commercial uhf or not..

[5teve]

Hi guys...

Just looking at the GME radios with a view to getting one shortly for the disco (been putting it off due to spending far to much on the boat)

they do a commercial (programmable) range and a standard range

the only difference i can see between the 2 is the power output 25w/5w against 5w and the programability (presumably by computer)

would it be worth getting a commercial and using at 5w? then if you get in the strife miles from anywhere and need the extra power you can switch it to 25w?

other than that... which one would you recommend?

Thanks as usual :)

Steve

[JDNSW]

You will not be able to licence the 25w, and in any case it will provide little if any extra benefit - since UHF is pretty much line of sight, all increasing the power does is enables you to talk over the top of other users who respect the 5w restriction. The extra power will in some circumstances get you a little bit of extra coverage by forward scatter, but it won't amount to much. I suggest that it is not worth the extra money.

John

[5teve]

You will not be able to licence the 25w, and in any case it will provide little if any extra benefit - since UHF is pretty much line of sight, all increasing the power does is enables you to talk over the top of other users who respect the 5w restriction. The extra power will in some circumstances get you a little bit of extra coverage by forward scatter, but it won't amount to much. I suggest that it is not worth the extra money.

John

what did you mean by this (im new to this), i know its not legal for non commercial frequencies, however i was thinking if i ran at it 5w and in case of emergency and emergency only i needed to use the extra power (although it sounds like it wouldnt add up to much extra coverage) its a risk i would be willing to take (pretty much like some people i know with marine VHF without being licensed, they dont use them other than to listen but if they are in trouble they would use them and not care about the consequences!)

Thanks

Steve

[beforethevision]

I bought an Icom in 5w/15w/55w selectable output, I only run it at 5w, but am happy knowing that i can crank it up if i ever got stuck (big risk in a freelander lol). In flat(ish) country it will travel alot further, and in transmission atleast, makes up for my shorter antenna (45cm). Ive been once in convoy and swapped over to 55W requesting updates from vehicles that had become separated, only to have them phone me, so im happy.

I realise its not for daily use, and i realise its close to line-of-sight, but im happier with it.

The decision is yours. Just make is respectfully, Ie dont use 25W unless its neccessary, dont overtransmit people, etc.

cheers!

[Sleepy]

which one would you recommend?


Hi Steve

All the rules are here:

ACMA - Citizen Band Radio Stations (http://www.acma.gov.au/WEB/STANDARD/pc=PC_1265)

Australian CB radio operates on what they call a "class license". In short you don't get a callsign or have to pay any money, but you do have to stick to the rules. (Located on the ACMA website.)

5 watts ouput is the standard on UHF. Having said that, if you're not annoying anyone and don't use it much around town, it's probably doubtful you'd ever get caught using a commercial unit with a larger output.

What most people forget is a greater output is no good if you can't hear the other person..ie It doesn't mean you can receive weak signals.

It is far better to spend some money on a good antenna. There is a wonderful thing called antenna "gain". Simply meaning, a good quality antenna with a higher "db gain" will multiply your effective transmitted signal and also help recieve weaker signal. I cannot stress this enough - A well tuned antenna, fitted correctly is the way to go. This may cost you another couple of hundred above the cost of your CB, but well worth the money. Once fitted, the Antenna must then be tuned for correct VSWR. (colloquially called "swering the antenna")

I have ventured off road in Victoria’s high country (notorious for losing UHF signals in the many valleys and hills) Each of us in the convoy had different equipment - the best signal was from the standard uhf cb with a good antenna.

The GME is a solid unit and there are a few others too.

If you really want high power consider a Amateur Radio license, they are much easier to obtain now (no longer need Morse code) and they have a "Foundation" license which is pretty straightforward to get too.

[rovers4]

I support all that has been said as to antenna tuning and the 5w limit. You need to hear the other party.

Don't forget to get the antenna installed in a good radio location on the vehicle. This may not be the best to suit you visually though, or for negotiating overhanging branches.

