View Full Version : VHF Low Band 30-50 Mhz
wa4ilh
05-27-2008, 02:32 PM
What's the deal with low band? Years ago, probably 25 years ago, the VHF low band 30-50 Mhz had a lot of activity. Now, I only hear stations around the 39 Mhz Public Safety band and 45 Mhz State Police. And, of course, baby monitors and older portable phones. I know we are at a low spot in the solar cycle but I can't believe that this band is not being used. I do hear some Military activity occasionally in the "government" portion of the band and some Spanish stations which I assume is TE from central or south America.
Or, maybe my scanner just has low sensitivity down there...... I used to enjoy scanning this band.
Tom WA4ILH
ab8ro
05-27-2008, 03:17 PM
What's the deal with low band? Years ago, probably 25 years ago, the VHF low band 30-50 Mhz had a lot of activity. Now, I only hear stations around the 39 Mhz Public Safety band and 45 Mhz State Police. And, of course, baby monitors and older portable phones. I know we are at a low spot in the solar cycle but I can't believe that this band is not being used. I do hear some Military activity occasionally in the "government" portion of the band and some Spanish stations which I assume is TE from central or south America.
Or, maybe my scanner just has low sensitivity down there...... I used to enjoy scanning this band.
Tom WA4ILH
Haha baby monitors. My neighbors saw me futzing around in the yard with an antenna and thought I was "spying" on their baby monitor. I told them, really, I have better things to do and tried to explain, in 2 minutes or less, what ham radio was. I also let them know that, despite their beliefs otherwise, that it was perfectly legal for anyone to listen to their baby monitor and that a long antenna wasn't necessary. I then tried to explain the relationship between antenna size and frequency, but, well, I could tell that they weren't really getting it. They seemed somewhat satisfied with the idea that the point of the bigger antenna was not to be "more sensitive" to the baby monitor. I suspect, however, that they continued to harbor the belief that their baby monitor transmissions would remain inside the house and could only be picked up with "spy like" receiving equipment not available to the average person.
Up until that point I hadn't bothered to "scan" low vhf, because, as you point out, it's pretty boring, but, well, this was an open invitation. Later that evening I found their baby monitor.
Which leads me to some advice for married couples.
DON'T FIGHT ABOUT "BEDROOM ISSUES" IN THE BABY'S ROOM!
I enjoy listening to baby monitors and cordless phones.
k8wpj
05-27-2008, 03:36 PM
Which leads me to some advice for married couples.
DON'T FIGHT ABOUT "BEDROOM ISSUES" IN THE BABY'S ROOM!
Maybe it was a 'bedroom issue' that cuased them to need the baby's room in the first place... in which case, it's a perfect spot to discuss those issues... kinda like the criminal returning to the scene of the crime... :rolleyes:
ve2nsm
05-27-2008, 03:47 PM
I enjoy listening to baby monitors and cordless phones.
Yup, me too, but today the old 49MHz phones are almost gone :(
Around here they aren't.
The SteppIR tunes down to 49MHz quite nicely. With a yagi on 49MHz I hear quite far out.
wa9cwx
05-27-2008, 05:18 PM
As far as the use of the low VHF band, I suspect that a LOT of public service users have, or ARE going to the various cell phone type trunked systems.
Many agencies on one system, with the flexibility to inter-communicate, etc. As far as I know almost ALL of that is 800 Mhz, not on VHF.
The problems with skip, interference, and and the larger antennas required, especially for any handhelds, ALL make low VHF less attractive, and, since the licensing is for non-trunked systems, (as far as I know), all this is becoming a quickly obsolete group of frequencies.
In areas with a lot of hills, like some rural counties in southern Illinois, I imagine low VHF will last a while, until the counties are sold on the idea of satellite comms.....
Frank
SHAME on you people for listening in on your neighbors !!!! :D
Did I mention I used to have a neighbor who had one of the ALWAYS ON Base units on their portable phone PLUS a baby monitor upstairs....Now THAT was intersting.
The old systems (going back to late 70's, early 80's) used the high end of the bradcast band for the base, and the house wireing for the antenna.....
WA6MHZ
05-27-2008, 11:32 PM
Probably the most active user of the band is the California Highway Patrol. Yep, Mister Smokey Bear himself!
http://www.freqofnature.com/frequencies/ca/chp.html
Mostly around 39 to 45 Mhz. I don't know which is the most active or which one is for what area, but it looks like 39.4, 39.6 and 39.8 are the base channels and 42.20. 42.66 and 42.80 are the mobiles. So, It might be nice to have a scanner in the car, just to hear Mister Smokey say to the dispatcher "We have a tan Lincoln Town car doing 90 plus, license number WA6MHZ. Request all aid and the spike strips to stop this rabbit!" Oh how they THIRST for a Kill!!!!
K4KWH
05-28-2008, 01:07 AM
And He's Using A Scanner To Evade Capture! Git 'em!!!! :d :d :d
J
N4AUD
05-28-2008, 01:33 AM
When I started as a police officer, we had low band VHF radios and the skip was terrible at times. Moving up above 150mhz was a tremendous improvement. I don't believe any of the local departments are on UHF frequencies yet, and there is probably no reason to do so since the VHF frequencies they use now are doing the job.
