gman1971

EDIT: I understand, it would be nice if someone here who owns this radio performed an actual ISO-tee test on the device connected to a 1/4 wave mobile, a 5/8 mobile, and a base antenna just to get actual effective sensitivity measurements. G.

Well, wouldn't this be considered an adapter too? an adapter to the recessed threaded connector inside the radio? I mean, the fact that there is a thread inside the radio means you could buy an RG400 cable that threads into the back of the radio and go straight to the cavity/duplexer/antenna... etc. Correct? G.

Good choice on the radios... Motorolas M1225... Good luck with your project! G.

EDIT: Well, I've measured a -15dBm average effective sensitivity loss in receiver sensitivity on those kinds of radios. I think its a figure significant enough to warrant concern about the quality of such equipment, compounded with the frequency stability also stated here. G.

and if it only was the frequency stability issue.... what are people expecting here? an APX8000 level of frequency stability with an APX8000 grade receiver? Lets face it: its just another piece of overpriced CCR garbage. There is plenty of high quality Moto/Icom/Vertex/Kenwood gear available on places like eBay that will be far better than that. But, its your money, waste it accordingly. G.

Meh... a CCR quality with a higher price tag... pass. Also, for that price you can find used XPR5550 radios on eBay. G.

I think its just better to have a cable go from the radio to the cavities, rather than another connector then cable, then cavities. G.

Just get a used Motorola/Kenwood/Icom/Vertex instead of anything made from Retevis, TYT, Baofeg... those are garbage, with 26.99 special one-wonder chips POS receivers. Range will be measured in tenths of a mile, rather in tens of miles. You can find higher quality used commercial grade LMR gear for dirt cheap on eBay, which will work better than any of that Cheap China Radio CCR garbage. ...but its your money, waste it accordingly. G.

NICEE!!! G.

Ugh, Baoturds detected near XPR repeaters... blasphemy.... Here is a glimpse of the the Motorolian Imperial Fleet under my command:

How is the R70 running? Is it all good to go now? G.

Yes, SLR is where its at.. these have the same amazing receiver as the XPR5550e mobiles... which is darn good.. but the XPR8x00 repeater is not bad either. G.

Yeah, +1 to the SLA stuff... avoid it. I have a bunch 6S and 4S 16Ah LiPos all wired on x4 separate 20S packs, all with Yimia BMS, those used to be my eBike/eTrikes batteries... They still well well with a 200W 12VDC regulator, and the radio barely puts any strain on packs that were used to deliver 7 kW on my eTrikes... G.

Lots of LiPos with a BMS, a 100W solar panel on the roof of the house and a 12VDC battery charger for LiPos. G.

Well, if you must... but if you need help picking a radio, just pm me... G.

Cheaper duplexers will have a bit more loss, but nothing that will make it or break it. The better the duplexer, the closer you can set your RX and TX frequencies apart without incurring in additional dB losses. G.

Well, I don't think anybody really knows what to look for at first, but you usually get decent at it after a couple of purchases, especially if you get burned early. Also, keep in mind that If price is too low sometimes is not indicative of a dead/bad radio either, as I've purchased a couple of VHF 6550 for 60 bucks, in mint condition... with charger... it depends on a lot of factors. One thing is for sure, most Motorola XPR radios will be in fairly decent condition electronically, even though the housing might be all beat up... also those radios are meant to be repaired too, and replacing housings, etc, on Moto radios is actually easy... and there are videos on YT that explain how to do it, etc. I don't know much about other brands besides Vertex and Moto... I have now an extensive collection of second hand Motorola XPR7550e radios now, a couple of them have a slightly scratched display, but that doesn't affect how the radios work... nothing cheap comes even close to the level of performance you get out of those radios. Using the gun analogy, you buy quality guns, not something that might fail, jam, or stop working when you might need it the most. Here is basically the same, if you want a good radio for GMRS and potentially ham, I think the XPR7550 is probably the radio to get. And if you have money, an APX multiband is probably a better choice, but you're talking more $$$. G.

Thank you! lol... yeah, of course nobody would buy an airsoft barrel... ahhaha... sorry if I wasn't more clear...

