Spurious RF emissions?

[WRTC928]

I don't want to ask this question in an amateur radio forum because I'm afraid I couldn't get a straight answer, so I'll try it here. If I understand correctly, any "spurious emissions" will not be retransmitted by a repeater. It will pick up the strongest part of the signal and retransmit that on a different frequency. So, my question is, how much harm can spurious emissions from a 5 watt HT actually do? Yes, I understand about the possibility of creating interference in a frequency allocated to public safety or commercial radio, but realistically, how likely is that? Hams tend to think of these things from the standpoint of tall antennas and high wattage, and you likely could muck up stuff with a 50' antenna and 1,000 watts, but a 5 or even 10 watt HT doesn't seem to have much potential to cause trouble.

Do commercial LMR and public safety radios have filters to eliminate the "fuzz" created by a low-power harmonic? I assume the technology exists, and if I were building a $1,200 radio for a police department, I'd certainly include it. I'm not arguing that a "cleaner" signal isn't better and more desirable, but I suspect the "dirty" signal from a cheap HT isn't going to actually matter to anyone.

I already know @OffRoaderX's opinion  but I'm curious what the rest of you think.

[Hoppyjr]

Just the opposite. Naked women cause Spurious Emissions.  

Only for some people.

[Hoppyjr]

Didn't know Spurtious Emissions caused woman to be naked.  Good to know.

Tightly wound describes some people.

[Jaay]

4 hours ago, LeoG said:

Well you get the sad hams complaining about radios that do -58dB when the upper limit is -60dB.  Good chance that -40dB isn't going to affect much.

IF you learn how to use a RF Analyzer, then you'd understand how to interpret the figures. Also Nobody's Sad, just Smarter .

[WRTC928]

11 hours ago, tcp2525 said:

 Some implanted medical device can be effected.

Hypothetically, yes, but any RF radiation has the same potential, not just the "spurious" ones. In-band transmissions have the same possibility of creating electromagnetic interference as spurious ones. Microwave ovens can cause problems because they leak considerable RF energy if not properly shielded, but they operate on around 600-1,200 watts, which is a bit more than the 5 watts of an HT. Most of the electronic devices around you are shielded to prevent leakage which can interfere with other electronics, but two-way radios are by definition not shielded. As soon as you press the PTT, unshielded RF energy is created (intentionally), and it matters not to the pacemaker whether it's on 462.550 or some harmonic, although some of them could be (hypothetically) more sensitive to one band than another. So, there's a non-zero chance that your radio could affect a pacemaker, but as far as we know, it's never actually happened, and it's not confined to just the "spurious" emissions, but includes the intentional ones as well.

[WRTC928]

5 hours ago, Jaay said:

Nobody's Sad, just Smarter . 

Sure. Let's go with that. 

[WRYZ926]

1 hour ago, WRTC928 said:

As soon as you press the PTT, unshielded RF energy is created (intentionally), and it matters not to the pacemaker whether it's on 462.550 or some harmonic, although some of them could be (hypothetically) more sensitive to one band than another. So, there's a non-zero chance that your radio could affect a pacemaker, but as far as we know, it's never actually happened, and it's not confined to just the "spurious" emissions, but includes the intentional ones as well.

There is always a chance of an issue but it is a very very slim chance of  a radio interfering with pace makers now days. 

And since microwaves were mentioned. I remember when people were warned to never stand too close to a running microwave if they had a pace maker.

And it's not just the spurious emissions as you mentioned. the 40m and 80 bands are very noisy. Though 40m seems to be worse. I had to install clamps ferrite beads on some appliances and electronics in my house along with on all of my computer cables and radio coax cables to keep them from picking up interference when transmitting on 40m with 50 to 100 watts.

[LeoG]

I can activate my stove if I put my 5 watt GMRS near it.  Only on 467MHz though.  And my neighbors motion activated light is activated by my 20 watt mobile, again on the 467MHz frequency.  Not sure but my base station doesn't seem to turn on the light and it's the same radio I have in my truck.  And I have headlamps that will turn on or change over to flashing if already on and my Fein vacuum sometimes gets activated.

I don't think it's from SE's, I think it's from the direct output of the radios.

[Lscott]

Just about every electronic device that is not specifically covered by some other part of the FCC rules is licensed under Part 15, which has extensive requirements for interference levels etc.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15

Here is an interesting thread on the issue of interference to Part 15 devices. Just about every consumer is ignorant of this particular part. It's hard to convince somebody where their expensive flat screen TV malfunctioning, when you key up your radio, isn't your fault. The notice of Part 15 is either on the device some place and or mentioned in the included documentation, of course nobody reads that fine print. 

https://electronics.stackexchange.com/questions/35189/fcc-part-15-must-accept-interference-from-other-sources-what-does-this-mean

[WRYZ926]

Cheap Amazon touch lamps are some of the worse when it comes to being interfered with from radios. And cheap LED light bulbs are noisy and will cause interference.

I have seen where public safety frequencies have had issues with spurious emissions from cheap amateur band radios. But that too is pretty rare. And the amateur radio would have to have SE's that are almost as strong as their primary frequency.

[HHD1]

11 hours ago, TDM827 said:

Just the opposite. Naked women cause Spurious Emissions.  

If they happen at night, would they be considered "nocturnal" ?  Asking for a friend...

[HHD1]

Aren't most law enforcement and emergency agencies running P25 now?  I don't know if they are susceptible to our walkie talkies... 

[WRYZ926]

7 minutes ago, HHD1 said:

Aren't most law enforcement and emergency agencies running P25 now?  I don't know if they are susceptible to our walkie talkies... 

