dosw
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Posts posted by dosw
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8 minutes ago, WSIZ258 said:
Thanks for the input and guidance everyone. Maybe I'm putting too much faith in an antenna and I just need to spend more time adjusting my frequencies, making sure I have the right tones, etc... Outside of NOAA and FM radio, I've only heard one other person on a repeater. Perhaps it's just a VERY quiet area.
Do I need to worry about offset settings or anything? I just key in the local repeater frequencies and add R-DCS codes that show up on the sites... I thought maybe a better antenna would help. Still learning! Thanks everyone.
UV-5G and 5G Plus are GMRS radios and come configured with channels for repeaters that are already with the +5MHz offset. You should only have to add the tones.
First, how are you testing? If you're testing by keying up one radio and wanting to hear yourself on another radio, that won't work. If the radios are within a block of each other, there's a good chance one is desensing the other. Think of it this way: If your wife is talking to you in a normal voice from the next room, you will hear her. Now turn on the window air conditioner in your room and keep listening. You can't hear her. Her voice is just as loud as before, but your ears and brain are desensitized by the fact that there's another loud noise nearby. Radios work similarly; if a radio is transmitting on 467.7000 (repeater input) at 5w and another is listening at 462.7000 (repeater output) only a few feet away, the dreaded "spurious emissions" and the "poor selectivity" of your radio are such that it's like the transmitting radio is shouting in its ears, so the listening radio cannot hear the repeater 20 miles away that is only whispering. So you have to adjust your test; someone needs to take the listening radio a block away.
If you've done that and still aren't getting through, turn OFF the tones on your radio and keep them turned off for a few days of listening. Do you hear people occasionally? If yes, then your tones were probably wrong. If no, then you haven't learned much; it could just be a quiet repeater. If you determine your codes were wrong, check them again and enter them more carefully. Retest.
What about a kerchunk? Do you hear that when you key up the repeater? If not, take antenna out of the mix. Get in your car and drive closer to the repeater. Set the tones that the repeater needs before you leave the house. Drive close to the repeater, and key it up. Do you hear the kerchunk? Yes? You're good. No? You're not configured correctly.
Now let's assume you get the kerchunk meaning you're configured correctly. Drive back home. Now do you get it? Then your antenna is also adequate. Not getting it? You're out of range. A different antenna *may* help, but more probably won't help.
- WSHE531 and SteveShannon
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12 hours ago, marcspaz said:
I'm not sure the mobile comparisons are a realistic comparison for the original statement of:
- A handheld
- UHF frequencies between 440MHz and 470MHz
- 2 watts compared to 10 watts
HT performance characteristics are significantly different because of the form-factor, antenna design and size, and several other conditions that make it unreasonable to compare them to a mobile radio.
We really need someone with an HT that is capable of both 2w and 10w. I have an HT that outputs 0.5w and 4w (about 9dB), but still not 2w and 10w (about 7dB).
I have an AR-5RM that will do 2w and 10w. I have a 701 style rubber duck, and a 771 style. And adapters to hook up to a variety of mobile antennas. And I can set up a radio at home to record into a VOX-activated recorder. So I think I have all the tools necessary to perform this test from a variety of locations around my city.
I can say that I've done similar tests in the past, and that at the fringes, things will get more scratchy at 2w than at 10, but that other factors are more important such as not sitting IN the car with the rubber duck antenna, and not having my signal blocked by terrain. In such situations, being in the car vs out of the car can make the difference of getting a recording to take place (ie, squelch breaking on the radio at home) and not getting through at all. Power has only ever made the transmission a little clearer, better quieting, and only at fringe areas.
But I'm happy to run the test with this specific equipment. I'll have some results Saturday. Ideally I'll be able to post the recordings and others can decide if they constitute proof or disproof.
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I have a "cheap" Jesverty SS-30V switching power supply. It has a pair of screw pole connectors, two Anderson ports, and both USB-A and USB-C. It works fine with my Wouxun KG-UV980P, Retevis RA87, and Midland MXT-275. I've never needed to plug in more than one thing at a time. I also bought a cig-adapter to Anderson port, so that I could plug in the Midland using its 12v plug. Anyway, I sort of put off buying one, but once I did, I'm glad to have it.
It makes a lot more sense for the PSU to be a separate piece. Building a PSU into each "mobile" device to call it a base station device just adds cost and size to the radios and limits where they can be used a little more. It's pretty nice to just be able to use any 12v powered radio with this PSU. Plus it will easily handle any 12v accessory, not just radios, so long as they're under 30A.
