TRX-2 Reception Issues in Car

[nholguin97]

Hello all,

I thought my setup would be perfect with everything mounted and all, but when a TRX-1 with a rubber ducky is outperforming all your mounted scanners, it is a bit infuriating.

So alas, I come to seek help with some issues I have ran into ever since I got my console install done in my Dodge Charger, and I'm going to give as much detail as I can. Essentially, my console consists of a Motorola XTL5000, a Kenwood TK6110 Low Band Mobile radio, and Three TRX-2 Mobile scanners that are remote headed in the console and go down to the floor of the car where the scanner units sit stacked on each other.

This may sound a bit ridiculous, but the scanners are attached to three Uniden bearcat 15-watt amplified speakers since they're so dang quiet. The scanners are all routed via three separate 3-foot RG58 BNC Male - BNC Male coaxes into a 4-port MCA204M amplified multi-coupler that routes out to a BR-137 Browning Tri-band antenna mounted in the trunk via a drilled in Eightwood NMO 3/4 inch Mount to BNC Male Coax Connector Extension Cable RG58 5M /16.4 feet.

So to simplify, 3 TRX-2 scanners > 3 RG58 3-foot coaxes > 1 MCA204A Amplified multi-coupler splitter > 1 16.4-foot RG58 Coax > 1 Browning BR-137 Tri-band antenna.

Everything is powered by a 12 way fuse block that is routed to the car battery in the trunk. The XTL5000 and Kenwood TK6100 radios are on separate antennas and coaxes.

So when I am scanning agencies like San Gabriel PD (P25 460.17500), Alhambra PD (P25 471.1375), or Monterey Park PD (P25 155.56500), they come in absolutely garbled on my TRX-2s. I can barely understand anything. However, when I turn on my TRX-1 handheld and put it in my cup holder with a rubber ducky, it comes in absolutely clear. The same issues can be said for the ICI Montebello Site (A trunked 470 - 483 MHZ system for those who don't know), where certain areas barely catch the Control frequency and intermittently show the "T" icon when I am well within the coverage area, but my handheld scanner is able to catch it better. Same can be said for the SBAY Site when I am in the middle of places like Manhattan Beach. Same goes especially for the Orange County CCCS 855 - 861 MHZ Countywide site.

So where am I going wrong, and is there anything I can do to improve what is going on with my given setup? Why is a small rubber ducky antenna inside my car shaming my extensive install?

 

[pgates]

Connect the TRX-1 to one of the three feedlines and see what the performance is like then.

Thanks for such a detailed rundown and the hyperlinks to so much detail.

 

[mmckenna]

So where am I going wrong, and is there anything I can do to improve what is going on with my given setup? Why is a small rubber ducky antenna inside my car shaming my extensive install?

Likely noise getting in via the power or coax to the mobile scanners.
Does this happen when the engine is off, only when the engine is on, or both?

You can start isolating things and see if something makes it go away:

Remove the power feed from the scanners and power it with a stand alone 12 volt power source. If the issue resolves, problem is with noise in the power feed.

-if that isn't the issue-

Remove the antenna input from the multicoupler and plug the antenna directly into one of the scanners. If that resolves it, issue is with the multicoupler. (bypass the multicoupler)

Some Dodge vehilcles are just known to be noisy. Even though some models are used in public safety, there can be variations from vehicle to vehicle. Proper power feed, grounding, etc. is important.

Make sure all your equipment is well grounded with short ground leads to the body as close to the radio/multicoupler chassis as possible.

 

[nholguin97]

Likely noise getting in via the power or coax to the mobile scanners.
Does this happen when the engine is off, only when the engine is on, or both?

You can start isolating things and see if something makes it go away:

Remove the power feed from the scanners and power it with a stand alone 12 volt power source. If the issue resolves, problem is with noise in the power feed.

-if that isn't the issue-

Remove the antenna input from the multicoupler and plug the antenna directly into one of the scanners. If that resolves it, issue is with the multicoupler. (bypass the multicoupler)

Some Dodge vehilcles are just known to be noisy. Even though some models are used in public safety, there can be variations from vehicle to vehicle. Proper power feed, grounding, etc. is important.

Make sure all your equipment is well grounded with short ground leads to the body as close to the radio/multicoupler chassis as possible.

It happens both when the engine is off and on. I removed the fuses to everything and plugged my scanners into an extension cord from my garage, bypassed the coupler with one coax direct into one scanner, and have noticed an improvement.

