XPR 7550e range issues

[Scatpack16]

We are in the process of taking over a railroad property. They were using kenwood NX 200 radios but are taking them with them. We brought in 10 new Motorola Xpr 7550e radios to replace these, but right out of the box they are complaining they can not talk more than about 30 rail cars, but the kenwood nx 200 is talking about 50 to 100(maybe). Now I have used the 7550e on many properties with no issues as this and have even proven in other situations the range capability compared to the NX 200. I just do not see anything between the 2 radios TX wise that would make a range difference between the 2 in analog .

Is there some adjustments in the programming that I am missing?The only thing I could think of is the battery saver is turned on,but that wouldn't cause a distance issue. Only a rx delay. They are communicating on AAR 91-91(161.475) in analog. Any help would be greatly appreciated.

Thanks!

 

[IAmSixNine]

If you didnt do the programming there are a few things to look for.
Main one is low power vs high power.
In an open environment like a rail yard i would assume that a radio on high power should cover it while a radio on low power might have issues. My first guess.

I work about 2 miles as the crow flies from a rail facility and have 3 channels programmed in to monitor them. I pick them up most of the time with an occasional reply from one guy being on the fringe of reception.

 

[Scatpack16]

Copy. Sorry for the co fusion. I did do the programming on the motorlas but not the kenwood. We are in property now doing a drive test. Both kenwood and Motorola are set to high power.

 

[RadioGuy7268]

I would also check the antennas that the radios were ordered in with.

161 Mhz is a little outside the range of some of the VHF antenna options.

 

[MTS2000des]

Portable antennas on VHF are already at a disadvantage. I'll bet your NX200s have the long "elevated feed" wideband antenna, and the XPRs have the smaller antenna. As the previous poster stated, if you're antenna is for the wrong sub range, you'll experience degraded performance.

PMAD4118 is the one that should be used, band split is 152-174.

 

[TampaTyron]

Second the stubby vhf antenna issue..... TT

 

[Scatpack16]

Ya the kenwoods have "extended range" antennas on them and the Motorolas have the standard 152-174 helical antenna. We found a big part of the issue was the locomotive clean cab radios were hooked to the wrong antennas. They were hooked up backwards to the EOT UHF antennas... on site test was actually very favorable for the Motorolas. We averaged 2.5 miles on the edge of town and I did about 50 cars from portable to locomotive with no problems. Do you think the kenwood wideband antennas would make that much of a difference? They are about 3 inches longer than the motorolas. I have also been looking online for longer Motorola antennas per the GMs request. I know Motorola does not make anything though.

 

[MTS2000des]

The 7550 uses an MX style thread but a short base. Don't see many aftermarket options, and Motorola doesn't appear to make a "high gain" or "full bandsplit" antenna for the 7550s like they do for the Jedi/XTS radios.
This one from EM Wave would be great IF they made it with your needed connector. You may want to contact them, they might be willing to OEM what you need if the order commitment was high enough.

 

[Scatpack16]

Awesome! Thank you! I will give them a call and discuss.

 

[TampaTyron]

There are several antenna options for those radios. Can you post the exact part number or a photo of the one you have next to a ruler? I am guessing you guys are using the 9cm stubby. TT

 

[Scatpack16]

Antenna is PMAD4118A

 

[TampaTyron]

That is the one I would use. Back when it was 6550 every where, we would put vhf APX antennas on 6550s to get better coverage. TT