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100%, grandma kept telling him to turn it off to save the battery whenever he wasn't using it. Kids left to their own aren't going to be thinking those invasive thoughts; they'll leave it on in their sock drawer for six months, or until years later when you clean out their room after they moved away to college (whichever comes later).
- GrouserPad, SteveShannon, WRTC928 and 1 other
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2 hours ago, Majik said:
Could also be Wide Band vs Narrow Band. (You should use Narrow).
That wouldn't prevent one from hearing the other over simplex within range.
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An antenna not designed for the frequency you're transmitting on could reflect power back into your radio instead of radiating it out as radio waves. If the reflected power is too high (high SWR), the radio will either scale back its power to avoid harm, or become damaged. A CB antenna is made for 26MHz, and a GMRS antenna is made for 465MHz. The difference is great enough the reflected energy will probably be quite high.
- AdmiralCochrane and WRTC928
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On 10/20/2024 at 10:58 PM, DominoDog said:
Sounds to me like you should spend more time in a book learning how radios work before jumping down someone's throat for having a question. This whole "hams vs gmrs" thing is the dumbest stuff I've seen in a while. It's perpetuated by certain individuals that like to use the phrase some people to stir the pot for engagement and clicky-clicks, but for the rest of us it's getting pretty stale.
There's a good observation here: "ham vs GMRS" doesn't help. People wanting to establish a good GMRS repeater would get a lot more traction on such projects by working *with* a ham club. In my area there are a lot of really good 2m and 70cm repeaters. And the groups operating those repeaters have solved a lot of the hard problems. If you can build a good relationship with them, you might get help navigating the waters of setting up a GMRS repeater.
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12 minutes ago, WRTC928 said:
I have gotten 20 miles HT-to-HT once when both of us were on elevated terrain features. Given the 140' elevation difference, you might be able to do it. The best-case scenario is if both stations are on higher elevations than everything in between, but one station higher than the other does improve your chances of getting a clear line of sight. You'll have to consider gain when you select your base station antennas. The more gain an antenna has, the "flatter" its signal, and it's possible to make the signal so flat it passes over the station at a lower elevation. There are some folks on here who know more about that than I do and might be able to help you figure out if that's going to be an issue. Generally speaking, more gain = more distance, so you'll have to balance the two factors.
It would be very hard to find a mass produced antenna with so much gain that it would cast its signal too high or too low for another antenna at a 140 foot offset 20 miles away. That's 0.00135%, or 0.076 degrees. That level of focus of signal is in the realm of laser beams, or antennas for communicating with equipment on the moon. Another way of looking at it is that a boat's radar, which is designed to have good resolution characteristics, could merge two objects into one if they're less than 300 feet apart at 20 miles.
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RF line of sight could be a problem, depending on how high you can realistically mount your antennas. An antenna mast with mounting hardware could easily set you back a couple hundred, to get your masts up 30 feet. On the other hand, mounting each antenna fifteen feet up on the roof, with one property 140 feet above the other property, could get you right around 20 miles. This is good news because it also means RF line of sight roof-top to roof-top is something you can verify with a couple of inexpensive handheld radios.
So before buying nice radios, and before buying masts and antennas, buy a couple cheap GMRS handhelds for $30 each. Each of you stand on your roof. And try to talk to each other. If you get nothing, no static, no roger beeps, nothing, you're just out of luck. Those wooded areas between you are attenuating too much of your signal. On the other hand, if you're able to break squelch and hear each other a little, you can proceed.
Now assume that you were able to break squelch for each other. What next? Each of you get a 25w to 50w radio, however many feet of LMR400 cable you each need, lightning arrestors, some fittings, and appropriate mounting hardware for the roof. Get a couple of antenna such as the Comet GP6NC GMRS antenna. Oh, and get 13.8v power supplies.
Adding it all up you'll be spending around $525 to $725 each.
As for repeaters; a repeater is useful if it can be higher than the other radios, and/or positioned somewhere between the other radios. It's useless to put a repeater on your roof, if the goal is just to extend range from your roof to the other person's roof. A repeater won't be giving you more range. What a repeater does is it allows one radio talking to the repeater to hear another radio talking to the repeater. If A and B cannot hear each other, but A can hear C, and B can hear C, then putting a repeater at position C will allow A and B to hear each other by talking through C.
