Tampa Bay Area - fox hunt for a bad transmitter (Metro Tampa)

[kd4efm]

05-26-2020
Evening, looking for anyone in the areas of McDill, Gandy (SOUTH TAMPA) who can get there scanners on
the following freq. 457.5250. This recently started becoming a issue for a customer and spent some time
doing a little DF'ing on it.
Here's what I can tell you,
Lakeland, tower site, I can hear the signal at -78 dBm from customer site to Lakeland, it's a strong output.
Skimmed around tampa 275 north from MLK to Fowler over to USF
USF / VA area, weak signal
275 and I-4 -100 to -110 range but consistent.
Took a spin to Ray-James stadium to see if anything over by TIA would peak, weak signal till i went south to the 275 interchange
east side (fairgrounds) about the same but customer gets it at -60 after preselector and splitter.
Best I can tell this almost sounds like a crossband repeater, and one thing for sure, the voice traffic heard
at times, is a shuttle service, but we doubt they are the culprit, just a casualty of the issue.
I have not been to the 50th street and 60 to towards the south end where TECO and a few other towers are to
sniff those sites, but be curious who hears what where

So McDill and Davis Island areas and south east Tampa areas, i'd be curious to see who hears what there.

Thanks
kd4efm if you have my email, email me.

 

[tampabaynews]

I might be able to help if it's slow tonight. I have UHF yagi I can use. Will text you.

 

[mmckenna]

Good idea. I was thinking of asking for some help finding some interference I'm getting at one of our sites. Considered posting it here to see if anyone could shed some light on it. If it wasn't for COVID, I'd offer up a 6 pack of beer to the winner. Trouble is, mines from a telemetry system, and it only transmits at 11:30am and 2:30 pm, polling sites, very difficult to DF.

Good luck on your hunt!

 

[ecps92]

Any PL/DPL ??

That Freq is a Common Fast Food and Cruise/Maritime Frequency
Altho shocked to see No Cruise Ships in Tampa CruiseShipsTrackingAIS

But plenty of Cargo in Port

MarineTraffic: Global Ship Tracking Intelligence | AIS Marine Traffic

MarineTraffic Live Ships Map. Discover information and vessel positions for vessels around the world. Search the MarineTraffic ships database of more than 550000 active and decommissioned vessels. Search for popular ships globally. Find locations of ports and ships using the near Real Time ships...

www.marinetraffic.com

05-26-2020
Evening, looking for anyone in the areas of McDill, Gandy (SOUTH TAMPA) who can get there scanners on
the following freq. 457.5250. This recently started becoming a issue for a customer and spent some time
doing a little DF'ing on it.
Here's what I can tell you,
Lakeland, tower site, I can hear the signal at -78 dBm from customer site to Lakeland, it's a strong output.
Skimmed around tampa 275 north from MLK to Fowler over to USF
USF / VA area, weak signal
275 and I-4 -100 to -110 range but consistent.
Took a spin to Ray-James stadium to see if anything over by TIA would peak, weak signal till i went south to the 275 interchange
east side (fairgrounds) about the same but customer gets it at -60 after preselector and splitter.
Best I can tell this almost sounds like a crossband repeater, and one thing for sure, the voice traffic heard
at times, is a shuttle service, but we doubt they are the culprit, just a casualty of the issue.
I have not been to the 50th street and 60 to towards the south end where TECO and a few other towers are to
sniff those sites, but be curious who hears what where

So McDill and Davis Island areas and south east Tampa areas, i'd be curious to see who hears what there.

Thanks
kd4efm if you have my email, email me.

 

[radioman2008]

457.525. I have an entry in my database that the McDonalds drivethru system in dunedin on SR580 had/has a constant carrier, i call them zombie systems. possibly theres a fast food place in south Tampa on the freq too.

 

[radioman2008]

guys, if any of you need me to check my discovery history for freq activity, send me a message. i run unidens in modified discovery mode all the time to cover the tampa bay area for history preservation. im currently searching years of history for any 457.525 activity.

 

[kd4efm]

No, this is a complex issue because it has a second harmonic at 467.525, that is 30 dB down, and is a duplicate of whatever is at 457.5250.
That's what makes this complicated. Something has gone into oscillation and is trashing out the 467.525. And yes I know who that is, no need to blast that out also. Thanks for the input in advance.

 

[ecps92]

Harmonic of actually a Repeater ??

Fast Food uses as 10.225 off set, but Cruise Ships and other UHF Maritime interests use 10.00 MHz [Internationally]
where-as the US uses 10.225 Khz and not all ships use PL/DPL some are CSQ

457.5250 R / 467.5250 in
or
467.5250 R / 457.5250 in

Hope some of this helps

Not all follow the U

No, this is a complex issue because it has a second harmonic at 467.525, that is 30 dB down, and is a duplicate of whatever is at 457.5250.
That's what makes this complicated. Something has gone into oscillation and is trashing out the 467.525. And yes I know who that is, no need to blast that out also. Thanks for the input in advance.

 

[kd4efm]

Harmonic of actually a Repeater ??

