intermod
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Posts posted by intermod
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1 hour ago, WSAK691 said:
Noise floor? not on my SDR. The biggest curse are the pagers. I get a low ambient noise floor here in a major city. 2 watt murs here gets out.
You may be one of the few. What does your SDR show for noise floor at 16 kHz bandwidth?
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55 minutes ago, WSAK691 said:
VHF is such a great slice of spectrum. I can’t understand why it wouldn’t be used more fervently.
High noise floor, particularly in the metro and suburban areas, can be the controlling factor. This is primarily caused by microprocessors, associated clocks and switching power supplies in electronic products (including many LED light sources). This effectively deafens VHF receivers so that they are no longer as sensitive as they used to be. If you ever get a chance to use 700, 800 or 900 MHz, or even 1200 MHz, it will become immediately obvious. As was said above, while VHF propagates really well outdoors, in some cases the 700-1200 MHz bands can actually do better, except when the signal hits dirt (hill or mountain) or a dense foliage.
Another factor to consider in VHF is portable antenna efficiency. Most portable radios are equipped with the 10" flexible helical antenna, versus something that more approximates a 1/4 wave length (18"). The 10" has an effective gain of -11 dBd. That takes a 2-watt MURS radio and degrades it to less than 0.2 watts. And it does the same to reception of signals......so VHF is really being hammered.
UHF has become degraded but not as bad. But the antennas (for a given length) are more efficient.
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IEEE TECH TALK: IS VHF DEAD?
Date: 13 Feb 2024
Time: 05:30 PM to 06:50 PMOnline Join link
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Join Zoom Meeting
https://us06web.zoom.us/j/87613850683?pwd=VGhYQmxsU0dlbE5qRnMyS3o2Vmxqdz09
Meeting ID: 876 1385 0683
Passcode: IEEESEA
https://events.vtools.ieee.org/m/401815
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Linking repeaters through the Internet, or via a private broadband connection (private point-to-point microwave radio, like using Ubiquity radios) is not prohibited by the rules. The FCC rep's opinion in the video is “hearsay” and is not considered authoritative. The female rep even notes this earlier.
Here is a brief tutorial on this matter.
§ 95.349 Network connection.
Operation of Personal Radio Services stations connected with the public switched network is prohibited, unless otherwise allowed for a particular Personal Radio Service by rules in the subpart governing that specific service. See e.g., §§ 95.949 and 95.2749.
Fact 1: The Internet is not a “public switched network”.
§ 47CFR § 9.3 - Definitions.
Public Switched Network. Any common carrier switched network, whether by wire or radio, including local exchange carriers, interexchange carriers, and mobile service providers, that uses the North American Numbering Plan in connection with the provision of switched services.
Fact 2: Internet Service Providers (ISPs) are not considered a “Common Carriers”. They were between 2015-2017, when Net Neutrality was in place. Net Neutrality was eliminated in 2017.
§ 95.1749 GMRS network connection.
Operation of a GMRS station with a telephone connection is prohibited, as in § 95.349. GMRS repeater, base and fixed stations, however, may be connected to the public switched network or other networks for the sole purpose of operation by remote control pursuant to § 95.1745.
§ 95.303 Definitions.
Remote control. Operation of a Personal Radio Services station from a location that is not in the immediate vicinity of the transmitter. Operation of a Personal Radio Services station from any location on the premises, vehicle or craft where the transmitter is located is not considered to be remote control.
§ 95.1745 GMRS remote control.
Notwithstanding the prohibition in § 95.345, GMRS repeater, base and fixed stations may be operated by remote control.
Fact 3: While “control” or “remote control” normally refers to the act of enabling or disabling the ability of a transmitter to “activate”, the term “operation by remote control” refers to people using the repeater remotely.
Conclusion: Linking GMRS repeaters through the Internet is not prohibited. Linking through a private connection (not routing through the internet) is certainly fine as well. Just don't install an autopatch on GMRS.
If anyone is aware of a formal case where a licensee received a formal NOV for linking after 2017, please let us know. I suspect one does not exist.