Another thing to do is to investigate what ham repeaters are in your area. If there are no GMRS repeaters, you may discover there *are* ham repeaters. Then you get licensed for whatever type of repeater exists in your area. If you find GMRS repeaters, great, get your GMRS license. If you find ham repeaters, you and the other party need to study for a couple weeks and get your ham licenses. If you are fortunate enough that there are good repeaters in your area (ham or gmrs), then you don't need to spend 500-700 each. You can each get a $30 radio that is made for the service type you're getting licensed in, and talk through the repeater.
In my area there are about seven or eight pretty good GMRS repeaters. But there are also at least 25 very good 2m or 70cm amateur/ham repeaters. If that ratio holds true elsewhere, even if you don't have a GMRS repeater in your area, you may find there are one or more decent ham repeaters.
- WRXB215, SteveShannon and WSIK532
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16 minutes ago, hxpx said:
My kid likes running around outside with an FRS radio and talking to me, which is fun for both of us.
He also likes kerchunking and hitting the call/alarm button until I take the radio away, which is only fun for one of us. But we all start somewhere.
Set his radio to channel 8-14.
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27 minutes ago, WRDJ205 said:
I agree with @dosw keeping it under $100 is going to be a challenge. I did a test recently using a j-pole antenna that i purchased online for ~$39 using both RG8X (~$40) vs. LMR 400 (~$130). It was very surprising to me the difference in power loss between the two cables. If you could put you budget closer to $150 it gives you a few more options. Alternatively, the mag base options from Midland work pretty well for a budget of just under $100 if you could use a ground plane.
This is true.
Out my window I have an MXTA26 antenna on a Midland magnetic mount, on a sheet of steel sitting on top of a window air conditioner. Fortunately it's not in a place where anyone would see it, because it does look janky. But it works fairly well, and the whole thing is antenna (70), mag mount (40), adapter (10), sheet of metal (had in the garage): $120. I really doubt you could do a base-station antenna installation with LMR400 for less. And with this, I have no problem hitting a repeater 64 miles away with a handheld hooked up to the antenna.
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1 hour ago, DaddyO said:
Hello all! New user here.
Recently purchased the dual pack of GM30 plus units. Since I live in “the suburbs” with lots of folliage, and houses and whatnot, about 10 miles from my city center (Dallas for those who care) I figure getting an antenna up on my rooftop is my next order of business.
Hardline with some unobtanium antenna is the “best”, but for those of us who want to pick a price point and go…
Where is the division between cabling cost vs antenna cost? 50/50?
Does an $80 antenna with RG8 make more fars than a $20 antenna with LMR400? Or vice versa?
Do I bother with N connectors for something like this, or, since I’m just going to SMA, do I just get something thin and not bother?
My particular application calls for about 50 feet of cable to get to the top of my chimney, and I’m hoping to budget around $100 on this simple setup.
Does LMR400 plus a $70 antenna and a resonable mount break the budget? I guess staying below 100 is a pretty tight constraint.
Be aware that you will probably want an antenna designed for "base station" use. A mobile antenna likes a vehicle body beneath it, whereas base station antennas usually have radials included with them.
Anyway, here's the very useful cable loss calculator: https://kv5r.com/ham-radio/coax-loss-calculator/
With this calculator you can experiment with different antenna gains and cable types to see what meets your needs.
At 50 feet, you're going to want decent cable.
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A true GMRS radio is not that complicated; you switch to a channel (1-22), make sure that neither radio has tones enabled, and then just start talking. If you add a tone (CTCSS / PL, or DCS), you will need both radios to use the same tone. Midland gives its tones different numbers than other manufacturers, so you might have to look up in a crossreference table in the manual if you have a Midland.
That's it for radio-to-radio communications. All GMRS radios should be compatible with all others at this level.
Then getting into repeaters, you'll need to select the correct repeater channel (sometimes named 15R, through 22R, sometimes R1-R8, sometimes R23-R30), and the correct tones for that repeater. But any repeater-capable GMRS radio will work about the same way, and all should be compatible so long as they support repeaters in general.
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22 minutes ago, SteveShannon said:
Manufacturers could design mobile radios to put out half a watt, but because FRS regulations require handheld radios and because GMRS regulations limit 8-14 to handheld radios, mobile radios could not be certificates, even if they complied with the output power requirements.
Absolutely correct.
Channels 8-14 have the following restrictions:
- Only handheld portable units
- The effective radiated power (ERP) of hand-held portable units transmitting on the 467 MHz interstitial channels must not exceed 0.5 Watt. Each GMRS transmitter type capable of transmitting on these channels must be designed such that the ERP does not exceed 0.5 Watt.
