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My Range Experience, Looking for Input


mbrun
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Over the last few weeks I have been doing some range experiments with my GMRS radios to get a feel for what I can expect under different conditions.

 

All my tests have involved use of a pair of Wouxun KG-805g 5 watt HT.

 

I have done:

1. HT to HT (both with rubber ducks).

2. HT to HT (one with rubber duck, one with Midland MXTA26 on car)

3. HT to HT (one with rubber duck, one with Midland MXTA26 on house roof on the back of the metal trash can serving as a ground plane)

4. HT to HT (one hooked up to a Comet 712EFC 9dBi at 25’ AFG and one hooked up to Midland MXTA26 on car.

5. HT to HT (one hooked up to a Comet 712EFC 9dBi at 41’ AFG and one hooked up to Midland MXTA26 on car.

 

All tests are conducted with one unit at home, the other unit mobile.

 

Every combination results in perfect communications out to 1/2 mile. Beyond that static gradually creeps in at various rates and with increasing usable distance with each.

 

Configuration 5 has been my best performer thus far which was expected but, to my surprise, it was still only a solid performer at 1 mile and then only moderately usable at 2.3 miles in multiple directions.

 

My Comet was jury-rigged as high as I can get it without purchase of a tower or mast. I must admit, at 41’ I was expecting much more solid usable coverage.

 

I live in an semi-rural area southeast of Cininnati and the terrain is a mixture of dense full-grown trees, fields, businesses and homes. Land is mostly-flat to mildly rolling.

 

My current objectives are solid reliable simplex coverage from home to HT out 3 + miles (much more would really be sweet); communication with home via a mobile system in the car from about 10-12 miles out; and hit the repeaters on the northern side of Cincy from the home so I an participate in various GMRS nets and local chats using a radio and not a phone app.

 

OK, so there you have some backfill.

 

So, given the modest distance I have achieved around my home, I am hesitant to go the expense of mast and guy system to get my antenna up to 56’ feet (the highest I believe I can achieve with my Comet and guyed mast alone) since the antenna will still not clear the trees, and the HT will still be near ground level. Thoughts? Experience? Advice?

 

I am wondering if others live in similar conditions and have experienced better results?

 

Also, although I can break squelch on the nearest repeaters (about 20 miles North) with the HT there really is no usable audio in to speak of. Repeater frequently drops halfway through while I am giving my call sign. WIth the HT and Comet there is enough signal to get me in but with inconsistent quality for good useful communications. I have to repeat messages regularly. I imagine (but don’t know for certain) that a 40-50W rig in the home would ultimately solve that.

 

Michael

WRSH965

 

 

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You might want to try using a different HT. ...

 

... As others said the radio your using to test is also not the best option for your plans.

 

I would differ on this view. It depends on what the goal is. If you want to know the maximum possible useful GMRS range in an area, then yes, equipment will matter a lot. However, if you want to know your maximum useful range, then you, by all means, need to test with the same equipment you are going to use.

 

An old developers saying goes something like: Test what you will use. Use what you tested.

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Thanks Lscott. According to the calculator, my theoretical distance HT to Base using 5’ for HT and 41’ for base is 12 miles. So, at least conceptually, my target of 3 mile HT to base does seem quite realistic.

 

You can try plugging numbers in to the calculator at the site below.http://www.hamuniverse.com/lineofsightcalculator.html

 

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Thanks. I was using 50’ of official LMR400 cable with factory terminated N Connectors. So my cable loss should only be about 1.5dB. The 9dBi antenna more than makes up for that.

 

You don't mention the antenna cable you use at home on your 40' antenna. If that isn't LMR400 or larger you probably don't have much power at the antenna. As others said the radio your using to test is also not the best option for your plans.

 

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Here is another website I stumbled upon that allows you to enter two points on a map, graph the terrain between them and then add antenna elevation to both to see what amount of elevation is needed to eliminate terrain blockages.

 

https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

 

WRHS965

 

 

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You obviously have an adapter of some type, going from the HT's (assuming SMA or reverse SMA) to the antenna cables (N/SO239/etc.).  I am curious if one of the adapters are damaged or has very high losses?  I would find a shop that can test them for you.

 

I live in an area where the average elevation change for about 40+ miles in any direction is about 200'.  Depending on where I am, my handhelds talk anywhere from as little as 1 mile with noticeable static on the back half of the mile, all the way out to repeater 22+ miles away.