Maybe you need a shortish one (45cm colinear - two section pre-tuned one above the other with a twisted coil in the middle), (as against a 1/4 wave straight whip that has no gain) on the bull bar, but then a ground independant type with some real gain, and therefore of multiple sections, able to be plug changed over, mounted up high - roof or rack.

This would give you max legal range when out in the backblocks but also can be removed when not required, leaving you with the bullbar job for everyday use.

Either way, get it done by a techo with the gear for checking the cables/location/mount.

The 25W jobs are for those who use commercial frequencies that are nearby, who pay for the license and the right to use those frequencies.

Amateurs also have licences and can operate on several frequencies allocated to them. They sit exams, pay money and enjoy good comms. Their systems can get them talking around the world.

The new study path they have to "get on air" is really easy compared to that of just a few years ago. Most can get their Foundatrion Licence in a weekend or over just a few weeknights.
Look up the local affiliated clubs on the WIA site, for a club near you.

Rovers 4

[jik22]

Just to add to and agree with the comments already mentioned, don't bother paying extra for a set which can do extra power. I have an iCom (Bought for a different reason) and although I have the programming lead and software, the power is still set at 5w. Spend the money on the aerial and getting it fitted properly with good cable and connections. A high gain aerial is worth far more than an extra 20w on what is a line-of-sight frequency anyway.

[5teve]

Thanks for the Info there guys... im aware about the importance of the antenna, im just going through this with the marine radio i have, we have tested the antenna with an swr meter and its very very poor at best! there is no way of tuning it either :O( we arent too sure if the swr meter is out tho.. so we are just building a dummy load to calibrate it.

i was mainly enquiring about the extra power due my curiosity about how much extra distance i would get.. and it sounds like it depends.. sometimes it can others it wont.. and i thought the ability to run at 5w but have say 25w or 50w on hand in emergency would of been handy..

is the amateur radio license the same as the marine vhf license? im wondering if i could combine the 2? they probably arent too far off the same!

again thanks for the info.. as per usual you are all incredibly helpful!

Steve

[Sleepy]

Steve,

The power distance ratio is logarithmic therefore double the pwr does not double the range. (So a rough estimate would be 25watts should be roughly double the range of 5 watts maybe a little more). But it still can't penetrate hills :D:D Maybe on your boat or in the desert or on top of a hill it would be significant but proabably negligble difference elsewhere.

Amateur radio VHF operates at around 144-148Mhz and is a bit lower freq. than your Marine VHF which, from memory, is around the 160Mhz mark (?).
You may get a radio that operates on both freq.s but it would be a compromise and you'd have trouble tuning the antenna for both freq.s.

An amateur radio licence limits you to only talking to other amateurs only on amateur bands. More info on the ACMA website or at The Wireless Insitute of Australia (http://www.wia.org.au/). The new Foundation Licences are an entry level Amateur licence and can obtain with weekend course in regulations etc. (Contact WIA if your interested).

I have found many “Hams” that are also 4wders the two hobbies tend to complement each other. (They both drain your wallet too:D:D) although sounds like you have a boat for that wallet-draining-experience :D:D;);)

Having said all that, I still run a UHF CB for close vehicle operation , as that is what most others are running. (Also have a couple of those cheap Chinese hand held uhf cb's which are handy for recovery ops, kids and campground comms. )

[jik22]

and i thought the ability to run at 5w but have say 25w or 50w on hand in emergency would of been handy..

Unless you're talking to a repeater, it's unlikely anyone will be able to talk back.


is the amateur radio license the same as the marine vhf license? im wondering if i could combine the 2? they probably arent too far off the same!

Can't speak for the marine one, but the amateur covers you only for talking to other amateurs on the amateur frequencies. So, I guess no overlap in license or frequencies, and probably not in equipment either.

As for your SWR meter, I'm in the US at the moment, but if you haven't got it sorted by the time I'm back, you're welcome to borrow mine. You might find you need to use an antenna tuner if it's really out and not down to poor connections or something else simple.

