Jump to content

Recommended Posts

Posted

Other than the few purposed built radios for MURS what other radios have people used for the service? I'm aware they are likely not Part 95 approved but I assume people use them anyway, like older Part 90 radios.

Finding good used Part 90 UHF radios seems fairly easy. The VHF models are harder to come by and generally sellers ask significantly more for them.

Posted

I don't have much use for a 2 watt limitation on VHF, so when needed, I go over to the 2 meter Ham band.

I do include MURS in my scanning and here in Los Angeles, I hear quite a bit of Spanish language use and English language construction site and traffic rerouting use.  And there is grandfathered Walmart use on MURS 5 (Green Dot) with probably older Motorola HTs and radios.

There are of course the non-certified typical Baofeng UV-5Rs and MARS/CAPS modified 2 meter HTs.

But for certified license free MURS use, I have seen some reviews of radios by Wouxun, Retevis and BTech,  and on some forums including this one, I do see much discussion of Dakota Alert products.

I personally would use MURS more, if they allowed up to 5 watts or more and repeaters.

In the interim I would like to get ahold of a certified 2 watt MURS unit to do distance comparisons to 2 watt FRS HTs.  I have done some experimentation on the low power setting on my Anytone AT-779UV (a/k/a Radioddity DB-20G), but that doesn't count!

@OffRoaderX did a YouTube comparison of MURS vs. GMRS.

Or of course, study up a bit and get a Ham Radio Tech license and all sorts of opportunities become available!

Posted

MURS,from my understanding is the former B/ILT colored dot frequencies so there were several Part 90 radios in use and may still be available on the secondary market.

Posted
17 minutes ago, BoxCar said:

MURS,from my understanding is the former B/ILT colored dot frequencies so there were several Part 90 radios in use and may still be available on the secondary market.

You are a better source for historical perspective of MURS, but my understanding is that only Blue Dot (MURS 4) and Green Dot (MURS 5) are incorporated into the currently unlicensed MURS scheme.  The other colors may have transitioned to other services, if they still exist.

UPDATE: From a google, I did find this discussion: Common Itinerant and Business on Radio Reference

Posted
10 minutes ago, MichaelLAX said:

I don't have much use for a 2 watt limitation on VHF, so when needed, I go over to the 2 meter Ham band.

I do include MURS in my scanning and here in Los Angeles, I hear quite a bit of Spanish language use and grandfathered Walmart use on MURS 5 (Green Dot) with probably older Motorola HTs and radios.

There are of course the non-certified typical Baofeng UV-5Rs and MARS/CAPS modified 2 meter HTs.

But for certified license free MURS use, I have seen some reviews of radios by Wouxun, Retevis and BTech,  and on some forums including this one, I do see much discussion of Dakota Alert products.

I personally would use MURS more, if they allowed up to 5 watts or more and repeaters, and in the interim I would like to get ahold of a certified 2 watt MURS unit to do distance comparisons to 2 watt FRS HTs.

Or of course, study up a bit and get a Ham Radio Tech license and all sorts of opportunities become available!

Unfortunately you can't conduct business activities on the Ham 2M band.

About range comparisons between MURS and FRS radios in the open I don't expect a huge difference between them. However if one is using external antennas that would be different, but FRS that isn't allowed to use external antennas so the tests would be between MURS and GMRS radios.

From a very basic technical view point the typical antenna on a GMRS HT is nearly a quarter wave long, about 6 inches, and the body of the radio is large enough to make a fair ground plane.

Compared to a VHF radio around 150 MHZ where a quarter wave antenna is 18 inches long so radio body is a poor ground plane. It's often mentioned the typical 6 to 8 inch rubber duck VHF antennas have a negative 5 to 6 db gain relative to a quarter wave ground plane antenna.

Without going through the math using quarter wave ground plane antennas for VHF and UHF the VHF radio has approximately a 9.5 db (a factor or 9) advantage due to "path loss" over a UHF radio. So for a 2 watt MURS radio the range would be equivalent to an 18 watt UHF radio with line-of-sight operation. Now using just the rubber duck antennas the over all gain difference is reduced to around 3 db more or less. In practice you might not even notice it. IMHO this is sort of the way I see it.    