What typically occurs is that an NOV is issued for harmful or destructive interference (IX). For example, if I operate a repeater in Boston, which activates a repeater in California, and the California repeater walks on top of another local repeater, then we have harmful IX. This is a violation. Not the linking.
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15 hours ago, tweiss3 said:
Those are ConnectPlus. You may have issues removing trunking firmware and going to a standard firmware. I have not personally made that change, so I cannot walk you through it.
Does the FW need to be removed, or can he just program a conventional channel in them and go with that? Or does CP preclude programming a conventional channel?
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6 hours ago, gortex2 said:
.... Dont run them on high power or they wont last long. Basicaly the XPR 8400 repeater has two of those in the box.
Good recommendation when using those model for repeater operation. But if/when the transmitting radio fails, just swap the radios around.
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See attached model number chart. These are 450-512 MHz models. These will work on GMRS but not amateur. I have many XPR4550 radios and a few 5550. They have superior receivers from a susceptiility/overload perspective. They are perfect radios for creating a repeater. Their accessory outputs are easy to program. They have a design flaw where their accessory port output of low frequency CTCSS codes (below 114.8 Hz) or DCS are poor. But that is fine. Not sure about cables.
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2 hours ago, WRQI583 said:
...If a digital signal comes along and happens to be as strong if not stronger than the analog signal you are trying to listen to, the digital will either make it impossible to hear the analog signal or you just wont hear it at all. ....
I will also add that if an analog signal comes along and happens to be as strong if not stronger than the digital signal you are trying to listen to, the analog will either make it impossible to hear the digital signal or you just wont hear it at all.
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On 11/29/2023 at 7:18 AM, Sshannon said:
The powers provided in Article 1, Section 8 laid the foundation for creation of various government agencies, bureaus, and commissions, including the FCC. Without regulation, telecommunications, which of course hadn’t been conceived at the time the constitution was written, could affect defense, commerce, and general welfare. The following paragraphs are those which are most clearly related, allowing for the natural evolution of context. Invisible waves traveling through the air can be understood to be a logical successor to the concept of commerce on the high seas:
1. The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
3. To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;
10. To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations;
and
18. To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.
Commissions, Bureaus, and other regulatory agencies are created in order to provide for the general welfare of the United States.
The General Welfare clause amounted to no more than a reference to the other powers of the subsequent clauses of the same Section. How could this be any other way? If "general welfare" was interpreted to mean virtually anything, it would destroy the entire concept of limited (federal) government and justify expenditures in any field. Limited (federal) government was one of the primary goals of the Founders.
However, I get that this has been the interpretation for a long time (re: Butler Case, 1936). I wonder if this has had any impact on our national debt?
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1 hour ago, WRKC935 said:
Welcome to the ignore list. You have joined a rare bunch that up to now only included OffroaderX. May the two of you find happiness in limb.
Uh - you followed *me* here.
Please add me to the list. OffroaderX can't be too bad if he studies the Constitution.
Did you have any comments on what in our Constitution authorizes the FCC to exist?
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3 hours ago, OffRoaderX said:
As an internet legal scholar and couch-based constitutional expert, you should know that complaining about it here is not going to accomplish anything other a bunch of back and forth verbal & grammatical masturbation.
Excellent term. Agree - such topics are truly meant to trigger g-m. Its so effective.....
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2 hours ago, Sshannon said:
Just imagine if all the radio spectrum were unregulated. It would be like CB!
I though this was just someone messing with the camera - but then I heard the voice modulation in the recording....cool.
Further - Imagine if the Great State of California tried to manage radio spectrum.
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16 minutes ago, PRadio said:
I don't know, without the FCC I can see all sorts of issues related to interference of aviation communications, not a good thing. Interference with police communications, railroad, emergency medical communications, etc. They also oversee and regulate spurious emissions from electronic devices. Are you sure you want a free for all?
Agree that some bands that are used over state lines need general administration - or those that involve life-safety.
Spurious are the same as non-spurious: if they don't cross a border, then its not their responsibility.
This is not a binary choice (regulation versus free-for-all). Each state may have unique wireless needs that they could address - interior to the state - away from the edges - that would add flexibility.
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28 minutes ago, OffRoaderX said:
Congress gave the FCC the legal authority to exist in 1934 when they passed the Communications Act of 1934.
