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Hi Does anyone know what the power output of the CFA tait portables are im guessing 5 watts on the Dispatch channel but ive been asked by many people what the Power out put is for the new digital fireground channels on the Truck radio's and the Portable Tait radios Many brigades are struggling to get over 1km line of sight on Digital simplex on 2m yet on uhf 70cm we are getting way over 18km's

thanks

vkcpolice wrote:Hi Does anyone know what the power output of the CFA tait portables are im guessing 5 watts on the Dispatch channel but ive been asked by many people what the Power out put is for the new digital fireground channels on the Truck radio's and the Portable Tait radios Many brigades are struggling to get over 1km line of sight on Digital simplex on 2m yet on uhf 70cm we are getting way over 18km's
thanks

The quoted nominal output of a UHF portable (irrespective of the maker) is 4 watts. For VHF 5 watts is the norm. It has been documented many times that while digital is either there or it isn't the performance of digital over distance is superior to analog.

This seems to fly in the face of everything that was know about digital communications. From someone who has experience, what I considered unbelievable handheld digital coverage, I can now say it appears to be common place.

R

Which is in part what the MFB discovered in a round about way when they migrated to their then new Fireground Talk channels on MMR.

There were five of them originally and they were Non-trunk P25. They soon discovered they were hearing other crews at other jobs several km's away in some instances.

The end result was to completely rework their trunked TGID's to what you see today in the 'Fireground' allocations and reuse the 5 non-trunk 'Fireground Talk' frequencies for what is now known as Local 1 thru to Local 5.

Sent from my SM-G920I using Tapatalk

I have to disagree. all the digital P25 testing i have Done with the CFA tait radio shows that even when in line of site P25 simplex does not work as well as Analogue. I had to Do some coms Testing for my brigade and the district and it was sad that a 70cm UHF Radio was out performing a 2M Digital Radio

vkcpolice wrote:I have to disagree. all the digital P25 testing i have Done with the CFA tait radio shows that even when in line of site P25 simplex does not work as well as Analogue. I had to Do some coms Testing for my brigade and the district and it was sad that a 70cm UHF Radio was out performing a 2M Digital Radio

Okay here we go.

Where was the portable located, on your belt or held in front of your face?

Are all power levels the same and have they been checked?

Were the tests conducted at the same time from and to the same location?

Were the batteries full charged on all portables when the tests were conducted?

Comparing a VHF to UHF portable is not valid. The test has to be like for like.

Again, aerials play a part here. UHF normally use a quarterwave aerial, VHF a helically wound whip. No comparison. Even if the UHF had a helical whip it would still not be a valid test due to different radiation characteristics of the two aerials.

As you can see, there are many factors at play here. Simple side by side tests are not always valid due to variations.



R

Being a long term user of a UHF P25 system which also uses encryption (and previously a long time user of the analogue UHF system it replaced) I agree that on any system that is setup correctly digital has better coverage than analogue (hands down) in a like for like comparison. Far clearer transmissions and excellent voice quality are other enhancements.