intermod

Agree with that....this is one benefit of amateur radio; more licensees understand the concepts. We should educate our GMRS licensees better.

You guys in the south are suffering worse than we are due to the terrain (bowls circled by huge mountains). DMR is the perfect solution to expand GMRS in Socal by providing 4X the spectrum. And you can place DMR repeaters close together compared to analog, so this provide even ore benefit. In Norcal, we have a somewhat greater number of smaller "bowls" and more mountain ranges and hills, but many are lower. So to get any reasonable range, you need more repeaters. Maybe another solution would be to reduce repeater transmit power based on repeater elevation; the higher the elevation, the lower the power you could run. They already do this in UHF, 800 and 900 MHz business bands.

This plan would not replace analog - both would be permitted. Analog is never going away. The people wanting to use digital must get a digital radio. But there is no need for anyone else to do this. For example, if I have a analog repeater today, and I need more capacity, I have two options. Replace it with a DMR repeater on the current 462.625 channel center, or move it +/- 5 kHz up or down. The former is really a waste of spectrum. The latter would provide me with two channels, and leave the other half of the channel open for another DMR repeater if another group wants their own repeater.

Not sure I understand your comment. Are you confusing channel steps or spectrum allocation with signal bandwidth? The 7.6 kHz is from the official emission designator, as is 20kHz for analog. That means ~99% of the power is within these bandwidths. So one can easily fit two DMR signals in the same or less bandwidth of the wideband analog signal and get 2X2 or 4 timeslots (or usable channels).

Are you thinking we want to implement DMR because we want to use digital? The San Francisco/Sacramento region is heavily congested and interference among repeaters is increasing. There is no practical solution using the same amount of spectrum unless you move to digital technologies. You are also trying to compare apples to oranges. GMRS is a more attractive solution to the majority of people because their priority is communication as opposed to technical pursuits. Here in California, CERT, neighborhood or fire watch, militia groups, etc. have implemented GMRS because 80-90% of their members have no direct interest in the technical aspects of amateur radio.

The eight current GMRS channels can handle eight simultaneous conversations today (in the same area). The proposal below would allow for 32 simultaneous conversations without expanding the GMRS service. For those not familiar with DMR technology, each DMR repeater signal has two "timeslots" which allows for two independent talk channels. Two DMR signals can fit within the same space as one analog FM signal today. This is possible because a DMR signal only requires about 7.6 kHz of spectrum, while todays wideband analog signals need 20 kHz of spectrum. Thus, four conversations can be supported within each of the current GMRS channels. The center frequency of each DMR repeater (and the radios it supports) would be programmed 5 kHz above or below the current center channel. +/-12.5 kHz might also be used. Below shows how this would work in reality. The FCC would not need to allocate new radio spectrum. They only have to allow more efficient use of what we already have. The other benefit of DMR is that two different repeater groups could invest in one DMR repeater, which splits the cost in two while each maintains their own "channel". As a DMR repeater takes the same rack space as an analog repeater and only requires one antenna, the repeater site lease costs could be split between the two groups as well. It would take the FCC some time to accomplish this, so if they started now, they might be able to complete this rule change in 2024.

There is always a debate whether digital messaging is analog or digital. You need to look at the emission designators. Every DMR voice mobile or portable radio is certified for 7K6F1E, with DMR repeaters additionally certified for 7K6F7E. Per § 95.1771 "GMRS emission types", only the following emissions are permitted in GMRS: https://www.ecfr.gov/current/title-47/section-95.1771 A1D, F1D, G1D, H1D, J1D, R1D, A3E, F3E, G3E, H3E, J3E and R3E Note the DMR emissions F1E and F7E are not in that list. On the issue of text data - you will find the radios that send messaging will be certified for one of the twelve emissions above, and its explicitly permitted. § 95.1731(b) "Permissible GMRS uses": https://www.ecfr.gov/current/title-47/section-95.1731 "(b) Digital data. GMRS hand-held portable units may transmit digital data containing location information, or requesting location information from one or more other GMRS or FRS units, or containing a brief text message to another specific GMRS or FRS unit."

I assumed he would eventually figure this out. He seems a bit challenged.

