Retevis RA-87 G.M.R.S. 40watt Repeater build and testing

[@JDubbsadventure]

After talking to Retevis we found out that the radio I had was a little low, they sent out another radio this one was putting out 37 watts. This is acceptable in my book.

[@SouthCarolinaSirens]

I have a VHF ham radio repeater made from two motorola radios. A CM300 and a CDM1250. Im planning on building a GMRS repeater for my area as well since there are none in my area of the state. I plan to use two Motorola CDM1250s you can find them for pretty cheap and they are easy as heck to make into a repeater. The software takes a little to learn but after that its really easy and they are great radios.

[@JDubbsadventure]

@@SouthCarolinaSirens I’m not a Motorola fan. Years of using there stuff have turned me away. The older radios were good. But I feel as they have went the same path of deWalt in Milwaukee. That said to each there own

[@SouthCarolinaSirens]

@@JDubbsadventure I feel ya and sometimes i feel that way. But the radios are great to me its just that the software can get really tedious and confusing alot. Even i still get confused and ive been using it for a few years. I tend to gravitate more towards used commercial gear since its cheap and tends to be a little more durrable. Works just as good as a new radio from my experience. I just get what i can get and use it and make it work.

[@JDubbsadventure]

@@SouthCarolinaSirens look into kenwood. If there is a problem with there old radios they will still try and help you and with give out wiring diagrams. Motorola will not help unless your the original purchaser and then you have to find one if there techs.

[@SouthCarolinaSirens]

@@JDubbsadventure i love kenwood as well. The reason why i went with motorola for my ham repeater is because at the time i didnt want to be soldering inside the radio to make them into a repeater like ive seen youd have to do with kenwoods. I was too scared i might bridge a trace or wreck something else and kill the radio. The RIB connector the motorolas have is was convinient to me at the time. I just realized as i was writing this i have two UHF kenwood 862Gs kicking around. I might see if i can make them into a gmrs repeater of some sort.

[@rohawaha]

I just ordered 3 BTECH GMRS-50V2 50W radios , two for a repeater station in my workshop behind the house and one for a 50 watt mobile unit in my work van, so I can always stay in touch with my family at home , because I usually travel 30-40 miles from home every day for work. I'm in Tarpon Springs Florida " the flat lands " and I work in Marine electric / electronics. your video will be helpful putting my repeater together. I plan to install 2 Lifepo4 batteries and 200 watts solar charging for a backup power source. I'm originally from Winchester Va.

[@JDubbsadventure]

I’ll check it out. New repeater site is bath county Va

[@rickdeweese8445]

Does Retevis offer a repeater package or did you buy the radios separately? Also, where did you source the cloning cable? Would really love a detail build video.

[@rickdeweese8445]

Ah, think I found the cable. Is it the 1-pin to 1-pin data cable?

[@JDubbsadventure]

Working on the video now for this I used an old audio cable that I had for all my microphone equipment

[@creepin9928]

I know I'm a few months behind your comment here but currently Retevis has a "repeater core" package that cones with both radios, the 1 pin to 1 pin, and 2 programming cables on sale for $340 and the have a package with all that plus a power supply and an enclosure for around $550.

[@ryanfralic1115]

Will you be doing a part list or video showing your software and everything youve used for this build in more detail? This is pretty much what id like to get set up for my area.

[@JDubbsadventure]

Yea I’m working on it now

[@ryanfralic1115]

@@JDubbsadventure awesome. love the build

[@andrewlehman618]

Love it! I’d welcome the parts list too…

[@Undertaking-Life]

Just a note, I used LMR400 for my patch cables and after watching your video again I noticed you specified that you were using LMR240 cable. I wanted a softer cable from the LMR 400 so I got the RG8X cable and lost 10 watts before the Duplexer. I thought that was crazy!!!

[@JDubbsadventure]

I’d check your swr. I had rg8x before i switched to the lmr240 and gained a little wattage (2-5) but nothing that significant. There’s a seller on eBay that makes good lmr240 cables with hight quality ends

[@Undertaking-Life]

@@JDubbsadventure I would be interested. Do you have a URL?

