FL DOT Low Band hits?

[Dispatrick]

I recently added the FLDOT low band freq's to my low band test bank and I've noticed the past few days I've been getting mic key ups on some of the freq's, no speaking, just key ups on the ones listed below

Has anybody else that monitors these channels ever heard the same thing? Database shows no other users using the same DPL's on any of the freq's.


47.16000 114 D7 2Hillsborough County (Temple Terrace)

47.20000 073 D5 7Osceola County (Kenansville)

47.38000 073 D5 6Seminole County (Sanlando Springs)

47.12000 346 D6 1Miami-Dade County (Hialeah)

47.20000 143 D4 4Palm Beach County (West Palm Beach)

 

[TowerNightWatch]

I recently added the FLDOT low band freq's to my low band test bank and I've noticed the past few days I've been getting mic key ups on some of the freq's, no speaking, just key ups on the ones listed below

Has anybody else that monitors these channels ever heard the same thing? Database shows no other users using the same DPL's on any of the freq's.


47.16000 114 D7 2Hillsborough County (Temple Terrace)

47.20000 073 D5 7Osceola County (Kenansville)

47.38000 073 D5 6Seminole County (Sanlando Springs)

47.12000 346 D6 1Miami-Dade County (Hialeah)

47.20000 143 D4 4Palm Beach County (West Palm Beach)

Ever since I heard FLDOT spent a ton of cash for this new low band system I programmed all the frequencies and only heard one voice contact and that was a truck calling Deland (Volusia County) on 47.38 MHz with no reply. Ever since just a single beep every minute or so. Really doesn't sound like a mic keying up though. I never even heard that on any of the other frequencies to this day. I see the crews all the time and the supervisors always seem to be using cellphones. Go figure.

 

[Dispatrick]

My recording of
47.20000 073 D5 7Osceola County (Kenansville)
is in fact just a single beep! could definitely be a hit on that channel at least!

 

[kkn50]

FLDOT spent a ton of cash for this new low band system - I see the crews all the time and the supervisors always seem to be using cellphones.

Your tax dollars well spent.

 

[wtp]

you should see what a hurricane does to cell towers.
sure a low band antenna will go down, but then you only have to put up one antenna.
and you can talk truck to truck.
cell phone service is useless, until they roll in those temporary towers.

 

[Dispatrick]

Today, again more open mics and a few beeps LOL. Can anyone confirm it is in fact FLDOT ?

 

[jeff]

Yes it is. Radio tests are conducted on the last Thursday of the month. I normally don't hear any traffic on there.

 

[N2AL]

Ever since I heard FLDOT spent a ton of cash for this new low band system I programmed all the frequencies and only heard one voice contact and that was a truck calling Deland (Volusia County) on 47.38 MHz with no reply. Ever since just a single beep every minute or so. Really doesn't sound like a mic keying up though. I never even heard that on any of the other frequencies to this day. I see the crews all the time and the supervisors always seem to be using cellphones. Go figure.

So here is the question. Why did they spend money on a “new” low band system? A lot of agencies are going to 700/800 MHz and UHF systems. I’m certain they had a reason to go low band, I’m not sure what it could be though.

 

[217]

So here is the question. Why did they spend money on a “new” low band system? A lot of agencies are going to 700/800 MHz and UHF systems. I’m certain they had a reason to go low band, I’m not sure what it could be though.

It was designed by amateur radio operators who have knowledge how things work in the real world.

 

[wtp]

since the start of this thread, i put all the dot 47 Mhz freqs in an old pro 2035.
it is the only thing i am listening to on that radio.
as you see i am in charlotte county.
i have not heard a peep.
i do have to try and get up earlier though.

 

[N2AL]

It was designed by amateur radio operators who have knowledge how things work in the real world.

As in everything, there are more than one group of skilled professionals who can properly get the job done. Who knows, maybe some of the engineers and technicians who built the system lacked ham radio licenses.