They have responded to numerous GMRS complaints I have made - and even traveling out to the suspected source. I just received an email today from the Regional Director asking for additional reports of interference. I am not sure why you are having so many problems. If there is a drug lab in your area you have likely made the right decision. For now, I would recommend getting a concealed-carry permit as well. But why would you operate a local HF station when the interference potential is so high? Just setup a remote station away from most population and you would be good to go. All of my equipment is located on a mountain top away from most all noise sources. If you need me to assist or tutor you on how to do this let me know. I understand that this stuff can be challenging to new hew hams. We are here to help.

Possible solutions so far: - Use a different service and/or band (business) - Use a different service and/or band (amateur) - Multi-user/shared repeater using different codes (community repeater) - Lower site/directional antennas - GMRS repeater/frequency coordination These groups are not performing firefighting or law enforcement, but they help out when there is no other option, so low-cost radios are a good solution. Many of the groups can only get 10-20% to license in amateur, so this is an issue. Community repeater use won't work during a local or regional problem when more than one group is using it (they can't figure out that "MON" button). GMRS repeater coordination worked in the past, but demand has outstripped supply. Agree on the lower site/directional antennas - since we usually don't have control over what site we get handed, I would use directionals on the higher sites; vert effective, but unenforceable. Agree on business band - one "organizational license", somewhat dedicated channel, and they can also operate other modes (NXDN, DMR, P25, etc.) and even encrypt it if they felt the need. I will add the following: - Public Safety spectrum - they are performing work for government (exceeding NGO status), so they qualify, and the PS spectrum is super clean and coordinated. Most agencies here have moved to 700/800 trunking, leaving their 453, 460 and even VHF somewhat clear. - Use NXDN 6.25 narrowband digital repeaters; you can place 2-4 of those in one current GMRS channel (FCC work required) - Use DMR repeaters; two DMR channels=4 timeslots can fit in one GMRS channel today (FCC work required) - Narrowband DMR or NXDN interstitial repeaters (462.5625 MHz, etc.) (FCC work required) The digital options above would simply allow greater use of what we already have. NXDN would allow each groups to have their own system, where each DMR would provide shared use to two groups (slot 1 and slot 2). With DMR each group would only have to fund 1/2 the repeater costs. What about targeting unused/lightly-used spectrum: - 450/456 Broadcast/fake media band - 454.7/459.7 Air-to-ground telephone - remember those back in the 90's (does anyone use these today???) Other lightly-used bands? We won't go after an entire band; just 10-20 repeater channels worth.

Due to the large number of emergency groups and individuals that have deployed new repeater systems over the past few years, GMRS repeater spectrum has become overloaded. What makes this a particular problem here are the hills and mountain ranges - repeaters must be placed on high-elevation sites to provide reasonable coverage; this worsens interference potential and limits how often a channel can be reused in a region. Should there be a regional emergency, there is a risk that many systems would not be usable due to interference from other nearby repeaters. These groups often coordinate nets and training times today to avoid each other - but this would not be possible during an emergency. We need to get more use out of our spectrum, obtain additional spectrum, or both. How can this be fixed?

Agreed. We have several GMRS DMR repeaters now but they are under temporary FCC experimental licenses. Testing SFR could fall under this license however. G

I look forward to trying DMR SFR mode out - my Hytera models are too old to have the option. SFR should dramatically reduce the cost and complexity of repeater deployment (like 30-40%). But it is challenging to efficiently fit this into the current frequency allotments as well as higher-elevation shared communications sites using a single antenna. - If the SFR transmits on the 462 side, its receiver is in the same portion of the band used by other co-located transmitters (460-465 MHz; desensitization and noise), and it will hear all the repeater outputs from miles away, as well as all the bubblepack traffic; its receiver will get interfered with. - If operated on the 467 MHz side, it will will interfere with other co-located site receivers, and well as other repeaters with receivers on 467 MHz. So today, this seems to be a great solution when you have limited co-channel signals, a site without many other UHF repeaters, low-elevation applications and temporary emergency use. The Hytera approach also seems compatible with some non-Hytera model radios (can I just set them for normal Direct Mode?), as I read here that Motorola's approach (using a repeater instead of mobile or portable radio) requires split Color Codes. But Hytera's approach may also need Pseudo-trunking capable radios (ability to listen for traffic on either slot). Motorola may be the only manufacture that refuses to provide this capability. Hytera, Kenwood, Kirisun and possibly some Anytone radios can do this today.

