The 433Mhz frequency and interference

[Squelchtone]

Isn't 433MHz a public safety band? My suburb's Police and Fire have not switched to Project 25 and they are still using frequencies around that range.

that starts at 450MHz and goes up to 470, and then the UHF-T band starts which is 470-512.

Confederate: a forum where others have interference issues on 433MHz http://www.doityourself.com/forum/commu ... auses.html

[jeffmoss26]

I looked on radio reference, our PD is 423.90000 and FD is 423.35000

[Squelchtone]

I looked on radio reference, our PD is 423.90000 and FD is 423.35000

I didn't think they used that side of UHF for public safety. interesting.

Where Confederate is from they use 156.2400 MHZ for the police so that shouldn't be the culprit.

Thanks for sharing that Jeff,
Squelchtone

[Tyler J. Thomas]

Thanks for the link Squelch. Suffice to say A LOT can be causing it. Full disclosure, this door is in front of a massive 4 story research center on campus with plenty of labs. Even if the problem wasn't caused by the building itself, there are literally TONS of scientific/lab equipment all over this building. I mean TONS.

The strange thing is that this door utilized this same frequency for I would presume 15 years, at the very least. Something must have been recently "turned on" or installed to create this.

I'm going to be turning this into an article because, sadly, nearly every article these days in the trade magazines are CHECK OUT WHAT THIS PRODUCT CAN DO or WANT TO SEE HOW I INSTALLED THIS PRODUCT and there aren't many articles about basic guiding principles. The ol' "Teach a man to fish" story applies. As I mentioned, I had only seen this ever occur during the installation of an access control system that was completely wireless but in that case, we just increased the number of gateways to compensate for the loss of signal around corners and through walls.

I'm just happy I didn't have to pull any hair or spend a fortune to figure it out. Just kinda had a "O RLY?" moment.

But yeah, if anyone's reading this thread from the future via the search function - interference.

[Squelchtone]

I have a GE Caddx (Interlogix/ITI) Networx alarm system and the glass breaks and wireless motions use 319.5 MHz, I heard low batteries were often a cause of mystery issues. But that's basic troubleshooting you probably already covered.

You should look into Marc Tobias' walkie talkie jamming techniques of cheaper home alarm wireless door contacts and motion sensors.

Squelchtone

[MatrixBlackRock]

Isn't 433MHz a public safety band? My suburb's Police and Fire have not switched to Project 25 and they are still using frequencies around that range.

Nope, 460 is the UHF band for anything Part 90 which public safety is allocated under.

http://www.ecfr.gov/cgi-bin/text-idx?tp ... ain_02.tpl

Wayne

[MatrixBlackRock]

I looked on radio reference, our PD is 423.90000 and FD is 423.35000

$20 to 450 is Part 97 and neither the PD nor FD can be licensed for those frequencies.

Wayne

[Tyler J. Thomas]

I have a GE Caddx (Interlogix/ITI) Networx alarm system and the glass breaks and wireless motions use 319.5 MHz, I heard low batteries were often a cause of mystery issues. But that's basic troubleshooting you probably already covered.

You should look into Marc Tobias' walkie talkie jamming techniques of cheaper home alarm wireless door contacts and motion sensors.

Squelchtone

Small world. I have Frontpoint and they use GE's Interlogix products. No motion sensors though, dogs too big.

Is that the SimpliSafe video? I've heard they've fixed that flaw; CNet claims they tested for it and found the control panel can detect it. FrontPoint claims that their Simon XT control panel can detect it as well. I hope so, at least. Can't afford to protect all my glass with security film.

[MatrixBlackRock]

You should look into Marc Tobias' walkie talkie jamming techniques of cheaper home alarm wireless door contacts and motion sensors.

Squelchtone

That's 419 MHz he's jamming, oddly enough 419.625 and 419.800 where at one time allocated to the DEA prior to refarming, their transmissions used to be in the clear and then in the 80's they migrated to the Motorola SECURENET digital encryption making their transmissions sound like open squelch, after refarning they moved to a 800MHz Motorola Smartnet II encrypted.

Wayne

[MatrixBlackRock]

Is that the SimpliSafe video? I've heard they've fixed that flaw; CNet claims they tested for it and found the control panel can detect it. FrontPoint claims that their Simon XT control panel can detect it as well. I hope so, at least. Can't afford to protect all my glass with security film.

The major problem with wireless is how to handle jamming.

Yes the control panel can detect a loss of the ability to receive it's sensors, but how does a Central Station handle that signal?

In most cases it's logged and maybe a callout is worked, but no PD dispatch.

False alarms are a major burden and loss of a detector or a "jamming" dispatch will produce many billable false alarms, which can become very expensive for the subscriber, who in the end either go's for no dispatch call out only or just cancels service.

Wayne

[dontlook]

In the end wire is king. Wireless is a fantastic, but in my experience(and I'm no fancy engineer) the wire is easier to guarantee, get quality, and consistency.
More expensive to put in place though.

I go through this all the time at work, with Ethernet.

[Tyler J. Thomas]

In the end wire is king. Wireless is a fantastic, but in my experience(and I'm no fancy engineer) the wire is easier to guarantee, get quality, and consistency.
More expensive to put in place though.

I go through this all the time at work, with Ethernet.

Agreed. I will fight the conversion to wireless tooth and nail. Troubleshooting is so easy as long as the original installer knew what he/she was doing.

We've been even sneaking in pull strings into conduit and around door frames of areas being renovated. "Future proofing".

[jeffmoss26]

I looked on radio reference, our PD is 423.90000 and FD is 423.35000

$20 to 450 is Part 97 and neither the PD nor FD can be licensed for those frequencies.

Wayne

They are definitely licensed and have been using them for years.
http://www.radioreference.com/apps/db/? ... ign=KJE337

[MatrixBlackRock]

They are definitely licensed and have been using them for years.
http://www.radioreference.com/apps/db/? ... ign=KJE337

They shouldn't be using them full time for dispatch as they are not allocated to do so under Part 90, they are licensed to KJE337 on a secondary basis, probably as part of a RACES or CERT/FEMA mutual aid agreement.

http://matrixblackrock.com/Assets/KJE337.pdf

If they are using those frequencies for day to day dispatch, all it would take is a call to David Dombrowski at the FCC's Enforcement Bureau Region One and in a month or so officer Daniel Green would receive a implied notice of violation directing him to immediately cease Part 90 operations on those frequencies or cause the department to held liable for a $5K per day, per violation fine.

Per day, per violation means, use one unallocated frequency $5K, use two unallocated frequencies $10K and so forth and yes it can get real expensive real fast.

Now where did I put that phone number for region one.

Wayne
WT4FEC

[Tyler J. Thomas]

Picture of the new receiver if anyone's interested in what they look like:



Red and black for power. In this scenario, white and green are tied into the operator itself (to configure for a normally opened circuit - closes upon button press/relay). Yellow (for a normally closed circuit) is capped off. Green wire up top is the antenna.