[@joeschnell5695]

If you put up a tram 1486 (or 1468? Can’t remember which number) gmrs base antenna, which has a gain of about 6.5db, that should increase your range.

[@JDubbsadventure]

I did which to the 1486 from the midland mobile 6db antenna. My range is limited by the mountains not really power

[@jiminsav]

get rid of the duplexer, use 2 antennas spaced 30 feet apart, and you'll get some watts back. the duplexer uses about half of the rf power.

[@JDubbsadventure]

I’m only loosing about 30% 26-18. I can live with that better than putting up another antenna. But I agree if you want every little bit of watts then that’s a good choice

[@WW5RM]

Vertical separation?

[@JDubbsadventure]

I like horizontal separation. That way both antennas have the best chance of rx and tx

[@WW5RM]

@@JDubbsadventure not sure about 462 or even 440 mhz but on 2 meters you put the TX on bottom. At 50 watts that usually pretty equal. But it's got to be at least 25ft of vertical separation. Only works due to the null at the top and bottom of the antennas. Horizontally it wouldn't. The TX would make the RX deaf! But it's 600 kHz split. At 5 mhz split that's a whole different ball game I guess. Still seems like it would desensitize the RX if it were horizontal. But I've never got the opportunity to work on UHF repeaters. Only VHF.

[@JDubbsadventure]

@Outdoors1776 good information. This set up hasn’t shown any desence problems. Me and a few other people are constantly testing it and can’t make it do it yet.

[@DrewB439]

Awesome video! Question: is it possible to keep the radio on low power, run it through a btech amp, into the duplexer or not recommend because the RA87 has a built in power regulator? What would be your best option before I mess up another repeater system 😂

[@JDubbsadventure]

I guess you could. That would keep your radio form heating up but your amp will take the load and I’m not sure it will take a lot of traffic

[@DrewB439]

@@JDubbsadventure I'm afraid to try it, and the reason being is I messed up my RT97 running it through the B-Tech amp. I had the RT97 on low power and everything hooked up correctly. Eventually it just stopped working.

[@JDubbsadventure]

@DrewB439 really? That’s the first time I. Heard that happening

[@DrewB439]

@JDubbsadventure Yes, I troubleshooted everything. Then I took the little 10 watt duplexer and ran 30 watts through it. Worked fine for a week then.. now I have a nice table weight lol.

[@JDubbsadventure]

@ oh you can’t put 30w in a 10w duplexer and have it last long term. That was probably the issue or it was high swr

[@mcc1146]

Regarding the "R" for reverse mode on my RA87 receiver unit, have you ever noticed that if your receiver unit has a brief power loss, the reverse mode "R" can become absent when power is again returned? I saw this sometimes occurring on my RX unit during setup and wanted to ask you if you noted this before your backup power effort. Thanks for the awesome videos!

[@JDubbsadventure]

I had someone else ask me this and yes the first time I think it did loose the R but now it doesn’t no matter how long I have it off not sure what changed

[@mcc1146]

@@JDubbsadventure Thanks for your reply! Today I discovered that the Retevis software has both Reverse and Relay options to activate --whereas Chirp Next ( even today's updated ver.20240618 still) lacks the Reverse option choice. The Retevis options were enough to fix the disappearing "R" issue and the Reverse mode remains after a loss of power/ a storm power flicker simulation --times many simulations. I will contact Chirp and request for consideration that this Reverse choice field be made available in future Chirp Next revisions for the RA87. Thanks again.😃

[@JDubbsadventure]

@@mcc1146 just talked with a guy that was having this problem after some time we found out he had one unit on 18rp and one on 20rp. Once we got both units on the same channel the R stays regardless of how long the power has been off. Hope this helps

[@rockytop441]

I believe you said 26 watts before duplexer so your output to the antenna is about 14 or 15?