One important aspect of GMRS is the ease of licensing and reduced message content restrictions. For example, while the comm leaders for CERT-like organizations, community fire-watch groups, etc. are often hams, most quickly find that only 10% to 30% of the members will take the ham exam. They just need to communicate. Many groups then try and equip these individuals with FRS radios - which fails miserably every time. GMRS is the perfect solution to this in most cases, and its a small ask to pay $35 for a ten-year family-wide license. The Chinese have begun to strongly address the GMRS market (unlike the US and Japanese companies) with more entry- and mid -level radios so this also helps. And of course, most long-time GMRS users operate commercial Part 90 radios (yes, yes, I know... for another discussion). You can conduct (small) or family business communications on GMRS too, so the repeaters can be put to better use when not used for emergency related comms. In general, they better promote community-oriented communications, and most GMRS licensees have less of an exclusionary "private club" mentality common in amateur radio. I am also seeing a trend in GMRS towards newer repeater equipment and who maintains it. Increasingly GMRS repeaters consist of purpose-build models (not two mobiles in a box or 30-year old repeaters) installed and maintained by people with two-way radio experience (many are technicians, some hams). Or they buy new. Is it me, or are the ham systems aging, kludged-together devices that are growing less reliable and lack experienced hams left to fix them? Many sound like trash, IMHO. In other words, many GMRS systems are simply more reliable and work better. Here in California, there is always at least one vegetation fire or "mostly-peaceful" riot occurring somewhere - and at least half of all traffic in the surrounding suburban and rural areas is related to CERT and/or firewatch comms. Most of their "nets" are used to familiarize new users on how to communicate - not on theory of how a radio works. The California State Militia and some Sheriff Posse groups also use it for security-related comms when such things threaten residents or private businesses. On a related note, GMRS radio congestion is a growing problem here in the San Francisco bay and capitol regions given our mountains and high-elevation repeaters. In some cases, moving emergency and security comms to business or public safety frequencies may be more appropriate if there are too many repeaters in an area and the group is large. Business and public safety licensing is even more practical as the organization can hold one license for all of its users (group licensing in GMRS was discontinued after business comms started monopolizing the channels to the exclusion of personal users). These services also allow for more efficient digital communications (DMR, NXDN, P25, etc.), including smaller radios with better battery life (feature of DMR-only radios), voice encryption and no (at least enforced) message content restrictions.

I guess we are the only GMRS system operating DMR - I have not heard from anyone (and for some reason I never got notifications after following this topic...). You either file for Special Temporary Authority (STA) or File from 442 under the OET.

If you are currently operating one of these technologies (or other digital) in GMRS repeater operation under a special FCC license please contact me offline. We are trying to determine how many are out there now and where. intermod@sngf.org Northern California GMRS Users Group (NCGUG)

I think what "Motorola figured out" is that once the users perceive that DMR operates the same as P25, and the system administrators discover that DMR is about 30% the cost and they get twice the channel capacity and more features than P25, they will no longer purchase expensive P25 hardware. Its a marketing decision by Motorola, that just happens to also be good for maintaining interoperability. Its the same game played by politicians. I agree with your comment on interop, except that 95% of the time, the locals can't talk to other locals or the feds anyway, either because they are on different bands (locals cannot afford multiband radios), or the Fed did not, or refuse to share their encryption keys. Of they fail to program in each others frequencies. An normally is bad practice to change channel to another system because your commanders need you on your normal channels. If DMR had a profit margins that P25 does, Moto would just come up with an excuse to promote that technology instead - and so would the politicians. It has noting to do with co-channel interference related to DMR - this is fake news (likely by Moto or Kenwood). DMR, P25, NXDN will all be similar at the co-channel distances we are talking about (DMR is noisier than most when strong, but they would not license someone that close). Frequency Coordinators assign co-channel stations based on carrier-to-interference ratios, and the modulation is not even a consideration, except when they look at adjacent-channel separation. Then they still don't care if its P25, NXDN, DMR, etc. - they only look at the bandwidth of the signal which is the first three of four digital in the emission designator. But I may be wrong.