KI4WCA
05-28-2008, 02:13 AM
Having a receiver like the R-8500 is fun.I thought that monitoring cordless phones was outlawed.Baby monitors are fine, but the phones are off limits.Before the evil ECPA you could listen to anything.Not anymore.
Of course, unless you are using a poorly shielded scanner that radiates the local oscillator, it might be hard to catch you.Unless you post it on the internet.DOOH!!
wb5ydk
05-28-2008, 04:00 AM
So, It might be nice to have a scanner in the car, just to hear Mister Smokey say to the dispatcher "We have a tan Lincoln Town car doing 90 plus, license number WA6MHZ. Request all aid and the spike strips to stop this rabbit!" Oh how they THIRST for a Kill!!!!Hey, Pat! The other day, I think I heard ol' Broderick Crawford himself calling in your tag number!:)
http://timstvshowcase.com/hwypat2.jpg
"It's that WA6MHZ fellow again."
...
wb5ydk
05-28-2008, 04:14 AM
We had a lady where I worked that bought one of those 49 MHz baby monitors. Unknown to her, her bachelor neighbor had a cordless phone on the same frequency.
So, one day, while in the kitchen, she heard a man's voice coming over the baby monitor. Her first thought: "What's a man doing in my baby's room?" She panicked, and ran to the room only to find the baby sleeping safe and sound: there was nobody else in the room.
Returning to the kitchen, she figured out that it was her neighbor on his cordless phone. As she continued to monitor her baby's room, she could not help but overhear her neighbor's phone conversation. This guy, who she first thought to be a nice man, was in reality a fairly perverted and strange individual (though fortunately not a child-molesting type). She was a bit terrified to be hearing his conversation.
One thing that she told me: "When my kids get a little older, I'm not going to let them play anywhere near that guy's yard!"
More and more public safety is migrating away not only from 30-50 but 150-170 and activity there is becomming less and less. Homeland Security $$$ and the manufacturers (often false) promises of great things on 700, 800 and 900 have caused many to abandon systems that actually work in favor of those that may or may not. In my state there was a concerted effort to migrate the entire state to 700 Mhz even though here in rugged and rural Eastern Oregon VHF is the best choice. When they found out that to cover the same land area the VHF system does with 10 repeater sites on 700 it would take nearly 40 (unavailable) sites they re-thought the issue.
BTW, the migration to UHF (and above) digital is causing all kinds of problems. Not a week goes by that I don't get messages from my public safety communications cohorts about problems with digital voice systems. Some agencies are refusing to use their new systems based on officer/firefighter safety concerns. Last night I was listening to streaming audio via the web from San Diego County (CA) becuase my cop son was working a major incident and I wanted to listen. The dispatcher repeatedly was telling officers he couldn't understand them because "you went digital". What he meant was that with their new digital radio system they (officers) were frequently dropping off the air mid sentence. With digital it's either there or gone.
ve2nsm
05-28-2008, 05:08 PM
Last night I was listening to streaming audio via the web from San Diego County (CA) becuase my cop son was working a major incident and I wanted to listen. The dispatcher repeatedly was telling officers he couldn't understand them because "you went digital". What he meant was that with their new digital radio system they (officers) were frequently dropping off the air mid sentence. With digital it's either there or gone.
With an analog system, it's really easy even for a non radio savvy person to position the antenna, HT or oneself to get a better reception, it's instinctive, just as moving the rabbit ears on the old TV set. With digital it's not anymore, and a slight movement can result in a complete loss. Moreso with the inherent delay of digital systems, one can quickly pass over a sweet spot and never notice it.
ab8ro
05-28-2008, 05:33 PM
Having a receiver like the R-8500 is fun.I thought that monitoring cordless phones was outlawed.Baby monitors are fine, but the phones are off limits.Before the evil ECPA you could listen to anything.Not anymore.
Of course, unless you are using a poorly shielded scanner that radiates the local oscillator, it might be hard to catch you.Unless you post it on the internet.DOOH!!
Well, I'm quite sure that everyone discussing said monitoring means that they were doing it BEFORE the ECPA, right fellas?
wa4ilh
05-28-2008, 05:51 PM
Well, I'm quite sure that everyone discussing said monitoring means that they were doing it BEFORE the ECPA, right fellas?
It may be illegal to monitor telephone calls but, to the best of my knowledge, it is still perfectly legal to monitor public safety (provided they are not encrypted). It is, however, illegal to "Repeat" what you have heard.
"Twenty-One-Fifty to Headquarters"
Tom WA4ILH
ve2nsm
05-28-2008, 06:05 PM
Is it really illegal to listen to wireless phones? I mean, really? :eek:
Many suburban police departments have moved to 800 MHz systems....
Most state wide systems are at 150 MHz and UHF - to get coverage, but a few still use low band 30-50 MHz.
Low band does have major skip problems at times, and the FCC tried to coordinate so the assignments were not in the optimum skip distance on the same freq.
