This is kind of wierd; my partner and I were in the back of the ambulance on scene with a patient approximately four miles from the hospital we were going to call on the radio. He selected the proper H.E.A.R. channel (VHF) on the Maxtrac to call the hospital and began to call.
The wierd thing is that we could not hear the hospital's reply over the Maxtrac but on my HT1000 of which was on a totally different VHF frequency! I programmed my HT1000 myself and I know that I do not have the H.E.A.R. vhf frequency programmed in. I was standing about five feet away from the Maxtrac. Was the Maxtrac rebroadcasting the channel onto one of the frequencies on my portable? Just very odd...
Wierd radio experience...H.E.A.R. radio ghost?
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Dan562
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Wierd radio experience...H.E.A.R. radio ghost?
Perhaps, Did this Ghost problem happen on Holloween?
The old H.E.A.R. systems on VHF had 1500 Hz Pulsed Digital Decoders in their Base Station Remote chassis. The Pulsed Digital Decoder was installed because of two reasons. First, not all of the Ambulances had the correct PL Encoder reeds for all the hospitals in their area that they shuttled patients into the ER Depts. Secondly the hospital's ER Dept didn't want to listen to all of the voice traffic on the RF channel so their Base Station receivers had PL Decoders to Mute the unwanted signals.
The Digital Decoders were originallly set up for three letters and three numbers to designate which city and what hospital. As an example I'll use Chicago and random numbers: CHI567. When the Ambulance needed to contact the nearest hospital's ER Dept to consult with the doctors, they would "Rotary Dial" in the CHI567 in and the hospital's ER Dept Base Station's receiver and 1500 Hz Pulsed Digital Decoder would decode the proper sequence, PL Disable the receiver placing it in the Carrier Squelch mode till all voice and/or data traffic was completed. Once all the traffic had been passed on the patient, the doctor or a nurse would push a button on the console plus the PTT switch and digital decoder would reset the station's audio path back to the Mute mode and ready for the next call.
As technology changed for PL Encoders / Decoders from "reeds" to electronic circuits, the mobiles ordered with standard options as multiple PL Encode / Decode would allow the Ambulances to just enter the proper PL code and transmit into the hospital's ER Dept. Many States dropped the requirements for the 1500 Hz Pulsed Digital Decoders because they were not needed any longer.
The 1500 Hz Pulsed Encoders / Decoders were giving way to newer technology. A request by the customers to switch to DTMF codes and these were developed and installed into chassis card cages in the Base Station and Consoles to perform the same or similar functions. The DTMF Encoder pads were incorporated into mobile microphones and on the Front Covers of handheld portable units.
These special 1500 Hz Encoders / Decoders were starting to wind down till roughly 1998 when many hospitals in various states required new Base Stations with the older requirements. /\/\ developed a new 1500 Hz Pulsed Digital Decoder but for some odd reason, all of the Hot field requests dropped off the face of the earth. They were doing 1 or 2 a year as SP Options. I suspect that Zetron was getting all of the sales since their product ran circles around /\/\.
Quite a while after Sept 11, 2001, the /\/\ Marketing and Brand personnel didn't envision any future sales with this product and decided to Cancel the C805ADSP Digital Decoder. During first quarter of 2004, roughly 4 months after the Product Cancellation, there were 10 separate SP Bid & Quote Request for the new Obsolete option but the materials group and warehouse personnel scrapped all of the required hardware and modules so the field requests had to be refused to the customers. The lack of vision by /\/\ Marketing and Brand personnel caused the company to lose out on revenue $$$$$$ for their decision. Oddly enough this time around the requests were from the new Homeland Security requirements. I'll bet Zetron is cleaning up big time $$$$$$ because of /\/\ mistake.
My question to the individual that has the HT1000. Was your HT1000 programmed in Carrier Squelch on that RF Channel while your receiver's audio opened up with the HEAR traffic? Since I'm guessing the Maxtrac is mounted in a remote location within the ambulance. I'm thinking that you could have experienced a frequency mix beating against your handheld portable's local oscillator producing a third frequency. If you had the proper test equipment and swept the RF Preselector, you would notice that those have very broad receiver bandwidths. The other issue when 2 frequency beat producing a 3rd there would need to be "X" amount of RF to produce the mix and it doesn't need to be on the HEAR frequency.
