Simplex Testing Comparisons

[JASII]

If I recall correctly, someone had done a comparison of VHF high band vs UHF vs 800/900 simplex, portable to portable communications, using a rubber duck antenna and posted their results. At the moment, I don't recall, specifically, if it was actually amateur radio or commercial land mobile gear. Anyway, I think they compared the radios on each band in various terrains to see how they compared. VHF high band did better out in the wilderness than UHF (440-40 MHz) and 800/900 MHz. UHF (440-40 MHz) did better in a city environment, etc.

Anyway, does anybody here have a link to any studies like that where they actually do the research, outside and measure how far they were able to talk?

 

[merlin]

I am fairly sure 'the doctor is in' column, QST, did an article about effectiveness of portables in different bands and different environments as you mention. Radios had similar antennas, TX power, RX sensitivity.
I don't recall the issue, it was some time back, 2 to 3 years perhaps.
Mostly about reliable communications for range in miles.
It included VHF low band that did best in wilderness, trees etc. VHF and UHF did better in urban settings.
700/800/900 Mhz just under UHF in urban outdoor but poor indoors.
You would have to find the article for the numbers.

 

[rescuecomm]

In my SAR experience, VHF High is considerably better than UHF outdoors. For VHF low band, the military seems to use it but with antennas far longer than most regular persons would be comfortable with. (Think nearly 5 feet). With so few ham radio handhelds on 6 meters, I have no reference for that. Years ago, my brother and I were able to talk almost 4 miles in the Myrtle Beach area using a pair of Motorola GP360 handhelds on 146.550mhz. Very surprised not having to use the local repeaters in the urban area.

 

[brownalan]

No links to studies, but I have done some “testing” of my own.

My wife and I are both licensed amateurs and I have dual band vhf/uhf radios as base and in two vehicles. We often attempt to chat when one of us is out driving somewhere.

My experience is that we can communicate slightly farther on 2 meter simplex than we can on 70 cm. Mobile to base we can reach 15-20 miles on simplex and 50 watts on 2 meters. Slightly less on UHF. The terrain around here is rural, low, rolling hills with lots of pine trees. Those hills and valleys make a huge difference in reception. We use analog FM most of the time and a little (Yaesu) C4FM.

I don’t have any 800-900 stuff.

 

[mmckenna]

I don’t have any 800-900 stuff.

800MHz will be a bit worse than your 440 stuff outdoors. Where 800MHz really works well is building penetration. Damp foliage can impact 800MHz as well.

 

[vagrant]

I do not have a link, but many amateurs during the ARRL VHF/UHF contests with the correct gear will first make a contact using their directional antennas on six meters. After narrowing things in (aim at each other) we step up to two meters and dial it in more. We then go to 1.25 meter, 70cm, 33cm, etc. etc. Some ops I know have stuff up in 45 GHz although it does not always work that high.

We do this with fixed station locations and or "rover" stations that move from grid square to grid square. This is all done via simplex over multiple terrain types. Considering the above, it should be clear that it is easier to make contacts on the lower VHF frequencies with open terrain and room for the antenna size at the lower VHF frequencies. Carrying a five element six meter yagi with a handheld inside a building is not an option, and the wavelength of 70 cm and smaller seem to fit through doorways, windows, etc. and result in better penetration in a city.

Sorry no studies, but I guess you could say many of us do the "research" at least three times a year during that contest. Sometimes guys have tried higher and have to step down in frequency until the make contact then step back up again after getting the aim. Again, this is using directional antennas. A rubber duck antenna is small, so 70cm and up in a city area for handhelds would be prudent.

Anyway, does anybody here have a link to any studies like that where they actually do the research, outside and measure how far they were able to talk?

 

[ClemsonSCJ]

No links to studies, but I have done some “testing” of my own.

My wife and I are both licensed amateurs and I have dual band vhf/uhf radios as base and in two vehicles. We often attempt to chat when one of us is out driving somewhere.

My experience is that we can communicate slightly farther on 2 meter simplex than we can on 70 cm. Mobile to base we can reach 15-20 miles on simplex and 50 watts on 2 meters. Slightly less on UHF. The terrain around here is rural, low, rolling hills with lots of pine trees. Those hills and valleys make a huge difference in reception. We use analog FM most of the time and a little (Yaesu) C4FM.