[@JDubbsadventure]

No if i said that, then i miss spoke. 26 watts after the duplexer

[@GhostSenshi]

I think the 50watt btech's are probably your best bet to have a 40watt repeater build. They transmit well above 40watts, closer to the advertised 50, and with a duplex you're probably gonna be right at 40watts. Since they're $219, I'd say it's the better deal for ya to have the 40watt repeater build you're aiming for.

[@JDubbsadventure]

There a good radio but there not easy to make into a repeater. This was a video showing anyone can build a repeater that works well without being able to build circuits and their own board. Thanks for watching

[@rohawaha]

I just bought three of the btechs from China direct for $150.00 each , saved about $210.00 . Two for a repeater and one for a mobile unit.

[@zelchcomoon1422]

i have a question about this setup. at work there are 2 maintenance departments. if use this setup will it be able to separate them on to different channels? i heard some can perform this.

[@JDubbsadventure]

No one repeater per frequency an I don’t think you can use gmrs for business Without everyone having a license

[@Undertaking-Life]

I'm building a Retevis Repeater just as you have in this video. I thought about using a Marine Battery Box as a Repeater Enclosure. It has some ventilation in the top lid and it would be easy to mount cooling fans for additional heat dissipation. What do you think about this idea?

[@JDubbsadventure]

I’m doing a video now that you might find interesting. I think you’re going to want something with more air flow depending on how hard it’s used.

[@jimjones2935]

Thanks for the video. The output on the meter may be due to the connectors that was used. Try using a male to male connector from the radio to the meter's RF in jack and then connect dummy load directly to meter's antenna jack. The less connections and less configuring of connectors to make a fit is best. Be sure the connectors are snugged but not over tighten. Be sure your power supply has enough current to supply the 40 watts. Maybe also try using a better meter such as one made my Bird or better a HP Meter. By the way I thought you were getting a decent signal at that distance with the lost of wattage using that particular Duplexer. And I did like your video, well Done...

[@JDubbsadventure]

You know I have a bird meter and everyone got mad I used it so I went with the cheap ones and believe it or not there right on with one another. So in my sample size I don’t see where the $800 meter is any better than a $30-60 meter. An the “cheap one” (relative term) is better because it’s more durable.

[@WSFF758]

Can you hit your repeater from the top of Back Creek mountain? Looks like its close to 10 miles.

[@JDubbsadventure]

Right now no, but the ingalls 650 yes you should be able to hit it we are still putting it up so the repeater is down at the moment

[@JamesLaVaccaTX]

Thanks JDubb you seriously helped in getting my system online - got the repeater setup but cannot locate the hangtime for the kerchunk - I thought it was the Squelch Hang Time in the Optional features section but even at 500ms I don't see a difference. Where is that set at?

[@JDubbsadventure]

To remove the squelch tail cut the tail off and make sure the tend I believe it’s 60 off that’s the Roger beep

[@JamesLaVaccaTX]

@@JDubbsadventure I actually want to turn the tail on - its nonexistent right now.

[@JDubbsadventure]

To have a squelch tail cut 62 tail on 60 tend on (Roger beep) 9 is your hang time

[@improvbros23]

I ended up buying the whole rar87 repeater kit from retevis because I wanted a little more power than the ra97. I think I have it working for the most part, however, I’m not sure I have my tones set right. I’m using dts and using the same dts tone for both transmit and receive, I’m just curious if you know if I need to A) have those tones set in both the radios B) just have them both on one, either the tx or rx radio. C) have one radio with r-cd and the other with the t-cd set to the DCS tone. Currently I have both radios set with the same C-cd which sets both radios to have all the same c-cd, r-cd, and t-cd. I seem to be getting good transmission while I’m near the repeater, however as I gained distance I seemed to be loosing the transmissions (very minimal distance) . I did not have that little r function set that you went over but I’ll see tomorrow if having that turned on helps the functionality. Any insight in setting the tones would be much appreciated.