Dan
The old H.E.A.R. systems on VHF had 1500 Hz Pulsed Digital Decoders in their Base Station Remote chassis. The Pulsed Digital Decoder was installed because of two reasons. First, not all of the Ambulances had the correct PL Encoder reeds for all the hospitals in their area that they shuttled patients into the ER Depts. Secondly the hospital's ER Dept didn't want to listen to all of the voice traffic on the RF channel so their Base Station receivers had PL Decoders to Mute the unwanted signals.
The Digital Decoders were originallly set up for three letters and three numbers to designate which city and what hospital. As an example I'll use Chicago and random numbers: CHI567. When the Ambulance needed to contact the nearest hospital's ER Dept to consult with the doctors, they would "Rotary Dial" in the CHI567 in and the hospital's ER Dept Base Station's receiver and 1500 Hz Pulsed Digital Decoder would decode the proper sequence, PL Disable the receiver placing it in the Carrier Squelch mode till all voice and/or data traffic was completed. Once all the traffic had been passed on the patient, the doctor or a nurse would push a button on the console plus the PTT switch and digital decoder would reset the station's audio path back to the Mute mode and ready for the next call.
As technology changed for PL Encoders / Decoders from "reeds" to electronic circuits, the mobiles ordered with standard options as multiple PL Encode / Decode would allow the Ambulances to just enter the proper PL code and transmit into the hospital's ER Dept. Many States dropped the requirements for the 1500 Hz Pulsed Digital Decoders because they were not needed any longer.
The 1500 Hz Pulsed Encoders / Decoders were giving way to newer technology. A request by the customers to switch to DTMF codes and these were developed and installed into chassis card cages in the Base Station and Consoles to perform the same or similar functions. The DTMF Encoder pads were incorporated into mobile microphones and on the Front Covers of handheld portable units.
These special 1500 Hz Encoders / Decoders were starting to wind down till roughly 1998 when many hospitals in various states required new Base Stations with the older requirements. /\/\ developed a new 1500 Hz Pulsed Digital Decoder but for some odd reason, all of the Hot field requests dropped off the face of the earth. They were doing 1 or 2 a year as SP Options. I suspect that Zetron was getting all of the sales since their product ran circles around /\/\.
Quite a while after Sept 11, 2001, the /\/\ Marketing and Brand personnel didn't envision any future sales with this product and decided to Cancel the C805ADSP Digital Decoder. During first quarter of 2004, roughly 4 months after the Product Cancellation, there were 10 separate SP Bid & Quote Request for the new Obsolete option but the materials group and warehouse personnel scrapped all of the required hardware and modules so the field requests had to be refused to the customers. The lack of vision by /\/\ Marketing and Brand personnel caused the company to lose out on revenue $$$$$$ for their decision. Oddly enough this time around the requests were from the new Homeland Security requirements. I'll bet Zetron is cleaning up big time $$$$$$ because of /\/\ mistake.
My question to the individual that has the HT1000. Was your HT1000 programmed in Carrier Squelch on that RF Channel while your receiver's audio opened up with the HEAR traffic? Since I'm guessing the Maxtrac is mounted in a remote location within the ambulance. I'm thinking that you could have experienced a frequency mix beating against your handheld portable's local oscillator producing a third frequency. If you had the proper test equipment and swept the RF Preselector, you would notice that those have very broad receiver bandwidths. The other issue when 2 frequency beat producing a 3rd there would need to be "X" amount of RF to produce the mix and it doesn't need to be on the HEAR frequency.
Dan
HEAR and the military.
Hello.
The standard military radio is set up in HEAR fashion.
The primary signalling tone is 1500Hz and/or 1600Hz low and 2600Hz high.
This follows the old IMTS standard, so the telephone dial.
The PL for ALL military radios is 150Hz.
Signalling is as follows.
RX 1600Hz, light the yellow lamp and/or buzzer, all units on channel.
RX 1500Hz, route to SelCal unit for decode.
RX 2600Hz, Idle and SelCal.
RX 150Hz tone, open audio, all units on channel.
Not all military radios can decode DTMF, and you need to send a 2600Hz preamble anyway, so the system secode set up for the military in the early 50s is still your best bet.
The standard military radio is set up in HEAR fashion.