There are still hundreds and hundreds of assignments on channels in 30-50 MHz.
wa4ilh
05-28-2008, 06:37 PM
Is it really illegal to listen to wireless phones? I mean, really? :eek:
In the U.S. it is since about 1995. Or is your point, "it's not enforceable?"
Tom WA4ILH
ve2nsm
05-28-2008, 06:40 PM
In the U.S. it is since about 1995. Or is your point, "it's not enforceable?"
Tom WA4ILH
No, it was serious, I didn't know. I heard about the cell phones but I didn't know about the cordless phones.
About the enforcement, it's stupid of course.
I heard somebody say once "if you don't want me to listen to you, keep your airwaves out of my property"
I thought it made sense :p
wa4ilh
05-28-2008, 06:58 PM
The Electronic Communications Enforcement Act of 1995 (or whatever it was called) was the stupidest monitoring law passed in the last 20 years! And, it was mostly redundant. It has been illegal to "repeat" intercepted communications in the U.S. (and I expect elsewhere) since 1932.
It is also illegal to monitor Remote broadcast feeds. Why would anyone make it illegal to monitor a broadcast feed? The whole restriction on listening to cell phones is now probably a mute point as there are no more analog cell systems left in the US.
Tom WA4ILH
WA6MHZ
05-28-2008, 07:12 PM
I find the stupidest monitoring law is what our UK friends have to put up with. From what I understand, you have to have a LICENSE to watch TV!!! They have DF vans that comb the neighborhoods looking for secret viewers trying to watch the TELLY behind closed doors, deep in the cellar or attic, hiding much like the Jews did from the Nazi Gestapo during WW2 occupation!!! I can just see Anne Frank trying to watch a rerun of Baywatch when the TV Police kick in the door coming in with their automatic weapons and cuffing everyone in the room for ILLEGALLY watching TV!!! Now, that would SUCK BIG TIME!!!! Good thing TV is free here (although my Cable TV bill is $120 a month!!)
wa9cwx
05-29-2008, 03:08 AM
Yep, that UK law sounds so bizarre as to be beyond my comprehension.
But the US law in '95 just sounds so basically UN-AMERICAN that I am still confused!!
The 1934 law made the most SENSE...Don't repeat anything that is meant to be private, don't use any private information for personal gain, don't use any information to aid in breaking the law. Is basically what it said.
Wasn't it someone from the FCC that said the '95 law was like putting up a house made of glass and telling people not to look at it ? :D
WW3QB
05-29-2008, 03:24 AM
I find the stupidest monitoring law is what our UK friends have to put up with. From what I understand, you have to have a LICENSE to watch TV!!! ... Good thing TV is free here
They pay a TV tax to fund TV programming and not subject themselves to 15 minutes of advertising every hour. We pay billions of dollars extra at the supermarket so companies can pay to advertise their products. When you pay for a beer you also pay so they can pay to advertise that beer during the Super Bowl.
Both systems sound ridiculous, but programming has to be paid for somehow.
cu2jt
05-29-2008, 09:26 PM
When my brother was doing his military service back in 1958, they used some VHF low power transmitters to direct the fire from the coast guard cannons. He was told by a Chicago police officer that it was unlawful to interfere with the police communication. The thing is that my brother was sitting just outside Stockholm, Sweden. That is what I call good propagation on VHF !
kb1ils
05-30-2008, 07:27 AM
That reminds me of one of the most interesting DX monitoring loggings I've ever had. I was in central Massachusetts enjoying listening to some low band skip during the summer, probably about ten years ago. I was using an Antron 99 11m base antenna mounted at about the roofline of the house. Somewhere around 31MHz I heard what I figured out to be the intercoms of some military tanks in the UK discussing a training mission.
n2zpy
05-30-2008, 10:20 AM
Our fire dispatch is still on 46.06. I use this to let me know when it looks like 6M will be open.
Kevin
wa4ilh
05-30-2008, 01:17 PM
A friend of mine who is a retired EMT tells the story of when they were out in a very rural area of southern Missouri, they had a medical emergency and tried to call the dispatcher on 39 Mhz at the far end of the county and could not raise him. A station in Manitoba ended up relaying their emergency traffic to their dispatcher.
Tom WA4ILH
Back in the late '60s when I was a Patrol Deputy with the Los Angeles County Sheriff's Department we were on 39 megs. So too was a law enforcement agency near Boston Mass. During certain times of the year we could talk back and forth with them and hear them better than our own dispatch center.
wa4ilh
05-30-2008, 03:11 PM
Back in the late '60s when I was a Patrol Deputy with the Los Angeles County Sheriff's Department we were on 39 megs. So too was a law enforcement agency near Boston Mass. During certain times of the year we could talk back and forth with them and hear them better than our own dispatch center.
Slightly different frequency range but I had a friend who was a patrolman in Norflok Virginia. They were on VHF Hi band (155 Mhz range) During certain times of the year, usually in the late summer, and late at night, they would receive calls from a law enforcement agency up north of Washington DC. (about 150 miles away?) They even had the same tone . Some kind of water path skip up across the Chesapeake bay. He said it could get confusing because some of their units had similar numbers.
Tom WA4ILH