In the western states, Motorola seems dominant, followed by Kenwood and Harris. Seems the east is Motorola, Harris and Kenwood. Kenwood tends to be very flexible and responsive to their customers as they are smaller. Governments and Districts qualify for special frequency bands. They are all over the map. In California: Rural areas: 150-174 or 453/460 MHz, with many exceptions Metro areas: 700, 800 MHz with many exceptions GMRS system can use the same type of conventional repeaters and radio that government uses - its identical technology in many cases. Gov can usually afford high-end models (its your money, not theirs....) where GMRS depends on how deep the owner's pocket is. GMRS uses the 462 MHz frequency range.

FCC List of Equipment and Services That Pose National Security Threat Released On: Mar 12, 2021 http://www.fcc.gov/document/fcc-list-equipment-and-services-pose-national-security-threat "FCC's Public Safety and Homeland Security Bureau publishes a list of communications equipment and services that are deemed a threat to national security, consistent with requirements in the Secure and Trusted Communications Networks Act of 2019" A later link takes you to a document with more detail on Hytera's issues: "Covered Equipment or Services Video surveillance and telecommunications equipment produced or provided by Hytera Communications Corporation, to the extent it is used for the purpose of public safety, security of government facilities, physical security surveillance of critical infrastructure, and other national security purposes, including telecommunications or video surveillance services produced or provided by such entity or using such equipment." Commentary: It looks like Motorola is getting great value for their DC lobbying investments. Some GMRS licensees that use Hytera products (including me) will find it amusing that they have again gone to the courts to kill their most viable competitor. So, instead of providing products that meet their customer's needs, Motorola has found it more cost-effective to pursue the low road. They are getting really lazy - not the same company when it was under the Galvins. For those not having used Hytera's higher-end mobile, portable and repeater products (similar build quality to Motorola in their DMR lines, designed originally for the Chinese police forces, etc.), you will find them to be superior from a feature, capability and ETSI compliance standpoint. Not even close. While I support death to the CCP (our greatest enemy) and the concern over camera equipment, I will give credit to Hytera for their product design efforts, even though they likely lifted some marginally important IP from Motorola (another ongoing litigation issue). As the repeaters have Ethernet connectivity, I can see a concern there that might be mitigated through a simple "air gap". This policy will really kick Hytera's a** in the utility market and elsewhere. They do not manufacturer any P25 products. FCC List of Equipment and Services That Pose National Security Threat:

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?

The FCC had recently proposed a reduction from $70 to $50, but there was push-back at least from Randall Knowles, KAA8142. The Commission subsequently reduced it further to $35. This reduction also applies to license renewals. Source: http://docs.fcc.gov/public/attachments/FCC-20-184A1.pdf Some passages: "41. One commenter, Knowles, contends that the proposed $50 fee for GMRS is too high, asthe application process is automated. There is no testing involved, as with the amateur license. Werecognize that the application process for GMRS licenses is highly automated. There are, however, somecosts involved in ensuring applicants are qualified and off-lined applications are individually reviewed,and we cannot conclude that there are no costs involved. 42. After reviewing the record, including the extensive comments filed by amateur radiolicensees and based on our revised analysis of the cost of processing mostly automated processesdiscussed in our methodology section, we adopt a $35 application fee, a lower application fee than theCommission proposed in the NPRM for personal licenses, in recognition of the fact that the applicationprocess is mostly automated.... 193. Rule effective date. As the Commission implements the changes to our application fee schedule, we anticipate that OMD, along with the Bureaus and Offices, may be required to update someof our licensing databases, payment instruction guides and/or adjust administrative internal proceduresbefore we may begin accepting the new fees for certain categories of application fee payors.Accordingly, we direct the Office of Managing Director, in consultation with the relevant Offices andBureaus, to cause a notice to be published in the Federal Register announcing when rule change(s) willbecome effective, once the relevant databases, guides, and internal procedures have been updated." $35 can still exceed the cost of some CCRs, but this is an improvement. While we would all want this to be zero, having some fee keeps the GMRS on the FCC's radar, if not for enforcement purposes. Randall Knowles, KAA8142, is from the North Shore Emergency Association. He has lobbied extensively for the GMRS for decades, working closely with Corwin Moore of the Personal Radio Steering Group (PRSG) back in the day. His call sign may be the oldest GMRS one I have identified; I think it was issued in 1976. Attachments area