I don’t have any 800-900 stuff.

I have had the opposite experience from what everyone says I should and what the “science” says should be the case. I live in upstate SC which is very hilly and turns to mountains the closer to NC you get. Most of the repeaters have a 2m and 70cm frequency and the 70cm channels pick up WAY better than the 2m. I’ve also noticed when testing my own radios simplex, 70cm will get about a half mile farther, sometimes as much as a mile.

 

[mmckenna]

I have had the opposite experience from what everyone says I should and what the “science” says should be the case. I live in upstate SC which is very hilly and turns to mountains the closer to NC you get. Most of the repeaters have a 2m and 70cm frequency and the 70cm channels pick up WAY better than the 2m. I’ve also noticed when testing my own radios simplex, 70cm will get about a half mile farther, sometimes as much as a mile.

If it's with a hand held, part of that is because the radio case makes a much better 1/4 wave counterpoise on UHF than it will on VHF. It's also easier to get an efficient antenna on a UHF hand held than it is with VHF.

That and I've found that UHF tends to penetrate some foliage better than VHF, even on mobile installs.

 

[ClemsonSCJ]

If it's with a hand held, part of that is because the radio case makes a much better 1/4 wave counterpoise on UHF than it will on VHF. It's also easier to get an efficient antenna on a UHF hand held than it is with VHF.

That and I've found that UHF tends to penetrate some foliage better than VHF, even on mobile installs.

I’ve tested handheld and mobile and gotten the same results as far as UHF performing better. The mobile could be be because of the dual band antennas being 1/4 wave on 2m and 5/8 wave on 70cm so they lend themselves better to simplex over relatively flat terrain.

 

[K6GBW]

I started my career as a deputy sheriff with an agency that used VHF low band. 100 watts simplex had pretty good range but it had huge shadows. Later, that same agency went to 480 MHz and we found the simplex worked better in the cities we patrolled because there were fewer shadows and you had to move the car less to get signals to "pop in." Eventually I moved to a smaller agency that used VHF high band. I found the VHF high band to be the best in terms of pure simplex range. The areas of fading were relatively small and we really liked it. Unfortunately we were an urban department and the second we walked into a building the VHF High went to nothing. After a few years we went to 800 MHz trunked radios. The 800 MHz radios worked much better inside buildings but they were absolutely dependent on the repeaters to work. Simplex was ridiculously short. Even in the cars on simplex we could only talk a few blocks. Handhelds on simplex were pretty much useless for anything more than talking around a building. So, my take is that for simplex VHF high is the best followed by UHF and 800 MHz last. Of course terrain, antennas and power all play a part.

 

[KA0XR]

I started my career as a deputy sheriff with an agency that used VHF low band. 100 watts simplex had pretty good range but it had huge shadows. Later, that same agency went to 480 MHz and we found the simplex worked better in the cities we patrolled because there were fewer shadows and you had to move the car less to get signals to "pop in." Eventually I moved to a smaller agency that used VHF high band. I found the VHF high band to be the best in terms of pure simplex range. The areas of fading were relatively small and we really liked it. Unfortunately we were an urban department and the second we walked into a building the VHF High went to nothing. After a few years we went to 800 MHz trunked radios. The 800 MHz radios worked much better inside buildings but they were absolutely dependent on the repeaters to work. Simplex was ridiculously short. Even in the cars on simplex we could only talk a few blocks. Handhelds on simplex were pretty much useless for anything more than talking around a building. So, my take is that for simplex VHF high is the best followed by UHF and 800 MHz last. Of course terrain, antennas and power all play a part.

Thank you for the very interesting post about comparing bands! From the various posts I've read on this subject over the years some folks will say that lowband VHF can have better range than VHF high band, at least in hilly or mountainous terrain (specifically posts about the CHP 42 MHz system). Perhaps lowband and highband are more or less equal in flatter terrain and/or forested regions. Of course so much depends on the site, elevation, power output, antenna, feedline and equipment quality. Maybe some others can comment on this.

I've heard that many years ago low band base stations ran insane amounts of power to overcome vehicle ignition noise, which may have given lowband its longer distance reputation at the outset of 2-way radio. The lowband "shadow" issue must have been a serious concern at times, being in law enforcement. Testing I've done on 6m vs. 2m vs. 70cm usually showed 2m to generally be the most reliable, but 6m seemed less affected by foliage, however much more susceptible to noise in general. Keeping all things equal makes fair comparisons like this a bit of a challenge. 70cm is highly attenuated by trees/foliage where I live and I would say is inferior to VHF for suburban or rural use, but great for short range or in built up environments.

