Fdny uhf vs vhf

Hi folks,

I've been away from NYC for awhile and I've noticed that the new UHF freqs for the FDNY are just AWFUL to monitor vs the older (and thankfully still simulcast) VHF freqs.

I've been in different parts of Manhattan and I just can't believe the difference. The UHF fades in and out and seems far weaker with the audio.

I'm using an Icom IC-R6 with a dual band MFJ ham antenna. I've also had similar (only slightly better) results with the Diamond dual bander (RH77CA), so it's not the antenna.

I hope the FF's aren't having the same problems. I'm going to continue monitoring the VHF freqs for as long as I can.

Any scuttlebutt on whether this is an ongoing problem? Does it indeed affect the pros and not just us scanner hobbyists?

Thanks!

UHF signals penetrate buildings better than VHF signals. The are talking through base stations with high antennas, which work better than a scanner on what, the first or second floor.

I understand, and in fact I receive the NYPD UHF frequencies with no problem. It seems to me that there is something wrong with the FDNY's UHF system, which is relatively new.

Is anyone else in NYC having the same reception issues that I am?

We use a 20-transmitter distributed transmission system. If one of the signals reaches you out of phase it could result in a dropout.

Audiowise, I'm not familiar with those radios but if they're not narrowband it will make us sound way lower than the VHF signal.

If that's not it, it might be the headsets we were ordered to use. They have crappy condenser mics as opposed to the boom mounted, broadcast quality, cardioid mics we were using.

Another cause can be all the analog-to-digital-to-analog conversions the audio path makes. From our mics it gets piped down a voice-over-LAN to Verizon where it gets sent on a T1 to the transmitter site, converted back to analog and sent out.

All of this is my own opinion.

I took the CTCSS off for Brooklyn and SI on the UHF because many times I am am unable to hear the units while when i flip over to VHF they are transmitting.

I also find since the UHF came out a few years, I have always had problems with my scanners hanging up on Brooklyn and The Bronx because the mixer appears to be left on.

FrankRaffa said:

We use a 20-transmitter distributed transmission system. If one of the signals reaches you out of phase it could result in a dropout.

Audiowise, I'm not familiar with those radios but if they're not narrowband it will make us sound way lower than the VHF signal.

If that's not it, it might be the headsets we were ordered to use. They have crappy condenser mics as opposed to the boom mounted, broadcast quality, cardioid mics we were using.

Another cause can be all the analog-to-digital-to-analog conversions the audio path makes. From our mics it gets piped down a voice-over-LAN to Verizon where it gets sent on a T1 to the transmitter site, converted back to analog and sent out.

All of this is my own opinion.

Click to expand...

Hi Frank,

I know your name and so your opinion counts a lot with me!

Maybe it is the digital to analog conversion scheme that you mentioned or a combination of some of the issues you mentioned.

All I know is that at this point, when I visit NYC, I am sticking to the VHF simulcast for monitoring so long as they are kept on the air.

Jimru said:

Hi folks,

I've been away from NYC for awhile and I've noticed that the new UHF freqs for the FDNY are just AWFUL to monitor vs the older (and thankfully still simulcast) VHF freqs.

I've been in different parts of Manhattan and I just can't believe the difference. The UHF fades in and out and seems far weaker with the audio.

I'm using an Icom IC-R6 with a dual band MFJ ham antenna. I've also had similar (only slightly better) results with the Diamond dual bander (RH77CA), so it's not the antenna.

I hope the FF's aren't having the same problems. I'm going to continue monitoring the VHF freqs for as long as I can.

Any scuttlebutt on whether this is an ongoing problem? Does it indeed affect the pros and not just us scanner hobbyists?

Thanks!

Click to expand...

Are you aware that most FDNY HTs do not even have access to the borough frequencies? Those are for mobile radios & command/special ops HTs only, and the equipment they use has much better interference rejection than an R6. Grab yourself a nice cheap Astro Saber or XTS3000 just for FDNY monitoring and see the difference.

Being on the other end from frank, I don't notice any issues. However some scanners i have hate the narrowband FDNY channels.
The UHF are non traditional splinter channels from what i understand, that could be an issue with your radio.

ResQguy said:

Grab yourself a nice cheap Astro Saber or XTS3000 just for FDNY monitoring and see the difference.

Click to expand...

Most UHF Astro Sabers are 403-470mhz, FDNY UHF is between 482-486mhz, keep this in mind if you go looking for an Astro Saber. I keep FDNY in an analog VHF Saber III, much more reliable than the UHF on even the Uniden 436hp.

ResQguy said:

Are you aware that most FDNY HTs do not even have access to the borough frequencies? Those are for mobile radios & command/special ops HTs only, and the equipment they use has much better interference rejection than an R6. Grab yourself a nice cheap Astro Saber or XTS3000 just for FDNY monitoring and see the difference.

Click to expand...

ResQguy,

If I still lived in NYC, I would definitely consider that! I know that the pro HTs are far more sensitive and selective than any scanner out there (not to mention more durable). However, when I travel, I take public transit and travel as light as I can. For visiting NYC, the Icom R6 is perfect because of it's small size and wide coverage. In addition, since all the action in NYC is still conventional analog, I don't even bother bringing my trunking HT here when I visit.

I knew several ARES guys in the NYC district that had Moto HTs and they were advocates of using them over your typical ham HT, for the very reasons you mention.

tbendick said:

Being on the other end from frank, I don't notice any issues. However some scanners i have hate the narrowband FDNY channels.

The UHF are non traditional splinter channels from what i understand, that could be an issue with your radio.

Click to expand...

It's funny you should mention that. Even though the R6 has the narrow band steps (6.25) for UHF, I'm pretty sure that the guts of the radio are not really adept at receiving narrow band. Now that you mention it, that might actually be a big part of the problem!

