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@marcspaz Assuming the repeater had been established for some time, folks using a channel that’s known to be in use by a repeater is a bit like fly fishing directly beneath a dam. Sooner or later the dam will spill.

I experienced something a few days ago, that I had not experienced before. Around my home, we have several repeaters that have 80%-90% reliability for 35+ miles and 70%-75% reliability out to 45-50 miles. We're talking over 7,800 square miles of coverage. With that kind of footprint, I have always suspected that repeater use could cause interference to simplex users, without the repeater users even realizing it. I can't hear a simplex conversation between mobiles when those parties are 60 miles away from me. So, what can you do as a repeater user to reduce that interference? Is it on you to be sure that doesn't occur? Is it up to the simplex users to try to use tone or digital squelch techniques. Or is it up to the simplex users to find a free channel? I got on a repeater the other day and started calling out for my son, and without realizing it, I was interfering with a simplex conversation. One of the other operators got on the repeater to let me know I was wiping out there local traffic. Thankfully the owners of the stations with the local traffic are friends of mine, so one of them came on to the repeater to chat. Everything was friendly, which they are both good guys and I would expect them to be friendly about it, even with a stranger. One of them simply came up and let me know I was stepping on them and I stopped using the repeater for awhile. Since we're all sharing radio space, it just seemed like a normal situation with a good and expected outcome. But, what would have happened if those people were not my friends? What if it was a group who doesn't know the person causing interference? What if the simplex operators don't have repeater access and the repeater owner or operator simply is unaware of the simplex conversation. Where does the onus lay to take action, and what is the proper action. I know we have discussed how unlikely it is to get GMRS expanded, but would it be worth trying to petition the government to expand GMRS to included dedicated repeater frequencies so we can avoid situations like this? I don't know the right answer, but I figure it could be fun to discuss.

For a one shot arbitrary pulse shape you can use the Fourier Transform to calculate the spectra. In a prior post I had a link for a paper that had the mathematical model for a nuke EMP for reference and testing purposes. The transform can be used to calculate the spectra. From that the parameters for shielding can be formulated. https://en.wikipedia.org/wiki/Fourier_transform

462.xxx5 (channels 1-7) are repeater-free. Perfectly adequate for local traffic between HTs or between HT and mobile. Local traffic between mobiles on 462.xxx0 at full power has a good chance to overpower repeater interference. The opposite happens only when mobiles are far and repeater is close. In this case use reserve frequency, according to your communication plan.

It is only going to get worse. With more repeaters coming online, more licenses and a limited set of repeater pairs. I don't see any easy solutions. With mobile radios ( most cant go below 15w) not being able to use lower channels. It is all compounding to be worse. I told Roland many moons ago, that gmrs will in time become uhf cb radio sadly. Kinda of why I preach, open the squelch, or use monitor to disable pl tones. To listen before transmitting. That still doesn't help if your station has poor ears. Best operating procedures are the only way to help clear up the clutter. I mean come on even in the Ham world people trample on each other tuning up, just because that can't hear the other station. No quick solution, if I think of anything, I will chime back in. Sent from my SM-S901U using Tapatalk

I was told figuring out the FCCs mess of a website and all the hoops to jump through in order to get the license was considered to be "the test" for GMRS.

Elapsed time between when something was certified by FCC and the time it shows up in the list you looked at.

Capacitive coupling is only for the AC of RF. Capacitors block DC. No DC ground for your antenna is needed. However, poor electrical connections between body parts can be a cause of noise so people frequently bond body parts together with copper braids.

I thought this might be a topic with general interest. How many out there have specifically prepped one or more radios, chargers, battery packs, programming cables, software and computers to safe guard against an EMP event or similar. That would be specifically Faraday boxes etc. to store the above items. If you have what radio(s) are you going to bet your life on and how did you do the prep? I’ve read about stuff as simple as a “shielded” bag to double storing sensitive electronics in metal trash cans stored inside of another while metallic tape used to seal the edges etc. The “event” doesn’t have to be human generated. Something like a huge CME would do. https://www.history.com/news/a-perfect-solar-superstorm-the-1859-carrington-event

