FCC Moves Ahead With 5G Regardless


Feb 11, 2017
Islander Freeport 36 Ottawa
There is a lot of discussion here about 5G effect on GPS but I cannot find anything that talks about what that effect is. Lots of sky falling talk but nothing actually describing the potential interference. Everything I see shows 5G in the 3.3GHz to 4.5GHz range and also around 26GHz. With properly designed transmitters this won't have any impact on GPS or any of the other GNSS frequencies.
The only FAA articles I can find discussing concerns with 5G are about altimeters, nothing about GNSS or GPS. Most boats don't worry too much about altitude.
The more concerning aspect of the original article is the impact on weather forecasting and the potential impact on the 23.8GHz atmospheric moisture measurements. Although I suspect that won't be much of an issue since the vast majority of the area where those satellite measurements are important are well outside of 5G range.
All FCC approved transmitters have very specific requirements about side bands and out of band emissions specifically to address the concerns everyone is presenting. The example by @dlochner about an amateur radio setup interfering with TV signals is a good example of why limiting out of band emissions is very important. As long as the FCC addresses the concerns regarding out of band emissions, adjacent frequency use can be accommodated.
Jan 11, 2014
Sabre 362 113 Fair Haven, NY
As long as the FCC addresses the concerns regarding out of band emissions, adjacent frequency use can be accommodated.
Well, that's the issue. Over the last four years there has been little trust in the FCC's decisions. They seem excessively swayed by large corporate interests and against the interests of the consumer and enduser, Net Neutrality being one example.

Ligando did agree to replace gps units that are affected by the 5g network, however, no one knows what that number might be and no one knows the cost. One concern is that the effects will be wide spread and the Company will not have the resources to meet this agreement, it will be violate the agreement and stay in business or try to meet the agreement and go bankrupt. Either way, for the end user it will be "So sad. Too bad." One of the largest users is the DOD, which means tax payers will end up being on the hook for replacement while the company execs walksaway.

Surely there must be a section of bandwidth that would create fewer issues.
Sep 15, 2013
Catalina 270 Baltimore
This all started when LightSquared (who went bankrupt and emerged as Ligado) bought a frequency licensed for low power earth to satellite communications with a ridiculous plan to use it for high power LTE communications. The frequency was restricted to low power by the FCC because it was right beside the critical GPS frequency. They could have bought a frequency meant for high power transmissions (like Verizon and ATT do) - but low power frequencies are cheap - it saved them a bundle of money. They bought the frequency knowing the designation but have been trying to get it changed for a decade through political pressure. It's like buying a small house lot on a wetland and then insisting that the town zoning board change the zoning to allow a 10,000 sq/ft mansion. Lots of evidence exists of the interference. There is a filing with the FCC in January 2011 by Garmin who tested the system and found that "widespread, severe GPS jamming will occur" if LightSquared's plans were approved." (see Expedia under LightSpeed for the links) Now, no one - not even Ligado - argues that Ligado's transmitters won't impact older GPS receivers. Their claim is that the jamming wont' be too severe and anyone who wants accurate GPS can buy new GPS units that have a hardware fix to reduce (but not eliminate) Ligado interference. The question remains why all of us have to spend money on new GPS equipment so that Ligado can make a huge profit on their frequency.
This ^^^. The key word is Lightsquared. They tried this during the Obama administration and DOD shot them down because of GPS interference. Now in true terminator II fashion they reformed and tried it again. They will probably succeed this time because they figured out who they neglected to bribe last time. Technical stuff was well covered in previous posts.
Sep 20, 2014
Rob Legg RL24 Chain O'Lakes
There are many GPS units that can not be replaced, as they are integral with the accompanying electronics that are part of a larger system. We all know that the funds to support the replacement of these older unit will never see the light of day, let alone replace these older systems. What would be interesting is a civil class action for causing interference. Name the FCC for not following its own rules regarding interference.
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Jul 13, 2010
Precision 23 Perry Hall,Baltimore County
I tend to agree. Generally for navigation our precision requirements are pretty low. Plus or minus 50 or 100 feet should be just fine for keeping us going in the right direction. There are other cases where the precision needs are much higher, and some of those likely have more lobby strength than Ligado Networks. It seems unlikely that the change would degrade the system so severely that it would impact not just those high precision cases but also our needs.
I agree with this for our needs, but others are not so lucky. I construction, sattelite gps is used for survey and layout work and precision is requiered for example to properly locate a concrete storm drain top to match the curb and gutter that will be staked out and installed at a later date. Kinda hard to move an installed concrete structure!
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Sep 20, 2014
Rob Legg RL24 Chain O'Lakes
DAVA390, How integrated is the GPS into the old equipment? Is the equipment automated, so the automation talks directly with the GPS, or is the operator reading the GPS directly and controlling the equipment manually?