HFU HF Underground
Technical Topics => Equipment => Topic started by: N1OQD on April 01, 2019, 2347 UTC
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I've been told that Kenwood is going to no longer be producing low band (30-50) mhz transceivers, they were the last major manufacturer of such equipment as Motorola no longer makes it. All of the fire depts around here (connecticut) have abandoned the band and ditched their old equipment. I wonder where this leaves the future state of the band (30-50) MHZ.
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30-50 MHz is still heavily used by businesses and public safety in rural parts of the country. The state highway department in the state I live in uses a massive 45/47 MHz base-mobile and repeater system that recently went through upgrades. My understanding is that Motorola still makes VHF low band equipment.
The state police here use a P25 digital trunking system in the VHF high band (150-162 MHz) as their primary system but all state police cars, local sheriff's department cars have radios that sit on 39.54 MHz (aka "SIRS - Statewide Interagency Radio System) and police departments big and small have base stations on 39.540 MHz, often with patches to their trunking systems, allowing cars with 800 MHz radios to get on SIRS for interop purposes. When the state upgraded to digital trunking (supplied by Motorola) they replaced all their in-car lowband radios as part of the purchase, Motorola CDM750 radios with the 36-42 MHz split. As part of the digital system upgrade the state police installed base stations on 39.5400 / SIRS at each state police office and included the capability to transmit/receive remotely through the same microwave backbone used by the Project 25 digital voice system. Basically a state-wide "overlay" backup system on VHF lowband. The favorable propagation characteristics and just-pick-up-the-mic simplicity means its used on a daily basis in more rural areas of the state (think rural sheriff's offices with a couple cars working with state troopers).
I know that the California Highway Patrol makes extensive use of VHF low band (39 MHz, 42 MHz, 44 MHz and 45 MHz bands) and the US military also uses 30-50 MHz extensively.
I know that Ireland recently allocated 30-47 MHz to the amateur service on a secondary basis, shared with military users. I live in an urban area and even here there's use of lowband by construction companies, asphalt paving trucks and ready-mix concrete trucks chatting away on 30 MHz, 31 MHz, and 43 MHz. In places like New York City the 30 and 31 MHz bands are full of car services, Ubers, taxicab dispatchers and all sorts of other land mobile users.
While a lot of public safety users have moved to higher bands, VHF low band isn't dead. I'm pretty sure Motorola still makes low band equipment and I wanna say Yaesu still does as well (under the VERTEX) brand name.
EDIT:
I stand corrected. It appears that Motorola now owns VERTEX STANDARD. Looks like the Motorola CDM750 series of radios are discontinued. I guess the state police upgrade was before they took those radios off the market.
There are still large VHF low band networks in operation in certain parts of the country. I wonder of the Vertex VX-4000 and VX-5500 series of high power VHF lowband radios are still in production. I believe that's what California Highway Patrol uses for their system (that or maybe Kenwood radios?)
Another edit: The Motorola Solutions webpage does list the Vertex VX-6000 series of radios (available in a low band configuration as the "B" band, 37-50 MHz appears to be the only option)
https://www.motorolasolutions.com/en_us/products/vertex-standard/vx-6000.html (https://www.motorolasolutions.com/en_us/products/vertex-standard/vx-6000.html)
The massive move to 700/800 MHz and digital/trunked systems has caused a huge dump of lowband gear onto the secondhand and surplus market. I know eBay is full of lowband gear. The US military still uses VHF lowband (and midband!) for their FM (SINCGARS) land mobile systems, both in single channel (SC) and frequency hopping (FH) modes and that equipment is still being produced for the 30-88 MHz band. Maybe amateurs will get an 8 meter band allocation around 40 MHz (there are still government users of the 40/41 MHz region, including the Tennessee Valley Authority's wide-area TVA Transmission and Customer Service lowband system:
https://wiki.radioreference.com/index.php/Tennessee_Valley_Authority#Transmission_and_Customer_Service_.28TCS.29 (https://wiki.radioreference.com/index.php/Tennessee_Valley_Authority#Transmission_and_Customer_Service_.28TCS.29)
One of the major utilities in my area uses a hybrid of UHF and VHF lowband (48 MHz) for electrical service purposes, with statewide 48 MHz backup capability.
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Major natural Gas companies still use VHF low band 48MHz. Dominion Transmission still did, since their wellheads, pump stations, and gas exchange sites, were mostly in the middle of no where, making cell coverage impossible. 100W from base to mobile at 48MHz could give up to 100 miles of good analog FM contacts. Back in 2010, Dominion (When I worked with them.), still used Motorola Spectra's and the Kenwood 100W mobile units, (The model with the goofy squelch that seemed to have a mind of its own.) So, look for TGP, Columbia / Trans Canada, Dominion, and other gas companies, getting rid of these rigs and see if you can snatch them up for pennies on the dollar. Most likely, most should have few problems to them, but minor, (Like broken power cables, damaged / dirty connectors, chewed up mic cords, etc.). The biggest expenses for your Two-Way shop is FREQ programming, installation / testing. Passing thoughts, but why go all new, unless it's a warranty you are looking for. And in that case, in used gear, ask the shop about used gear and work warranty policy.
