth stating that Japan situation wasn't, and still isn't the same as China's situation. Also, these old Japanese made radios were actually surprisingly good radios, and whether the "perceived" opinion was they were a joke or not, they weren't bad radios. Those radios did gave the US-made stuff a good run for their money, whereas the CCRs simply do not. Also, by the time the CCRs catch up to the rest of the world, the prices won't be CCR prices anymore. When something is too cheap to be true its b/c there is a catch somewhere, someone is getting shafted somewhere along the way, either cheap labor, stolen designs, dangerous device... something. G.

What he said, for a 100 foot run its certainly worth considering LDF (aka. Anaconda coaxial)

Hey n4gix, sorry to hear. What repeater did you get? (and sold? Thanks! G.

What are you even talking about, CB? a Ham tech license? a 2m ICON?? With N? I guess you're going all in on CCRs now...So, what is that? a knockoff of the Japanese ICOM brand? Also, this is GMRS, UHF, 462/467 Mhz, pal, you don't need a ham license to operate on GMRS, maybe the IcoN CCR puts out so much dirty RF that you can hear it even on GMRS while rocking the 15w spurious emission Santa on 2m?? Whether you want to believe these radios suck, or not, it doesn't change the fact they are indeed, pieces of crap. I own more than 50 of those CCRs, from all sizes and shapes, from the $8 dollar BF-888S to the $400 dollar Anytone AT-578UV mobile... and almost everything in between. After measuring with a service monitor, I can state, unequivocally, that the majority of those CCR radios suck, and some suck so bad that even two cans and a string would yield better range... If you think you know better, by all means, waste your own money at your own peril. G.

Who cares, they are both mediocre radios at best. And for the money you sink in any of those two, you can easily buy a much better performing used LMR radio, from Motorola, Kenwood, Icom... and yes, there are part 95 LMR radios too.... but I wouldn't harp much on that "legality" as its been stated that it won't be a problem to run Part 90 gear on GMRS. G.

Been using this for years as well. I've posted a link to it on ever "what is my range" thread I've posted... Thanks for sharing, tho.... G.

Well, my recommendation goes to a 2nd hand (used, but not abused) Motorola XPR4550 mobile. These XPR4550 are very nice, and they can be found in decent condition for around 100-150 bucks on the bay, cable can be had for 20 bucks, and the legacy CPS can be purchased on eBay as well. These mobiles have a proper superhet receiver with a multiple tuned varactor front end, which will allow you reach more than 2 miles on a lot less power than 50W. To give you an idea, my XPR6550 portable, (which uses the same receiver as the 4550 mobile) can easily reach 1.5 miles on just 1 watt. Where? in the Madison WI area, which is super-hilly suburban terrain... All my 6550 radios are used (2nd hand), some have small scratches, etc, but the scratches didn't stop them from demolishing all the crap inexpensive radios I own... Some background: most of those GMRS cheap mobiles usually show a 10-20 dBm loss in effective sensitivity, a loss that cannot be made up by just cranking power to 50W. 20dBm means you'll need 100 times the power to make up for it... So, if a radio has 95 dBm effective sensitivity means that it won't be able to hear anything below the 95 dBm mark... vs. a radio which has 115 dBm effective sensitivity, which will be able to hear equally good a signal coming from a 1 watt radio as a 95 dBm effective sensitivity radio would hear a 100 watt signal. That is the importance of having a real receiver with tuned front end... etc. G.

Well, 75' to 100' is a large difference, remember that crimping heliax is not easy without the right tools... I know this b/c I botched it before... with the tool is a lot easier. Use a string to find out the exact length, then find the next cable in size. For a 100' run I think its probably better to ask here, pretty certain others can sell you a 100' FSJ4-50B with crimped N connectors on both ends, and even a sweep of such cable. G.

Yes, FSJ4-50B 25 feet. PNMNM . Its about the same thickness of LMR400 and its fairly flexible compared to the LDF4 heliax, which is basically like wrestling with an anaconda... Attached is a picture of LMR400, left most, FSJ4-50B heliax, center, and LDF4-50A heliax (mini anaconda) G. EDIT: What length do you need?

Why? B/c those radios don't suck. If you are looking for excuses to keep buying garbage then you are doing a great job, keep it up. Hearing you is just like hearing myself 6 years ago... wasting my money away... Radios Part 90 certified have tighter and stricter requirements than Part 95 toys. Yes, part 95 radios are usually overpriced toys.. its like buying an Airsoft replica vs buying the real gun... which one would you rather have if things go south? Pretty clear answer to me. Using the dubious legal argument to sell P.O.S. radios is just blatantly misleading customers into buying inferior products that won't perform as advertised when you might need them the most. I am using the XPR7550e as an example here, but there are other quality brand LMR radios made by Motorola/Kenwood/ICOM that are also part 95 approved... you just have to look around. I chose the XPR7550e b/c I love how it looks, it has the best audio I've ever heard on any radio and the best range I've ever tested on a portable simplex. To conclude: other people here aren't just exclusively licensed on GMRS, other people here are also hams, or even LMR operators who might hold an Itinerant Business Radio license... where encryption is legal too... G.

Mostly true, that last statements... b/c I do own cucumbers and zucchini... and its a verifiable fact, with data, which ones are better in terms of radio performance. This is more than just a cheap labor issue, there is rampant IP theft and plagiarism too, which is seemingly encouraged overseas... I feel the same way about the cheap labor situation too. At this point the only way to stop the onslaught is by enacting tariffs at the borders to allow US made products, crafted by workers paid 20+ dollars an hour, to compete with products made by overseas workers paid under 2 dollars a week. Then enact treaties which state that if you want to sell something in the US, you'll have to pay your overseas workforce a competitive rate comparable to US workers, or something like that. That is the only way we are going to get manufacturing jobs back, plus those kind of treaties also help the guys overseas not being abused. As for the T800, I am not exactly sure where its made, but it is very likely made in Malaysia, like my XPR7550e are. G.

Yes, absolutely. I did the same thing when I replaced my 25 foot LMR400 UHF-UHF feedline with FSJ4-50B N-Male N-Male, same length. The heliax I got was factory made. I got mine from eBay as a NIB New Old Stock, I paid 35 bucks for 25 foot with 2 preinstalled trimetal N-male connectors, which are like 29 bucks a pop. To give you quantitative figures: The antenna feedline connector at the base now reads a near perfect 50.03 Ohms impedance, and the return loss is -38dBm... as expected range now is measured in tens of miles, too, as opposed to the LMR400 which had an impedance of 43 Ohm and a -28 dBm return loss, while not bad, range was at best 10 miles. There are people here who can also make these cables. I just wanted a factory cable with the datasheet and sweep chart to ensure I wasn't getting a dud. The keyword on eBay to find a N to N heliax is "PNMNM" if you type that you'll get every cable on eBay that has N-male (NM) to N-male (NM) There are a ton of listings, just look for FSJ4-50B. G.

FSJ4-50B is the same diameter as LMR400... and it won't suck after it gets exposed for a few months. Been there done that.. I used to have spools of the USA made LMR400, all gone now. G.

n4gix, I ended up getting another XPR7550e... thanks for the offer. G.