[JDNSW]

Just to repeat the point - since UHF is essentially line of sight, increasing power will not increase range except in the case where you have a sufficient line of sight distance that 5w is inadequate. I am not sure how far that is, but I have regular, easy communications (or interference) between here and Cook's Gap Fire Brigade base station. That is about 90km from here, although both of us are on top of hills with significant antenna towers, high gain antennas, but both operating on 5w.

John

[isuzurover]

Whilst we are on the topic of commercial radios. Anyone have experience with the Phillips PRM80?

[Sleepy]

Whilst we are on the topic of commercial radios. Anyone have experience with the Phillips PRM80?

I know of them but haven't used or programmed one.

Someone here UHFworld Forum - Powered by vBulletin (http://www.uhfworld.com/forum/) will know.

[isuzurover]

I know of them but haven't used or programmed one.

Someone here UHFworld Forum - Powered by vBulletin (http://www.uhfworld.com/forum/) will know.

Thanks Sleepy, but that forum seems pretty dead, and a search comes up blank... ???

[Tote]

An interesting point on antenna mounting, I used to have a work panel van with a ground independant 3DB antenna mounted on the gutter above the drivers door and could reliably communicate with the Dubbo repeater at Nevertire, a distance of approximately 100KM. Subsequent setups on the Bullbar of my Maverick could never match this even with a ground independant 9db antenna and It was usually south of Trangie before I could hit the repeater, a difference of about 40 KM. As anyone who has been out there knows this is very flat country but the difference in antenna mounting made a significant difference.

Regards,
Tote

[Sleepy]

Thanks Sleepy, but that forum seems pretty dead, and a search comes up blank... ???

Sorry bout the bum steer isuzurover. Haven't used that one for a while. Looks like they're all too busy with their soldering irons ;)
Some more info here SKINNYS HOME OF RADIO (http://skinny.8k.com/prm.html)

[LandyAndy]

Hi Steve
If you can afford the high output units get one.
There are is an extensive repeater network thruout aust.You may not be able to hear back but you may be able to get a signal out in an emergency.
Andrew

[rover4life]

ok heres the drum forget what u have been told about 25w working not much better than 5 watt i have a tait 2020 an icom 400 pro and a simoco 9020 and i can on a average day talk upto 70 km with a good antenna u get a good 30-50 out of them and off a look out i can talk over 150 km a 5 wat radio is ****e in comparrison yes they work good line of sight but whats the use when you are **** up in the bush 25 will get out much better if not for some 1 to tlk back if you could relay msg over and over and your location you are bound to get help.... like i said i have a gme 3200 on a 1.2:1 vswr response and my simoco running the same antenna kills it ..also on top of all that you also have the added bonus of powerd mics and the such as a gme is 3 wats out and 2 wats modulation making it a 5 watt radio and a 25 is 25 watts out and 4 watt modulation ..out of the technical stuff the comercial will recieve clearer and lower signals you can programme them to do many things and much clearer for the guy listerning to you but if you get a comercial i may suggest a tait 2020 uhf 400-470mhz or 450-480 mhz as they can be tricked to run the 477 band and pic up off ebay 250 and a great reliable radio i had mine for 3 yrs now second hand from hong kong not a problem also can get remote head kits:)
Cheers Shaun

[Sleepy]

ok heres the drum forget what u have been told about 25w working not much better than 5 watt i have a tait 2020 an icom 400 pro and a simoco 9020 and i can on a average day talk upto 70 km with a good antenna u get a good 30-50 out of them and off a look out i can talk over 150 km a 5 wat radio is ****e in comparrison yes they work good line of sight but whats the use when you are **** up in the bush 25 will get out much better if not for some 1 to tlk back if you could relay msg over and over and your location you are bound to get help.... like i said i have a gme 3200 on a 1.2:1 vswr response and my simoco running the same antenna kills it ..also on top of all that you also have the added bonus of powerd mics and the such as a gme is 3 wats out and 2 wats modulation making it a 5 watt radio and a 25 is 25 watts out and 4 watt modulation ..out of the technical stuff the comercial will recieve clearer and lower signals you can programme them to do many things and much clearer for the guy listerning to you but if you get a comercial i may suggest a tait 2020 uhf 400-470mhz or 450-480 mhz as they can be tricked to run the 477 band and pic up off ebay 250 and a great reliable radio i had mine for 3 yrs now second hand from hong kong not a problem also can get remote head kits:)
Cheers Shaun


An FM signal is just that - modulates the frequency not the amplitude - 5 watts out is just that. If you send an unmodulated signal it has the same output - therefore power mikes make no difference (Unlike the old SSB 27Mhz stuff.:twisted:)
I agree that commercial radios are of a higher quality and your receiver may also be better. The problem is it is illegal to run one on CB 477.

