KG-1000's as a repeater

[WhiteOak]

I set up a repeater with my KG-1000's using an XLT-50 duplexer from BuyTwoWayRadios and the performance was not good. I used a Tram 1486 fed with 55ft of LMR400 with a height of about 50ft. The receive range was only a couple of miles. Thinking about two antennas and separating the two radios by extending the coupling cable that came with the radios. I would like to separate the radios by about 70ft or so. Each end of the house. Question, does anyone have any experience in such a situation, and if so, do you have any info on how far you can extend this connecting cable without affecting the performance of this repeater configuration? I'm thinking this would help greatly reduce the affects of desensing.

[MichaelLAX]

Reach out to OffroaderX here on this Forum, he built such a repeater 

https://forums.mygmrs.com/topic/2964-beginner-here/?do=findComment&comment=27933&_rid=5516

and posted this YouTube video:

 

[mbrun]

I set up a repeater with my KG-1000's using an XLT-50 duplexer from BuyTwoWayRadios and the performance was not good. I used a Tram 1486 fed with 55ft of LMR400 with a height of about 50ft. The receive range was only a couple of miles. Thinking about two antennas and separating the two radios by extending the coupling cable that came with the radios. I would like to separate the radios by about 70ft or so. Each end of the house. Question, does anyone have any experience in such a situation, and if so, do you have any info on how far you can extend this connecting cable without affecting the performance of this repeater configuration? I'm thinking this would help greatly reduce the affects of desensing.

I have experimented with the interconnect cable but as of yet have not tried to figure out a max length in my environment. Here is the functionality of the connectors/cable in repeater modes.

Because the audio carried on the cable is unbalanced long lengths of the cable makes ground loops and RFI more likely, but it will be location specific. Ordinarily, one should try to keep unbalanced audio cables short (20’ or less) but I have seen hundreds of cases of success with runs of 50-100’ and just as many of that length that did not work well (audio suffered). I recommend that you give a longer cable as shot and see what you get. If it were me I would use shielded cable for any extension I used.

While you reported you have desense, which is not uncommon, I am curious what your simplex performance was using the same base radio and field HTs before you configured that KG1000Gs repeater operation. The delta in range between the before and after can be an important piece of information.

OffRoaderX on this forum (NotARubicon on YouTube) has experience using the KG1000 for repeater use, in both dual antenna and single antenna configuration. Perhaps he will jump in. But if I recall he had better success with dual antennas, and has since switched over to a bonafide commercial repeater.

One consistent theme with the duplexers is that cheap and improperly selected duplexers consistently yield poor results, and all duplexers must be meticulously tuned for optimum results. Most of us do not have the quality equipment necessary to tune them, this means a quality radio shop needs to do that for us.


Michael
WRHS965
KE8PLM

[gortex2]

cheap duplexer gets cheap results. Is the duplexer tuned to the frequency ? There are other posts on here that folks saw close to 3db of loss thru the cheap ones. Dual antenna requires separation and further if horizontal than vertical. Id suggest just getting a real duplexer and a better antenna. 

[WhiteOak]

Thanks for the feedback everyone. On simplex my trans and receive is excellent from the base to mobile. And I regularly key a repeater about forty five miles to my west. The duplexer (DP-GMRS-50) came without documentation. I'm a newbie, trying to learn as much as I can about duplexers and repeaters and now wonder if I ran my radios into the wrong ports on the duplexer. I only tried it once and ran the transmit radio into the side marked "Low", and the receive radio into the side marked "High". Not knowing pass from reject, could I have plugged the duplexer in backwards? I've been unable to find any documentation on the XLT-50. The duplexer came pre-tuned to the center of the GMRS band (low 462.550-462.725 and high side 467.550-467.725). Not ideal but should do better than what I got. I'm still diggin' for info. Thanks again.

Bill, WRMA851

[n4gix]

5 minutes ago, WhiteOak said:

The duplexer came pre-tuned to the center of the GMRS band (low 462.550-462.725 and high side 467.550-467.725). Not ideal but should do better than what I got. I'm still diggin' for info. Thanks again.