 

 

Posted
24 minutes ago, Lscott said:

Unfortunately you can't conduct business activities on the Ham 2M band.

About range comparisons between MURS and FRS radios in the open I don't expect a huge difference between them. However if one is using external antennas that would be different, but FRS that isn't allowed to use external antennas so the tests would be between MURS and GMRS radios.

 

 

Oh, so your OP is about "business use" on MURS?

I thought that currently issued GMRS licensees cannot conduct business activities on GMRS, as well; is that incorrect?

If correct, then the comparison is MURS to FRS, even with FRS' antenna limitations, as both are unlicensed services.

Posted
4 minutes ago, kb2ztx said:

My 1 watt HT1000 talks further than a FRS radio time and tome again. Love to have 5 watts to use but for what I use it for 1 watt is perfect. 

 

A google search for "HT1000" brings up an 800MHz Motorola; is that what you are using and with which licensing program (or is there a license free band there, too?)

Posted
2 hours ago, MichaelLAX said:

Oh, so your OP is about "business use" on MURS?

I thought that currently issued GMRS licensees cannot conduct business activities on GMRS, as well; is that incorrect?

If correct, then the comparison is MURS to FRS, even with FRS' antenna limitations, as both are unlicensed services.

I mentioned GMRS since you can use external antennas, same as with MURS. Using external antennas mostly eliminates issues with the compromise antennas, rubber duck types, you commonly find used on HT's. The range tests would be more depended on the characteristics of the frequency used than on antenna gain and efficiency. Has nothing to do with what type of communications are being conducted. 

Posted
1 hour ago, Lscott said:

I mentioned GMRS since you can use external antennas, same as with MURS.

I agree. 

That is why I gave my grandson my Pofung P15UV, a clone of the Radioddity GM-30, to use instead of his Motorola bubble wrap. 

Posted

I see a lot of Motorola RDM20X0 series radios in use in y area, 2020/2050/2080 radios. Every now and again I see a reprogrammed HT-750/1250 though. I know that even on low power some HT-750/1250 radios can become a little unstable, and may actually be putting out slightly higher than 2 watts output, but they do work well for this purpose (MURS).

Posted
2 hours ago, MichaelLAX said:

Ah, OK: I found this informative:

MOTOROLA HT1000 INFORMATION

Further anecdotal evidence that VHF travels better than UHF on a watt-per-watt basis.

With adequate antenna and ground plane, as well as acceptable noise floor and minimal structures between stations. Anecdotally, our VHF simplex testing in a suburban area was laughably bad even using multiple different radios and antennas on each end. VHF portables just don't work very well in that setting. UHF was full quieting on 1W where VHF was noisy and hard to copy with 5W.

In a mobile application or with external antennas, it's a different story.

Posted
3 hours ago, DeoVindice said:

With adequate antenna and ground plane, as well as acceptable noise floor and minimal structures between stations. Anecdotally, our VHF simplex testing in a suburban area was laughably bad even using multiple different radios and antennas on each end. VHF portables just don't work very well in that setting. UHF was full quieting on 1W where VHF was noisy and hard to copy with 5W.

In a mobile application or with external antennas, it's a different story.

I sort of expected the results being a wash between VHF and UHF given how the VHF rubber duck antennas are rather inefficient. The would be in open country without obstructions. In an urban environment there are too many variables that can affect range tests to draw conclusions. 

As another post mentioned what model radios did you try out?

Posted
4 hours ago, MichaelLAX said:

I agree. 

That is why I gave my grandson my Pofung P15UV, a clone of the Radioddity GM-30, to use instead of his Motorola bubble wrap. 

Those bubble wrap FRS radios many use a stubby antenna that really defeats the gain in performance of a full 1/4 wave if it was used. The difference of a few inches shorter for the stubby I can’t figure out why a manufacturer would do it knowing the performance hit. Maybe they don’t get busted off as easy compared to the longer one.

