building a repeater out of two Kenwood TK-880

[Steve]

Hello everyone!

 

i'm looking to integrate a Kenwood TK-880-1 ver2 with a repeater controller.... I'm about to pull the trigger on a pair or 880s and just wanted to do a bit more research before i do.   On some other models like TK-805D, there is a way to open it up and solder some connections for the rx tx, ptt, tone, gnd, etc. (see link below)  I can't seem to find anything on interfacing those.... wondering if the front RJ-11 would allow a custom cable?  I'm going to most likely order a NHRC-3.1 controller so I'll have to make a custom cable anyway.  

 

Parts include:

 

Kenwood TK-880-1 ver2 40 watt (or Kenwood TK-840-1 25watt) - both inside the GMRS band.

 

NHRC-3.1 repeater controller

NHRC-Squelch controller

 

to be figured out later:

antenna tuned for GMRS

duplexer tuned for my channel

cables

 

I could also go with TK-840 - because i can also get a good deal on a pair of those. 

 

or maybe an older TK-805D because i found detailed plans on how to build the interface cable here:

http://www.repeater-builder.com/kenwood/pdfs/tk-805-wiring.pdf

 

I was looking to stay away from the 805 and 840 because the volume and ch knobs wear out, and become noisy.  The 880 has a digital volume control and more features, so i think it would last longer, and i'd get more life out of it.  plus, its a bit higher powered, not that i need that high of power anytime soon.

 

any experience connecting the 880's or 840s to a controller?  I'm leaning more towards the 880s, for a few $ more, the version 2 gives me 40 watts.  but i'm not sure i need all that power, so i hope there is a lower 10 watt option for normal use.  the 880 is hard to find details on, but i'll keep looking!

 

Steve

 

yes, i'm GMRS licensed.

[Steve]

okay, cables and other misc parts still on their way, getting ready to make the inner connectors but still need to decide on a controller.   while i'm debating over that, (price vs features) i'm looking at getting the order in soon for a duplexer.   I found a nice one one ebay for a fair price but the more i think about it, the more i think i want to focus more on portability and not on super high performance.  i think that's two different projects.  I mean, if i make something super high end and expensive, i wont want to move it, and i'll keep it at home and maybe extend the range by a mile or less (lots of hills around me, and my antenna is down in the valley)  i think if i knew i had a great location or home for the system, such as a hill top or tower, i would def put more into tweaking it and squeezing out the best performance.  

 

 

thoughts on duplexer:

 

so that leads me to the ~$100 small duplexers.  i'm wondering about making a commitment to a channel... has anyone tuned it to ch 5 (in the middle) and then had the ability to change to a different channel without losing any performance?  there is some room but i'm not sure how much.     Another question is should i get the longer sized one like 8 or 9 inches long, or go for the really small one (easier to put in a box later) since i'm not looking for the best performance for this build.  

 

 

thoughts on controller:

 

Then I figured a cheap controller or no controller would save a little money, BUT i find value in having a full featured controller because i want to play with and learn the system.  Even if i'm only covering 1 to 2 miles, (1.7 miles is the farthest i could test and that was hiking up a mountain to reach home antenna in the valley) I think the features of a better controller will benefit me. For example, just putting it in simplex repeater mode would help me do some range testing around the neighborhood without someone at the other end.  another example, if i want to move this repeater somewhere, i like the ability to shut it down remotely if I’m not there.

 

one controler i'm looking at is:

http://hamtronix.com...p?id_product=60

 

i really like this squelch controller would be helpful... during some of my testing, the squelch does cut out a lot during the reception of the HTs and it would be easier to understand if it would just hold open for a bit longer when the signal is weak.

http://hamtronix.com...p?id_product=82

 

another one i'm looking at is:

http://www.nhrc.net/nhrc-3.1/

 

and the:

http://www.arcomcont...210/rc210-board

 

 

 

other thoughts:

 

do i need a pre amp?  if i get a preamp only and put it between the duplexer and receiver radio, would that help?  Should i pay 3 times the price for one that will switch off during transmit and put one between the duplexer and antenna and allow transmission through it?  I know that if my feed line is long, you'd want the pre amp as close to the antenna as possible.   I'm currently using 65 ft of RG8x cable from roof to shack.    my thought is if i can help pick up the 4w HT better, i can then reach the HT with no problem because I’m blasting out at 10w or 25w.