[@JDubbsadventure]

A I set both radios to the same tone B the little R means your reverse transmitting so your receiver has to have the R also make sure your receiver is plugged into the high side of the duplexer and use the frequency your duplexer is tuned to

[@improvbros23]

@@JDubbsadventure thanks for the reply, I’m wondering if not have the reverse transmit on was what was causing my issues, I’ll test it tonight and see how it works!

[@kenanderson7321]

Great work. Can you please give us the info on the computer and program you are using for the station ID and weather? Do you have a video on it?

[@JDubbsadventure]

The computer is the cheapest one Walmart sells I think it was $118 and the links to the computer programs are in the vidoe description. There also I other videos I have showing them better but I can do a video showing how to use them

[@jeffworkman1982]

What software and device did you use to interface? Also how does it connect

[@JDubbsadventure]

This might answer your questions This may be the BEST Zello interface | GMRS / Ham radio kzbin.info/www/bejne/g3y5ZH6aj56VjZI

[@Undertaking-Life]

OK, I built the same Repeater that you have in this video.I'm still al little confused about setting the CS tones. If you set both "CTCSS or DCS" tones or what? Both radios are set just like you instructed in your video. I am getting 40+ Watts on the antenna port at the duplexer with a SWR of 1.06. Best I can tell that is super!

[@JDubbsadventure]

I set both radios to the same ctcss tone for example. The receive radio has ctcss tone 67.0 and the transmit radio has ctcss tone 67.0 set. You can use either ctcss or dcs but not normally both. Your getting 40w after the duplexer that’s really good the duplexer normally takes away 30-50% of the watts

[@Undertaking-Life]

@@JDubbsadventure I set the radios to Simplex mode before entering the repeater settings. One radio output was 48W and the other was 45W. I used the higher watt radio as the transmitting radio.

[@Undertaking-Life]

@@JDubbsadventure Another thing I don't understand is the duplexer tuning. I selected a duplexer set to 462.6750 / 467.6750 - Channel 20. In your video, you selected channel 19 in the setup so I assume your duplexer was tuned to 462.650 / 467.650 - Channel 19. How does the Retevis Repeater build know to use the 5K offset on the transmitting radio?

[@Undertaking-Life]

@@JDubbsadventure When I complete my build I am going to make a youtube video showing my build. Would it be OK to credit you and your youtube channel in my description?

[@JDubbsadventure]

The offset is preprogrammed into the radio. Make sure you have that small R on the receive radio so it will reverse transmit

[@dempseydoodles]

You should be able to install a peltier cooler on your setup here and get well below that 80°-90°

[@JDubbsadventure]

I’ll have to look into it, thanks for watching

[@dwaynehall686]

Great video 👍

[@JDubbsadventure]

Glad you enjoyed it

[@Undertaking-Life]

I watched your video fully and read every comment but I didn't see anything about the Duplexer that you used. Did I miss it or can you tell us what you used?

[@JDubbsadventure]

You don’t need the duplexer to make it work, that said you will need to antennas, separated, far apart. The duplexer I have is a “cheep” one from buytwowayradio.com you can get them from eBay and Amazon but you will have to tune them and that takes special equipment

[@randallbright]

Thanks for the video. Can you tell us more about the automatic on fan system?

[@JDubbsadventure]

What would you like to know?

[@dysfunksion]

@@JDubbsadventure I would like to know the size, cfm and voltage?

[@JDubbsadventure]

@dysfunksion 12v cfm depends on the fan you choose and the one I’m using is 80x20

[@uncledanny7]

What’s your thoughts on this repeater setup versus say the RT97 repeater

[@JDubbsadventure]

I have both it Depends. This one has more watts. So it does a lot better with leaves trees buildings hills ect. But the rt97 I have on solar power on top of our mountain and and can hear it and use it from 47 mile away.but I can’t hear it inside the house unless I’m near a window, One is built the other you have to build.

[@uncledanny7]

@@JDubbsadventure I’m looking at either buying or building one just not sure which direction I am going to go yet. Have you looked at the Btech repeater any.

