Jump to content

Search the Community

Showing results for tags 'interference'.

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • General Mobile Radio Service (GMRS)
    • Guest Forum
    • General Discussion
    • Technical Discussion
    • Equipment Reviews
    • FCC Rules Discussion
    • myGMRS.com
    • National and Regional GMRS Nets
  • Other Radio Services
    • Family Radio Service (FRS)
    • Multi-Use Radio Service (MURS)
    • Amateur Radio (Ham)
    • 900 MHz License-Free Radios (ISM)
  • Off-Topic
    • Miscellaneous Topics
  • TreasurecoastGMRSclub's Radio Etiuette
  • TreasurecoastGMRSclub's Radio gear
  • South Western PA GMRS's Repeaters
  • NOVA GMRS's Area Repeaters
  • ISLACOMM GMRS's Topics
  • Alaska GMRS's Welcome!
  • Southwest Virginia GMRS's Topics


  • Community Calendar
  • ISLACOMM GMRS's Events
  • Southdade GMRS Club's Events
  • Southwest Virginia GMRS's Events

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start



Website URL




Unit Number




GMRS Callsign

Ham Callsign

Found 7 results

  1. Here in the San Francisco Bay and Sacramento regions we have started hearing a "baby monitor" type devices using GMRS 462 and 467 MHz primary repeater frequencies, in nursing home settings (given the message content). We are aware of about twenty incidents of this over the past three months, but the rate of occurrence is rising. The most recent was strong enough to interfere with a CERT/Fire Council repeater out here. These typically operate during daylight periods, and appear to be continuously keyed for up to 12-16 hours at a time, although background noise, such as televisions, could be keeping them transmitting if set for VOX. They do not have time-out timers enabled. These change channels occasionally, but usually end up on 462.625, 462.725, 467.625 and 467.725 MHz. They use a D754 or a D734 DCS code. This kind of device was explicitly mentioned in past FCC GMRS rulings as it was feared that manufacturer's might use these channels for such things. Given most repeaters here in California are on 1500-4000 ft. mountains, continuous destructive interference will occur to our repeater inputs. I tried to DF the source of one of these last week, but it was found to be in San Francisco and we ran out of time. SF is a particularly difficult place to do this due to the density, hills and other sources. Thankfully these are constantly keyed. The device I was looking for was horizontally polarized, making it about 10-20 dB weaker when received on a vertical vehicle antenna. A Yagi in horizontal worked best. My goal was not to go after the user (they don't know better), but instead get a picture of the device, determine its manufacturer and model number, and establish who is selling it. As these may be used in nursing care facilities, they will likely have to bring the device out to us to be safe. Please let us know here if you hear these as we are trying to keep a list of the channels and codes in use so we can identify the specific radio model. This is clearly in violation of §95.1733(a)(10) and §95.1763© for GMRS, and §95.587(3) for FRS. It also appears to violate §95.533.
  2. I have been involved with GMRS for almost 30 years and have never seen such an abrupt increase in business radio use of the 462 MHz primary channels until the last two years. It has accelerated over the past year to the point where many of us can no longer communicate with more distant repeaters from my base station between 6 AM and about 8 PM, M-F due to co-channel radio traffic. Weekends are increasingly becoming a problem as well. I have also seen an increase in adjacent-channel interference from the 12.5 kHz interstitial channels on the base station, primarily because a large number of these commercial users have FRS radios improperly programmed for wideband (25 kHz) operation. I am located in the suburbs east of San Francisco/Oakland, with 2200' mountains between me and the busy bay region. I can only imagine what the bayside users are experiencing. Anyone else seeing this problem?
  3. I have noticed a pulsing interference in my town (Butte, MT) that affects all GMRS channels. It does not sound like your typical Morse code keying but repeats regularly at ~1Hz. While it only covers a few blocks in the center of town, it is detectable up to SQL 5, which confuses me. Any ideas what this might be? Thanks, WRKL926 Butte, MT