 

You have to keep a few things in mind.  Assuming all your gear is perfect, you are only going to talk a max of about 15% further than the visible horizon.  Also, in densely populated areas there is a lot of RF interference from homes, businesses, electrical lines, even traffic lights have two-way radios on them now.  All of this will desensitize your receiver and your transmitted signal gets harder to hear.

 

So, if you are 5'5" tall and you hold the radio in front of your head, on a perfectly flat location, the RF horizon is only about 4.5 miles.  If you have a 100' high hill a mile in front of you and you want to talk to someone on the other side, its not going to work. 

 

I have seen mobile to mobile comms with 200+ watts on each end, fail on Amateur radio UHF band segments, with as little as a 150' hill being between me and the other station.

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Hey Marc. Yes I am using an adapter. I have an SMA to N adapter with about 36” of RG-58. What method would you recommend be used to verify loss? I would image using a power meter with dummy load and contrast my radio and cable with a known good cable.

 

I believe I understand the radio horizon issue pretty well now, and certainly understand the net effect of shadowing when dropping down in a valley. I will admit that it did not register how close the radio horizon was from a mere height of 5-6’.

 

I used the web app I posted previously to confirm that my coverage targets were realistic (at least from a terrain and radio horizon stand point). So I do not appear to be fighting that. But I most definitely have the mixture of dense acres of trees, homes and other obstructions you would find in a semi-rural area.

 

Nice additional thoughts in the desense.

 

 

You obviously have an adapter of some type, going from the HT's (assuming SMA or reverse SMA) to the antenna cables (N/SO239/etc.). I am curious if one of the adapters are damaged or has very high losses? I would find a shop that can test them for you.

 

I live in an area where the average elevation change for about 40+ miles in any direction is about 200'. Depending on where I am, my handhelds talk anywhere from as little as 1 mile with noticeable static on the back half of the mile, all the way out to repeater 22+ miles away.

 

You have to keep a few things in mind. Assuming all your gear is perfect, you are only going to talk a max of about 15% further than the visible horizon. Also, in densely populated areas there is a lot of RF interference from homes, businesses, electrical lines, even traffic lights have two-way radios on them now. All of this will desensitize your receiver and your transmitted signal gets harder to hear.

 

So, if you are 5'5" tall and you hold the radio in front of your head, on a perfectly flat location, the RF horizon is only about 4.5 miles. If you have a 100' high hill a mile in front of you and you want to talk to someone on the other side, its not going to work.

 

I have seen mobile to mobile comms with 200+ watts on each end, fail on Amateur radio UHF band segments, with as little as a 150' hill being between me and the other station.

 

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Your power levels are so low and you have so much going on, a dummy load and power meter won't tell the whole story. You need an antenna and feedline analyzer. If you can find a used one cheap or a friend who has one, it would be worth checking both antenna circuits at the house and mobile.

 

If there is a Ham or CB shop around, they may have one to test with, too.

 

I think your expectations are more than reasonable for the gear you have. Either the HT's are too poor of quality on the receiver side or something is broken.

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Looking at this page: https://fccid.io/WVTWOUXUN16 I see that 467MHz channels are below 300mW and narrow-band. As it should be! Make sure you are testing on 462MHz channels and on wide-band.

 

I did similar test with my equipment some years ago. I have Kenwood TK-3170 with a proper receiver, not the "radio-on-a-chip" kind. Antenna is stock 1/4 wave.

1. HT-HT, flat suburbia, almost no trees, 1-2 story buildings: 1 mile reliable, after that unpredictable.

2. HT-HT, flat field, no trees: 1.5 miles reliable, after that quickly drops to nothing. At 2 miles it's nothing.

3. HT-HT, dense coastal redwood forest: 0.5 miles is a max. You can go to 1 mile maybe if one HT is elevated on the edge of the canyon or something like this.

4. HT-HT, rocky canyons: unpredictable. Could be 1 mile, with no line of sight.

 

Same HT with TK-880H mobile (40W), antenna 5/8 wave on a flat roof of SUV

5. HT-Mobile, flat suburbia, almost no trees, 1-2 story buildings: 4 miles reliable, after that unpredictable.

6. HT-Mobile, flat field, no trees: 5 miles reliable, after that quickly drops to nothing. However, if one of the points elevated, then range is much longer. Max range I had a chance to test with this combination was around 10 miles.

7. HT-Mobile, dense coastal redwood forest: 1.5 miles is a max. However, if you hike above the tree line with your HT, range becomes very long. I haven't been able to hike far enough from the parked car (maintaining LOS) to not have a somewhat reliable communication.