[@JDubbsadventure]

@uncledanny7 I haven’t seen it but my friend has. It’s 2 mobile radios hooked together. Just like kenwood and Motorola does it

[@ricdonato4328]

Very interesting, nice setup. Suggestion, mount the camera. Your camera movement almost made me nauseous, had to look away and listen only. With a bouncy camera where does one focus their attention?

[@JDubbsadventure]

10-4

[@ClementhHannah]

So I have question what is the downfall to turning your rx radio down on low and leaving your tx in high school

[@JDubbsadventure]

@@ClementhHannah I think you’re talking about reversing your low and high side? It’s not gonna hurt your radio short term. The only reason to do it is you believe there labeled wrong

[@ClementhHannah]

@@JDubbsadventure I put my rx on low power and left my tx on high power

[@JDubbsadventure]

@@ClementhHannah put them both on high or low both should be the same other than one having the little R

[@n3qdz]

That’s awesome great build. I’m working on my build using QYT mobiles

[@JDubbsadventure]

Should be a good build. Do a video on it!

[@Jason-gc7vv]

Hey Dubb’s were you able to find the mic Pin out for these radios?

[@JDubbsadventure]

I did but when the radio is in repeater mode then the mic (rj45) plug is disabled sadly.

[@Jason-gc7vv]

Strange.. mine still operates like normal. But also my 87’s only have 2 power settings high and low. I notified Retevis and they said “ that is what it is now” Not much help. Where did you find the pinouts?

[@JDubbsadventure]

@Jason-gc7vv when mine is in repeater mode it will key up and immediately shut off. I emailed them and they sent it to me

[@Jason-gc7vv]

@@JDubbsadventure Thanks man I will check it out!!

[@brettmorefield3455]

Do you prefer this repeater set up better than the RT97s or Midland? Thanks

[@JDubbsadventure]

So far yes and no I think the midland is alittle more sensitive but the ra87 is a lot better for my area since my antenna isn’t extremely high and the leaves hurt me in the summer. Both are extremely good and useable. The ra87 will need fans and a box made. where the midland is plug and play

[@brettmorefield3455]

@@JDubbsadventure Awsome thanks for the reply and info. Trying to make up my mind between the two.

[@JDubbsadventure]

@@brettmorefield3455 really just depends on your area.

[@oldbodpromod]

Question...doesn't the "R" stand for "reverse" and not "receive"? So technically, that would be your transmitting radio, right? I have these radios also and the instruction manual is one of the worst I've ever seen. Holy cow, it's bad. I'm having some trouble with mine staying on high power. Intermittently, I notice that I lose coverage and go check the radio, and it's on low power. Switch it back to high, but it does it again later. It's a very low use repeater, too, so I don't think it's getting hot. Initially when we installed it (with a duplexer, 50 ft LMR400 and a Tram 1486) I was able to talk on it 33 miles away. But since that day, we never been able to do it again. I'm baffled.

[@JDubbsadventure]

I don’t have the manual with me but on mine the R is on the receiver. Make sure your on channel RP___ make sure both radios are set to high power if one is on low and the other is high then it will switch back and forth. Make sure your duplexer turned to your frequency and that your low side is your tx and the high is your rx. Also if your wondering witch radio is transmitting you can put your swr meter on the back of your radio with a dummy load the rx radio will not show anything and the tx will give you a reading of something

[@mrcummins3]

I just got mine and got it all set up it works as a repeater but as I got everything dialed in with my ctts tones now the mic will key up on the unit but only for a couple seconds then it just turns off. Any tips?

[@JDubbsadventure]

@@mrcummins3 the mic doesn’t work when in repeater mode it will key up for half a second then cut off.

[@mrcummins3]

@JDubbsadventure Oh ok. So have to go out of repeater mode to talk on it?

[@JDubbsadventure]

@@mrcummins3 yes it’s not a repeater and base all in one it’s a base or a repeater

[@mrcummins3]

Thanks!

[@mrcummins3]

Sorry to bug you but it seems you are pretty into this set up. I'm new to all this and Upon playing with mine more, I can only get a half mile or mile from my house before I loose voice feedback. I can talk with my handhelds miles longer than this. Thoughts on where to start?