And just FYI, complaining/arguing/chest-beating about it in an online forum wont change anything - If you really want to change/eliminate the FCC start by contacting your congressman or an attorney.
Correct, but any law in violation of the Constitution is null and void on its face ("pretend legislation").
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30 minutes ago, Sshannon said:
That’s amazing! How do they know when to stop?
We simply use the magnetic field versus the electric field as a measurement basis. It falls off much faster with distance.
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Does anyone know what gives the federal government the right to get involved in local wireless communications - or their justification to even exist as an agency?
I can understand that they could justify involvement in long-distance HF, and any wireless signals that cross state or international borders (i.e., commerce clause, etc.).
But I operate on UHF where the signals don't cross any state or international border.
Their authority to exist is not defined in the US Constitution (of course). Thus, this responsibility should either fall to the State, or the People.
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2 hours ago, Lscott said:
It's going to take some careful thought to figure out how to do it. IMHO for the moment we should just forget running digital voice on repeaters. I think the major gain is digital voice on simplex. The logic there if you need a repeater the analog FM types seem to do a very good job of providing good coverage. The digital voice modes would primarily benefit HT to HT, or HT to mobile/base communications.
Also remember UHF spectrum is limited. The FCC mandated most services move to narrow band in an attempt to free up more spectrum. Asking the FCC to allocate more spectrum to GMRS is very likely dead on arrival. We would be lucky to keep what we have now.
Lscott's proposed plan using a narrow NXDN or dPMR type emission (~4K00 - if am I correct) is absolutely the easiest way to approach this when we have a federal bureaucracy to deal with. And the manufacturers will jump all over digital in any form to sell more equipment or differentiate their products (ant least temporarily). So he would likely have both GMRS licensee and manufacturer support. And all the hate that comes with mentioning the D-word.
As we have many mountains here in our Northern California area (repeater signals travel great distances), GMRS interference and capacity issues can only be dealt with by addressing repeater use. So that is why I focus here.
Agree that getting more spectrum is unlikely.
If we eventually have to discontinue use of DMR, the two main users groups (on Slot 1 and Slot 2) will now have to share a common (single) repeater channel, but they are more likely going build a second repeater on a different channel, in an attempt to get the same level of service. This will create as much or more interference than the single DMR repeater did before and eat up more of our limited spectrum. So these things need to be looked at broadly to really understand the overall picture.
The horse has expired.
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2 minutes ago, WRQI583 said:
I am sorry to have triggered you. So I understand - are you suggesting I try amateur radio?
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4 hours ago, Lscott said:
That annex is huge. I think the relevant section starts on page 92 of the linked document. Most of that annex after that is just the specific test conditions for each mode.
See attached. This is the key table for determining what the required C/I ratio is for a given voice quality and technology. Much of the other data was use to generate this table. DAQ3 column is what should be used from commercial and GMRS.
For others who have not used this, it shows that:
1. Analog FM ± 5kHz (25 kHz) requires a Carrier-to-Interference (C/I) ratio of 17 dB (e.g., any interfering signal, regardless of type, must be 17 dB weaker than the signal you are trying to receive for good voice quality)
2. ETSI DMR 2 slot TDMA (AMBE +2) (12.5 kHz) requires 14.3 dB
This indicates that DMR and other digital signals can tolerate more interference than Analog (2.7 dB greater interference tolerance in this case).
This table also indicates why you really don't want to use analog narrowband. Narrowband analog (Analog FM ± 2.5kHz (12.5 kHz)) requires a C/I of 23 dB, which is 8.7 dB worse than DMR and most other digital technologies. Anyone that has used narrowband has already realized this.
So - if the FCC ever proposes narrowband analog, I would hope they would also allow digital so we could maintain the range and performance of our radio systems.
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46 minutes ago, Lscott said:
You're one of the examples of those that have no interest digital voice modes, at least DMR, on GMRS. That's perfectly fine. Any implementation has to take those kind of interests into consideration. Undoubtedly, and from other posts, you aren't the only one.
NXDN is not very complex to use. It can be used without talk-groups, unlike DMR. That deceases the complexity for the user.
