APRS 144.4 Interference Along US Mexico Border?

[N7MXO_1]

VHF APRS on 146.39 seems to be blocked by a tail from a signal on about 146.4 when I get within about 20 miles of the US Mexico border in the Nogales and Sasabe areas. Planning to check further east when time permits. Anyone else had this occur? I'm using a newer Yaesu FTM-400 that performs well elsewhere to the North.

Thanks in advance
N7MXO de DM42

 

[n2nov]

Isn't the APRS freq 144.390 Mhz?

 

[N7MXO_1]

Yep, but the signal is splashing out across a broad-band, opening the squelch on .39 enough that I could not get a signal out. Center freq was around .40 - that is just by ear and limited display capability in the truck.

 

[n2nov]

But you mention 146.390 when the APRS freq in this area is 144.390, a whole 2 Mhz away. Your APRS radio should be on 144.390 Mhz.

 

[N7MXO_1]

typo - 144.40.

 

[wd9ewk]

typo - 144.40.

I live in the Phoenix area, but regularly head down to Nogales. Haven't ever heard interference on or around the 144.390 MHz frequency that you described. When I run APRS, I use either a Kenwood TH-D72 or TH-D74.

I checked with a ham friend who lives in Nogales, who also operates APRS on 144.390 MHz from time to time. He said he's not hearing any interference on his radios around that frequency. In fact, he mentioned there are some new digipeaters operating in and around Nogales, improving APRS coverage.

 

[N7MXO_1]

Thanks - weird. I have an older D7 sitting on a shelf. I'll take that with me on my next trip and see if I can narrow the issue down some. Interference was oddly located - like directly between the tower near the Buenos Aires refuge and Sasabe on 286 - then between Patagonia and Nogales on 82. Cleared right up on I-19 northbound out of Nogales. Maybe just the Yaesu sensitive to some intermod - or knowing my luck - my truck is sensitive to intermod from one of the frequencies in use. Again, thanks.

N7MXO-9 when mobile

 

[wd9ewk]

Thanks - weird. I have an older D7 sitting on a shelf. I'll take that with me on my next trip and see if I can narrow the issue down some. Interference was oddly located - like directly between the tower near the Buenos Aires refuge and Sasabe on 286 - then between Patagonia and Nogales on 82. Cleared right up on I-19 northbound out of Nogales. Maybe just the Yaesu sensitive to some intermod - or knowing my luck - my truck is sensitive to intermod from one of the frequencies in use. Again, thanks.

I have never goine south of AZ-86 between Tucson and Why, so I don't know anything about what might be out on AZ-286 down to Sasabe. As for AZ-82, I have only been on that section a couple of times, and don't remember any intermod. Different radios may behave differently in those areas, so maybe a comparison betwen you FTM-400 and TH-D7 will be useful in tracking down whatever you were hearing in those areas.

73!