[@christophersmith1155]

I WOULD LOVE TO KNOW MORE ABOUT THE DUPLEXER AND ANTENNAS ? DO WE NEED 1 OR 2 ? AND WHAT SPECS ?

[@JDubbsadventure]

Duplexer is only needed if your gonna run one Antenna if your gonna use two then the duplexer isn’t needed and I’m using a tram 1486

[@christophersmith1155]

HOW FAR DO I NEED TO KEEP THEM APART ?

[@BMG-]

What duplexer are you running? I like the setup

[@JDubbsadventure]

The further apart the better for the antennas. And the duplexer is www.buytwowayradios.com/xlt-dp-gmrs-50.html

[@PANICFPV]

I have these two radios setup exactly like you with a duplexer but when I key from a little bit of a distance it gets stuck transmitting and sounds like it's in a tunnel. Any ideas?

[@JDubbsadventure]

Make sure your duplexer if hooked up right and all your settings are correct. I haven’t heard of this issue

[@PANICFPV]

@@JDubbsadventure Thanks for the quick response! I have checked all that so many times and upgraded all my coax to lmr400. It's stumping me so hard. I'm not new to this hobby so I don't get it either. About to replace the power supply. I have replace everything else.

[@JDubbsadventure]

@@PANICFPV I’d try a 12v battery that will let you know if your getting noise from the power supply

[@esava2874]

Do you happen to have a list of everything needed? What antenna are you using?

[@JDubbsadventure]

I’m doing a video on that. But real quick 2 radios 1 15-30amp power supply 1 duplexer 25-100 foot of good quality coax Tram 1486 antenna 2 Lmr240 or lmr400 patch cables An swr meter The cool guys cooling fans kit (Amazon) Miscellaneous hardware

[@jackpeoples1105]

Just received the Retevis's repeater package and just like your units getting much less than advertised/promised. At best getting about 31 watts at high power setting, and once through the duplexer getting about 24 watts. Many thanks video and information.

[@JDubbsadventure]

I’m working with them now on this problem. On the bright side you have 6 more watts than me. My unit is working great make sure to put cooling fans on them

[@KO4RXE-WRMR358]

​@@JDubbsadventureis it possible to elongate the squelch tail?

[@JDubbsadventure]

@KO4RXE-WRMR358 not that I’m aware of it’s either on or off

[@KO4RXE-WRMR358]

@@JDubbsadventure Roger that Brother always a Great Video keep it up 👍 I have a similar set with Kenwoods, Vertex Standards lol a couple UHF Commercial radios...very versatile setup also connected to zello...works great with the surecom repeater box and a 50watt XLT Duplexer ! Keep encouraging the Hobby Brother!

[@zoofster7392]

Can you please tell me what app you use on your phone Great channel thank you

[@JDubbsadventure]

Zello and AnyDesk

[@offgridbydesign3826]

Great project! what software are you using on your phone?

[@JDubbsadventure]

Thank you and it’s AnyDesk works awesome

[@daveengstrom9250]

Place our radios side by side instead of on top of each other to keep them cooler. Leave them at a least a foot apart.

[@JDubbsadventure]

To answer your first question the radio had an issue that was covered in the pinned comment. I have a video showing how we set up the repeater. The receiver doesn’t get warm so having them close together isn’t a problem

[@without_bounds]

looking good. ill have too think about a low pwr here in the rv.

[@JDubbsadventure]

It’s a nice unit

[@ecooled93]

Can you give us a list of things you bought?

[@JDubbsadventure]

There in our Amazon store

[@dylanspademedia4581]

What software is reading off the weather?

[@JDubbsadventure]

Check the videos description all the links are there

[@dylanspademedia4581]

@@JDubbsadventure some of the link don’t work.