The primary signalling tone is 1500Hz and/or 1600Hz low and 2600Hz high.
This follows the old IMTS standard, so the telephone dial.
The PL for ALL military radios is 150Hz.
Signalling is as follows.
RX 1600Hz, light the yellow lamp and/or buzzer, all units on channel.
RX 1500Hz, route to SelCal unit for decode.
RX 2600Hz, Idle and SelCal.
RX 150Hz tone, open audio, all units on channel.
Not all military radios can decode DTMF, and you need to send a 2600Hz preamble anyway, so the system secode set up for the military in the early 50s is still your best bet.
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Dan562
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H.E.A.R. Decoding
Now the HEAR Decoding scheme makes more sense as a derivative of a TELCO Standard. I believe the first HEAR decoders were developed in the 1960s for the Motrac Product Line. These decoders also had a feature called "All Call" a two digit code like 22 and every Base Station receiver would open up and be placed in Carrier Squelch. I supposed this could have been used for a disaster scene.
Unlike the military radios all using the 150 Hz PL ot CTCSS Decoder, all of hospitals were set up with different PL Codes so the co-channel users did not bother each other while passing voice traffic.
I had heard earlier this year that Homeland Security was making requests to hospitals that their Digital Decoders should be capable of a combination of 1500 Hz Pulse and DTMF schemes which both outputs would need to feed an "And Gate" before disabling the PL Decoder into the Carrier Squelch mode. This requirement seems like one step forward and 40 years back by adding precious time to save people's lives. That's our government at work for us!
Dan
Unlike the military radios all using the 150 Hz PL ot CTCSS Decoder, all of hospitals were set up with different PL Codes so the co-channel users did not bother each other while passing voice traffic.
I had heard earlier this year that Homeland Security was making requests to hospitals that their Digital Decoders should be capable of a combination of 1500 Hz Pulse and DTMF schemes which both outputs would need to feed an "And Gate" before disabling the PL Decoder into the Carrier Squelch mode. This requirement seems like one step forward and 40 years back by adding precious time to save people's lives. That's our government at work for us!
Dan
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chipjumper
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Dano,
Yes, the VHF Maxtrac is in the rig with a VHF "plastic domed" transit antenna on the roof above. I don't have the HEAR freq in my HT1000.
Its just really wierd because the Maxtrac would not receive the hospital and my portable would receive them without difficulty (it was on scan;didn't even think about locating the spooky channel in question).
Worked last Tuesday and couldn't recreate the problem.
Yes, the VHF Maxtrac is in the rig with a VHF "plastic domed" transit antenna on the roof above. I don't have the HEAR freq in my HT1000.
Its just really wierd because the Maxtrac would not receive the hospital and my portable would receive them without difficulty (it was on scan;didn't even think about locating the spooky channel in question).
Worked last Tuesday and couldn't recreate the problem.
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Dan562
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H.E.A.R. a Ghost in my radio
H.E.A.R. YE, H.E.A.R. YE!
I believe what you experienced was an intermodulation signal mixing on your HT1000 handheld portable since it was in the scan mode and you don't recall what RF channel the scanner stopped on, it would be almost impossible to recreate that same scenario. Since the HT1000 and the Maxtrac radios are both synthesized, the internal VCOs could radiate enough signal in the receive mode to create such a problem between the units.
What has me a little bit puzzled is why the Maxtrac didn't receive the RF signal from the Hospital's Base Station unless the intermodulation signal was strong enough to block the Maxtrac's on channel receive frequency while all the conditions were just right for this to take place.
Dan
I believe what you experienced was an intermodulation signal mixing on your HT1000 handheld portable since it was in the scan mode and you don't recall what RF channel the scanner stopped on, it would be almost impossible to recreate that same scenario. Since the HT1000 and the Maxtrac radios are both synthesized, the internal VCOs could radiate enough signal in the receive mode to create such a problem between the units.
What has me a little bit puzzled is why the Maxtrac didn't receive the RF signal from the Hospital's Base Station unless the intermodulation signal was strong enough to block the Maxtrac's on channel receive frequency while all the conditions were just right for this to take place.
Dan
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chipjumper
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Maybe this may help ...