Fast Food uses as 10.225 off set, but Cruise Ships and other UHF Maritime interests use 10.00 MHz [Internationally]
where-as the US uses 10.225 Khz and not all ships use PL/DPL some are CSQ

457.5250 R / 467.5250 in
or
467.5250 R / 457.5250 in

Hope some of this helps

Not all follow the U

if that was the case, and there was a ship in downtown tampa, I would have gotten a stronger signal when I went west on 60 to 22nd street.
The signal diminished when I got past IKEA. Not to say with all the building in downtown tampa, there was multi-pathing happening, but not ruling this thought out. I will have to look some more. Have you plugged it in and take a listen to it yet?

NOTE: if I have it as -65 to 70 at the fairgrounds, and 600 feet up and south lakeland, at -78 dBm, that's a pretty hefty output.

 

[kd4efm]

There is so much noise I can not get a pl or dpl lock.

 

[ecps92]

Not currently in the area, FLED back to 617

Also don't rule out any US Navy as well.

Spent quite a time years ago tracking down GMRS interference that turned out to be a Cruise Ship
and the signals bounce all over the place as it is designed for on-board

Best of luck in the hunt

if that was the case, and there was a ship in downtown tampa, I would have gotten a stronger signal when I went west on 60 to 22nd street.
The signal diminished when I got past IKEA. Not to say with all the building in downtown tampa, there was multi-pathing happening, but not ruling this thought out. I will have to look some more. Have you plugged it in and take a listen to it yet?

NOTE: if I have it as -65 to 70 at the fairgrounds, and 600 feet up and south lakeland, at -78 dBm, that's a pretty hefty output.

 

[kd4efm]

Well, since about an hour ago, this has just gone quiet, so whatever was broken, it is now BROKE or fixed.
-05-27-2020 @ 11:00

 

[ScubaJungle]

I was wondering why I couldn't see it when I just checked. Hopefully it stays off now.

There seems to be quite a bit of interference and frequencies with multiple protocols/systems on them here in Tampa. 461.875 is another frequency that has some kind of heavy interference - I believe it is Kinder&Morgan, and I think the interference may be from Moffitt's cap+ system, which seems to be causing issues on a few different frequencies.

 

[radioman2008]

reviewed some recordings,
there was a DPL 071, which may or may not be what was contained in the recording, sometimes the actual user of the code starts talking, then a stronger signal takes over, the Uniden continues recording as if it was the original user.

DPL 071 has a woman's voice, I have records of it being heard while in Orlando, and local to Tampa bay
on one recording a stronger signal keys over woman and says "Springhill 3"
these recordings were from 2019

 

[kd4efm]

STATUS UPDATE; the interference has returned and has gotten really bad, from the DF'ing that has been done, it is somewhere around
the fair grounds area close to Hard Rock. If you all could do some listening again on the channels I posted a few months back, this is something going way wrong, for way to long.

457.5250 467.5250
Any hits or RSSI (signal strength) would be helpful.

Thanks

 

[zlandmedia]

I'm a good <10 minutes away up in Thonotosassa off of 301 and I'll see if I can hear anything. Right now those frequencies are silent, but I'm not sure if the transmitting range is that far out either

 

[Bolt21]

Going back through my recordings, on Tuesday morning I had activity on 467.525 while I was inside the Port of Tampa. Freq was being used by a vessel that was berthed at the port. Recordings don't indicate RSSI, but it was loud and clear for sure.

Also FYI, 457.525 (designated US 01) is part of a group of 16 UHF freqs that are designated for United States maritime use. I can't for the life of me find where I found the list on the innerwebs. US 01 receives a decent amount of use by large vessels coming in the port, especially tankers operated by Crowley.

Update - found it: https://scanmaritime.com/frequencies.htm (near the bottom)

 

[ecps92]

Any tone on that Vessel in Tampa ? thoughts on which Ship ?

BTW, altho the US has certain pairs, you will find the International used regularly and even both used inverse
457 is not always the Repeater output

Going back through my recordings, on Tuesday morning I had activity on 467.525 while I was inside the Port of Tampa. Freq was being used by a vessel that was berthed at the port. Recordings don't indicate RSSI, but it was loud and clear for sure.

Also FYI, 457.525 (designated US 01) is part of a group of 16 UHF freqs that are designated for United States maritime use. I can't for the life of me find where I found the list on the innerwebs. US 01 receives a decent amount of use by large vessels coming in the port, especially tankers operated by Crowley.

Update - found it: https://scanmaritime.com/frequencies.htm (near the bottom)

 

[Bolt21]

No tone, and no idea which ship. It did have an American crew, however.

 

[dlwtrunked]

No, this is a complex issue because it has a second harmonic at 467.525, that is 30 dB down, and is a duplicate of whatever is at 457.5250.
That's what makes this complicated. Something has gone into oscillation and is trashing out the 467.525. And yes I know who that is, no need to blast that out also. Thanks for the input in advance.

Do not call 467.525 a "second harmonic". Harmonics are always multiples of the fundamental frequency. It could be a spurious signal from a malfunctioning transmitter (look for more of them in that case), either the input or output of a repeater with the other frequency doing the other purpose (the cruise ship possibility seems like a very good one), or one or both could be the result of intermod (the fact that you hear a second voice on it makes that a definite possibility). Note that intermod is sometimes not caused by the receiver system but either at the trasmitter or other objects near it. When I lived in CT, the signal of one broadcast station antenna got into the transmit antenna of another some distance away, and intermod was generated and transmitted by the second station.

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