- Bandwidth: narrowband; 12.5 kHz for GMRS transmitters operating on any of the 467 MHz interstitial channels
- Deviation: on the 467 MHz interstitial channels must not exceed ± 2.5 kHz, and the highest audio frequency contributing substantially to modulation must not exceed 3.125 kHz.
- Accuracy within 2.5ppm of channel center
Also, you cannot design a radio to have a maximum effective radiated power of 0.5w if you don't control what antenna is used, since antenna gain is a factor in ERP. So it might be an oversight but I don't see in the regulations where it says that on 8-14 the antenna must be a fixed antenna.
I just noticed today that even channels 1-7 are supposed to have their power calculated by ERP. The "mains" don't have that limitation; 50w is the maximum permissible on repeater inputs and primary 462 channels, measured at the feed line, not in ERP (and nobody cares, nor should they).
Anyway, no type approved GMRS mobile radio would be approved if it could transmit on 8-14.
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I don't know why someone would specifically want a mobile radio that transmits at 2w. Nothing wrong with 2w if that's all you need, but it's a weird requirement. But the MXT-105 is 5w max, and has a low setting that is probably very close to two watts. I haven't measured, but guestimated using paper napkin math and hunches, based on its advertised power input requirements at low and high.
If someone has this whimpy radio and a power meter, they could confirm. But they'll likely find low is about 2 watts.
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36 minutes ago, WRTC928 said:
I set duplex to off on 8-14 so I can monitor them but not transmit. Should there be a legitimate reason to do so, I can pretty quickly restore the transmit capability on that frequency. It's hard to imagine a situation where that would be necessary, but I can do it if I need to. I just do all my GMRS communication on the other channels.
I do the same. I was just curious what bandwidth problem he thought we would be out of compliance on
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On 6/14/2025 at 9:34 AM, WSAQ296 said:
I am curious tho, to those of you 'unlocking' the ham style, how are you complying with the bandwidth of gmrs?
Which bandwidth requirement are you looking at?
GMRS allows 5kHz deviation in channels 1-7 and 15-22, along with repeater inputs. It's not out of line with what 70cm ham radios will emit.
Usually where ham radios are problematic is that they often won't transmit as low as 0.5w ERP unless you're transmitting them into a dummy load.
So channels 8-14 are often impossible to be in technical compliance on, when using a ham radio.
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Just now, Jaay said:
The Comet SBB-5 are Excellent for mobile and even base use, and are ground independent.
Also the Diamond SG-7900 as well with much more gain, and ground independent, but requires a permanent mount, or a 5" Magnet.
Thank you, I'll check them out. I've looked into the SBB-5 but couldn't tell if it's NGP or not. Its product sheet says something like non-radial, but the CA2X4SR says the same on its product sheet, and definitely needs a ground plane.
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15 minutes ago, Jaay said:
They Are solid antennas, although there are Better models out there for the 2m/70cm bands.
Open to suggestions. The criteria:
- 2m, 70cm, GMRS.
- Acceptable SWR with a lip-mount with its inadequate ground plane (pictured in my original post).
- Mobile
- NMO mount
I have the following, already:
- Laird/TE B4505CN - GMRS only, no ground plane required. Works great in that application. 5dBi gain.
- MXTA26 - GMRS only, prefers a decent ground plane to achieve reasonable SWR. 6dBi gain.
- MXTA25 (ghost) - GMRS only, ground plane preferred to achieve <2.4SWR. 3dBi gain.
- HYS-1T - GMRS only, 3dBi gain, ground plane required for reasonable SWR.
- Comet CA2X4SR-NMO - 2m, 70cm, GMRS. Fantastic with a good ground plane. Poor SWR with an inferior ground plane.
I don't mind buying the right thing for my application. The Larson NMO2/70B seems to check the boxes, but if there's something better I'm overlooking please let me know.
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2 hours ago, tcp2525 said:
The NMO2/70B is the only antenna I will ever use. Both my motorcycles and truck have them and they are excellent performers. I had one trunk lip mounted on the front hood of my Lincoln and it performed great eventhough some people said it should not. I would recommend this antenna if you want the best long range communications oj any vehicle. Oh, and SWR is under 2.1:1 on GMRS.
Thanks so much!
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I'm wondering if anyone has used the Larson NMO2/70B, and if they have an antenna scan from it mounted in a hood-edge location.
It's supposed to be 1/2 wave at 2m, colinear in 70cm. I'm looking to see SWR curves that cover amateur 2m, 70cm, and GMRS.
My Comet CA2X4SR isn't going to do it because of my mount location. Its SWR gets out of hand in weird ways.