 

as i connect everything , i want to make sure i pay attention to the audio levels of everything.  on one of the controllers, the Elektra 2000, it has the ability to eq the audio a bit to make it sound more full (using a small cap across c10 or c11).    I'm also going to pay attention to emphasis on the ins and outs to make sure that i can get as close to "full volume" on the other end as i can without too much distortion.    I did notice that my uv5-r radio sounds louder than the 888s radios, all things equal... i have to talk loud into the 888s to get the volume to match on the receiver.   So i'd like to try and get the best signal to noise ratio on these... does anyone use an audio compressor or any kind of volume management on these?

 

finally, shielding...i need to make sure that the controller card is inside a metal box, or at least wrapped with some tin foil.  everywhere i read says this is necessary. (except less of an issue on the NHRC 3.1 style because it "doesn't use a bus" and is less prone to electrical noise".

 

as for the antenna, i'm going to use what i have for now, and then after the repeater is running i can swap it out for a better one.  i think i need to put the money into a duplexer and controller to get this thing going first.

[Steve]

yeah, the location is key! i'm stuck in the vally, so if it works in the vally and the hill ridges around me then that's good enough for what i need now.

 

 

 

Would have good coverage range of about 50 miles or more if i had it on a hill top {:>) and I would quit trying to get

this thing on a tower at my house.

[gortex2]

Spend the money on the mobile duplexer and you should be fine. I have mine tuned to the middle frequency and can go up and down without much degradation. There is some but 99% of the time i am in the middle. The only time i had to go to the bottom of the list was at a NASCAR race and i was only using low power anyway. 

[zap]

We have a NHRC 3 on a local amateur repeater. It's okay…

 

I've got one of those Electra's sitting at my house right now. In the past, we've used the kill feature in MDC to kill transmit radios on basic repeaters.

 

All of those controllers are link capable. Personally, ID rather have stuff that is PC programmable versus DTMF.

[Steve]

ordered:

 

mobile duplexer w tuning from china

cables and connectors to build the control wires

inner connects from the dupler, radios and antenna. 

metal project box to fit conroler and wires. 

I'll have one gang of wires coming out which will connect to the radios, and power with exta ones for fan out if i want to add that later.

 

power connectors are all anderson pole connectors.  everyhign will be quick release and fused where needed.

 

for the controler: I decied on the Elektra 2000 / VZ with voice - i'll order that once the funds fill up again....  got to sell off a few more things on ebay...

 

i'm going to hold off on the pre amp and intelligen squelch, too much for now....

 

once i get it all in, i'll start putting the cables together and testing everything.  i have all the tools for that, heat shrink, using old serial cables and 9 pin connector to connect everything.  Also i have the TK whatever cables for the back of the kenwood radios, and i'm building everything else custom to fit right into that... so everything will litterally just plug together.  i like this so i can swap out parts later as i need to.

 

For everything will be connected to the antenna on the roof at home and it will live on the shelf for a while as a test...  if it stays there, i'm only going to get a mile out of this, maybe 2 depending on the area.

 

down the road i'll figure out a portable case to put everything in... and then start testing batteries, solar pannel, etc.  So everything i'm doing is considering how i can save space.

Edited February 3, 2015 by Steve

[Steve]

I got the radio bug big time!

 

The controler is ordered, duplexer ordered, cables arrived, metal project box arrived, extra connectors and cables, heatshrink for custom cable, etc...  I even ordered a Motorola HT1250 to test and compare to my Baofang UV5-R.  I can tell you that my Baofeng 888s has very low sounding audio.  The voice is very low in the noise floor.  ... i only paid $15 for that radio, maybe that's why.

 

then i find this killer deal on a GR1225 that I can't pass up.... here's the thread on that unit, and my post in there:

 

https://forums.mygmrs.com/topic/195-motorola-gr1225-uhf-repeater/page-2?do=findComment&comment=3280

 

I plan to continue my DIY repeater becuase I have learned so much by it.  Once its done, I will either keep it as my base or sell it.   This is getting really expsnsive.

[Steve]

brief update: all parts are in except for the duplexer.  I will start making the custom cables in soon.  I am going to try and build the cables and connectors so that they are universal, that way, i can swap out the radios at will.  I might upgrade to other mobiles, or maybe use some HT radios for light weight low power portable use.

[KimOlarte]

Hello,

 

 

      Were you able to acomplish the repeater with the Two Kenwood TK-880H's ? Need help with programming

 

Kim

Kenwood USA

1999-Present

[gdavis316]

Kim,

Welcome to the site. It's good to have another technical person on here who is willing to help us who don't have the knowledge. That is what it's all about.

