SteveShannon

You can vote an answer up or down along the left hand side, but that's the only way I know. I'm just glad it helped. Yes, you can have areas near tall towers with high gain antennas that are dead-zones. Some antennas even have an RF downward tilt to minimize that area. One way to do that is with slightly out of phase antennas in a colinear array. They're pretty fascinating. The harness running to the antennas has very slightly different lengths of feedline to create a delay to some of the antennas in the array, causing a downward shift in the radiated pattern. Fortunately, the manufacturer does all the math. Steve

Somethings to keep in mind is that height above ground of an antenna has a huge effect on gain. Although gain patterns look pretty regular; gain is not. It can look like tendrils emanating in all kinds of directions. Here's an idealized picture from https://www.netxl.com/blog/networking/antenna-gain/: But here is a pattern generated from EZNec, an antenna simulation tool:

You bet. Did it answer your questions?

One thing that can really trip up an application is to load the software or plug in the interface cable before loading the factory software. If W10 thinks it knows what driver to use that can prevent the correct driver from being recognized. If that happens you frequently need to completely unload the software and delete the device from Device Manager and start over. Edited to add: The communications cable is the most important element. It must be working correctly or the CSP software has no chance of working. Installing the device driver for the cable will typically do two things: Create a device under the list of USB devices. The driver software installation instructions usually reveal what the name of the USB device will be. If you don't see that device in Device Manager, you need to stop and figure out why. Each step is crucial to the next. Then, a virtual com port will usually be created (not always, but if your software expects a com port, the virtual com port must be created first!!!) This will appear in Device Manager whenever the cable is plugged in and disappear whenever the cable is unplugged. It might not be numbered the same each time!!!! Only if the correct device appears under the USB devices AND the com port correctly appears should you start the software. If the virtual com port hasn't been created you will not see it when you go to select the com port in the software.

Theoretically radio waves would be radiated from a single point at exactly the same strength in all directions, forming a perfect sphere. That’s unity gain, or no real gain. However, in real life that sphere may take on other shapes, with more strength in a specific direction, or flattened at the top or bottom. But there’s just as much RF energy being emitted, so just like a water balloon, if you flatten it, the circumference becomes larger. That’s said to be gain in that direction. When there is gain in a direction, other directions suffer. Those may be directions that don’t matter. For instance, directly above or below the tower. The size and shape can be simulated using antenna simulation software or it may be estimated using past experience or it may be measured using a field strength meter. Most commercial antennas have some kind of published information.

I would expect it to do 15-22. He specifically mentioned 16 and 20 because you said those were the most utilized in your area.

For $80 more the Icom IC-2730 does dual band (70 cm and 2m) cross band repeat. This would all be so much easier and legal to do in amateur radio.

The more I think about this, the more I wonder why two back to back radios on different frequencies wouldn’t work. One would be on simplex to talk to the nearby handhelds and one would be configured to transmit and receive from the repeater. Neither would be capable of simultaneously transmitting while receiving and most importantly, none of the input frequencies would be able to receive any of the frequencies that could be transmitted simultaneously. That last is key. So, the central mobile/base station would be configured to transmit to the repeater and receive from the repeater, but because it’s not a repeater it cannot transmit while receiving and it cannot receive while it transmits. The audio from its headphone jack is connected to the mic input on another radio which is set to a simplex channel. I’ll call it the simplex radio. It’s set to a completely different channel than the receiver of the central mobile/base station. That audio triggers PTT or VOX on the simplex radio and is retransmitted to the OP’s handheld while he’s outside. Because the simplex radio is incapable of receiving while transmitting, he could not interrupt the transmission, but once it ends, he can push his PTT. The simplex radio receives his transmission and via a connection between its headphone jack goes into the mic input of the central mobile/base, triggering PTT and sending it to the repeater. Getting the two radios to coexist without de-sensing might be a problem. Might have to mount the antennas with some vertical separation. Getting PTT to work on each might be a challenge. Maybe one of those amazon simplex repeater boxes would help there. But this seems too easy. What simple and stupid thing am I missing?

So, here’s how others have done it professionally using Vertex mobile radios. It’s a store and forward module that extends the range of a mobile radio to a handheld. Of course you would need to use a Vertex mobile radio, configured to communicate with the other repeater, but I’ve heard they’re available. Also, Midian makes these for other radios as well https://www.ameradio.com/product/512159/description.html If you like to tinker, you could probably do something similar and much less expensively using one of these: https://www.argentdata.com/catalog/product_info.php?products_id=98 However, thinking about this, it must do the forwarding on a different frequency (not band or service) than the mobile, otherwise you would simply end up with a time delayed feedback loop.

So, how could a person legally design some kind of “range extender”? @markskjervehas the simplest solution; but I’m doubtful of the legality because of the cross-banding. It’s more than simply cross-banding; it’s going between two different services. The problem with the original idea is that two full duplex devices connected to each other form a feedback loop. But what if you use simplex GMRS (store and forward) on the end you’re trying to extend so you can be outside of the cabin?

If you have internet, you might be able to connect your repeater to the other repeater using a network connection. There are networks of repeaters. That’s about as far as my knowledge extends on that.

“Stupid questions” are sometimes the most fun to chat about! Off the top of my head I don’t know for sure. I think there’s a rule against retransmitting between services. Of course the technical challenges would add a whole other level of problems to solve. Your MURS handheld would have to transmit and receive on two different frequencies. You would need a translator to receive MURS and connect to a GMRS transmitter and another one to connect to a GMRS receiver transmit to MURS. It might be easier to hook it up to a cordless phone! ?