8. HT-Mobile, rocky canyons: unpredictable and surprisingly long range. My personal best - crystal clear voice at 2 miles (as crow flies) and 1200 feet of mountain range between HT and car. It was at Pinnacles park, car was at Chaparral parking (west side of the range) and I was at Old Pinnacles trailhead on the east side of the range, for those who know the place.

 

Same HT with TK-880H mobile (40W), no-gain antenna 25' above ground: no sport to test. It covers pretty much the whole valley where I live. In some places there is a shadow from big buildings, but besides that it is mostly reliable with static at the range of 8 miles.

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Thanks Marc. I will connect up with someone with the equipment to assist.

 

Your power levels are so low and you have so much going on, a dummy load and power meter won't tell the whole story. You need an antenna and feedline analyzer. If you can find a used one cheap or a friend who has one, it would be worth checking both antenna circuits at the house and mobile.

 

If there is a Ham or CB shop around, they may have one to test with, too.

 

I think your expectations are more than reasonable for the gear you have. Either the HT's are too poor of quality on the receiver side or something is broken.

 

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Good point on the frequency.

 

I have been testing with 462.7125 (ch 7), wide-band, at the high-power setting which is actually 4w on this channel.

 

Looking at this page: https://fccid.io/WVTWOUXUN16 I see that 467MHz channels are below 300mW and narrow-band. As it should be! Make sure you are testing on 462MHz channels and on wide-band....

 

 

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  • 3 weeks later...

Good Day Marc.

 

This weekend was a weekend of more tests. I even made my first 1/4 wave ground plane antenna. I mounted it on top an 11’ pole and walked around the neighbor hood. I looked like Moses, but I digress.

 

I took delivery of an entry level SWR/power meter (SureCom 102) and dummy load so I had at least something of my own to use. I have also started to make friends with a local ham who owns some additional test equipment. He was the one that inspired me to go for my tech license.

 

Using two different power meters (with dummy loads) I now know that my radios are outputting 4-5+ watts on all but the 7 mandatory low power FRS frequencies.

 

I confirmed the SWR of my Comet 712EFC and Midland MXTA26. Both antennas measure less than 1.10:1 across the whole GMRS spectrum. This was done with two different meters with consistent results.

 

My local ham friend also supplied a small digital antenna analyzer that scans the antenna system. Pretty cool! (Similar to an audio band impedance and acoustics analyzer I own). The output graph was nice and smooth and the resulting SWR measurements were substantially consistent with what was obtained with the SureCom. At least no gross anomalies observed.

 

I am starting to gain confidence that equipment is working.

 

I have also purchase some 1/2 wave Nagoya 771G and 1/4 wave 701G antennas for HT use as well as some Ed-Fong antennas to use. The arsenal is growing fast.

 

Michael

WRHS965

 

Your power levels are so low and you have so much going on, a dummy load and power meter won't tell the whole story. You need an antenna and feedline analyzer. If you can find a used one cheap or a friend who has one, it would be worth checking both antenna circuits at the house and mobile.

 

If there is a Ham or CB shop around, they may have one to test with, too.

 

I think your expectations are more than reasonable for the gear you have. Either the HT's are too poor of quality on the receiver side or something is broken.

 

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An yes, I LOL'ed about the Moses reference.  That was funny!

Yeah, until the local PD shows up because you look "suspicious" and won't believe you're just doing a radio range check. Even a few Hams get hassled by the local PD for having a "scanner" in a vehicle and or hearing police radio dispatch calls coming from their VHF/UHF mobile. The recommendation is keeping a copy of the local/state law showing the exception for Hams handy along with your license just in case in the glove box.

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That is very interesting to learn that. Was their a case that decided this, or is there specific exceptions written into the law for this? Does the ARRL have information about this for the various states?

 

Yep. I am in VA and distracted driver laws do not apply to two-way radios at all. Licensed or not.

 

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That is very interesting to learn that. Was their a case that decided this, or is there specific exceptions written into the law for this? Does the ARRL have information about this for the various states?

 

 

 

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So we don't completely derail this thread...

 

https://forums.mygmrs.com/topic/2068-state-laws-operation-of-mobile-two-way-radios/

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  • 2 weeks later...

Hi there,

I own several Motorola and Vertex Standards radios and I am not an expert, far from it. I also have a very large CCR collection, radios like the Wouxun, etc. These CCRs served their purpose which was to got me hooked in this hobby, unfortunately I kept buying them for too long before I realized I made a mistake. Why? B/c after trying nearly every other CCR out there, the moment I tested my first XPR6550 I realized I wasted all my time and my money for far too long on these CCRs. Yes, you can call me a Moto snob now, I am not BTW,... whatever... its your money... Point is I am not an expert, and just don't hate CCRs, but they sure have a lot of limitiations. Once you acquire enough knowledge/gear/equipment to perform useful measurements on your own, you'll begin to realize the same thing I did: why these radios are just called CCRs.