I wish there was more quality equipment for the 1.25m band to see how comparable it would be to VHF highband in simplex range. Here in Minnesota there is a statewide digital 800 MHz system that most every law enforcement agency is on and they had to build towers to make the state like a porcupine to equal what they had on VHF high. This echoes your observations about 800 being such short range despite having an adequate ground plane on handheld radios. Prior to this conversion, by my count, there were only something like 56 sites to cover the entire state on VHF high, with Iowa only needing 28 towers to cover their state on VHF.

 

[nd5y]

I wish there was more quality equipment for the 1.25m band to see how comparable it would be to VHF highband in simplex range.

Back in the late 80's there were several of us active on 220. We did a lot of mobile simplex.
Signals seemed to be stronger most of the time with less noise than 2m but slightly more picket fencing.
It seemed to work better than 2 meters but we had no way to actually measure or prove it.
This was in N TX where it's flat with fewer trees and virtually no pine trees.

 

[mmckenna]

I've heard that many years ago low band base stations ran insane amounts of power to overcome vehicle ignition noise, which may have given lowband its longer distance reputation at the outset of 2-way radio.

250-300 watts was pretty common for repeaters/base stations.
Mobiles often ran 100 watts.

But so much of it is about the antenna.

Good noise blanker circuits help. Most of the big manufacturers had that down. So did quieter ignition systems, proper installation, etc.

 

[mass-man]

Back in the late 80's there were several of us active on 220. We did a lot of mobile simplex.
Signals seemed to be stronger most of the time with less noise than 2m but slightly more picket fencing.
It seemed to work better than 2 meters but we had no way to actually measure or prove it.
This was in N TX where it's flat with fewer trees and virtually no pine trees.

Yes sir...the Midland 13-509 and 513 were my 220 rigs of choice back then. No CTCSS code necessary and it was quiet! We did a lot of simplex at nite all over DFW with beams and homebrew amplifiers. There was a very good repeater in Irving but can't remember others! I still should get my hands on a Moto CDM 1550 for 220, mod it and put all of the repeaters in TX in it!!!!

 

[K6GBW]

I love 220! It has the characteristics of VHF high but without the paging interference, adjacent channel interference and other "noise" that can occur on VHF high. In truth though, the VHF high band has quieted down as public safety moves away from it and toward the 700/800 trucked systems. Motorola pushes those so hard and departments buy them, whether they are the right band for the area or not. I remember with Low band if we were in a bad spot we would have to move the car 50 to 100 feet to get things to pop in. With VHF high band we could just back the car up ten feet and that would usually do it. When you were in a fringe area you could hear the difference in the bands. Low band had these slow fading losses. High band was a faster fading loss and UHF was more of a stuttering sound. The thing I hated about 800 was that it had a weird underwater sound due to the co-phased transmitters. I also found it hard to hear because the narrow banding and the line levels seemed to always be off. When it rained the 800 also had an almost constant static sound. It reminded me of the radio transmissions from the Apollo space craft as they came through the atmosphere. I will forever be a fan of good old fashioned VHF high band simplex remote base systems and or repeaters!

 

[KA0XR]

I love 220! It has the characteristics of VHF high but without the paging interference, adjacent channel interference and other "noise" that can occur on VHF high. In truth though, the VHF high band has quieted down as public safety moves away from it and toward the 700/800 trucked systems. Motorola pushes those so hard and departments buy them, whether they are the right band for the area or not. I remember with Low band if we were in a bad spot we would have to move the car 50 to 100 feet to get things to pop in. With VHF high band we could just back the car up ten feet and that would usually do it. When you were in a fringe area you could hear the difference in the bands. Low band had these slow fading losses. High band was a faster fading loss and UHF was more of a stuttering sound. The thing I hated about 800 was that it had a weird underwater sound due to the co-phased transmitters. I also found it hard to hear because the narrow banding and the line levels seemed to always be off. When it rained the 800 also had an almost constant static sound. It reminded me of the radio transmissions from the Apollo space craft as they came through the atmosphere. I will forever be a fan of good old fashioned VHF high band simplex remote base systems and or repeaters!