...and the antenna in the picture is a Laird/TE B4505CN, which is a great match in GMRS, and even extends into upper 70cm alright, but has an unusable SWR in 2m.
If there are other options to consider I'm curious to hear.
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Base station 50w radios are mobile radios that aren't installed in a vehicle -- usually installed in a home or some other place that doesn't drive around.
To run a 50w radio you need a 13.8v (approximately) DC power supply of some sort.
One option is a 110v to 13.8v DC switching power supply. You would want one that provides no less than 20A continuous. That provides some level of overhead capacity. But most people buy a 30A unit for $85-$200 depending on the model.
Another option is a portable car starter. Connect the alligator clips to the power lead of your radio. Assure that they are insulated from each other to avoid a very unfun experience. I used to have a portable lead acid battery powered starter that had two 9AH fire alarm (or lawn mower) type batteries in it. And it worked just fine, but when the batteries eventually grew old it was not designed for easy replacement. Nevertheless, it lasted 15 years.
And another option is to build something with a lawn mower style battery or lithium battery, and an inexpensive charger. The charger would be an automotive style, and must be appropriate for the battery chemistry you choose.
And a last option is to simply wire it to your car's battery or your RV's battery, if by "base station" you just mean something you can take with you and set up somewhere, so long as that somewhere is near your vehicle or RV.
Powering off of USB-C is probably unrealistic for a 50w radio.
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My MX275 radio goes between my RV, boat, and occasionally my wife's car, depending on the activity. It always has been kind of a handful of stuff. Harbor Freight had a coupon that I used a week or so ago, purchasing an inexpensive Pelican case knock off. There was room in the case for the 275, its cig plug, two UV5Gs, one "RM", three rubber duck antennas, a charging base for the UV5Gs, and the stock mag mount antenna for the 275, which I don't use, but seemed like a good thing to toss in for completeness sake. I used the lower foam layer for the Baofeng charging base, cig plug, and stock external magnetic mount antenna for the 275. The MX275 instructions are underneath it all, since you need them to translate real PL tones to the codes that Midland uses.
None of this is high end stuff, but it should be relatively convenient.
- GrouserPad, FishinGary, amaff and 7 others
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So channels 8-14 are often impossible to be in technical compliance on, when using a ham radio.
optimize signal for a Baofeng AR5RM
in Guest Forum
Posted
If you and your family member are both holding the radio at five feet off the ground, and there are absolutely no contours to the earth or other obstructions between you, you'll get about 5.5 miles range. This is because even lacking contours, at 5.5 miles the curvature of the earth will block your signal, if both antennas are at 5' off the ground.
If you can get both antennas 20 feet off the ground, the curvature of the earth will attenuate the signal at just under 11 miles. So, again, if there are no contours to the terrain, and there is nothing else between you, the curvature comes into play at just under 11 miles.
If you can get one antenna 30 feet off the ground, and the other is 5 feet (base station to handheld, for example), you will get 9.44 miles of range.
To get ten mile coverage with one handheld radio (antenna 5 feet) and the other radio a base station, the base station's antenna needs to be 36 feet off the ground.
Here's a formula you can use: range[miles] = 1.22459*sqrt(height[feet_antenna_A]) + 1.22459*sqrt(height[feet_antenna_B])
But that formula applies if the earth doesn't have any variations in the terrain. This is Kansas, but it's not *that* flat; there is some variation. That variation can help you or harm you. If you're able to take advantage of slight hills to get the antennas higher, great. If the slight hills block your antennas, not great.
As for a repeater, it doesn't change physics, it just adds a third antenna to the mix that, if placed in a location between you and your family members, or if placed high on a hillside that all of you can "see" at the same time, is able to be the antenna you talk through. Repeaters make a lot of sense where I live; there are mountains around me, and everyone lives in a valley below the mountains. So if someone has the ability to place a repeater 1000 or 1500 feet above the valley, everyone can access that repeater all over the valley. But you're in flatter terrain, and may not find such advantaged repeaters.
Also, this isn't a power issue. A 50w radio can't blast through the curvature of the earth. And if you all could "see" an antenna elevated a thousand feet over the area, you could all hit it at 2w from many miles away, until you reach the curvature limit again. A theoretical 1000 foot high antenna communicating with a handheld at 5 feet would have 41 miles range. The farthest repeater I can hit is 64 miles away, and I'm at 5000 feet elevation, the valley floor is 4200 feet, so we're both well above the obstructions around us and the curvature probably wouldn't eliminate our "line of sight" until we get to a distance of about 75 miles.