The duplexer must be tuned to the precise pass frequencies being used in order to perform optimally.

[WhiteOak]

n4gix, thanks  I'll either send it off for tuning, or look for a better quality duplexer. bill

[daschnoz]

A couple of the guys I know who have repeaters, both GMRS and HAM, are running flat pack duplexers like the one you are running.  They noticed the same thing... reduced Rx range due to the insertion loss of the duplexer.  Their solution was to insert a preamp in the Rx line between the duplexer and the RX radio.  The cheap ones can be had from Amazon or eBay for under $25.  +30dB, which may be too much, but you can usually adjust that by controlling the supply voltage to the module.  There are better ones out there, but the price increases with the quality.  For under $20, it may not be bad to try.  If it works, upgrade to a better quality device if you want.

[WhiteOak]

Excellent idea, I'll take a look at them. bill

[wqpn591]

I traded out my XLT-50 duplexer for a Sinclair Technologies MR356-N-2. Ordered it tuned to the channel I wanted to use.

Ordered from the theantennafarm.com 

Works much better, and costs $500 instead of $150. But we get what we pay for.

I also send my XLT-50 to John at BuyTwoWayRadios.com and he is tuning it to my freq so I'll try it again when it comes back.

 

[WhiteOak]

Thanks for that info. I'll look into that.

[Coronamoto]

On 8/22/2021 at 1:59 PM, WhiteOak said:

Thanks for the feedback everyone. On simplex my trans and receive is excellent from the base to mobile. And I regularly key a repeater about forty five miles to my west. The duplexer (DP-GMRS-50) came without documentation. I'm a newbie, trying to learn as much as I can about duplexers and repeaters and now wonder if I ran my radios into the wrong ports on the duplexer. I only tried it once and ran the transmit radio into the side marked "Low", and the receive radio into the side marked "High". Not knowing pass from reject, could I have plugged the duplexer in backwards? I've been unable to find any documentation on the XLT-50. The duplexer came pre-tuned to the center of the GMRS band (low 462.550-462.725 and high side 467.550-467.725). Not ideal but should do better than what I got. I'm still diggin' for info. Thanks again.

Bill, WRMA851

I am working on a similar build with the same duplexer tuned by John at twowayradios.  Tested it at 20ft up and I get about 600 yards.  After 600 yards it is completely static then nothing come through.  It was doing this same thing before I got the duplexer tuned (Didn't know I needed it tuned) and called twowayradios and they said send it to John to get tuned. However, now that I have the tuned duplexer the problem remains. I live in a fairly flat area and can get 2 miles on my handheld in the same area.  Also sometimes the kg1000 will show a green transmit light after I have transmitted a couple times.  Do I need to adjust dwell time?  Is there something wrong with the duplexer or power source?  Any help would be great.

Coronamoto

WRPQ909

[gortex2]

Still sounds like desence. What jumpers do you have between each radio and the duplexer ? What RF line goes to the antenna ? What power source are you using ? As said in the past the price your going to spend piecing parts together yo could have bought a commercial repeater. 

First test I would try it one mobile to the antenna and test to a known location with your portable. Next hook the duplexer inline and do same test. If TX from one radio to another is fine then most likely its desence and without real equipment you can do proper testing. 

 

[WROZ250]

5 hours ago, Coronamoto said:

Tested it at 20ft up and I get about 600 yards.  After 600 yards it is completely static then nothing come through.  It was doing this same thing before I got the duplexer tuned (Didn't know I needed it tuned) and called twowayradios and they said send it to John to get tuned. However, now that I have the tuned duplexer the problem remains

OK, this is not intended as a 'stupid question', but are you sure you are connecting the duplexer correctly? 

By that I mean do you have the RX connected to the higher frequency and the TX to the lower??  I can get 600 yards on a dummy load!  Even a mistuned duplexer (unless extremely mistuned), connected properly, will do better than a dummy load. 

Have you tested your cables?

 

[Peashooter]

https://youtu.be/hISllcf3Kg4

This YouTube video from a user of the two Wouxun KG-1000G transceivers as a repeater may answer some of your issues.