I absolutely agree with @WRUU653. Setting up a repeater just to reach another repeater using RF would probably cause severe interference. In order for your handheld signal to be received by your repeater and transmitted to the other repeater you would have to reverse your input and output frequencies, but then, the signal received from the other repeater would be instantly retransmitted to the other repeater, causing a feedback loop. GMRS Regulations simply do not permit a repeater to transmit on the “467 MHz Main Channel” input frequencies necessary to transmit through another repeater. Just set up a mobile radio in your house with a decent antenna on the roof and configured to hit the repeater.

There’s no doubt that a “true base station antenna and feedline” is better for a full time repeater, but I wouldn’t be so quick to declare “Well, that’s your issue.” The losses through 10 feet of LMR400 aren’t enough to cause this problem and a decent mobile antenna can be expected to transmit and receive just as far on a repeater as they do on a mobile radio. The O.P. really needs to rule out other things before investing money in hardline and a Laird antenna. He might spend quite a bit of money trying to build your concept of a repeater, only to find that his friends have a wrong setting somewhere. He already said this is a test setup; let’s help him get as much out of the test as possible before sending him back to the store. @WRMN374 Are your friends able to communicate when they get closer? Can you loan them your handheld radios and have them see how far away they can get before they no longer make contact? If it’s just a matter of range, then @gortex2 may be correct, that it’s a matter of not getting enough signal out, but if that is the case they should have no problem hearing you when they’re closer. Let’s take the repeater configuration out of the picture for just a second. If you clear the tones and use a simplex frequency can you contact your friends using one KG1000 as a mobile/base station from your location? I would make sure that you can do that before adding the complexity of a repeater. Where is your antenna and cookie sheet located? Is it up on the roof or on a mast outside or do you have it in the house? Notarubicon (@OffRoaderX) recently released a really good video that illustrates the value of a good antenna compared to adding more power that you might find interesting.

No problem. Some of us here are the “well, actually“ types, including me, but I’ve noticed that Marc isn’t. He seems pretty friendly and humble. From a loss standpoint I’d say you’ve made your case for going with KMR400 over LMR400. I would also look at how well the cable will withstand weather, how the connectors are attached, and do be sure to seal them so they don’t admit moisture over time. That’s something I’ve noticed, that people install cable and everything works great but then it gradually starts worsening. These cables are sensitive to moisture and the pl259 connector is not sealed so you’ll need to do something to seal it. Good luck!

Although I don’t know him personally, Marc isn’t the type to act that way. I think his question was because cable loss is usually described in dB, not percent and hearing it referred to as a percentage was slightly confusing.

First thing I would check is the incoming voltage; see if it sags when you power up.

No - it really couldn’t. A repeater works by transmitting while it receives. If you disconnect the receiver while it’s transmitting you prevent the repeater from repeating; it has nothing to transmit. Repeaters are only able to work because transmitters transmit on a completely different frequency from the receiver AND duplexers (or antenna locations) filter out the high power RF that is being transmitted to prevent it from entering the receiver and causing feedback or actual damage. The input stage of a receivers must be very sensitive to “hear” a signal at any distance. Being connected to the same feedline as a transmitter is like having a gun go off right next to your ear. Turning off a receiver after the transmitter has completed transmitting does nothing but prevent future use of the repeater.

Looks like it’s made for Ozark Trail by Gocom: https://fccid.io/2ARRE2019LT001/User-Manual/user-manual-4481388

You can always listen to the 467 frequencies. There are limitations to transmitting. Here’s what the regulations say about that: 467 MHz main channels. Only mobile, hand-held portable, control and fixed stations may transmit on these 8 channels. Mobile, hand-held portable and control stations may transmit on these channels only when communicating through a repeater station or making brief test transmissions in accordance with § 95.319(c). The channel center frequencies are: 467.5500, 467.5750, 467.6000, 467.6250, 467.6500, 467.6750, 467.7000, and 467.7250 MHz.

Some GMRS handhelds do have a talk around reverse function. Such a function doesn’t violate any regulation. For instance, the Retevis RT76P sold on this site’s shopping site has it listed as a feature. https://shop.mygmrs.com/products/retevis-rt76p-repeater-capable-gmrs-radio-5w

It’s also very useful in diagnosing tone problems. Once, after resetting my radio, I forgot to put in the repeater input tone. I could hear everyone else on the repeater but none of them could hear me. Another person got on the repeater and said that he could hear me fine on the reverse so I should check the tone. Bingo!

@tweiss3 Thank you! That’s exactly the level of detail I hoped to hear.

Alex, I think you read way too much into his previous posts. He wasn’t arguing against licensing. I felt that he was pointing out the same thing I was: that only a small minority of GMRS users get licensed and that it’s a waste of time and energy to lose sleep over it, I.e. Let it Go. It was a comment on the status quo, not a post advocating anarchy. And I like Frozen as well, and the song. Watching my grandkids enjoy it and sing the song is great. ? Happy New Year, my friend! Steve

I never thought about using Fixed Stations to connect two different Repeaters. If that's correct (I don't recall anything in the regulations that prohibits it) then you might as well use full duplex. Fixed Stations may transmit on both 462 MHz main channels and 467 MHz main channels, thus they could communicate in full-duplex. They are limited to lower power, but that helps with the technical challenges anyway, as you pointed out. The technical challenges you mention are the biggest challenges. [Repeater] <--- wired connection ---> [Fixed Station] ((((((RF)))))) [Fixed Station] <--- wired connection ---> [Repeater]