"Splinter channel" refers to 800 MHz, not UHF.

There is nothing at all special about the FDNY UHF frequencies. They are plain old 12.5 kHz narrowband with standard 6.25 kHz stepping.

As always, it helps to have the correct receiving equipment that is setup correctly before blaming the radio system.

Just my observation

Ok if I may add my observation from my location.
A little background.... I am a few hundred feet from Long Island Sound and up 130 feet above sea level. I use a Diamond discone antenna among others. It is up on a 20 foot mast from the ground.
I can receive the New Jersey State TRS North Zone from the west, and I get into the Cape Cod Amateur repeaters on a daily basis to the east. So as far as NYC, I can hear most of the UHF NYPD precincts using the discone, and all of the citywide repeaters (like SOD) just using a rubber duck on an HT sitting on the kitchen table. I hear all of the FDNY boroughs on VHF loud and clear. Of course band conditions vary on a daily basis where some days we get some VHF band enhancements better than other days. But in general, the UHF FDNY repeaters are by far among the weakest NYC transmitters that I receive out my way. And I also notice the phase problem here where the signal varies up and down. I understand the type of system this is. They use several lower power transmitters instead of a handful of high power transmitters as on VHF. Much like the Coast Guard Rescue 21 system. No more "Hi Sites" like they used to have.
So yes, even at my great receive location here, the FDNY UHF reception is fair at best. And I monitor them using a very sensitive Kenwood TK-390. For comparison, I can receive the Manhattan Zone 1 on 476.5625 using this Kenwood with the rubber duck far better than the FDNY repeaters.
Good to hear from Frank out there. This is a great thread with a lot of knowledgeable folks.
Bob
Milford Ct.

dmb41crash said:

"Splinter channel" refers to 800 MHz, not UHF.



There is nothing at all special about the FDNY UHF frequencies. They are plain old 12.5 kHz narrowband with standard 6.25 kHz stepping.



As always, it helps to have the correct receiving equipment that is setup correctly before blaming the radio system.

Click to expand...

Well, again, all I can say is that I am an average scanner hobbyist at best and the portable equipment I use has been more than adequate for years. As I stated before, I receive the NYPD UHF, both the precinct zones and special ops, etc, with no problems, both indoors and out, as well as never having had any issues whatsoever receiving the FDNY VHF channels.

So, my conclusion is that if there is nothing actually WRONG with FDNY's UHF system, then it is certainly DIFFERENT enough in some ways so as to make reception on my part difficult. I concur that my consumer grade equipment may not be up to snuff for receiving this system.

It's not an actual problem for me, so long as FDNY continues to simulcast in VHF.

I started this thread as I was curious to know if anyone else was having a similar issue with this UHF system.

Thanks to everyone for your input!

I was in NYC last week for 3 days,I have noticed the UHF FDNY frequencies tend to fade in and out on my Kenwood radio while driving around in Manhattan vs the VHF.(Does the 6.25 spacing affect it?) Im not a tech,Just curious.

When I go into the city, all of my ham/general coverage stuff gets desensed to the point of being noticed - even on ham frequencies. We have to use HT1000 radios because the other ones are too wide and don't have as much usable range despite them being about equal in other less RF dense areas. That may be part of it. The 6.25 kHz offset from the standard channel centers may make reception sound "fuzzy" if the receiver can't tune exactly on frequency. And, as Frank mentioned, simulcast systems have multiple transmitters coming up in phase. If there's multipath (in Manhattan? Who knew?) there could be cancellation and nulls. If the signals were digital, the error correction usually compensates for those, but they could be noticeable in analog, especially when the passband is either too tight, too loose, or the receiver is off frequency.

Those are just my observations. It's hard to armchair what you're experiencing without actually seeing/hearing it in action.

What is the future regarding FDNY radio communication? Are they eventually going to dump the VHF frequencies? Someone mentioned that many of the mobile units do not have the capability to access the main borough dispatch frequency, therefore I am assuming they use the simplex tac channels mostly? I noticed there are several tac channels listed in the db, but which ones are used primarily "on scene" most often? Lastly, I also always wondered if the FDNY Ambulance vehicles used the EMS frequencies or FDNY frequencies? Sorry for all the questions, but I wanted to take advantage since this thread was started.

FDNY fire units have UHF mobile radios.
They can access any fire or ems dispatch channel

The portable fire radios are only TAC no dispatch in them , with some exceptions

Ems mobiles have ems only
Ems portables have ems and will have fire TAC channels soon

Support vehicles might still have vhf but they are switching everything to UHF. Exceptions would been grand Central and penn station which have in building vhf repeaters

This is what I always thought was the issue. From one of the DOITT/FCC documents

Use of Non-Standard Channel Centers
DoITT is currently licensed for non-standard channel centers under its current
licenses. Non-standard channel centers were fully coordinated by APCO, as allowed by
the rules. Instead of licensing on the “original” channel centers and on channels offset by
12.5 kHz from those, DoITT is licensed on channels offset from the “original” channel
centers by 6.25 kHz. This permits DoITT to form two 12.5 kHz bandwidth channels
within each “original” 25.0 kHz bandwidth channel.4
DoITT believes that this
channeling plan is more efficient that using standard original and offset channel centers,
as the DoITT channeling plan has no impact on adjacent 25.0 kHz bandwidth licensees.
DoITT can always obtain two 12.5 kHz bandwidth channels from each original channel.
This might not always be the case if standard offsets were used, as use of those offsets
could be blocked by incumbent original channel licensees. Use of the standard offset
channels affects two original 25.0 kHz channels, whereas the DoITT plan never affects
more than one original 25.0 kHz channel.

Any words if FDNY will simulcast on the 700 system?