Glenn

[Steve]

Hello,

 

 

      Were you able to acomplish the repeater with the Two Kenwood TK-880H's ? Need help with programming

 

Kim

Kenwood USA

1999-Present

thanks for asking!  I have not finished it yet.  my next step is to make the custom cables to connect it all together.  My only question at this point would be about audio quality through the repeater.  I want it to sound as close to normal as possible, meaning that when i talk through it, the receiver will hear what they normally would if it was simplex.    the local 2m and 70mm ham repeaters sound so good.  There is this whole concept of pre emphases and emphases.  I'm not sure i can easily get that signal out of the service cable tk-19.  as for programming, i seem to have it figured out at this point, its just a matter of building it.  i will def check in later and let you know how its going.  

[zap]

Best way to run audio is on line or flat levels.

 

 

Sent from my iPhone using Tapatalk

[Sticks]

Did you get it up and running? I have two TK880s and a Ham Gadgets ID-O-Matic III. I've run all the cable and wired it up but it's not transmitting. Something is wrong with my wiring.

[zap]

Is your Id-o-matic set for active low keying?

 

 

Sent from my iPhone using Tapatalk

[zap]

Is your Id-o-matic set for active low keying?

 

 

Sent from my iPhone using Tapatalk

[Steve]

Did you get it up and running? I have two TK880s and a Ham Gadgets ID-O-Matic III. I've run all the cable and wired it up but it's not transmitting. Something is wrong with my wiring.

not yet. its stilling on my desk now... waiting to be put together.  I have been playing with my GR1225 repeater in the meantime... I will def update here once i do.  Check the low and high key settings.

 

do you have any plans for making it battery powered?  I was thinking of building this as a grab-and-go box w separate battery pack / solar charger for camping and trips to the lake.

[Sticks]

Sorry, guess I need to check my notification settings. Just saw y'alls replies. I have not had a chance to look at it again. I will double check active low keying though. 

 

Steve this particular one will go in a permanent location. If it works, I'll build another in a go box. We have plans to create a battery system with solar panels and multiple outputs. 

[Sticks]

Ok, I've verified active low keying. I've checked voltage on pins 3 and 7 of the ID-O-Matic. Pin 7 is COR input. I get about 3.2v on the line when the radio is not receiving. Voltage grounds out when it should. Pin 3 is PTT output. I get voltage drop to key the transmitter but it is not keying. So it sounds like the receiving radio and controller are working just fine. No?

 

I'm started reading that I could just make a RICK cable for these radios to just jumper across. 

[zap]

Almost sounds like not enough drop to key the radio.

 

 

Sent from my iPhone using Tapatalk

[WQOJ953]

Following....  I have a Tk880 as well and would like to get a 2nd of and make a repeater. I also have a Motorola M1225 I could use are a RX radio and pick up another 40W M1225 for the TX radio. I would prefer to go the Kenwood route.

[PastorGary]

Following....  I have a Tk880 as well and would like to get a 2nd of and make a repeater. I also have a Motorola M1225 I could use are a RX radio and pick up another 40W M1225 for the TX radio. I would prefer to go the Kenwood route.

 

 

Hello, Ken, and welcome to MyGMRS Forums.  Thanks for your input.

[zap]

Don't get me wrong, I love the 1225 radios. I started playing with an RKR1225 not too long ago. I have several (new in box) UHF M1225's sitting in my closet and several VHF M1225's laying around. (Also have some PM400's laying about).

 

However, Ken, I would say it would probably be easier to pick up another M1225 as the 16 pin repeater cable runs about $10 online. There are also some 4 channel versions laying about here and there. Takes a little more time and effort to get it done with a Kenwood. Another plus, the Kenwood can be enabled for FPP (all the info is in the service manual which can be found on the Repeater Builder site). 

[WQOJ953]

Ah, I figured that is what most people would say. Is the programming software and cables available at a reasonable cost? My local radio shop wants $35.00 just to look at the radio.

 

The one I have now is a 25W 4 channel. It would make a good RX radio and has the 16 pin connector. I've seen the cables on eBay and they are very inexpensive. Probably the best way to go even with the cost of programming.

 

Thanks for the info. I'll have to go look for a M1225 repeater thread now.

[zap]

The way Motorola built their PAs, the 10W-25W radios are actually the most efficient. The RSS can be found online for free (P25 forums) and the same generally runs $20-$30 for a ribless model.

 

Depending on what version 880's you have, that software can also be found online for free.

[WQOJ953]

I have the software and cable for the 880 already.

 

OK, I'm not up to snuff on the Motorola lingo.  RSS = ? 

 

I'll go look for a Motorola forum.   Thanks!

[PastorGary]

Usually stands for "Radio Service Software".