I had a similar sitation happen about 15 years ago and here's what we found out:
The Micor-era HEAR base stations (with those infamous red, black and white T1600 tone remote control units with a telephone dial mounted on them) were capable of transmit and receive on multiple frequencies. In our area, 155.34 MHz was the regional call-in channel and was shared by dozens of hospitals and scores of ambulances throughout this part of the state. The hospitals had a second frequency, 155.22 MHz or 155.28 MHz (I can't remember) which was supposed to be used for "regional inter-hospital coordination". If The Big One ever occured and normal modes of communication (the phone) failed, the ER nurse or whoever was supposed to switch to "F2" and dial up other area hospitals to see who had available bed space, etc.
Works great on paper.
These Micors had auxiliary receivers that always monitored 155.34 MHz regardless of where the frequency selector was set and would decode with (a) the correct PL tone, or (b) the correct 1500 hZ pulse dial code. The ER staff could switch everthing to carrier squelch AND monitor more than one frequency by pressing a button on the T1600 marked "Emergency". When that occured, the auxiliary receiver on 155.34 MHz went into carrier squelch along with whatever channel had been selected on the regular F1/F2/F3/F4 button rack.
Regardless of what was being received, the Micor would only transmit on the manually selected F1, F2, F3 or F4 button. There was no visual indication to the ER staff which channel was being received. All they knew was that someone was calling.
To complicate this mess, 155.34 MHz became overloaded and the city and county where the hospital group was located switched their squads to 155.40 MHz, with 155.34 MHz still being used for out of county EMS services and private transport services that couldn't afford -- or didn't have the channel space -- to re-crystal those Micor, Mocom 70 and Mastr II rock bound radios. The ER staffs were now required to identify the squad calling in and switch to the appropriate frequency first before transmitting.
Radio service on the HEAR bases was a hodgepodge affair, with a number of radio service vendors doing their own thing. In one hospital, 155.40 was placed in the auxiliary receiver to always be "hot". At another hospital, the F1 button wouldn't make contact correctly. Instead of fixing the switch, they moved F1 to F4 because that button was unused and still worked. In yet another location, the inter-facility channel was removed and 154.54 MHz was inserted to allow the ER to talk directly with their hospital security officers.
The nurses had no idea about all these inner workings. All they understood was when the radio talked to them, you picked up that telephone handset and squeezed the button and talked back to the ambulance. They didn't know about auxiliary receivers or understand they should check the transmit frequency first. Most of the T1600's I saw had Dymo labelmaker, handmade signs and hospital tape covering certain buttons and telling staff what buttons and switches to push or not to push under specific circumstances.
In our situation, we found the ER staff hearing the call on 155.34 MHz, but the wrong transmit button had been pushed. The Emergency button had been pressed and both channels were in carrier squelch mode on simultaneous receive. The nurse was (unintentionally) transmitting back to the squad on the hospital security channel, but could still hear the EMS unit calling back on 155.34 MHz thanks to the always hot auxiliary receiver. That particular squad had the hospital security channel installed in their main 99 channel radio, and heard the hospital talking back on the 'radio in the front of the truck'.
Sometimes truth is a better story than fiction. Find out the hospital's set-up and see what common frequencies your portable shares with the HEAR base station. Most of the original HEAR bases are a rat's nest of cob job modifications. Have fun!
I had a similar sitation happen about 15 years ago and here's what we found out:
The Micor-era HEAR base stations (with those infamous red, black and white T1600 tone remote control units with a telephone dial mounted on them) were capable of transmit and receive on multiple frequencies. In our area, 155.34 MHz was the regional call-in channel and was shared by dozens of hospitals and scores of ambulances throughout this part of the state. The hospitals had a second frequency, 155.22 MHz or 155.28 MHz (I can't remember) which was supposed to be used for "regional inter-hospital coordination". If The Big One ever occured and normal modes of communication (the phone) failed, the ER nurse or whoever was supposed to switch to "F2" and dial up other area hospitals to see who had available bed space, etc.
Works great on paper.
These Micors had auxiliary receivers that always monitored 155.34 MHz regardless of where the frequency selector was set and would decode with (a) the correct PL tone, or (b) the correct 1500 hZ pulse dial code. The ER staff could switch everthing to carrier squelch AND monitor more than one frequency by pressing a button on the T1600 marked "Emergency". When that occured, the auxiliary receiver on 155.34 MHz went into carrier squelch along with whatever channel had been selected on the regular F1/F2/F3/F4 button rack.