[@JDubbsadventure]

@@dylanspademedia4581 there download links. You have to be on a computer to start the download

[@TheRealLifeoutdoors]

What duplexer do you have and did you tune it, or was it pretuned

[@JDubbsadventure]

It’s retuned from buy two way radios, it’s the 50w gmrs duplexer

[@Jason-gc7vv]

Nice video! Curious I see your repeater’s receive freq is 462.650 and transmit 467.650. Shouldn’t this be reversed? My assumption was for the Duplexer high would be 467.650 (repeater receive) Duplexer low would be 462.650 (repeater transmit)?

[@JDubbsadventure]

You know you’re the only one who noticed that. I saw that when editing the video if you look at the newer videos you will see I fixed it, but good eye

[@Jason-gc7vv]

Hey Dubb’s have a question for you, need your expertise. I’m working with 2 HT’s for local repeater with amp and duplexer for about 20w. Output from repeater great but have issues with getting into repeater knowingly because of using HT’s. Would you recommend these RA-87’s… or something like your midland MXR-10? Your distance tests seem great with both set ups. Any info would be great thanks man!!

[@JDubbsadventure]

@@Jason-gc7vv I think your saying yours using two ht as a repeater? Depending on what your looking for the MXR10 is great no fuss works right out of the box and my friend makes a plug and play interface board. Both the MXR10 and the ra87 have a squelch tail so that will let you know that you’re hitting the repeater.

[@Jason-gc7vv]

Hey Dubb’s. I went with ra-87 but cannot get squelch tail after hitting. It’s there but short. Any idea how to adjust? Thanks man!

[@JDubbsadventure]

I’m out of town but I believe you can change the time in the S something in the menu and you can cut the tail on it’s the last setting

[@quandoomniflunkusmoritati9359]

Couple of suggestions from someone who learned a lot the hard way. LMR or any of the similar type "dual shielded" coax is really not a great idea for repeaters due to something called Passive Intermodulation or PIM. LMR is great simplex cable, however you can get a lot of "angry pixies" in the line on repeaters with duplexers (single antenna RX/TX setups). This shows up as RX desense, a static or distortion on the incoming signal etc. I built a repeater happily using what I thought was a good idea, real LMR-600. Turns out there is a reason most "real" repeaters are built with Heliax or other air core hardline. When you have tinned braided shield resting on another metal (in this case aluminum foil) you can created millions of small contact points that (due to bi-metalic properties) act as diodes. This creates RF intermod that inherits the coax. It is to weak a signal to radiate out your antenna but it comes back down the coax as a distorted common mode current signal and your RX has to deal with it. This is not always the case, some installation with LMR style cable get away with it, often with really high end commercial grade filters/duplexers/radios. However for the home DIY'er this can make you crazy if you experience it. I ripped all the LMR dual shield out of my system trying to track down desense. The short runs were replaced with R400 or 402. The long run was with cable found on ebay that was "commercial install remnants" of Heliax (Trilogy 1/2" Coax Cable from Antenna World on ebay). All the desense went away, so this was the magic bullet for me. I wanted to share this as this info was really hard to find until you go to HAM repeater builder sources. It never occurred to me that when you transmit into the LMR coax that power "could" be converted to noise by the very low loss properties of the cable and cause repeater problems. If you use separate antennas this is not an issue. Also, LMR is GREAT coax, just for simplex. Do yourself a favor and research RF PIM! Cheers!

[@JDubbsadventure]

That’s true, and Iv looked into it and if there ever is a problem than I may order hard line as of today no issues

[@alexpode]

I'm new to gmrs, I want to setup a repeater at my house as i'm trying to reach my office that is 25 miles away, if that is not possible i want family to be able to use it on a 5 miles radius. I saw retevis sells the same equipment in a box, but being new, i'm not sure what cable to get, what connectors it would take, i did see you are using a tram antenna in the comments. I want to get all the possible power so I don't think i would be using a duplexer, do you have any tips?