 

If you need range you are going to need a lot more than a portable Wouxun, especially if you live in a suburban area; a lot more than a high gain antenna and an 11 feet pole (like Moses :) ). For these CCR radios, i.e Wouxun, et. all, you'll need a lot of filtering, and I mean, LOTS of it... Then, the more gain you have in the antenna, and the higher up you raise it, the more RF signals you'l pick up, which is good, but unfortunately not so good for those CCRs which can't deal with such a rush of incoming RF, why? b/c they lack any front end filtering (back to why you'll need filtering)... So what do these CCRs do instead? they desense like its going out of style. What is desense? Desense is like when you have to close your ears at a rock-and-roll concert to hear your friend trying to scream you something... radios have to reduce sensitivity (desense) to be able to hear anything.

 

Don't believe me? well, I guess I would've not believed myself talking about this when I got started either... But here are some real numbers obtained with an ISOTEE and a signal generator. So, hooked up a GD77 to my a Hustler G6 GMRS (6dBd) antenna, placed 40 feet AGL. Measurements read the GD77 desensed ~40 dBm... Yes, you heard that right, -40dBm... it doesn't sound like much... but a -40dBm desense means the radio is now useless. I wish I could tell you this was the only CCR radio that showed this massive desense, unfortunately ALL my other CCRs (under 180 dollars) that I tried desensed about the same figure: -40dBm. That is why they are called CCRs b/c they aren't that good. Now, for comparison, on the same Hustler G6 antenna, placing a portable Motorola XPR6550, also unfiltered, I was able to hear the Signal Generator (SG) all the way down to RF site noise threshold. The usable sensitivity on the GD77 was measured at -72 dBm, and the Motorola XPR6550 usable sensitivity was -116 dBm (unfiltered). To give perspective, on the stock rubber duck antennas, the GD77 had a -100 dBm usable sensitivity, whereas the Motorola XPR6550 had -118 dBm usable sensitivity. (see correction values at the end)

 

If you want range, you should start by acquiring measuring tools. To me, a VNA, a Signal Generator and a simple ISOTEE changed how I see the hobby completely... Now I can unequivocally measure things and make an informed decision, rather than an educated guess, or a guess, or "bro'science".... and those tools are just "basic tools" compared to what more expensive service monitors can do. Once you have measuring equipment you'll be in a position to measure things like noise floor, cable quality, connector quality... and you'll be able to tune your own filters, cavities... After you have those tools, then you'll quickly realize you need better radios than a Wouxun. Nowadays, when high quality radios like the XPR6550 can be found used on eBay for ~100 bucks, there is literally zero reason to own a CCR for GMRS... While some XPR6550s might be a bit scratched, some might be rehoused... etc... they still work great for GMRS... and how much better than a CCR? At best, ~21 dBm better than nearly all CCRs I measured with rubber duckies... at worst, -44dBm better using a high gain 6dBm base antenna placed 40 feet AGL. 

 

Again, I don't hate CCRs b/c I now I own Motorolas and everything else is is crap. I still own a ton of them CCR and they are great, just not when the word range is involved. For small stuff, like giving to your 3 year old to start liking radios, loaners... plenty of uses.... all great, but once you find you like the hobby, don't be fooled by the CCR's fancy color screens, bells and whistles, gazillion contacts, etc etc... Buy high quality used commercial grade radio(s)... which might or might not even have a screen, screens don't make radios great... good RF performance does... and there are a LOT of good used commercial grade great radios on eBay (like the XPR6550.) There are also many very helpful members here (like @Marcspaz, thank you) who will help you setup these commercial radios if you are stuck.

 

G.

 

EDIT: Correction, after going over my notes the ISOTEE figures I quoted from memory for the rubber duck are actually for a 1/4 wave magmount, and the Motorola XPR6550 UHF is -116 dBm and the GD77 is -93 dBm...  I am sorry for the mistake.

EDIT2: The rubberduck I just performed the test with the ISOTEE, and the Motorola XPR6550 yields the same -116dBm as with the 1/4 wave, and the GD77 is -96 dBm. This was measured in the quietest RF place in my house with a noise floor of -123 dBm average. on 462.600 MHz.

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That is really great input on your part. Thank you.