Regardless of what was being received, the Micor would only transmit on the manually selected F1, F2, F3 or F4 button. There was no visual indication to the ER staff which channel was being received. All they knew was that someone was calling.
To complicate this mess, 155.34 MHz became overloaded and the city and county where the hospital group was located switched their squads to 155.40 MHz, with 155.34 MHz still being used for out of county EMS services and private transport services that couldn't afford -- or didn't have the channel space -- to re-crystal those Micor, Mocom 70 and Mastr II rock bound radios. The ER staffs were now required to identify the squad calling in and switch to the appropriate frequency first before transmitting.
Radio service on the HEAR bases was a hodgepodge affair, with a number of radio service vendors doing their own thing. In one hospital, 155.40 was placed in the auxiliary receiver to always be "hot". At another hospital, the F1 button wouldn't make contact correctly. Instead of fixing the switch, they moved F1 to F4 because that button was unused and still worked. In yet another location, the inter-facility channel was removed and 154.54 MHz was inserted to allow the ER to talk directly with their hospital security officers.
The nurses had no idea about all these inner workings. All they understood was when the radio talked to them, you picked up that telephone handset and squeezed the button and talked back to the ambulance. They didn't know about auxiliary receivers or understand they should check the transmit frequency first. Most of the T1600's I saw had Dymo labelmaker, handmade signs and hospital tape covering certain buttons and telling staff what buttons and switches to push or not to push under specific circumstances.
In our situation, we found the ER staff hearing the call on 155.34 MHz, but the wrong transmit button had been pushed. The Emergency button had been pressed and both channels were in carrier squelch mode on simultaneous receive. The nurse was (unintentionally) transmitting back to the squad on the hospital security channel, but could still hear the EMS unit calling back on 155.34 MHz thanks to the always hot auxiliary receiver. That particular squad had the hospital security channel installed in their main 99 channel radio, and heard the hospital talking back on the 'radio in the front of the truck'.
Sometimes truth is a better story than fiction. Find out the hospital's set-up and see what common frequencies your portable shares with the HEAR base station. Most of the original HEAR bases are a rat's nest of cob job modifications. Have fun!
DTMF or pulsed tone.
Hello.
The reason for the request for this is quite simple.
Military radios 'round the world have this standard.
It does nothing more than drop the radio out of PL/DPL.
It has NO effect on the radio in ANY other manner.
It does not slow anyone down, and will allow the military and local hospitals to communicate directly
The reason for the request for this is quite simple.
Military radios 'round the world have this standard.
It does nothing more than drop the radio out of PL/DPL.
It has NO effect on the radio in ANY other manner.
It does not slow anyone down, and will allow the military and local hospitals to communicate directly
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Dan562
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H.E.A.R. the truth
As the dust settles on this subject .... Rick W8CMI jogged my memory regarding the multi-frequency with if I'm not mistaken Rotary Dial Encoder and Handset on the T1600 TRC Consoles. So let me say I was mistaken about a possibility of Intermodulation as being part of the cause to this problem that the ambulance personnel experienced enroute to the hospital's ER.
I can understand Rick's observation as the H.E.A.R. systems were deployed out to the hospital market ... almost no ryme or reason for frequency assignments T1 through T4 and all the receivers switching from PL (CTCSS) to the Carrier Squelch mode up on Pulsed Decoder Squence. And on top of that the Doctors / Nurses knowning which channel you're suppose to be on to respond to the ambulance. In today's ER, the Doctors and Nurses are so overwhelmed with critic care patients, they can barely the patients straignt and under control.
On today's /\/\ Base Stations and Consoles, it would be easy to enable the 2175 Hz Status Tone down to the Console having either a flashing LED or on the high tier consoles flashing display field indicating the activity on the H.E.A.R. channel. It the LED or CRT Field flashing? Then activate the Channel button and PTT. Of course, there's got to be a Standardized T1 - T4 system configuration and acceptance throughout the U.S. which might be the most difficult to accomplish with every hospital's political polocies.