Yes most are using P25 and trunked systems. But some are still using analog and have not made the switch to P25. I know of at least 2 law enforcement agencies in my local area that are still using analog. And some of the small town volunteer fire departments are still using analog also. Missouri is a very rural state once you get outside of the 4 big metro areas of Columbia, Kansas City, St. Louis, and Springfield.  Even the state capital is not that big.

[WRUE951]

22 minutes ago, WRYZ926 said:

Yes most are using P25 and trunked systems. But some are still using analog and have not made the switch to P25. I know of at least 2 law enforcement agencies in my local area that are still using analog. And some of the small town volunteer fire departments are still using analog also. Missouri is a very rural state once you get outside of the 4 big metro areas of Columbia, Kansas City, St. Louis, and Springfield.  Even the state capital is not that big.

I'm pretty sure all public safety communications in the United States is now Digital as required by the Digital Transition and Public Safety Act of 2005.   When i left Sacramento in 2020 one of my friends who works in communications was scrambling to finish off some transitions that had to be done by 2021.   A lot of cities added state and county measures to pay for it and some cities got federal grants.  Even the school districts were involved.  Pretty much why Ebay was flooded with good commericial radios and repeaters for good deals the last two years.  

[WRYZ926]

10 minutes ago, WRUE951 said:

I'm pretty sure all public safety communications in the United States is now Digital as required by the Digital Transition and Public Safety Act of 2005.   When i left Sacramento in 2020 one of my friends who works in communications was scrambling to finish off some transitions that had to be done by 2021.   A lot of cities added state and county measures to pay for it and some cities got federal grants.  Even the school districts were involved.  Pretty much why Ebay was flooded with good commericial radios and repeaters for good deals the last two years.  

Well I can tell you that not all have switched over to digital modes. The Montgomery County Missouri Sheriff department and Mexico, Missouri Public Safety (fire and police) most definitely are still using analog. And again a lot of the rural/small town volunteer fire departments around me are still using analog.

Now the MCSD is currently in the process of switching over the state wide trunked P25 system.  But they are still currently using analog at this time. And even the Mo Highway Patrol still have analog radios in their vehicles so that they can still communicate with agencies such as the MCSD that are still using analog.

We were listening to a car chase on Interstate 70 in Montgomery County just yesterday afternoon. MCSD and MoHP were using analog radios the entire time.

MCSD is on 158.730 analog and Mexico Mo PS is on 155.925 analog.

[WRUE951]

36 minutes ago, WRYZ926 said:

Well I can tell you that not all have switched over to digital modes. The Montgomery County Missouri Sheriff department and Mexico, Missouri Public Safety (fire and police) most definitely are still using analog. And again a lot of the rural/small town volunteer fire departments around me are still using analog.

Now the MCSD is currently in the process of switching over the state wide trunked P25 system.  But they are still currently using analog at this time. And even the Mo Highway Patrol still have analog radios in their vehicles so that they can still communicate with agencies such as the MCSD that are still using analog.

We were listening to a car chase on Interstate 70 in Montgomery County just yesterday afternoon. MCSD and MoHP were using analog radios the entire time.

MCSD is on 158.730 analog and Mexico Mo PS is on 155.925 analog.

well sounds like some of them Hilly Billy's dropped the ball.  Wanna have some fun, give their public safety communications director a call and ask why they are breaking the law.  

[Lscott]

54 minutes ago, WRUE951 said:

Wanna have some fun, give their public safety communications director a call and ask why they are breaking the law.  

Why? If they are using narrow band FM they’re OK. The government recommends P25 for communications across agencies etc. However I’ve seen more smaller departments going with NXDN since it was cheaper than P25. Plus they has little to no need to communicate with outside agencies. 

[WRUE951]

14 minutes ago, Lscott said:

Why? If they are using narrow band FM they’re OK. The government recommends P25 for communications across agencies etc. However I’ve seen more smaller departments going with NXDN since it was cheaper than P25. Plus they has little to no need to communicate with outside agencies. 

pretty sure he said he was monitoring analog with a scanner.  That does not meet the Digital Transition Act.   Not claiming to be an expert on this, just relying on information from a friend who is a communications director for the state of calf.   

[wrci350]

2 hours ago, WRUE951 said:

I'm pretty sure all public safety communications in the United States is now Digital as required by the Digital Transition and Public Safety Act of 2005.   When i left Sacramento in 2020 one of my friends who works in communications was scrambling to finish off some transitions that had to be done by 2021.   A lot of cities added state and county measures to pay for it and some cities got federal grants.  Even the school districts were involved.  Pretty much why Ebay was flooded with good commericial radios and repeaters for good deals the last two years.  

The "Digital Transition and Public Safety Act of 2005" mandated that TELEVISION move from Analog to Digital, to free up space for public safety.  It did not mandate that public safety move to digital.

Either you misunderstood your friend or he is misinformed.

Federal grants for new communications systems mandate P25.  That doesn't mean a new DMR, NXDN or analog system can't be set up, it just means that system won't qualify for those grants.  There is nothing "illegal" about analog or non-P25 digital public safetey radio systems.

[WRUE951]

36 minutes ago, wrci350 said:

The "Digital Transition and Public Safety Act of 2005" mandated that TELEVISION move from Analog to Digital, to free up space for public safety.  It did not mandate that public safety move to digital.

Either you misunderstood your friend or he is misinformed.

Federal grants for new communications systems mandate P25.  That doesn't mean a new DMR, NXDN or analog system can't be set up, it just means that system won't qualify for those grants.  There is nothing "illegal" about analog or non-P25 digital public safetey radio systems.

this topic will get interesting.