Plugging them back into the multi-coupler with just power on to that, reception has gotten dramatically worse. In the past though, having the coupler off by accident and having the scanners still plugged in to the coupler makes it almost impossible to receive anything. The coupler is not screwed down to the car, so that very well may be an issue when it comes to grounding it.

It’s a 2015 Dodge Charger if that helps with picturing anything.

 

[mmckenna]

It happens both when the engine is off and on.

Key on/Engine Off, or Key off/Engine off?

I removed the fuses to everything and plugged my scanners into an extension cord from my garage, bypassed the coupler with one coax direct into one scanner, and have noticed an improvement.

OK, so something in the vehicle and/or an issue with the coupler.

Plugging them back into the multi-coupler with just power on to that, reception has gotten dramatically worse. In the past though, having the coupler off by accident and having the scanners still plugged in to the coupler makes it almost impossible to receive anything.

OK, so the amplifier in the coupler will amplify everything, including noise. If you are getting the noise with the coupler off, it's likely some noise inside the vehicle. When the amplifier is on, it's amplifying the noise.

The coupler is not screwed down to the car, so that very well may be an issue when it comes to grounding it.

It’s a 2015 Dodge Charger if that helps with picturing anything.

I'd screw down the coupler, or at least make sure it's grounded.
Make sure everything is bonded/grounded. You may need to start by removing fuses one at a time.

Also, disconnect any 12 volt -> USB adapters, some of those are big noise generators.

 

[CycleSycho]

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One of the best OP descriptions I have seen in many years (since 1966) of a problem presented for advice/help. Thanks nholguin97, for being very detailed in your presentation! Only question I have, did you install one (or separate) noise suppressor's on either or both the power sources for each devices, and maybe its accompanying antenna inputs if necessary?


.

 

[nholguin97]

Key on/Engine Off, or Key off/Engine off?



OK, so something in the vehicle and/or an issue with the coupler.



OK, so the amplifier in the coupler will amplify everything, including noise. If you are getting the noise with the coupler off, it's likely some noise inside the vehicle. When the amplifier is on, it's amplifying the noise.



I'd screw down the coupler, or at least make sure it's grounded.
Make sure everything is bonded/grounded. You may need to start by removing fuses one at a time.

Also, disconnect any 12 volt -> USB adapters, some of those are big noise generators.

I appreciate all the pointers and I’ll try to work on getting all that done over these next few weeks. It isn’t the worst reception the way it is but it is definitely disappointing. The noise is regardless of anything, whether the vehicle is on or off, key on or key off. My installer did run the radio power cables extremely close to the Coaxes so that may very well also be an issue. I also noticed a long time ago in my old car that coaxes under the floorboard tend to not like reception as much.

.


One of the best OP descriptions I have seen in many years (since 1966) of a problem presented for advice/help. Thanks nholguin97, for being very detailed in your presentation! Only question I have, did you install one (or separate) noise suppressor's on either or both the power sources for each devices, and maybe its accompanying antenna inputs if necessary?


.

I have never really dove into the noise suppression thing, as I have never dealt with one before. I don’t know much about them. So to answer that question, no I do not. What would be a good suppressor to use if I were to go that route?

 

[mmckenna]

I appreciate all the pointers and I’ll try to work on getting all that done over these next few weeks. It isn’t the worst reception the way it is but it is definitely disappointing. The noise is regardless of anything, whether the vehicle is on or off, key on or key off. My installer did run the radio power cables extremely close to the Coaxes so that may very well also be an issue. I also noticed a long time ago in my old car that coaxes under the floorboard tend to not like reception as much.

That shouldn't be an issue unless something is damaged.

If power is fed directly off the battery, as in the Positive power feed directly off the Positive battery post, and your ground is to the body, then you are likely not having an issue there.

If the noise is there with engine on or off and key on or off, but it is reduced when you pull all the fuses, then it's likely something in the car that is powered all the time.
That could be the computer, AM/FM goodtime radio, or some accessory you've added. Big culprit is the USB cigarette lighter adapters, cheap inverters, LED lamps, HID lamps, or even one of the other radios.

A good troubleshooting step would be to pull each fuse one at a time until the noise goes away, boom, there's your noise source.