The attached images are screen shots of the programming software for the example Kenwood dPMR radio in that file. As you can see it's very simple. One is for the analog channels while the other is for the digital ones.
I had not seen NXDN programming before. Was is the "Common ID" field? Is that the "RAN"?
Completely agree that this is easier than DMR. I hope some of the the DMR settings (not the slot, CC, Talkgroup) that nobosy ever plays with will get accepted and not be present eventually.
But also, Kenwood makes things much easier compared to the others.
G
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10 hours ago, RayP said:
Or if you really want to play digital mode on simplex, do it on one of the five MURS channels.
MURS does not permit common digital voice modes like DMR. See § 95.2771 MURS emission types.
Another reason why GMRS is the right place for digital.
But thanks for suggesting the idea. I had forgotten whether MURS allowed this or not.
But both MURS and GMRS permit DMR, P25 and NXDN data, such as for texting. Or maybe GPS...not sure about this one though.
Retevis made one last year - could not remember the model. DMR on GMRS, but only for texting. Analog voice.
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3 hours ago, WRYZ926 said:
....If things are not setup correctly then anyone using analog will hear a bunch of noice when someone transmits using digital. ...
Is this a digital problem or a poorly-design analog radio problem (e.g., is the analog radios CTCSS/DCS decoder to apt to false on digital noise)? We have run dual-mode on our repeaters and have not experienced that - except with a few Boafengs that were really low-end. We were able to false those decoders by just talking on analog - they would open their speakers intermittently.
Yea - the thing that sucks is that all the digital modes are incompatible. But do you think that the world is headed towards a digital radio nirvana (one standard - all compatible) or is the trajectory in the other direction?
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12 hours ago, WRKC935 said:
...There is a requirement under part 90 that a user much first monitor the frequency in use to be sure that there isn't another user on it. That is what the MONITOR button is for, and why there is a 'Hub defeat's PL' that turns off the PL requirement on a mobile radio when you take the mike from the hanger. Now I don't believe that GMRS has such a requirement. It's also why there is a channel free and color code free setting in DMR radios. When using a DMR programmed channel it's suppose to be set for channel free if there is another user close enough that their licensed coverage area overlaps your coverage area. GMRS doesn't have 'licensed coverage area's. We are power limited but that's it, as long as your transmitter is 50 watt's or less, the sky's the limit on antenna height and antenna gain. Yes, if your tower is over 200 feet you have to have it registered and have obstruction lighting, but that's not a height limit, it's an additional requirement by the FAA not the FCC for towers exceeding a certain height.....
Correct - GMRS does not have that requirement, but it more broadly states that users should avoid interference and cooperate. But the "listen-before-talk" (LBT) concept generally remains.
I found that the vast majority of Part 95 analog radios lack a Busy Channel Lockout (BCLO) feature - and in practice, nobody uses or remembers how to use the Monitor button. And many new bubbleplack radios come with CTCSS/DCS enabled on their receivers.
In contrast, all DMR radios have BCLO, and many have dual-mode capability that allows monitoring of digital or analog signals on the same channel.
DMR repeaters also have BCLO built in, and you can manually fine tune the lockout threshold. Few analog repeater ever had such a feature.
So the DMR radios and repeaters are much better at channel-sharing and protection than analog radios.
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12 hours ago, WRKC935 said:
.....It's the same dead horse with a different bridal.
And I have NO idea where you got the idea that DMR is somehow better suited to deal with analog signals than other analog signals. Any type of signal getting into a DMR receiver will raise the BER and cause artifacting and digitization of the audio......
Of course, but we are comparing analog to digital. Your statement is a bit too broad. Empirical tests have proven that for a given digital voice quality (BER-related), DMR, NXDN and P25 are about 1-3 dB better at rejecting interference than legacy wideband analog signals are (See TSB-88.1, Annex A). Its 6-8 dB better than narrowband analog. This is the same data the Part 90 frequency coordinators often refer to when licensing those systems.
GMRS vs MURS at 5 Watts.
in Technical Discussion
Posted
Looks like about -119, which is low for VHF. If you have good coax then you are doing better than my area....