The radio related items I see for sale on eBay in value packs, multiple units, are antennas and belt clips. I guess that’s what careless users bust most often.

Posted
4 hours ago, PACNWComms said:

I see a lot of Motorola RDM20X0 series radios in use in y area, 2020/2050/2080 radios. Every now and again I see a reprogrammed HT-750/1250 though. I know that even on low power some HT-750/1250 radios can become a little unstable, and may actually be putting out slightly higher than 2 watts output, but they do work well for this purpose (MURS).

I don’t know if I would worry about the radio outputting more that 2 watts. Given the gain figure I’ve read about for the typical VHF rubber duck antenna of negative 5db, a factor of 0.32, a 5 watt radio would only be radiating about 1.6 watts anyway. And, of course, using an external high gain VHF vertical the ERP could be even higher.

Posted
14 hours ago, Lscott said:

I don’t know if I would worry about the radio outputting more that 2 watts. Given the gain figure I’ve read about for the typical VHF rubber duck antenna of negative 5db, a factor of 0.32, a 5 watt radio would only be radiating about 1.6 watts anyway. And, of course, using an external high gain VHF vertical the ERP could be even higher.

Very true, handhelds are already less efficient. What gets me are the UHF RDM series Motorola radios that have GMRS frequencies in them, but need to be programmed for what each channel uses, sold for up to $400 that seem to have proliferated corporate use. Find of few of those and admonish the users as they could have had an XPR series handheld that meets internal standards. My employer tries to keep to standard models for ease of repair and service, as well as licensing. There is one site I put on mobile radios for everything, and they do not need repeaters, and I never get the complaints of sites trying to use handhelds for everything. Luckily, those people do not leave their site, so they do not gripe about the lack of portability with their mobiles.....

Posted

Yup, it’s a PIA trying to keep various radio models synchronized. I have a good collection of HT’s just for my own use. I have around 10 to 12 separate radio programming suites installed, mostly Kenwood stuff, with some CCR’s and Motorola in the mix. There are even more than than in folders holding the code plugs since I have both the VHF and UHF versions of a particular Kenwood model series. For examples, TK-270G/370G, TK-2170/3170/3173 are just a few.

I have a few of the Motorola XPR-6550’s as well, VHF and UHF models, I got just to experiment with. Unlike the Kenwood’s the code plugs are linked to a radio by serial number. Thus I need separate folders for each radio. For more than a few I can see where one has to use their RM, radio management, database software to keep track of things and make changes. For the few I have the RM is just not worth it to use.

Standardizing on a specific model makes sense from code plug maintenance and various accessories point of view. 

Posted
On 12/7/2021 at 12:45 PM, Lscott said:

Unfortunately you can't conduct business activities on the Ham 2M band.

About range comparisons between MURS and FRS radios in the open I don't expect a huge difference between them. However if one is using external antennas that would be different, but FRS that isn't allowed to use external antennas so the tests would be between MURS and GMRS radios.

From a very basic technical view point the typical antenna on a GMRS HT is nearly a quarter wave long, about 6 inches, and the body of the radio is large enough to make a fair ground plane.

Compared to a VHF radio around 150 MHZ where a quarter wave antenna is 18 inches long so radio body is a poor ground plane. It's often mentioned the typical 6 to 8 inch rubber duck VHF antennas have a negative 5 to 6 db gain relative to a quarter wave ground plane antenna.

Without going through the math using quarter wave ground plane antennas for VHF and UHF the VHF radio has approximately a 9.5 db (a factor or 9) advantage due to "path loss" over a UHF radio. So for a 2 watt MURS radio the range would be equivalent to an 18 watt UHF radio with line-of-sight operation. Now using just the rubber duck antennas the over all gain difference is reduced to around 3 db more or less. In practice you might not even notice it. IMHO this is sort of the way I see it.    

