Problems with Douglas County 453.3250 tonight

[realgeo]

Greetings, once again, everyone!

Shortly after the 2130 Douglas County Fire & Rescue pager test sequence tonight, there were some odd things going on.

During the pager test cycles, it sounded like one of the DC paging towers was repeating a 2kHz. tone interspersed with communucations from a radio that was transmitting GE's STAR singalling at the end of the transmission. Very odd.

Also, I caught a first for me during the paging tests - a test coming from the "Ponca Tower", which I'd have to assume is on the massive OPPD tower north of Ponca Hills. So, that would mean that 453.3250 is at 5 different locations in Douglas County!

Just some random thoughts and observations on a Thursday night!

73's

[IrvingtonVFD43]

Originally Posted by realgeo

Greetings, once again, everyone!

Shortly after the 2130 Douglas County Fire & Rescue pager test sequence tonight, there were some odd things going on.

During the pager test cycles, it sounded like one of the DC paging towers was repeating a 2kHz. tone interspersed with communucations from a radio that was transmitting GE's STAR singalling at the end of the transmission. Very odd.

Also, I caught a first for me during the paging tests - a test coming from the "Ponca Tower", which I'd have to assume is on the massive OPPD tower north of Ponca Hills. So, that would mean that 453.3250 is at 5 different locations in Douglas County!

Just some random thoughts and observations on a Thursday night!

73's

Evening George, that 2khz tone is coming from Des Moines Police, when the tropo gets heavy, DMPD is received at the east tower (Immanuel).

The Ponca tower has been in the works for a few years, mainly to page Ponca Hills Vol Fire. I don't know where exactly the tower is, but it's intended use is to cover areas of Ponca Hills that that east tower cannot reach, due to terrain. A lot of the PHVFD fire/ems staff have complained for years on missed calls due to coverage issues.

[KG4WHM]

Des Moines PD is on 460.xxxx so how are DC911 receiving them. I don't think they use GE STAR Signaling, I don't remember hear it the last time I drove through there.

[NeFire242]

Hmm, that is odd.

I am hearing Gage County on 453.225 with a DPL 026.
UNO has the 156.7 PL on that freq.

Pretty impressive for UHF, quite a long haul.

Maybe several signals being mixed and you're hearing it locally?

[realgeo]

Originally Posted by IrvingtonVFD43

Evening George, that 2khz tone is coming from Des Moines Police, when the tropo gets heavy, DMPD is received at the east tower (Immanuel).

Hey, Rich!

Very interesting.

The older Motorola SpectraTAC analog voter system uses a constant 2kHz. tone over the link from a receiver to the voter to indicate that the receiver is "idle". When a signal is received, the 2kHz. tone is replaced with the received audio. Can it be they're still using an old system like that, coupled with non-microwave links? Odd, indeed!

Maybe Douglas County needs to configure PL / DPL squelch on that repeater to eliminate such repeating!

Originally Posted by IrvingtonVFD43

The Ponca tower has been in the works for a few years, mainly to page Ponca Hills Vol Fire. I don't know where exactly the tower is, but it's intended use is to cover areas of Ponca Hills that that east tower cannot reach, due to terrain. A lot of the PHVFD fire/ems staff have complained for years on missed calls due to coverage issues.

Makes sense - the Immanuel site is quite high, but it's no match for the variable terrain north of I680 and HW75. The OPPD tower would actually be a better location for a transmitter that would probably have no problem replacing both the "east" and "north" towers in the county, as it sits atop the highest hill in the area.

73's

[IrvingtonVFD43]

Originally Posted by KG4WHM

Des Moines PD is on 460.xxxx so how are DC911 receiving them. I don't think they use GE STAR Signaling, I don't remember hear it the last time I drove through there.

Des Moines PD was the suspect transmission that was coming through over east tower. I should have clarified that last post about DMPD it could be most anything east tower is receiving.

Hey, Rich!

Very interesting.

The older Motorola SpectraTAC analog voter system uses a constant 2kHz. tone over the link from a receiver to the voter to indicate that the receiver is "idle". When a signal is received, the 2kHz. tone is replaced with the received audio. Can it be they're still using an old system like that, coupled with non-microwave links? Odd, indeed!

Maybe Douglas County needs to configure PL / DPL squelch on that repeater to eliminate such repeating!

The east tower, does not have a PL/DPL/CTCSS tone. When the 930pm test tones come through, my PRO 96 does not show a PL tone from that tower, unlike south, north and west towers. I asked the chief about that tower, but he didn't have an answer. I am not real sure how the towers are linked. There are no directional/microwave antennas located at either of the sites.

Something noteworthy, the east tower is co-owned by Irvington Vol Fire Inc. and Ponca Hills Vol Fire, Inc., not Douglas County. We contract with them to tone us and, was, Ponca Hills Fire. I'm certain OPPD owns the new Ponca tower, as you mentioned, George.