marcspaz

Wow! That's awesome! I'm still trying to learn this stuff. I know book smart often doesn't match reality, which is why I am glad I have folks like you to talk to. That tests sounds like a brilliant idea. I'll have to keep an eye on the geomagnetic weather and see if I can run that test. With any luck, I learn something in the process. LoL I appreciate the convo with all of you. I'm going to take my General exam on November 8. Hopefully I'll pass and get some new gear. Oh, I almost forgot... do you guys (or gals, if you're out there) know how to repeat tropo ducting? I read that fog and cloud cover helps... but should I be mindful of takeoff angles, etc.? Any advice would be much appreciated.

I'm not trying to be a pain, but the previous and current official General Class training material is stating exactly what I said (I copied and paste a portion of it). Also, I have a copy of the current test pool, of which there are test questions on the material specifically asking about these values. I didn't study physics for my profession, but I am currently studying for my upgrade. Like I said... I could be wrong, it could be ducting and not NVIS. However, I am basing my guess on what I am currently being taught to pass the FCC General exam. EDIT: Ignoring the training guides, because they are written by someone for ARRL... this is straight from the official question pool, which I got from the FCC... G3A09 (A) What benefit can high geomagnetic activity have on radio communications? A. Auroras that can reflect VHF signals B. Higher signal strength for HF signals passing through the polar regions C. Improved HF long path propagation D. Reduced So, we are not discussing a regular D layer / F layer skywave propagation method... we are talking about geomagnetic storms causing anomalies that can reflect signals that are not normally reflected back to earth.

It must have been awhile since you studied for your general exam. LoL

That seems a bit harsh. Why do you have that opinion? Serious question. Not trying to be argumentative. As far as I can tell, the 880 has a few nice features over the MXT400 that have very little value (if any) in the GMRS world. Don't get me wrong. It's hard to argue that the price is higher with the Midlands. Also, I have owned several Kenwood radios and they are nice radios, but I also currently own three MXT400's that have been running great for some time now. If you have someone who is non-technical, would like a warranty and a plug-and-play setup with a compliant radio, I would say the MXT400's are the best option. Not 1/10th the value. Just my opinion.

LOL... You may have a point there, and I wouldn't rule out tropo. Typically NVIS maxes out around 70MHz. I use it a lot down in 27MHz for QRP contacts on CB. However, I think its NVIS and mentioned it because high geomagnetic activity regularly creates auroras that reflect VHF and the lower portion UHF, allowing NVIS as far as 400 miles. Especially in the tropics... which is where Florida is and I am. And... even though we are in an aurora "break", the K index is above 5, which is severe enough for NWS to issue an alert for the 24th (when the contact was made) and 25th. Its primarily poleward of 60 degrees Geomagnetic Latitude, but that is enough to impact RF performance globally, wherever an aurora occurs. I could be completely wrong... but I think. I can always test again when the storm is over... that would probably tell me for sure if its tropo or NVIS.

I have something for you guys to try. Near Vertical Incident Skywave propagation. I had my ham antenna about 5 degrees off the horizontal plane, running 35 watts on 446MHz. I made a contact from Ft. Lauderdale to Panama City Beach... 300+ miles. GMRS is in the same service band (UHF 462 and 467) so the same principles apply. You should have someone on the other end to set it up to conduct the Comms. In ham, it's a bit easier because it is a regular contact/propagation method. Using a long whip antenna helps, too.

Well put. I experience the affects of this on a repeater in Virginia pretty regularly. I can be 22-25 miles away and be full quiet and as I drive closer, I lose the repeater completely. I don't actually get back into it until I am about 18 miles away or closer. I think the environmental conditions in the location I am usually at when in that 22-25 mile range is a geographic sweet-spot.

I'm a bit more that 20 miles north... can't reach it. :-(

Oh, man... now I get what you are trying to do. That's actually a good idea. I'll have to think about that for a few. I don't see any legal issues... just need to think of the best method. Split PL for sure.

Don't use an extra frequency. I'm no lawyer, but I think that violates FCC rules. Use one pair for all nodes and overlap coverage, use RF linking, or use internet linking. EDIT: Again, I'm not a lawyer, but as far as I can tell, there is no legal limit on how many approved pairs you can use in an RF linked network. However, your link pairs should use extremely narrow focused beam directional antennas on the lowest usable power, so you avoid harmful interference. Otherwise the FCC will shut you down after a handful of complaints. That image is a mesh network. That is why I told you to lookup how mesh networks work, and then apply the principles to your GMRS Network. Ham clubs and amateur radio repeater owners do this all the time. Especially for regular nets and emergency operations. The repeaters are all linked via an RF PTP controller or via an internet controller. Then, when they have their daily/weekly meeting on the radio, regardless of the location, everyone on every repeater can hear each other. Two members here have meshed their systems together using the overlap method. Its the cheapest and easiest. However, if you happen to be somewhere that you can hear two or more repeaters at the same time, there is a very slight echo. Almost not noticeable. That is the only drawback I am aware of, but together they cover more than 6,000 square miles.

It is perfectly legal to create a mesh network and/or use RF or internet linking. The only problem I see with your original post is, the pairing offsets for duplexing. You have 2 options. 1.) use a simplex repeater which records what it receives and then re-transmits the recording, or 2.) you must use a proper duplex (split mode) frequency pair (462.7250 MHz and 467.7250 MHz, for example). The other 2 things to track is your max transmit power and bandwidth.