Now I understand Homeland Security policy to incorporate the military's signaling format into our commercial business band Land Mobile Radio enterprises to reintroduce older technology into the 21st century equipment. (This is only my opinion) If our government really was forward thinking about the future, why in the world didn't they make a mandate to change the hospitals to the digital formats just like they have directed all of their agencies, the state and the local governments??
Oh I better get off of that issue, it burns me to no end.
Dan
I can understand Rick's observation as the H.E.A.R. systems were deployed out to the hospital market ... almost no ryme or reason for frequency assignments T1 through T4 and all the receivers switching from PL (CTCSS) to the Carrier Squelch mode up on Pulsed Decoder Squence. And on top of that the Doctors / Nurses knowning which channel you're suppose to be on to respond to the ambulance. In today's ER, the Doctors and Nurses are so overwhelmed with critic care patients, they can barely the patients straignt and under control.
On today's /\/\ Base Stations and Consoles, it would be easy to enable the 2175 Hz Status Tone down to the Console having either a flashing LED or on the high tier consoles flashing display field indicating the activity on the H.E.A.R. channel. It the LED or CRT Field flashing? Then activate the Channel button and PTT. Of course, there's got to be a Standardized T1 - T4 system configuration and acceptance throughout the U.S. which might be the most difficult to accomplish with every hospital's political polocies.
Now I understand Homeland Security policy to incorporate the military's signaling format into our commercial business band Land Mobile Radio enterprises to reintroduce older technology into the 21st century equipment. (This is only my opinion) If our government really was forward thinking about the future, why in the world didn't they make a mandate to change the hospitals to the digital formats just like they have directed all of their agencies, the state and the local governments??
Oh I better get off of that issue, it burns me to no end.
Dan
Hosptial's
Extremely
Antique
Radio
Hmmmmmmmmm?
Oh, c'mon now. Doesn't everyone have an 800 apco 25 astro system like we do in S.E. Mi.?
WHAT A CROCK!!!!!!!!!!!!!
No wonder there are ham/turkey/pastrami's on rye radios for back-up.
Jimmy
Extremely
Antique
Radio
Hmmmmmmmmm?
Oh, c'mon now. Doesn't everyone have an 800 apco 25 astro system like we do in S.E. Mi.?
WHAT A CROCK!!!!!!!!!!!!!
No wonder there are ham/turkey/pastrami's on rye radios for back-up.
Jimmy
"well, well, well, A drunk driver doesn't go out and drive once drunk now do they?"
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chipjumper
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I only use H.E.M.S. (HEAR contractor in western wayne county, they are the human equivalent of a PL selector) on the radio for principal of the matter. If I really need to call without the "say again, you were broken BS" I can call a landline number on my cell and get a phone patch that works flawlessly! Its just the principal...I don't know why we just can't dial in the PL. sillyness...
HEAR contractor in western wayne county, they are the human equivalent of a PL selector.
The one operator has got to be pushing 80 yrs. old. and have to wake her up in the early morning .
Wow, a neighbor! With this new system coming on board, I think that operatons may go on the wayside. Look what hapened to Oakland co.
The HEAR gets get overloaded especially during skip season, whereas all the distant high/lo-power stations can be heard even on an HT. But ya gotta have the power to cut through the metro area.
Jimmy
The one operator has got to be pushing 80 yrs. old. and have to wake her up in the early morning .
Wow, a neighbor! With this new system coming on board, I think that operatons may go on the wayside. Look what hapened to Oakland co.
The HEAR gets get overloaded especially during skip season, whereas all the distant high/lo-power stations can be heard even on an HT. But ya gotta have the power to cut through the metro area.
Jimmy
"well, well, well, A drunk driver doesn't go out and drive once drunk now do they?"
HEAR
THIS HAPPENS ALL THE TIME HERE IN N.W JERSEY!WE DISPATCH ON 155.295/PL#141.3.,THE HEAR RADIO IS ON:155.340/PL#141.3.ITS JUST TOO CLOSE!
CHUCK....YOU SHOULD HAVE KNOWN THIS!!!!!!!!
CHUCK....YOU SHOULD HAVE KNOWN THIS!!!!!!!!
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chipjumper
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and this wundeful thing they try to do with the phone patch from the console............Jeeeeeeeeeesh!!!!!!!
You'd be pulling into the ER before someone answeres the phone. Yes a regular cell phone does a much better job.
