Does cell tower(s) null the P25 receive on the 536?

[n0wla]

I live a block from a cell site. I can not receive any trunked system in my area while at home. Put the 536 in the car and 3 blocks down the road I hear every system I have programmed in. At home I am also Line-of-site about 10 miles from the transmit site, so lack of signal is not the issue. Any clues?

 

[dave3825]

I am not sure about the cell tower deal but I know a 7 years back, I started using my 436 after not using it for a few months, that I could not receive my local trunked system on 800mhz. Same as you, it would work out of my home. Turns out that the wireless baby monitor was the problem. Only found It after killing breakers one at a time.

 

[phask]

Others have had issues. Personally - I can see 1 1500', one about 900' from my QTH. Seemingly no issue. I did have one about 300-400 away but it has been de-commisioned. No issue from it either.

 

[IAmSixNine]

De sensing from cell towers is an issue but not as bad pre rebanding when Nextel 800mhz usage was a few Mhz away from public safety.
Post rebanding the issue is with 700mhz LTE being over powering near cell sites that have those antennas.
There is a local whataburger that when i pull into the parking lot my G4 will go out of range. Walk in the building and works great. Mainly affects 700mhz systems as well. But everyones results will vary.

 

[mmckenna]

I live a block from a cell site. I can not receive any trunked system in my area while at home. Put the 536 in the car and 3 blocks down the road I hear every system I have programmed in. At home I am also Line-of-site about 10 miles from the transmit site, so lack of signal is not the issue. Any clues?

Strong 700MHz LTE signals can certainly overwhelm the fairly wide open receiver front ends on many scanners. Filtering the LTE segments of the 700MHz band may help.

I had issues with some equipment when Verizon turned up LTE on one of my towers.

 

[RFI-EMI-GUY]

I see a market for an aftermarket band filter box , something the 536, SDS and SDR folks might want or need. A shielded box, inside a PCB with transmission lines forming a passive band splitter with various branches of TOKO filters including: VHF Low pass, Aero Band, Milair Band, UHF, 700 PS, 800 MHz PS and 900 MHz high pass. It could have an option for either single or band specific antennas. Places on the PCB to install optional custom VHF paging and WX notch filters. Basically everything the manufacturer leaves out.

 

[jhsands]

I see a market for an aftermarket band filter box , something the 536, SDS and SDR folks might want or need. A shielded box, inside a PCB with transmission lines forming a passive band splitter with various branches of TOKO filters including: VHF Low pass, Aero Band, Milair Band, UHF, 700 PS, 800 MHz PS and 900 MHz high pass. It could have an option for either single or band specific antennas. Places on the PCB to install optional custom VHF paging and WX notch filters. Basically everything the manufacturer leaves out.

PM'd you a developer.

Sent from my S7 using Tapatalk.

 

[RFI-EMI-GUY]

PM'd you a developer.

Sent from my S7 using Tapatalk.

Found his website. A lot of preamp and filter stuff. there.

Filtered Preamps

 

[KR7CQ]

Depends on what cell site. A GSM site transmitting at 1.9 GHz? No. A Verizon tower transmitting at 700 MHz? Absolutely! Around here a Verizon tower will wipe out 700 MHz reception on ANY scanner, and on the Unication G4/5, every single time, once you come within a few hundred feet of the tower.

I would be curious to see what people with real radios have to to say in their situation. I can't help but think that public safety equipment has to perform better than this for obvious reasons, but I don't know...always wondered.

 

[mmckenna]

I can't help but think that public safety equipment has to perform better than this for obvious reasons, but I don't know...always wondered.

It does. Better filtering.

 

[HogDriver]

I live about a quarter mile from a 4-tier cell tower and it completely knocks out one trunked system but I able to pick up another one Ok. I guess my proximity to its closet tower or something makes the difference. They both have freqs in the 850’s


Sent from my iPhone using Tapatalk Pro

 

[IcomIcR20]

My BCD436HP gets some desensitization when I get close to cell tower, but I have to be very close for it to really be a problem. I am about a half-mile from a cell tower and can see it through the trees, but it causes no problems. It's only noticeable when I am within a hundred or so yards.

 

[KB7MIB]

Within about a quarter mile of a Verizon 700 MHz LTE tower here in the Phoenix metro area, and my GRE PSR-500 has no 700 MHz reception at all. (It won't decode simulcast to begin with, but even the IR sites of the RWC, and the non-simulcast AZWIN sites are wiped out.)
I don't recall off-hand if 800 MHz, where Maricopa County has its mixed analog/digital trunked system, is similarly affected.

John
Peoria, AZ

 

[KR7CQ]

Within about a quarter mile of a Verizon 700 MHz LTE tower here in the Phoenix metro area, and my GRE PSR-500 has no 700 MHz reception at all. (It won't decode simulcast to begin with, but even the IR sites of the RWC, and the non-simulcast AZWIN sites are wiped out.)
I don't recall off-hand if 800 MHz, where Maricopa County has its mixed analog/digital trunked system, is similarly affected.

John
Peoria, AZ

I haven't seen the issue at 800 MHz. I don't believe any of the cell sites in the Valley transmit at 800 MHz at this point, haven't seen that band used for mobile phone since the days when analog cell phones were still operating.

 

[nd5y]

The 869-894/824-849 MHz band is still heavily used for cellular in most places. Just no analog or TDMA-136 any more. There is a common misconception that the carriers abandoned it when they shut down analog.

 

[nessnet]

Any/all of the below could be used by Verizon.
It depends on the market and if the market is a 'legacy' area.
Legacy meaning it was operational in the old A/B (AMPS) days
(some markets were acquired since AMPS and may be 1900 PCS).

Phoenix is a legacy market, so it is with 99.9% certainty that most/all sites in the Phoenix metro use 800Mhz.

LTE:
B2 1900Mhz (PCS)
B4 1700/2100Mhz (AWS1)
B13 700 (c)

CDMA:
BC0 800Mhz
BC1 1900Mhz (PCS)

 

[baayers]

850 MHz Is also known as LTE Band 5. AT&T and US cellular have been rolling out LTE service on this band for the last few years. Verizon as we are approaching the CDMA shut down at the end of this year has been rolling it out in more areas. For example when I was in Charlotte a few weeks ago I saw a lot of active band 5 service. Since Verizon owns both channels of 850 MHz in Phoenix and Tucson I would not be surprised to see this area quickly converted after the CDMA shut down.

 

[Ubbe]

A Uniden BCD536 uses a fixed filter for 760-1300Mhz and Whistler TRX-2 has one filter for 660-1300Mhz.
The Uniden BC780 has tuned filters at about +/-10MHz wide that follows the frequency when monitoring 108MHz-173MHz frequencies.
A commercial 2-way radio has a tuned filter that follows the channel frequency and are probably +/-2MHz wide.
The narrower filters you can use the less strain it puts on the receiver amplifier and makes it possible to keep its sensitivity and are less likely to overload or get intermod problems.

/Ubbe

 

[n0wla]

Update. I purchased sds100 and it works just fine inside my home so my opinion it's far superior to the 536!!

 

[Anderegg]

My TV station has a freaking AT&T (and now with added Verizon bands!) CELL PHONE TOWER on our roof (smartest descision ever)...50 feet from our 800MHz scanner antennas. YES, cell phone towers can fade out scanners,a nd even commercial equipment. You will not so much hear as much as the scanner signal may just go very low on your target system, sort of like a loud noise in the next room keeps you from hearing the TV in your room.

The location where the pic below was taken, Motorola radios even get faded, and this location is line of site to several of the actual trunking towers!

Paul