The idea/concept you are looking for is an RF-linked mesh network. Same concept as cell phone service. It's legal and easy, but expensive. I have done it for IT wireless networks, but not voice. There are many clubs and owners who have networks that may be willing to talk to you about it. Some of them are members of this forum. I would stay far, far away from simplex rebroadcasting devices. They are more annoying than helpful. I would put them in the category of "when all else fails, its better than nothing."

I'm not hearing anything. We were at the beach today and didn't hear a single person. When I move down here permanently, I'm going to look into stuffing a couple of repeaters on the roof of a hotel or some other building... maybe the SunTrust Financial Center.

LoL I'm pretty sure we've all done it.

The advantage of GMRS is that radios have a 50 watt cap, not a 2 watt cap. Also, you can legally use GMRS repeaters as a licensed user, which can extend your range to 60 or 70 miles, depending on your radio and location as well as the repeater and its location. Also, getting more distance being your goal, more power and things like detachable/exchangeable high gain antennas is the trick. FRS radios don't have removable antennas. Therefore you can't even use antenna tech to your advantage. With regard to HT's, unless you get legacy UHF part 90 radio, you are going to max out at 2 watts on GMRS approved hardware. Some legacy part 90 HT's go to 8 watts. Most are 5 watts. And again, detachable antennas allowing for performance upgrades are standard on part 90 HT's. There's more, but hopefully this is a helpful start.

My longest ground level to ground level simplex contact has been 5.5 miles. Which is an achievement in my area. That was ragged edge. My longest simplex contact, regardless of elevation, was 46.6 miles from Strasburg, VA to Second Mountain, mobile to mobile. It was full quiet. My longest repeater contact was from a mountain top near Glengary WV to Dumfries VA... 70 miles as the crow flies, but 77 miles for the RF path. Also full quiet. I was on a MXT400 with an MXTA11 antenna. Don't know what the other guys had. In the Amateur radio world, I have talked from Flagpole Knob VA (mountain top) to South Houston TX on 446MHz with a homemade 1500 watt amp and a beam antenna. I would love to try a high-gain beam antenna on GMRS, but I don't think its legal because of the limit on effective radiated power... I may research that a little.

Sounds like a void to be filled for an aspiring repeater owner. Get it 200' up and you can easily get a 50 mile radius. I have a duplex in Hollywood that I am on my way to. Stopping in St. Petersburg first, but I'll do some testing to see if I can find d anything when I'm here.

That's a handy tool. Thanks for sharing.

Good info. Thanks for sharing!

I think you are going to be hard pressed to find a current production raidialess dual-band mobile antenna that will go all the way to 470 and be under 2:1 SWR. The Diamond NR73BNMO is probably the closest, but you're going to be looking at 2.5:1 at around 467. Maybe 2:1 at 462.

Thanks.... I forgot. Old habits die hard. LOL

I love my Midland radios. I have been very happy with them. That said, there was issues with the Gen 1 MXT400's that had nothing to do with being narrow band. There was a problem with their repeater mode in general, as well as some overheating issues. Those issue are resolved with the Gen 2 radio. I also used a MXT275 on a repeater for the first time, tonight. It worked very well. When it comes to wide band vs. narrow band, the most noticible differences are the audio level and the signal to noise ratio. The narrow band signal is half of what the repeater receive is expecting to hear. Because you are only going to fill half the band width, your volume will be a little low and the noise level will be a bit higher... thought its not noticeable until your signal (generally speaking) is weak into the repeater input. I regularly talk on repeaters ranging from 20 miles to 50 miles away from me and I have many operators tell me they are shocked my radio sounds so good from those distances. I definitely would not disqualify the MXT400 or MXT275 because they are only narrow band. Someone can correct me if I am wrong, but I think there are only 2 major brands currently making new FCC Part 95 compliant GMRS mobile radios. Midland and BTech (AKA Baofeng, Pofung, QYT, Luiton, etc. All the same radio.) After messing around with several BTech and Baofeng Ham and GMRS radios, I'll take the Midland all day long, every day of the week. Are some better performing radios out there? Sure, but it requires buying a Part 90 device and re-purposing it for GMRS (which is perfectly legal and pretty smart). Many people who are buying used Part 90 devices are having great success with them. There are some good radios out there... but I'll leave those recommendations to the folks who own them.

For the most part, yes. Though 8 through 14 are exclusively FRS and the GMRS repeater inputs are between those dedicated FRS frequencies. Power and radio type are (for the most part) the only significant characteristics that set them apart from each other.

That's going to end up getting people in legal trouble (maybe?). While the FRS frequencies are shared, the GMRS frequencies are not, and those radios definitely operate on the GMRS frequencies.

Hi James. Thanks for checking in. Some ares are very quiet. Especially because the band (frequency group) is somewhat short-range / Line of Sight tech. Unless someone is within a couple of miles, you likely wont hear them. The most I got out of my HT's are about 6.3 miles. Normally its 2 miles or less. Did you buy the radio for entertainment, looking for others to talk to or did you get it for another purpose and just trying to find users outside of that intended purpose? Also, not trying to give you a hard time, but the UV5R isn't approved for use on GMRS and FRS frequencies. You can listen with no issues, but they are Ham/Amateur radios, so you can't legal transmit on GMRS/FRS frequencies. They are capable of operating in unapproved modes, capable of using too much bandwidth and are not capable of going to a low enough output power setting to stay within the 0.5 watts on some of the FRS channels. I figured I would just give you a heads-up on those points.