Jimmy
You'd be pulling into the ER before someone answeres the phone. Yes a regular cell phone does a much better job.
Jimmy
"well, well, well, A drunk driver doesn't go out and drive once drunk now do they?"
Landline.
Hello.
Digital may be fine for some applications.
Fireground, it would seem, is not one of them.
The reason that homeland security is pushing things like SMART signalling is that it works.
After a tornado ripped out the local telephone exchange in a community in Texas, ALL the telephones were dead, landline AND cellular.
The state police VHF radios did not skip a beat (DPS).
The military radios worked just fine, Thank you.
The only hospitals with working radios were the ones with "this old ___, etc,".
Again, dial-up pagers, no go, cell phones, no go.
The area wide trunking system was dead, and talkaround on 800MHz is really short range.
The attacks of Sept 11 2001, likewise, cellular was all but dead.
You Could make a call from some payphones, if it worked and you were willing to stand in line.
New Yorkers will stand in line for anything.
The bad thing about all of this?
This has happened several times in Texas.
Digital may be fine for some applications.
Fireground, it would seem, is not one of them.
The reason that homeland security is pushing things like SMART signalling is that it works.
After a tornado ripped out the local telephone exchange in a community in Texas, ALL the telephones were dead, landline AND cellular.
The state police VHF radios did not skip a beat (DPS).
The military radios worked just fine, Thank you.
The only hospitals with working radios were the ones with "this old ___, etc,".
Again, dial-up pagers, no go, cell phones, no go.
The area wide trunking system was dead, and talkaround on 800MHz is really short range.
The attacks of Sept 11 2001, likewise, cellular was all but dead.
You Could make a call from some payphones, if it worked and you were willing to stand in line.
New Yorkers will stand in line for anything.
The bad thing about all of this?
This has happened several times in Texas.
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Wile E. Coyote
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In Iowa they have had a H.E.A.R. standard in place since 1972. somewhere around here I think I have a copy of the origional specs. Like many states they use 1500 pulse dial. I feel that the state needs to take a close look at these standards and update them to newer technology. All to often I have put a nice new radio in a nice new ambulance with an aging cobbled up pulse dialer jerry rigged into the radio.
sorry for the vent but it is time for a change - nothing drastic, just an update.
-WEC
sorry for the vent but it is time for a change - nothing drastic, just an update.
-WEC
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chipjumper
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- Joined: Thu Nov 21, 2002 10:14 pm
- What radios do you own?: XTS5000 for work
They do a phone patch from my cellphone to the radio...works VERY well; they have a special phone number to call. I have no clue how they do it but when she answers the phone, she acts like you were calling on the radio---I also treat the conversation as if I was using a radio too.ALF 935 wrote:and this wundeful thing they try to do with the phone patch from the console............Jeeeeeeeeeesh!!!!!!!
You'd be pulling into the ER before someone answeres the phone. Yes a regular cell phone does a much better job.
Jimmy
But yes you are right; if you call an ER direct you usually ring...ring...ring...ring...
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PropellorHead
- was LACityFD
- Posts: 224
- Joined: Mon Dec 09, 2002 10:35 pm
- What radios do you own?: XTS 5000 to Mocom
We use HEAR in Los Angeles County, but only as a backup. Normal base contact is made via cellular or on UHF frequency pairs. However, all paramedic (advanced life support) units must still carry a VHF HEAR radio.
In LA it stands for Hospital Emergency Alert Radio, although I have heard it referred to as Hospital Emergency Ambulance Radio.
Louie
In LA it stands for Hospital Emergency Alert Radio, although I have heard it referred to as Hospital Emergency Ambulance Radio.
Louie
HEAR and updating.
Hello.
I asked myself the same question.
Why not update the dial format, at least DTMF.
The answer I was given was 3 fold.
The military radios actually key the transmitter with the tone, pulsing with the tone, this makes for EXCELLENT range.
No trouble with tone pair twist.
The second reason is that although you could generate the tone and key it at a 10 or 20 pulse per second rate, 60/40%, this is not a consumer item.
The chances of some hamtastic getting a wild hair is less this way.
The last, almost every military in the world, former warsaw pact included, have this.
The reason 1500Hz was picked is to allow for military radios to be able to decode this if need be, but allow the military 1600 Hz standard to stay.