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Major natural Gas companies still use VHF low band 48MHz. Dominion Transmission still did, since their wellheads, pump stations, and gas exchange sites, were mostly in the middle of no where, making cell coverage impossible. 100W from base to mobile at 48MHz could give up to 100 miles of good analog FM contacts. Back in 2010, Dominion (When I worked with them.), still used Motorola Spectra's and the Kenwood 100W mobile units, (The model with the goofy squelch that seemed to have a mind of its own.) So, look for TGP, Columbia / Trans Canada, Dominion, and other gas companies, getting rid of these rigs and see if you can snatch them up for pennies on the dollar. Most likely, most should have few problems to them, but minor, (Like broken power cables, damaged / dirty connectors, chewed up mic cords, etc.). The biggest expenses for your Two-Way shop is FREQ programming, installation / testing. Passing thoughts, but why go all new, unless it's a warranty you are looking for. And in that case, in used gear, ask the shop about used gear and work warranty policy.
I live in Dominion Energy's, well, dominion (i.e., most of The Old Dominion, the southwestern portion is covered by American Electric Power, and they operate a very wide area 800MHz trunking system) and have monitored their 48 MHz system in action during storms/large scale outages. Dominion is still using 48 MHz, I see their trucks with lowband antennas (always in conjunction with UHF antennas). I haven't gotten a look at the radios in the trucks but I work near the Dominion headquarters building and there's always trucks with lowband antennas around.
There's other smaller energy co-ops that use 48 MHz (as well as 47 MHz and other lowband frequencies). The Dominion 48 MHz system has some very impressive range on it. I wonder if they're going to be getting rid of their lowband system and completely switch over to UHF for everything. In the three high population suburban/urban areas of Virginia, Dominion uses 451 MHz/452 MHz UHF and uses it well, most of it is still in analog FM with some sporadic use of DMR (digital voice). The line crews, etc. still use analog, either on UHF or VHF lowband, for truck to truck comms.
I can also say that the Virginia Department of Transportation still uses their 45/47 MHz VHF lowband system and they're licensed for something like 10,000 mobiles and hundreds of base stations/dozens and dozens of repeaters (each VDOT site has its own license for base/mobiles and there's a statewide license for 5000 mobiles on top of that). VDOT's radio system is quite impressive. 47 MHz repeaters on mountaintops cover huge areas of rural Virginia. VDOT has 411 active licenses for VHF lowband and my understanding is they're not planning on abandoning it anytime soon. It's impractical to put all those snowplows and maintenance trucks on the statewide VHF trunking system [STARS]. The Safety Service Patrol [Motorist Assistance] trucks use the STARS trunking system to talk to each other, their dispatchers and the Virginia State Police, because they need to. Snowplows and the other VDOT trucks do just fine with regular old VHF lowband FM. As I mentioned before, the Virginia State Police use 39.54 MHz (SIRS) as an "overlay" system that covers the whole state (via remote base stations on mountaintops and the fact that every sheriff's office has a base station on that frequency). The SIRS 39.540 MHz frequency is used daily in the rural parts of Virginia and even when the Virginia State Police upgraded their analog VHF high system to digital trunking on VHF (150-162 MHz) they made it very clear that SIRS (39.54 MHz lowband) remains the law enforcement interoperability standard.
Also, doesn't the California Highway Patrol use a massive VHF lowband system?
For long-haul communications in rural areas, its hard to beat VHF lowband.
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Isn't this VHF Low band rig still available? https://www.kenwood.com/usa/com/lmr/tk-6110/
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Isn't this VHF Low band rig still available? https://www.kenwood.com/usa/com/lmr/tk-6110/
Would be a shame if they took it off the market. 70 watts output and 29.7 MHz - 37.0 MHz / 35.0 - 50.0 MHz splits. More practical than the Motorola lowband splits (29-36 MHz, 36-42 MHz and 42-50 MHz). It is a shame that Motorola is out of the business though. I used to own a Motorola Maxtrac that covered the 36-42 MHz VHF low band split. It was the basic 2 channel version, both channels being 39.5400 MHz (the statewide law enforcement interoperability/state police backup system frequency). I had intended on building a dedicated monitor receiver station for 39.54 [SIRS] using the Maxtrac as the receiver but that never came to fruition. I wish I hadn't ended up selling that radio...
This rig is still listed on their website as well:
https://www.kenwood.com/usa/com/lmr/tk-690_790_890/ (https://www.kenwood.com/usa/com/lmr/tk-690_790_890/)
110 watts, 29 MHz - 37 MHz / 35-43 MHz / 39-50 MHz
I'm pretty sure the TK-690/TK-790/TK-890 radio is the one used by VDOT for their 45/47 MHz lowband system.
Maybe they're off the market and the website hasn't been updated to reflect this?