Anecdotal, I know, but in my own experience there are very few people I wheel with that are amateur radio operators. All of them use FRS or GMRS when they wheel anyway. Moving to amateur service for offroad is seriously going to limit who you talk to on the trails. If you are not worried about that or don't trail ride, I suppose it's a non-issue. If you are planing on using VHF and UHF, the same limits apply as in GMRS. While you can run 1,500 watts on amateur bands, the extra power doesn't do much if the LOS isn't there. Most of the time, VHF simplex around me, is limited to between 3.5 and 20 miles depending on terrain. However, I few days ago, from a mountain top I talked to someone almost 250 miles away. GMRS works the exact same way. The only thing that gets you more range without repeaters and mountain tops is HF. You can work the world with just a few watts... but you won't talk any further locally there either, as LOS still limits local comms. Usually once you hit the LOS barrier, either you need 40m, 80m or 160m NVIS to talk, say 20 to 350 miles. Otherwise, you aren't talking to many people inside the 350 mile radius there, either. What specifically are you looking to do. Myself and many others have a ton of experience over many decades in different areas. There is a good chance we can help if we know what you want to do.

Or "Handie Talkie". A portable handheld radio; what many call a "walkie talkie".

I can confirm that they are hard coded into my MP31s but I had to add them in my UV-5R GMRS.

When we go on road trips, I’ll check our route against the repeaters mapped on this websites map tool. I’ll enter these in to my radio’s channel memory by local name/repeater name. Usually in order of our departure point to arrival point. Most of the time I’ll put in access permission requests on MYGMRS. Unless you are in a caravan or convoy, I would not expect to hear other simplex users. I used the DB20G, it has plenty of memory for most trips, if you want to save some cash the RT95/AT778uv is good too. RA87 looks interesting if you want more power.

You’re fine. You’ve answered or been involved with most of my questions in the past….for the good. Appreciate it. Just seems things get a little too technical for every day normal folks with no radio background here. But it’s all good. Have a great day.

Thanks man. Don't worry about if you missed anything. That's plenty of reading material for just a guy who wanted to know if a repeater, at the same location, will interfere with his Base/ (now) Control setup. WRXU693

OK, now I understand a little better about what you're asking. In my world, terminology of a "base" station means you are transmitting on the lower (462.x) frequency, and speaking in simplex to other people on the same 462.x channel. A Control station is what you use to work a distant repeater, and those transmit on the higher 467.x frequencies. Then they receive on the 462.x The appearance of a Base or Control station can be the same (a mobile radio on a desktop) but the programming and functionality would differ. You're not going to work a distant repeater by transmitting on the Base (462.x) frequency. If you have a repeater using a duplexer, you're not going to be able to do what I suggested (plugging in a mic) to do what you want. If you key your Control station on a 467.x frequency that's the same as your repeater, you're going to overpower the receive side of your repeater. Not recommended.

On the other hand, isn't this a case of simplex users not expecting repeater operation even though they were on the simplex/repeater frequency? kidphc is correct, proper understanding of best operating procedures calls for listening FIRST, but GMRS is a no test, buy your license and transmit service. In this case, all the parties knew 10 times more than the average GMRS licensee; consider that EVERYONE on this forum is probably 5 times more knowledgable than the average GMRS licensee, even those who have come here and asked only a single question. Separating the repeater frequencies would be the only solution but I don't know if that would even be possible since GMRS is already democracized, there would be older repeater operators that would never switch to the new frequencies.

This is a great question. I think if you are in an area where you have simplex frequencies open to use and you can use the lower power successfully for your contact it makes sense to do so. It reduces your own exposure to interference. Use what you need to get the job done and not more. While some inadvertent interference is inevitable having a separate set of repeater frequencies would certainly help eliminate a lot of it. This is where I think linked repeaters is also an issue. You may be stepping on people you don't hear who are on simplex. I don't know how successful you would be getting this done but separate repeater frequencies is the best reason I have heard for expanding GMRS frequencies

I think the mistake was made early on that there are not already frequencies that are exclusive to repeaters. The amateur radio band plans contain repeater frequencies and offsets, which are already built into radios and attempt to minimize interference between simplex and repeater users. The idea that simplex frequencies overlap GMRS repeater frequencies in seems odd. Just my two cents, which adjusted for inflation works out to not much.