Just close enough to fall in the bandpass, just far enough to tell them apart.
I asked myself the same question.
Why not update the dial format, at least DTMF.
The answer I was given was 3 fold.
The military radios actually key the transmitter with the tone, pulsing with the tone, this makes for EXCELLENT range.
No trouble with tone pair twist.
The second reason is that although you could generate the tone and key it at a 10 or 20 pulse per second rate, 60/40%, this is not a consumer item.
The chances of some hamtastic getting a wild hair is less this way.
The last, almost every military in the world, former warsaw pact included, have this.
The reason 1500Hz was picked is to allow for military radios to be able to decode this if need be, but allow the military 1600 Hz standard to stay.
Just close enough to fall in the bandpass, just far enough to tell them apart.
The reason 1500Hz was picked is to allow for military radios to be able to decode this if need be, but allow the military 1600 Hz standard to stay.
Ahhhhhhhhh, yes. It reminds me of the old days of the SECODE/Plectron/and Cook radio tuneable encoders/decoders. No wonder I have carpal tunnel!!!!!!!!!!!!!!
Jimmy.
"well, well, well, A drunk driver doesn't go out and drive once drunk now do they?"
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allplowedout
- Registered User
- Posts: 245
- Joined: Sat Nov 20, 2004 6:15 am
Dan562
Dan562, I read this thread in it's entirety, I must say I was quite impressed with the knowledge you posted and found it to be interesting and informative reading.
I've been interested in radios for quite some time and one thing I find apalling is that govt,, be it State, local or Feds can't require a MANDATED inter agency/inter-op freq on a per County basis or somewhere along those lines to allow cops and fd's to talk WHEN and IF needed.
What kills me is that every county is setting up their own "wide area this and digital that" and where is the benefit of all of this when we had the major blackouts, or better yet, 9-11. On Long Island, NY cell svc did not work AT ALL, be it Nextel, Verizon ( I had both) worked one of every 30 tries... Point I am trying to make is that there should be some mandated solution which will allow SIMPLEX talk ability on a wide level.
Currently there is some of this, but it's crap that has to be "authorised by command" and then enabled via controllers,etc...
Sorry to yap, just heats my pants to hear how Homeland security wants to get involved in digital decoders and such with hospitals but in reality, (being that it was CLEARLY evident on 9-11) should be working on inter-op between agencies everywhere...
I know I've deviated a bit from the thread's title, and I alologize for that but I did not plan on typing this much initially.
Opinions are welcome though.
I had heard earlier this year that Homeland Security was making requests to hospitals that their Digital Decoders should be capable of a combination of 1500 Hz Pulse and DTMF schemes which both outputs would need to feed an "And Gate" before disabling the PL Decoder into the Carrier Squelch mode. This requirement seems like one step forward and 40 years back by adding precious time to save people's lives. That's our government at work for us!
Dan
I've been interested in radios for quite some time and one thing I find apalling is that govt,, be it State, local or Feds can't require a MANDATED inter agency/inter-op freq on a per County basis or somewhere along those lines to allow cops and fd's to talk WHEN and IF needed.
What kills me is that every county is setting up their own "wide area this and digital that" and where is the benefit of all of this when we had the major blackouts, or better yet, 9-11. On Long Island, NY cell svc did not work AT ALL, be it Nextel, Verizon ( I had both) worked one of every 30 tries... Point I am trying to make is that there should be some mandated solution which will allow SIMPLEX talk ability on a wide level.
Currently there is some of this, but it's crap that has to be "authorised by command" and then enabled via controllers,etc...
Sorry to yap, just heats my pants to hear how Homeland security wants to get involved in digital decoders and such with hospitals but in reality, (being that it was CLEARLY evident on 9-11) should be working on inter-op between agencies everywhere...
I know I've deviated a bit from the thread's title, and I alologize for that but I did not plan on typing this much initially.
Opinions are welcome though.
I had heard earlier this year that Homeland Security was making requests to hospitals that their Digital Decoders should be capable of a combination of 1500 Hz Pulse and DTMF schemes which both outputs would need to feed an "And Gate" before disabling the PL Decoder into the Carrier Squelch mode. This requirement seems like one step forward and 40 years back by adding precious time to save people's lives. That's our government at work for us!
Dan