 

It would be nice to have a couple of premium radios to contrast and experience first hand the difference.

 

You know the phase “seeing is believing”? “Hearing is believing” is appropriately applicable in radio.

 

73s

 

Michael

WRSH965

 

 

Hi there,

I own several Motorola and Vertex Standards radios and I am not an expert, far from it. I also have a very large CCR collection, radios like the Wouxun, etc. These CCRs served their purpose which was to got me hooked in this hobby, unfortunately I kept buying them for too long before I realized I made a mistake. Why? B/c after trying nearly every other CCR out there, the moment I tested my first XPR6550 I realized I wasted all my time and my money for far too long on these CCRs. Yes, you can call me a Moto snob now, I am not BTW,... whatever... its your money... Point is I am not an expert, and just don't hate CCRs, but they sure have a lot of limitiations. Once you acquire enough knowledge/gear/equipment to perform useful measurements on your own, you'll begin to realize the same thing I did: why these radios are just called CCRs.

 

If you need range you are going to need a lot more than a portable Wouxun, especially if you live in a suburban area; a lot more than a high gain antenna and an 11 feet pole (like Moses :) ). For these CCR radios, i.e Wouxun, et. all, you'll need a lot of filtering, and I mean, LOTS of it... Then, the more gain you have in the antenna, and the higher up you raise it, the more RF signals you'l pick up, which is good, but unfortunately not so good for those CCRs which can't deal with such a rush of incoming RF, why? b/c they lack any front end filtering (back to why you'll need filtering)... So what do these CCRs do instead? they desense like its going out of style. What is desense? Desense is like when you have to close your ears at a rock-and-roll concert to hear your friend trying to scream you something... radios have to reduce sensitivity (desense) to be able to hear anything.

 

Don't believe me? well, I guess I would've not believed myself talking about this when I got started either... But here are some real numbers obtained with an ISOTEE and a signal generator. So, hooked up a GD77 to my a Hustler G6 GMRS (6dBd) antenna, placed 40 feet AGL. Measurements read the GD77 desensed ~40 dBm... Yes, you heard that right, -40dBm... it doesn't sound like much... but a -40dBm desense means the radio is now useless. I wish I could tell you this was the only CCR radio that showed this massive desense, unfortunately ALL my other CCRs (under 180 dollars) that I tried desensed about the same figure: -40dBm. That is why they are called CCRs b/c they aren't that good. Now, for comparison, on the same Hustler G6 antenna, placing a portable Motorola XPR6550, also unfiltered, I was able to hear the Signal Generator (SG) all the way down to RF site noise threshold. The usable sensitivity on the GD77 was measured at -72 dBm, and the Motorola XPR6550 usable sensitivity was -116 dBm (unfiltered). To give perspective, on the stock rubber duck antennas, the GD77 had a -100 dBm usable sensitivity, whereas the Motorola XPR6550 had -118 dBm usable sensitivity.

 

If you want range, you should start by acquiring measuring tools. To me, a VNA, a Signal Generator and a simple ISOTEE changed how I see the hobby completely... Now I can unequivocally measure things and make an informed decision, rather than an educated guess, or a guess, or "bro'science".... and those tools are just "basic tools" compared to what more expensive service monitors can do. Once you have measuring equipment you'll be in a position to measure things like noise floor, cable quality, connector quality... and you'll be able to tune your own filters, cavities... After you have those tools, then you'll quickly realize you need better radios than a Wouxun. Nowadays, when high quality radios like the XPR6550 can be found used on eBay for ~100 bucks, there is literally zero reason to own a CCR for GMRS... While some XPR6550s might be a bit scratched, some might be rehoused... etc... they still work great for GMRS... and how much better than a CCR? At best, ~18 dBm better than nearly all CCRs I measured with rubber duckies... at worst, -44dBm better using a high gain 6dBm base antenna placed 40 feet AGL.

 

Again, I don't hate CCRs b/c I now I own Motorolas and everything else is is crap. I still own a ton of them CCR and they are great, just not when the word range is involved. For small stuff, like giving to your 3 year old to start liking radios, loaners... plenty of uses.... all great, but once you find you like the hobby, don't be fooled by the CCR's fancy color screens, bells and whistles, gazillion contacts, etc etc... Buy high quality used commercial grade radio(s)... which might or might not even have a screen, screens don't make radios great... good RF performance does... and there are a LOT of good used commercial grade great radios on eBay (like the XPR6550.) There are also many very helpful members here (like @Marcspaz, thank you) who will help you setup these commercial radios if you are stuck.

 

G.

 

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