 

[mmckenna]

Going to add this again just for emphasis:

Big culprit is the USB cigarette lighter adapters

 

[n4jri]

I agree with that. Bought what I thought was a nice one, but it just flickered and acted weird in the car.

I have two TRX-1's that I just hang from dashboard air vents with their stock rubber duckies. For the most part, reception is as good or better than PSR500's w/outside antenna.

I no longer use external power for the TRX-1's. I have two sets of NiMH's for each one--purchased from Harbor Freight for a very reasonable price. The two sets will get me through an all-day trip.

73/Allen (N4JRI)

 

[CycleSycho]

I have never really dove into the noise suppression thing, as I have never dealt with one before. I don’t know much about them. So to answer that question, no I do not. What would be a good suppressor to use if I were to go that route?

Sorry my friend, it has been quite a many years I have installed mobile equipment so I am out of touch in that regard. You might start by looking into some articles, or researching amateur radio sites like ( electrical noise EMI ). Suffice to say these days with all the EM radiation around everything inside and outside vehicles (and the equipment's generic FCC disclaimers about accepting interference), by the time you find the culprit your probably going to have a limited reception (the signal side). The DC side and checking shielding around your equipment would be your best bet but nothing is guaranteed any more. In my location, my 08 MB is getting emi/rfi from the USAF base and weapons range locally. Drives the car alarm system wacky when the right bird flies close enough when they run their gear. Good luck reducing the interference but BE AWARE of pulling any fuses in the car dealing with the SRS system, you might trip a code/dash light requiring a visit to a dealer/mechanic to reset it.


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[emsflyer84]

Hey there, just a quick note, I am working through a similar problem with a TRX-1 I have at my house that is connected to a tuned antenna on the roof of my house. In my case I get better reception with the rubber duck when driving around in my car then I seem to get at my house with the roof top antenna. I’ve done lots of testing and my problem seems to be specific to my house. A few hundred feet from my house and reception improves greatly.

I think what I’ve concluded at this point is that the Whistler scanners are very prone to overloading from signals outside the actual scanned frequencies. In my case, I think either something in my house, or a signal being picked up by my roof antenna is overloading the front end of the scanner and causing decreased receptionon my chosen scanned frequencies.

I haven’t totally tracked down the culprit, but at this point I’m thinking of picking up a Uniden scanner to see if I have the same problem...

 

[buddrousa]

The only thing I have not seen is OVERLOAD try to turn the ATTINUATOR on

 

[Skypilot007]

Have you tried a different antenna? I'd swap in a 1/4 wave whip on each band and see what happens. The Browning antennas aren't what they used to be, I believe they are a knock off of a Laird commercial grade antenna.

I have a very similar setup in my car (TRX-2, Stridesburg active multicoupler, Larsen tri-bander) and it receives much better than my portable sitting in the cup holder.

 

[APX8000]

Bypass the multicoupler. The front end on the TRX's are easily overloaded. They use minimal amplification to make up for the loss of the coupler, but the noise figure specs on them are not that great. Add that to the hot front end and you can see how the issue evolves. I would never recommend an active multicoupler in a mobile environment as your noise floor will constantly change.

I'd also throw a 50 ohm dummy load on the unused 4th port.

So try running one TRX directly to the antenna to rule out the multicoupler.

Keep your power wires away from your coax.

 

[PrivatelyJeff]

Going to add this again just for emphasis:

Big culprit is the USB cigarette lighter adapters

And wireless charging pads. I have one attached to my phone mount in my car and it puts out a regular pulse on VHF if something isn’t charging.

 

[mmckenna]

And wireless charging pads. I have one attached to my phone mount in my car and it puts out a regular pulse on VHF if something isn’t charging.

I'll have to keep my eye on that. My wife's new truck has a wireless charging pad and I have a Kenwood TK-7180 mounted in it. No issues so far, but the antenna is up on the roof and well shielded from the inside.

 

[PrivatelyJeff]

I'll have to keep my eye on that. My wife's new truck has a wireless charging pad and I have a Kenwood TK-7180 mounted in it. No issues so far, but the antenna is up on the roof and well shielded from the inside.

Mine’s after market but same setup.

 

[mmckenna]

Mine’s after market but same setup.

Ah, OK. This is a GM pickup, and they tend to be pretty good about RFI.

 

[Progline]

Late to the party, has the OP any further updates on his issues? How has analog reception been?

Have been thinking of a TRX2 install in my Colorado, so will follow the rest of this with interest.