To elaborate: These CCR have no filters that prevent every other frequency from getting into the receiver, even when the CCRs are tuned to a frequency, all others still get through... so what happens is when the desired signal gets inside the receiver, it gets mixed with a dozen or so kW (kilowatts) level strong signals coming from commercial antennas, broadcast, etc, etc. So your little 5W signal is mixed with a bunch of those kilowatt monsters, and radio goes into clipping, or in layman terms: your radio receiver is overwhelmed, so it lowers the sensitivity in hopes to try to make something out of the signals, so it doesn't clip.... and you lose sensitivity. How much? A LOT. 10-20 dBm average. Now, when you add more gain to the antenna all you're doing is basically making the problem worse, b/c the CCR radio has no front end filtering, and you're "amplifying" all these kW (kilowatt) super strong signals even more... result is that you end up with an even more scrambled mess, thus receiver will desense even more, thus range will be even lower. This is the reason why I now recommend people buying an XPR6550 as their first GMRS radio. And please, save the legal Part 90 excuse to have an excuse to buy crap radios... there hasn't ever been a single part 90 problem or case in GMRS from the FCC. In regard to the "its only valid for close to RF towers" fallacy: Sorry, that is not true. Police might be putting out 100W 150W, that isn't much, but the six megasupeduper 200 kW ( YES, 200,000 watts) TV stations that are coming from that angry 1000 footer antenna located like 20 miles away from your house are also being picked up by the CCR receiver, and those kW signals have a stronger dBm presence than your 50W GMRS mobile placed 2 miles away. They get mixed in, and your 50W mobile is drowned by the angry antenna towers spewing CBS, FOX, MSBNC... whatever... So, to sum it up: Those radios are just inferior, plain and simple, I hope my explanation was clear. And since most people live in cities, or where some sort civilization exists, the fallacy falls apart really quick. I hear people having 2 mile range out of 50W mobiles... so you wonder, and then you find out what kind of mobiles... not Motorola XPR4550 or XPR5550e etc... you find out they are running some lousy overpriced CCR... they think they need more power... 20dBm of additional power to make up for the loss of sensitivity would be the equivalent of running a 5000 watt mobile... I think its pretty clear why receivers are the most important part of the radio. How do I know? Well, I've measured many CCR radios with ISOTEE time and time again, in many places, and in different situations, etc, and the average Effective Sensitivity loss is in the order of 10-20 dBm compared to an XPR6550, and 20-30 dBm compared to an XPR7550e... so, there is your answer: a 30 dBm is the difference between 50W reaching barely 2 miles, and 50W reaching 10+ miles. In the end its your money, and your time, so waste them accordingly. I wasted too much of mine, sadly, before I realized I wasted my money and most importantly, my time. G.

Cheaper hobbies? LOL, there ain't such a thing as cheap hobbies, otherwise it wouldn't be a hobby wouldn't it? Radios on eBay are plentiful b/c most are airsoft toys... would you buy an airsoft barrel b/c its cheaper? .... G.

Also, the higher gain you hook up to those Baofengs the less you'll actually hear... as they desense really bad... a -20 dBm Effective Sensitivity Loss is typical on those things with a 1/4 wave antenna. They might be hearing you, but you can't hear them... G.

Hi there Sean! G.

Nice... 18 miles is not bad for a home setup... terrain helps a lot... here in Madison WI reaching 18 miles is very difficult without some elevation... XPR repeaters are bargains in a box... the R70 is basically an 8400 with different firmware... Congrats. G.

With 40-60' AGL you can have some decent performance for a family repeater network. Also while height is very important, its not the only thing you'll need to have a decent usable range... high quality radios, preselectors, cavities, duplexer, coax, connectors, and most importantly a good antenna, will make a huuuuge difference in how well the repeater works, and that is applicable whether its placed at 40 feet or 200 feet. G.

I asked around back in the day b/c they had some nice features, but the Hytera audio isn't as good as the Motos, and receivers are merely a slight step up from the CCRs derelicts. As for Bluetooth, all my Motorola XPR/SL radios have Bluetooth too, and the e models have WiFi as well. Then there is the fact that Hytera was caught stealing tech, patents, employees and who knows what else from Motorola... after I found out about that it became a "dead before caught with a Hytera..." G.