I prefer HF for reliable long distance comms or a SAT Phone. (ELT for emergencies!!)

Nonetheless it sounds like your happy with your radio Shaun.- which is all that really counts ;)

[rover4life]

not illeagal to run 477 on commercial only if higher than 5 watts and they sound much clearer and also recieve is better as they are built better as for the distace i can only go on what i have expirenced and that is long distacne and clear signal
Cheers Shaun

[Sleepy]

FWIW:

Here's the Class License (http://www.comlaw.gov.au/ComLaw/Legislation/LegislativeInstrument1.nsf/0/24642FD88C9A7B39CA256FC700798969/$file/cbrsCL.pdf)
"Operation of a CB station must only employ FM or PM with a transmitter power not exceeding 5 watts pZ with a necessary bandwidth not exceeding
16 kHz."

Also the radio itself must comply with the the approved standard which most commercial units don't. (Even though it could be argued that they are of a higher quality.)

More stuff here too:
ACMA - Citizen Band Radio Stations (http://www.acma.gov.au/WEB/STANDARD/pc=PC_1265)

[mark2]

Whilst we are on the topic of commercial radios. Anyone have experience with the Phillips PRM80?

I currently own 3 PRM80's and have been using and programming them for quite a while. They came in lots of different bands so its important to get one includes UHF CB in the band if want to use it for UHF CB. I like to monitor emergency services and find the 450 -520 (UW Band) is the most versatile in this regard).

They're a great radio and these days dont cost any more than a basic 5w GME (often a lot less) yet the construction and features are so much better than the 'CB' radios even though they were built about 15 years ago. They are still in use by many companies and councils, although emergency services have phased them out with perhaps the exception of rural fire brigades who keep everything for much longer than everyone else.

I'm an advocate of the extra power when needed, primarily when using repeaters. Often it makes the difference between being able to access a repeater or not. I agree its not necessary for convoy type use.

[nzoliver]

I currently own 3 PRM80's and have been using and programming them for quite a while. They came in lots of different bands so its important to get one includes UHF CB in the band if want to use it for UHF CB. I like to monitor emergency services and find the 450 -520 (UW Band) is the most versatile in this regard).

They're a great radio and these days dont cost any more than a basic 5w GME (often a lot less) yet the construction and features are so much better than the 'CB' radios even though they were built about 15 years ago. They are still in use by many companies and councils, although emergency services have phased them out with perhaps the exception of rural fire brigades who keep everything for much longer than everyone else.

I'm an advocate of the extra power when needed, primarily when using repeaters. Often it makes the difference between being able to access a repeater or not. I agree its not necessary for convoy type use.

Hi from NZ!
These radios show up here from time to time, is there a specific model you can tell will cover the bands you use yours for?
Thanks

Oliver

[mark2]

This link: PRM80 mods & information: PRM 80, PRM8030, PRM8010, PRM8020, PRM8025, PRM8040, PRM8041, PRP80, 8010, 8020, 8025, 8030, 8040, 8041 Philips Simoco Radio mod (http://www26.brinkster.com/mitaux80/index.html) should help.


I prefer the UW band versions (450 - 520 Mhz) as it works for UHF CB and emergency services frequencies (programmed for recieve only)

[isuzurover]

Thanks Mark. That website seems to be permanently down though.

I have a PRM8030. What antenna do you use?

EDIT - OK - found a copy of the web page you posted
http://tas.wicen.org.au/Resources/PRMs_mods_esentials.htm
very helpful

I have a W4 :( However when I bought it I was told it had been modified to work as a CB. Guess I will have to test it...