 

 

By "In the open", you mean, mountain top to mountain top?, even then, the 9.5 dB difference is a massive difference, several hundreds of miles in the open kind of difference if you do the math. So, no contest in VHF vs UHF in terms of range. I yet have to find my UHF XPR7550e beating my VHF XPR7550e both on 1W.

So, if you use quality gear, as in: XPR7550e radios, the range in VHF will always be greater than in UHF, under ALL conditions, given the noise floor remains low and close in RSSI value. You might ask why is the noise floor important? Well, the noise floor determines the weakest signal you can hear, which is part of the receiver dynamic sensitivity when doing ISO-tee. In VHF the noise floor can be much higher than UHF sometimes, as much as 20dBm higher or more... wow... how so? well, thanks to all the RF harmonics spewed by all these made in CCR land garbage LED fixtures, PV (solar) installations, and all the other smart-CCR-land garbage made that are pumping into the RF spectrum without caring the least about the FCC Part 15 "shall not cause harmful interference", etc etc... that is why those things are so cheap, no filtering, but who cares... right? its cheap, so why should anyone care what it pollutes if the RF spectrum so long it measures how many steps have walked today... (dang I sound like a tree-huger for RF pollution... along being a Motosnob... guilty as charged.... okay, time to end this post then...

<signal fades under the noise floor>

G.

Posted

Your points are right on.

Even with the often quoted negative 5db, more or less, gain of the typical VHF rubber duck antenna that still leaves a theoretical 4.5db advantage, a factor of 2.82, for VHF over UHF when using an HT with the factory supplied rubber duck antennas. So, a 2 watt MURS radio on VHF could generate a signal strength equal to a 5.6 watt UHF radio, assuming the UHF radio is using a good 1/4 wave antenna on it.

In a variable environment like suburban and urban the advantage for VHF over UHF might be hard to qualify even with the gain advantage. In line of sight open areas VHF would likely do better. In an urban area UHF likely would because the signal bounces off buildings better than VHF.


This might be an interesting test comparing VHF MURS to FRS/GMRS using the same power and factory supplied antennas in different environments.


https://youtu.be/JGSLe39gh8k

 

Posted
8 hours ago, Lscott said:

Your points are right on.

Even with the often quoted negative 5db, more or less, gain of the typical VHF rubber duck antenna that still leaves a theoretical 4.5db advantage, a factor of 2.82, for VHF over UHF when using an HT with the factory supplied rubber duck antennas. So, a 2 watt MURS radio on VHF could generate a signal strength equal to a 5.6 watt UHF radio, assuming the UHF radio is using a good 1/4 wave antenna on it.

In a variable environment like suburban and urban the advantage for VHF over UHF might be hard to qualify even with the gain advantage. In line of sight open areas VHF would likely do better. In an urban area UHF likely would because the signal bounces off buildings better than VHF.


This might be an interesting test comparing VHF MURS to FRS/GMRS using the same power and factory supplied antennas in different environments.


https://youtu.be/JGSLe39gh8k

 

Well, testing MURS vs FRS range with CCRs is like testing how accurate an AR-15 would be by using an airsoft replica... 

All those radios have nearly equal, or equally poor dynamic sensitivity, measured around -90 dBm, in both V/U bands. The Gen1 XPR 6550 has about -110 dBm dynamic sensitivity, so if you want to test MURS vs FRS, get a pair of 6550, one U, one V, and run the test with genuine Motorola VHF/UHF antennas, and while at it measure the RSSI too. Gives you real data, rather than "can you hear me now", which is so "reliable" and reminds me of an old TV commercial for cell phone coverage, when coverage used to be poor at best... just like CCR range.

G.

Posted
On 12/7/2021 at 5:29 PM, MichaelLAX said:

Which VHF HTs did you use on what frequency?

On my end, a Kenwood TK-290 and NX-200, as well as an EFJ 5100ES, all on 146.52 with Kenwood and Motorola wideband antennas. Not sure what my buddy was using; it's possible that his equipment was the problem. He has some quality LMR equipment and some CCRs.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.