Having to move the car 50 to 100 feet is quite the dead spot indeed. VHF high band probably strikes the right balance between massive shadows and the variable in/out picket fencing signals found at 70cm and above. There are a few locals in my area that use 28.3 to 28.4 MHz USB for routine simplex and some claim it equals 2 meters in range. However, my guess is stations (both base and mobiles) are running considerably more power and there are essentially no vertically polarized mobile 2 meter SSB setups around to make a fair comparison.

220 should be utilized more for the reasons mentioned but the age old problem of equipment availability often comes into play, especially with Alinco recently discontinuing the DR-235 Mkiii. I agree that in many areas 2 meters/VHF high band is probably quieting down and has a lower noise floor. Maybe the vacating of VHF for UHF by many big power TV stations is helping with this as well?

It seems that lowband/6m will always be prone to noise and RFI in any populated setting, or where there is are powerlines, cutting down on simplex range. I had a local RFI problem and every time the power company RFI detective came out and fixed one spurious noise problem in the neighborhood a new one seemed to pop up, rendering my base capability on 6m or lower pretty degraded.

I wonder if anyone using 900 MHz (33cm band) has noticed the constant static sound you mentioned during rain? I recall hearing something like that while listening to the local electric utility crews operating on their analog 800 MHz trunking system (repeaters) after storm damage. I thought it was weird to be hearing static when the FM signal from a local tower should be much quieter. The Apollo spacecraft static sound reference - was that on their Unified S-Band system (2.2 GHz) or on the military "UHF band" that I read they used closer to Earth?

 

[K6GBW]

The static sound, I've been told, had to do with the microwave links we had between our three sites. When it rains I guess it's just enough to cause the hiss. They were cophased transmitters so when you were right in the center of them the received signal sounded like you were under water. I also thought that the audio at 12.5khz basically sucked compared to 25khz but since that was mandated there wasn't anything we could do about it.

Around here we used to run 110 watt GE Orion base stations with big quarter wave ground planes. We could talk base to base for forty miles! The LA area is separated by the Santa Monica Mountains and the 6 meter bases were the only thing that would climb over them. Sadly, the original members of that crew moved away to moved into town homes, so no more power base glory, but the 2 meter simplex out here is very active.

 

[KA0XR]

With enough gain and/or antenna height and more local activity is 2 meters able to make it over the Santa Monica Mountains you reference? Or is 6 meters/low band unique in this ability? Were the ground planes used the commercial DB-201 style with the folded dipole or something more homemade?

Local 6 meter FM is dead where I live (Twin Cities) which I think is unfortunate. There are no mountains here to really test each band's capabilities in hilly terrain but plenty of trees and vegetation. You'd think with the the summer E-skip openings more folks would be willing to try base station 6m FM but nowadays all I hear and read about for 6m DX is FT8.

 

[KC3ECJ]

If I recall correctly, someone had done a comparison of VHF high band vs UHF vs 800/900 simplex, portable to portable communications, using a rubber duck antenna and posted their results. At the moment, I don't recall, specifically, if it was actually amateur radio or commercial land mobile gear. Anyway, I think they compared the radios on each band in various terrains to see how they compared. VHF high band did better out in the wilderness than UHF (440-40 MHz) and 800/900 MHz. UHF (440-40 MHz) did better in a city environment, etc.

Anyway, does anybody here have a link to any studies like that where they actually do the research, outside and measure how far they were able to talk?

I've done some tests myself.
I'm in a valley that's fairly wide with high mountains on the sides, hills common inside the valley.
The immediate area is suburban houses.

11m CB, 2m, and 70cm compared on mobiles, all at about 4/5 watts, 1/4 wave antennas for 70cm and 2m, an antenna about 3-4 ft for CB.

70cm FM got out the best, 2m FM was second best, 11m AM CB performed the worst.

I think I even found I was getting out better with narrow FM than wide.

 

[ShawnInPaso]

800MHz will be a bit worse than your 440 stuff outdoors. Where 800MHz really works well is building penetration. Damp foliage can impact 800MHz as well.

Yes. In my former work life I was tasked with a project to determine the most effective band for portable radio use inside of a nuclear power plant. As you could imagine, everything is concrete and rebar...everywhere. The 800mhz band won out by quite a margin over lower freqs.