 

[TampaTyron]

I second the comment that it was designed by hammies. Normally, that is a good thing. However, in this case it seemed to work against the users. The group who designed this network has a real disregard for 800mhz and any sort of trunking. I get it, trunking systems requiring Telco links can be an issue in a disaster. What has happened is that because the system is old school multicast and low band and has a lack of portable radio coverage (I know there are vehicular repeaters in certain districts), it is more difficult to use than the average modern radio system. Over time the users have left the system and moved to cell phones.

The DOT maintains a robust microwave system and has backup power, batteries, etc at their sites. I feel the above issues (mostly related to portable coverage) are holding the system back. I really believe that the time is approaching for a modern trunking system in another band (UHF or 800). There are many great products in the commercial space that could do great things with just a few frequencies at each site. Since I am a Moto fanboy, I would recommend Capacity Max, but it could be anything modern. However, I am guessing that as users get used to doing everything via phone that the demand for radio has diminished enough to become no longer a priority. TT

 

[RFI-EMI-GUY]

The 47 MHz project got a big shot in the arm after one of the major hurricanes where the FDOT had been heavily relying upon NEXTEL and cellular for day to day operations and suddenly cellular service was entirely unavailable in several central and west coast counties for days. The FDOT had already invested in low band mobiles and those worked fine from the field to the yards and offices when the cellular failed. The state had a surplus of 45 and 47 MHz frequencies and Maratrak mobiles galore so that is where it started. At the time SLERS was in its usual state of flux where FDOT was not encouraged operationally nor financially to buy into it.

The reality of making 47 MHz a reliable and viable back up system required much engineering and the utilization of a multicast/voter backbone.

Stand alone low band repeaters were anemic due to the environmental noise floor. However, the cost of this system is relatively tiny compared to SLERS (version 3) and utilizes an existing microwave backbone and towers. It is tremendously simpler than SLERS and thus, if need be it will operate when SLERS fails.

It would be nice to see it get more use. There are some VHF to 47 MHz vehicular repeaters, but not enough to convince folks from dialing in on a smartphone to use a portable. Maybe some 800 MHz vehicular repeaters might attract some SLERS users?

I am told it is tested one day each month. I have been meaning to monitor it.

Some trivia, and full disclosure. I was the principal consultant who designed the FDOT 47 MHz multicast system. There have been some changes. But the frequency plan, sites, noise floor and mobile coverage and interference analysis. That is all on me. The design was performed to EIA TSB-88C, not a hammy thing. Mobiles are supposed to scan for repeaters above a signal threshold and use of DPL (vs CTCSS) was most definitely not part of MY original design (too slow!). A lot of the design work was begun around 2003 per my files.

Would UHF DMR be better? Yes, but it did not exist then, nor does the spectrum exist today.

 

[RFI-EMI-GUY]

Some more trivia

 

[wtp]

still, not a peep.

 

[RFI-EMI-GUY]

It will probably be active for the Zombie Apocalypse!

I think it is tested the last Thursday of each month. You might try dedicating a recorder to it. I am sure the EOC tests it during hurricane events.

The group that manages it, also operates the SARNET UHF amateur radio network on their own time. That system uses same microwave backbone and many of same towers. There is a bit more activity on that.

 

[wtp]

i have a pro2001 with sarasota and fort myers sarnet in, but i know i am out of range of those two.
i have heard ft myers when in their town

 

[TailGator911]

It will probably be active for the Zombie Apocalypse!

Let me just enter that frequency into my Zombie Apocalypse bug-out scanner.

Just in case.

 

[RFI-EMI-GUY]

still, not a peep.

What is your antenna situation?

 

[wtp]

back of the radio, so i expect very little.
i do extend the antennas for the low band.
i am trying to set up an old CB whip, and give that a try.
after many lightning hits in the neighborhood the wife like the "nothing outside" thought.
one electric pole about 1500 feet away was hit 3 times last month.
and i hate to think how many times the UPS boxes have beeped lately.