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Fdny uhf?

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SCPD

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I know the FDNY is moving to a UHF system and abondoning their VHF system eventually. My question is, why didn't they just go UHF initially when they installed their radio system? Was UHF not availible at the time? I've always been told that UHF works better in big cities. OK thanks.
 

W2PMX

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I know the FDNY is moving to a UHF system and abondoning their VHF system eventually. My question is, why didn't they just go UHF initially when they installed their radio system? Was UHF not availible at the time? I've always been told that UHF works better in big cities. OK thanks.
Initially? I don't think even VHF-hi was available at the time. Remember, FDNY was an early adopter of radio - we're probably talking pre-WWII, back when NYPD was using a transmit-only system on 1650 kHz. (The precinct would transmit to the cars. Replies, if needed, were done by callbox or pay phone.)
 

k2hz

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UHF technology was not very viable until solid state radios became available in the 1960s. FDNY was a pioneer in the use of VHF and stayed with it.
 

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The VHF radio system dates back to 1952.

Fire Department, City of New York
By Paul Hashagen


1936 - Two-way, low-band AM radio (WNYF, 1630 kHz) for fireboats

1937 - Two-way radio for Commissioners' and Chiefs' cars and Rescue Companies

1952 - Two-way VHF FM radio for all units; separate channels for Manhattan/Bronx, Brooklyn/Queens, Staten Island
 

W2PMX

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UHF technology was not very viable until solid state radios became available in the 1960s.
I think Motorola would take issue with that statement. They had some very nice tube radios operating on 450. The T44, using a 2C39 lighthouse, came out around 1955.

GE came out with the MC 306/316 series (all tube) in 1954. Vibrator powered, with 2C39s in the final.

Viable? Thousands of each were sold and used for many years before 450Mhz transistor transmitters came out. (The U44BBT was used through the 70s and into the 80s commercially, and some hams probably still run some.)
 

k2hz

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I think Motorola would take issue with that statement. They had some very nice tube radios operating on 450. The T44, using a 2C39 lighthouse, came out around 1955.

GE came out with the MC 306/316 series (all tube) in 1954. Vibrator powered, with 2C39s in the final.

Viable? Thousands of each were sold and used for many years before 450Mhz transistor transmitters came out. (The U44BBT was used through the 70s and into the 80s commercially, and some hams probably still run some.)
I agree that UHF equipment was available from the mid 50s but by "viable" I mean I do not believe performance was comparable to VHF in reliablity for critical Public Safety use.

I have been involved with 2-way service since 1962 and I did not consider these early UHF radios as "very nice". I do consider VHF and Low Band versions of equipment from that era true classics that performed very well for a long time but not so for their UHF counterparts.

Sensitivity of early UHF radios was terrible by todays standards, maybe 1uV with new tubes and recently aligned. The life and efficiency of the final tubes was poor and the radios were just not very reliable. Yes, there were a lot sold, manly for urban taxi use. The whole state of the art for UHF then was limited by poor equipment stability, lossy feedlines, poor antennas, low base station power etc.. that made it not generally competetive when VHF or Low Band was an option.

I found it was the mid 60s with the development of repeater systems along with radios like the original GE MASTR series that made UHF competetive with other bands for widespread use. I remember the first UHF MASTR repeater system we installed for a business user and we were amazed by the performance compared to prior experience with UHF.

NYPD stayed with VHF until the shared UHF TV spectrum became available. I beleive the huge increase in available channels was the main reason NYPD moved to UHF.
 

W2PMX

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I agree that UHF equipment was available from the mid 50s but by "viable" I mean I do not believe performance was comparable to VHF in reliablity for critical Public Safety use.
As a user of the T-44, I'd have to disagree. It was as reliable as any of the VHF boat anchors of the time.

I have been involved with 2-way service since 1962 and I did not consider these early UHF radios as "very nice". I do consider VHF and Low Band versions of equipment from that era true classics that performed very well for a long time but not so for their UHF counterparts.
I'd stack a T-44 against a GE VHF-lo pre-Prog any time.

Sensitivity of early UHF radios was terrible by todays standards, maybe 1uV with new tubes and recently aligned.
About the same as the VHF receivers of the time.

The life and efficiency of the final tubes was poor and the radios were just not very reliable.
I replaced VERY few lighthouse tubes. Fewer than the 829Bs I replaced.

Yes, there were a lot sold, manly for urban taxi use. The whole state of the art for UHF then was limited by poor equipment stability, lossy feedlines, poor antennas, low base station power etc.. that made it not generally competetive when VHF or Low Band was an option.
Lossy feedlines, connectors that were designed to work up to about 30MHz, low gain antennas and low power (base and mobile) because generating high power at 450 was more difficult then than generating high power at 1.9GHz is today.

But the equipment was viable. I still have a few working T-44s - with the original 2C39s. (And I may still have a working U44BBT modified into a repeater buried in the old radio stack.)

I found it was the mid 60s with the development of repeater systems along with radios like the original GE MASTR series that made UHF competetive with other bands for widespread use. I remember the first UHF MASTR repeater system we installed for a business user and we were amazed by the performance compared to prior experience with UHF.
UHF simplex is no worse than VHF simplex, allowing for the shorter range due to the higher frequency. Which has nothing to do with the viability of the radios.

NYPD stayed with VHF until the shared UHF TV spectrum became available. I beleive the huge increase in available channels was the main reason NYPD moved to UHF.
That, and a few other things - like much of the city was already on UHF (Sanitation, Traffic, etc.)
 

k2hz

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I don't want to beat the topic to death but I do want to first clarify my original comment. The question raised in this topic was why, given that UHF propagation has advantages over VHF in an urban environment, did FDNY not initially adopt UHF. I used the word "viable" rather than "availlable" because I knew that UHF radios existed at the time.

My basic point was that in the 1950s the current state of UHF technology did not support this advantage to the point it does today. The general perception of use of UHF vs VHF taught while in was in tech school in 1960-62 was that UHF was suitable only for short range use like taxis in an urban downtown area or on-site industrial systems. This perception was reinforced by my early field experience until the technology improved during the 60s and 70s.

I don't beleive FDNY would have been able to use UHF in the 50's other than for lower Manhattan. The idea of Boro-wide coverage on UHF, especially in Queens or SI would have been considered out of the question.

With all the improvements in equipment performance, antennas etc.. plus voting receiver and simulcast technology today UHF is clearly a good choice.

While I can't dispute that the T44 might work well in a controlled environment, that was not my experince in servicing equipment in the 60s. The earliest dynamotor VHF radios like the GE "Pre Prog" ES-1B and Motorola "80D" lasted many years in urban taxi service. The trunk of a cab is probably the worst possible environment. Later UHF radios like your T44 or a GE "Prog Line" did not stand up well compared to the VHF models. While the 2C39 tube may last in a good environment, the tube sockets constanly failed with the buildup of crud common in cab radios that caused arc-over and corrosion that made for a major repair. Comparable VHF radios were seldom in for repairs with vibrator failure probably the most common problem. I found that most VHF radios had and maintained sensitivity of 0.5 uV or better with rare need for realignment. UHF sensitivity was not comparable and any I have seen in Ham use had a preamp added to make them useable.

The T44 is what it is and I don't doubt that your experience with it has been satisfactory for your use while my experience with it and comparable UHF radios of the era was otherwise.
 
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