The SFR (for the reason you stated) is one of various radio applications digital allows. The lowest cost hi-power commercial SFR unit I posted elsewhere is $400 (plus $120 shipping): https://www.belfone.com/bf-sfr600-single-frequency-repeater_p66.html This Hytera portable also has this built-in: https://www.hytera.us/products/pd982i-1 I can only imagine how handy the portable would be for search and rescue, etc. - just duct-tape it to a tree on a high hill in SFR mode (with an extended battery) and you are done. Other division duplex (TDD) products would include low power, 10-100 mW "hotspot" devices for under $150 - these are already developed for DMR in amateur. They could then be networked..with full-duplex repeaters if needed. Greg

As we only have eight shared channels, the linking would need to be tightly controlled. We are already seeing one conversation tying up 2-3 channels today over a wide area - and the repeaters don't even monitor for other active co-channel repeaters before activating right on top of them. Really poor practice. We have local mountains rising to 4,000 ft. here, so its only appropriate to tie one high-elevation system to really low-elevation ones (like local residential repeaters or hot-spots). Or to be more drastic about it - additional repeaters should not be linked to extend coverage, only to fill gaps in existing coverage (e.g, fill-in areas that would have been otherwise covered, if not for terrain blockage and/or buildings). FCC tables of range have existed since the 1950's and are still in use today to estimate this based on repeater elevation and power. Just jam it in Part 95 with a simple math equation. G

While physics shows that the signal strength from DMR will be exactly the same at the same distance, I think you mean analog is more susceptible to interference, and DMR is a bit more noticeable even when compared to P25 Phase I or NXDN. Another major contributing factor is a DMR repeater's duty-cycle. Repeater duty cycles can be greater because they support two analog channels worth of radio traffic (Slot 1 and Slot 2). In addition, the primary manufacturer's default hang time is 6 seconds to ensure that field radios are synced up with the repeater slot, particularly for reply messages (otherwise access times increase). And, since many DMR radios have a direct IP connection (through USB) and built-in GPS, running data application and vehicle location applications further increase to the duty cycle. Add to this analog narrow-banding. Narrow-banding increased analog FM's susceptibility to co-channel interference by 6 dB, while also reducing effective range by about 3 dB (which may explain your 50W>>300W affect). GMRS remains wide-band so it will have less impact. I don't know if the FCC ever considered a DMR power reduction, but the frequency coordinators did about 5 or 10 years ago. One system we went to license was hit with an automatic 50% power reduction before they would approve it. Listening to UHF commercial spectrum, it seems there are significantly more DMR systems than analog in the metro areas (maybe just because of the DMR duty-cycle??). At least three to one here. Its just a cost-benefit issue; DMR allows two separate families or groups to use one repeater at the same time - in half the spectrum; a 100% capacity increase). We only have eight GMRS repeater channels today - so with DMR, fewer repeaters need to be built, creating less GMRS congestion overall. And it reduced all of the user's initial and recurring costs 50% as they could now be split among twice as many users now. Once two adjacent channels in an area convert to DMR, you can then (after a minor FCC rule change) run DMR repeaters on the interstitial channels without interference between them - quadrupling use of the band overall. And digital users get texting, private calling and greater voice clarity..... Greg Add to this analog narrowbanding. Narrowbanding increased analog FM's susceptibility to co-channel interference by 6 dB (which partially explain your 50W>>300W affect). GMRS remains wideband so it will have less of an imp

That would have been a great opportunity to do the opposite: sell the analog user a new digital system Digital technology has a lower C/I requirement than analog and would have reduced the effects of the interference from the other system (but maybe not enough). But seriously, the company did the right thing if they could not use directional antennas to reduce the issues (sometime this is a mobile uplink issue making it more difficult to resolve). Greg