All of that is only good for a damped sinewave pulse.... maybe. If you know a head of time, every wavelength that will occur. Likelihood of that is zero. Truth is, every frequency from DC to daylight comes from an EMP. It will be in the form of electrical, magnetic, electromagnetic, radiation, and photon energy. Even the smallest of pinholes leaves you are risk.

One of the things here that needs to be addressed is gaps and holes. Remember folks that you are trying to keep out RF and not water. If it happens to be water tight, so be it, but it's NOT needed. As mentioned before, hole size in the mesh is directly related to the frequency that can pass. For those of you that are familiar with the DUGA over the horizon radar system that is in the former USSR. That antenna design had a reflector behind the active elements of the antenna. If you go look at some pictures of the site you will notice behind the horizontal cage elements there are vertical wires that are running top to bottom of the structure. Those are the reflector for the 13Mhz signal that was used for the system. Being that it's 13Mhz the wire spacing needed to be less than 1/4 wavelength apart from each other to be effective. But those wires in their spacing were completely effective for that design frequency. On the other end of the spectrum look at the large home satellite dishes that were a mesh. Those operated at 4 to 8 Ghz and KU band was 12 to 18Ghz. Now those mesh dishes were an effective reflector for both C and Ku bands and if the dish was physically large enough it would have worked at any frequency below the max useable frequency of 20Ghz typically. This again had to do with the hole size in the mesh. So small holes or perforations in the container (Faraday Cage) isn't going to have a drastic effect on the attenuation performance of the cage. Getting all crazy and trying to seal up the smallest pin holes with aluminum tape is pointless. Yes, all the sides need to be electrically connected but small holes are NOT going to destroy the ability of the cage to attenuate an EMP or other rouge signal source. Something else to consider is rise and decay time of a pulse. Although the pulse is only going to have one polarity, it can still be treated as an AC source. This is the reason that the inner and outer shields are required for a proper Faraday Cage and the EXTERIOR is the only part that gets grounded. This creates a capacitor of sorts that is single ended with one end floating (the inner shield) and the other grounded.

I'd go even more basic as lag is not a "radio" specific term and is used in many forms of communication like computer networking A lag is simply a delay in transmission or reception of a communications signal. As we all know whenever a federal entity is involved the lag time increases dramatically!

If the two radios are not keyed at the same time, they should not interfere with each other. If the repeater and the base would be keyed at the same time, the stronger signal from the base would likely walk all over the repeater's output. Assuming you would be the one in control of the base radio, why would you knowingly create your own interference? I guess my biggest question is "why?" Other than being in love with the concept of a small 5 watt self contained repeater, you could just put in a larger and higher power repeater using the existing antenna & line that you've already got in place, and then plug a mic into the repeater so you could use it as a dispatch point. Pretty much every mid-range commercial repeater offers that option, especially if they're made from two mobile radios - like a CDR700 for example:

That sometimes happens (at least I recall it happening once before.) It doesn't necessarily mean it's not legit. Might just be a lag.

Well I'm pretty much bored and done with her. Off to the ignore list. I had a good time though.

Part of me wants to put him on the ignore list, but part of me wants to see what he says next.

You mean one can be licensed in multiple categories by the FCC and carry multiple call signs? /scarcasm

Given that a significant amount of people on GMRS and in the form are also amateur radio operators and there is an amateur radio section of the form, I would say it's quite relevant. Steve's signature definitely brings more value than a single post you have made so far. How about bringing some value to the conversation, instead of insults.

No, they don't make Microwaves, just coax. Pretty sure its Times New Roman.

It’s a conscious choice. So the party on the other end knows if someone is on the channel in simplex and/or the repeater.

Old video, but creative idea:

Paint the pole and antenna a neutral color, hang some potted plants or bird feeder(s) on it (the mast) and only a Karen would give it a second look. There are lots of ways to hide antennas with a little creativity. Then you do not have to remove/install it when you want to use it. Leave the pole collapsed for some time and then raise it a couple feet every few days/weeks and most won't even notice the change. If you are on a second floor or higher, most people don't look up. I know a person that had a large ham radio wire antenna in an apartment complex. He used a drone to drop it across several trees at night. Had it up for maybe a year before he purchased a house.