• To anyone looking to acquire commercial radio programming software:

    Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.

    If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.

    To obtain Motorola software see the Sticky in the Motorola forum.

    The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.

    For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).

    This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.

Bad Duplexer?

hockeyref2

Member
Feed Provider
Joined
Mar 26, 2002
Messages
112
Location
Northern MI
I bought a new motorola SLR5700 repeater and 'motorola' DSCP10725 mobile duplexer from a large national dealer to replace a Motorola XPR8400 repeater. UHF, IG band.

I kept hearing static and had poor reception/range issues with the new system on both analog and DMR. After lots of troubleshooting (3 repeaters, 2 duplexers, 2 sets of jumpers, 2 different antenna systems, 3 different antennas (2 unity gain, 1 3dbd gain), running 10-20 watts output) I narrowed it down to the duplexer.

What could cause this type of issue?
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
13,799
Location
SNCZCA01DS0
Mobile duplexers tend to suck.
If it's not tuned well, desense can really impact performance. Did you have someone check it on site, or did you rely on a dealer setting them up and mailing them to you?
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
5,102
Location
Stockholm, Sweden
Nothing wrong in using that 6 cavity duplex filter. It's a Procom duplexer (or is it a Cellwave?) that have been used at numerous repeaters.

Can the repeater be put into analog mode and then run it against a dummy load instead of the antenna and then use a 30dB-40dB inserter at the dummy load, perhaps just a T-connector and a 30dB-40dB attenuator where you connect a signal generator and key the repater and adjust the filter for maximum output and best sensitivity. It should be no, or barely detectable, degradation of sensitivty when the repeater is keyed.

The coax to the antenna and the antenna in itself could be problematic so use an antenna analyzer to check those.

It could also be interference from another transmitter at that location. Then check coax and antenna and for external interference by just substituting the dummy load for the coax to the antenna and check sensitivity when the repater are keyed while connected to the outside antenna.

If you have access to a check VNA it can be used to check the coax/antenna and can sweep the filter while you check if it's coarse tuned properly in all cavities and then do the final tune with the live system and antenna.

If the repeater cannot be switched to analog mode then it is a bit more uncertain to adjust the filter and have to be done just by a VNA sweep and then VNA check the coax/antenna.

/Ubbe
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
5,102
Location
Stockholm, Sweden
That Telewave are only two cavities for TX and two for RX, and the OP's duplexer have three for each TX/RX. The difference are power handling at 250W for the Telewave but no problem with a 25W repeater for the OP's duplexer and it's good for up to 40W, so that repeater should not be running at full otput of 50W.

/Ubbe
 

hockeyref2

Member
Feed Provider
Joined
Mar 26, 2002
Messages
112
Location
Northern MI
Thanks for all the replies!
Yes, I relied on the dealer to tune it and ship it. It appears to be in good shape physically.

It is an combilent 6 cavity. I am in a rural area and I don't believe there is much going on in UHF. The problem is 'always' there so I don't think its some interference. (the working one is a celwave)

The problem moves with the duplexer, and I tried it on two completely different antenna systems in different parts of the plant, and with different repeaters..

The repeater is setup in mixed mode but we use analog. I cant get people to use the RSM's properly in analog... DMR would be a disaster - we are a manufacturing plant with people in very loud places.

I don't have the expertise (and probably budget) to get all that fun test equipment so I get to rely on the out of state large dealer with some 'free' or 'moderately priced' help if I ship them things (Hooray for corporate contracts?). Or I can call in a local people. With COVID they frown upon bringing in outside people unless its mission critical.
 
Last edited:

MTS2000des

Member
Joined
Jul 12, 2008
Messages
3,547
Location
Cobb County, GA Stadium Crime Zone
You really need to get a baseline on what your noise floor is, with and without your filtering system. A spectrum analyzer on the uplink of the repeater for 24-48 hours in log/capture mode is a start. Then PM the repeater and ensure it's not part of the problem. Then a proper sensitivity test with an iso-T.

Keep in mind, your tuning of your duplexer is affected by physical shock of transit. It really should be done on site when it's in the environment it's going to be used in, with the antenna/feedline it's going to be connected to.

I would consider having a functional communications system in your plant to be "mission critical", so a qualified vendor should be able to resolve your issues. It does require specialized test equipment, and someone with experience (please don't take this personally). Repeaters aren't plug and play like consumer electronics devices such as wireless routers/access points, and it does take someone with experience and the right tools to sort it out.
 

WA0CBW

Member
Joined
Dec 8, 2011
Messages
1,376
Location
Shawnee Kansas (Kansas City)
There are a lot of mechanical things that could be defective. Check all the connectors (especially the TX, RX and Antenna ports) for dirty or expanded or missing "fingers" on the female connectors.
Bill
 

prcguy

Member
Joined
Jun 30, 2006
Messages
9,994
Location
So Cal - Richardson, TX - Tewksbury, MA
The last service call I did on a mountain top I had a customers complete repeater with duplexer in my shop and it was tuned to perfection and working great. I drove up the nasty trail to the 5,000ft hill and installed everything and it worked like crap. Fortunately, besides my service monitor I brought my spectrum analyzer with tracking generator and found the duplexer was all out of whack. A quick tune up on the hill and everything was perfect again and the customer commented they have never seen the system work that good with hand helds.

Duplexers do not like vibration and I would expect one to go out of tune being shipped across the country. Its just what they do.
 
Top