  4. Im very excited that this resource exists. Thank you for allowing me to join here. Like many others the my introduction to the radio world was when I had bought the midland GXT 1000's handheld bubble-pack for the reasons one would have handhelds: mostly at campsites and other similar occasions. I was impressed with what they could do and wanted to explore more. I added the 15 watt midland to my truck for the same purpose but to add some capabilities. And again dollar for dollar am pretty impressed. So....now ive go the bug and want to try to cover my neighborhood as back up comms for my family and friends. so im going to pursue getting answer to these questions and if seasoned members would like to share their thoughts here I would be grateful I did get my license and im ready to rock. 1) if I build a radio shack ( just talking gmrs right now-- but i can tell its the gateway drug already) in my home office, will my wi-fi router cause any interference . Literally like 3 feet apart. 2) im looking at the midland 40Watt or the Btech 50 watt any strong opinions on this? 3) looking to put antennae in the attic. thoughts on that? 4) why can I hear people from 20 or 30 miles away or even more, but no one can ever hear me? 5) Are there good resources out that where I can go as a total novice?
  5. I am sorry if this has been covered previously, but I searched the forums (and the InterWebs) an could not find any information as to interference between GMRS (or even 70cm) and cell tower/WIFI signals. My reason for asking is this-a mountain that is a few miles from my house has been one of the sites that I was dreaming of putting a repeater on. I have done to rough coverage mapping using the radiomobile app, and this peak looks like it would give excellent coverage in my target area (and about 50 miles to the south and west). I am trying to find out what the likelihood of intermod is between the bands before I reach out to the tower owner (it is a line of sight wifi internet company). The tower has not gone up yet, they got the AOK from the county last summer. The "cell tower" will be a monopole style one,so I do not know if any other antennas could be attached to it. The site is what I am really interested in, more than the tower itself. Thanks in advance for any advice. WQXU640
  6. While scanning the GMRS input frequencies last week I found a strong repeater output operating on 467.550 MHz using a 118.8 Hz output code. It was heavily-accented maritime traffic. We found their input on 457.550 MHz (10.0 MHz lower). I presume they were using 118.8 in as well. There were there for 48 hours before departing out the Golden Gate into the Pacific. The choice of 118.8 is interesting as we get lots of spurious signals on that code (almost 2X 60 Hz??) most everywhere in the bay region - so most repeater owners have disabled that code. So this helps them hide. Yea, a conspiracy theory... Both the 467.55 and 467.575 have been taken over by maritime traffic here in the San Francisco area for many years (and sometimes includes 467.600, .625, .650 and .675), but it has always been direct mode/simplex. This is a disturbing development... I am bringing these incidents up because if we lose control of our repeater input channels, high-level (and some low-level) repeaters will become impractical. Greg KAF1291
  7. The FCC’s Consumer Complaints page for reporting interference recently added a category for reporting interference to GMRS stations. Previously, there was no way to report issues specific to GMRS, but there was for Broadcast, Amateur, etc. This is a small but important development and may help combat the FCC’s recurring claim that “…we have received no reports of interference...”. This statement has been common in most all Part 95 and GMRS rule-making proceedings over the last few decades to help justify further encroachment of FRS and support other policies that licensed GMRS licensees generally opposed. We are not suggesting the Commission lied about the lack of complaints – they had not provided a way to report, categorize and centrally store them! The Northern California GMRS Users Group (NCGUG) encourages repeater owners and users to report recurring interference problems, such as unlicensed operation on repeater uplink channels, intentional jamming and abuse, and of course interference from FRS (co- or adjacent-channel). We have been reporting recurring interference from maritime operations on our repeater uplinks for some time. While the FCC rarely responds to such complaints, this may go a long way to eventually reducing the rising tide of interference sources that we all have to deal with. Brief instructions on how to use this site follow. ____________________________ https://consumercomplaints.fcc.gov/hc/en-us Create an account (different from your ULS account) File a complaint Radio Fill in Subject and Description Radio Issues: INTERFERENCE Radio Interference Sub Issue: TO LICENSED TWO_WAY RADIO SERVICES (LAND MOBILE, AVIATION, MARINE) Your Radio Method: PERSONAL RADIO SERVICES (CB, FRS, GMRS) Fill-in the remaining fields marked with “*”. The site provides a selection of “To Unlicensed Service (CB, FRS GMRS)” under Radio Interference Sub Issue. This incorrectly refers the GMRS as an unlicensed service, which it is not. While we have requested a correction, we recommend using the “Licensed….” selection noted above instead. Greg
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.