[@JDubbsadventure]

Distance is determined more by terrain then wattage, watts help you for example penetrate walls, trees, etc. I’d buy the radios as cheap as I can I know fight before Christmas I saw them at $98.99 for 5 days. The cable is a simple audio jumper cable that amazon sells for $3-10 I got a 3 inch one since everything was close. My cable came with a rode microphone I had extra. Check out my zello channel and you can hear the repeater and play with it. I have a short video on the pole I’m using it’s cheaper than anything that’s radio specific

[@carlleon1604]

Two comments. First, I think you will get just as good range results using mid or low power rather than high power (and reduce your own desense). Antenna makes all the difference in the world (quality, and height). Second, if your intent is to have a permanent, long term repeater, get a real duplexer (you'll barely be able to measure power drop through it, unlike the mobile duplexer). That will also let you run higher power (if you really need to) with less or no desense.

[@JDubbsadventure]

I have several videos showing there is no noticeable desense. furthermore, If you can only measure the desence with really expensive gear and you only a notice it with expensive testing gear is really an issue? No because In the real world we just want to talk from radio to radio. The fact you use the term “real duplexer” is a bit pretentious. An as you stated I could get the same range with less watts so why then do I need a better duplexer to increase my watts? Watts equal penetration (trees buildings ect) not necessarily distance. I have a video showing a .5 watt radio talking to another radio at 90 ish miles. Radio gear has come a long way in the past 30-40 years even the “cheap” ones work just as well if not better than my Motorolas and Kenwood radios. I believe the larger brands have sold off of their name for too long and there quality has gone down exponentially over the years. Thanks for the input and info

[@markkelley2183]

Very nice WRVB405

[@JDubbsadventure]

I hollered back at ya Today, it was crystal clear I forgot the Repeater was only on 3 watts while I was testing something out the other day it’s back on full power if you come through

[@Ibelieve218]

HOW DO I GET THE RADIOS TO THE INTERNET FOR ID??

[@JDubbsadventure]

Just finished that last night video coming soon

[@without_bounds]

hows that rf radiation?

[@JDubbsadventure]

Swr 1.05

[@АлексейЛесуков-ч3ь]

If your SWR is high it won't put out the full power output.

[@JDubbsadventure]

True, you test power on a dummy load

[@markallan4849]

This radio needs to draw around 10 to 12 AMPS to put out its 40 watts of power. Proof, watch the Radio 2.0 video on this exact radio with the right power supply and a better power meter, you will see it put out 43 to 46 watts. Also, my KG-1000 draws 11 AMPS when on high putting out 50 watts. When checking radio power you need a good power supply of at least 20 amps or more. Not good to use a low Amp power supply and say the radio is an underachiever. 👎

[@JDubbsadventure]

Ok let’s unpack. 1. My FT-991 only uses 15-16 amps at 100 watts so a 50 watt should be around 7-10 amps just based off the math. Also my icom 7000 is 75watt uses 9 amps 2. 2.0 is a larger channel so a lot of what is sent to him is cherry picked. That’s just how KZbin works and dealing with companys. There’s a lot of reports of the radio tx watts being 25-65 watts so there all over the place right now. 3. If you use for example 10amp power supply then it would trip/ blow a fuse if the radio pulls to many amps 4. A higher amp power supply will not put more “power” into the radio so your comment of “the right power supply….” Is moot. Iv tried this setup with 3 30 amp (like the video showed) and 1 50 amp. With no change. They pulled the same amperage on the 30 and the 50 amp supplys 5. I use 3 meters to check swr and power levels as long as they all match then that’s close enough for this small test I’ll use my fluke 196c next time. 6. I love these radios and recommend them all the time but I will show you the truth on them. there not perfect but there good enough for this job. So no one is calling it an “underachiever” 7. This was the first video on this radio as a repeater so this is one of the first samples so maybe they have gotten better.

[@w3prl]

Ur video is all over the place. You need a script steady video. Bet no one can build this repeater after watching the video.

[@JDubbsadventure]

Haha yet several have been built. Thanks for watching

[@АлексейЛесуков-ч3ь]

Why does it put out 26 watts before the duplexer? isn't that radio suppose to be a 40 watt radio? 🤔

[@JDubbsadventure]

@@АлексейЛесуков-ч3ь did you even look at the pined comment?