# UFH 400MHz or UHF 800MHz

**URL:** <https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938>\
**Category:** General Discussion\
**Created:** [May 25, 2017, 12:46am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938 "2017-05-25T00:46:54Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![margioa](https://www.twowayradioforum.com/user_avatar/www.twowayradioforum.com/margioa/32/312_2.png) [@margioa](https://www.twowayradioforum.com/u/margioa)\
**Post date:** [May 25, 2017, 12:46am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/1 "2017-05-25T00:46:54Z")

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Greetings all,

I have one important question for a project.

In general terms what is better to penetrate concrete (inside buildings) standard UHF or UHF 800 MHz?

I would be grateful for your help.

Thanks.

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**Author:** ![paulears](https://www.twowayradioforum.com/user_avatar/www.twowayradioforum.com/paulears/32/408_2.png) [@paulears](https://www.twowayradioforum.com/u/paulears)\
**Post date:** [May 25, 2017, 2:32am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/2 "2017-05-25T02:32:21Z")

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Not so much the concrete, but the rebar in the concrete.

There’s a decent paper on it here. [http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1027&context=ceendiss](http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1027&context=ceendiss)  
Graphs of attenuation compared to frequency.

The simple answer is that low frequencies are attenuated less than high, which is what we’ve always been taught.

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**Author:** ![Chickenhawk](https://www.twowayradioforum.com/letter_avatar_proxy/v4/letter/c/ce73a5/32.png) [@Chickenhawk](https://www.twowayradioforum.com/u/Chickenhawk)\
**Post date:** [May 25, 2017, 11:58am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/3 "2017-05-25T11:58:21Z")

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Simple experience with handheld radios has shown me that VHF does poorly through building; UHF does better and 900MHz is the best.

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**Author:** ![paulears](https://www.twowayradioforum.com/user_avatar/www.twowayradioforum.com/paulears/32/408_2.png) [@paulears](https://www.twowayradioforum.com/u/paulears)\
**Post date:** [May 25, 2017, 1:33pm UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/4 "2017-05-25T13:33:12Z")

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That fella who wrote the research paper will have to do some re-writing as the absorbtion is worse as frequency gets higher. Interesting question isn’t it?

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**Author:** ![Chickenhawk](https://www.twowayradioforum.com/letter_avatar_proxy/v4/letter/c/ce73a5/32.png) [@Chickenhawk](https://www.twowayradioforum.com/u/Chickenhawk)\
**Post date:** [May 26, 2017, 2:13am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/5 "2017-05-26T02:13:25Z")

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I don’t write research papers. I just use handheld radios every day.

I have used VHF, UHF and 900MHz spread spectrum radios every single day for many many years.

I can point out a hundred thousand web sites that support what I say, but why bother. He asked. I answered, based on MY real world experience.

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**Author:** ![paulears](https://www.twowayradioforum.com/user_avatar/www.twowayradioforum.com/paulears/32/408_2.png) [@paulears](https://www.twowayradioforum.com/u/paulears)\
**Post date:** [May 26, 2017, 3:13am UTC](https://www.twowayradioforum.com/t/ufh-400mhz-or-uhf-800mhz/6938/6 "2017-05-26T03:13:51Z")

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Hang on! I wasn’t having a pop, so no need for the slap back - I was pointing out that exactly like you say - real world usage appears to differ.

Care to calm down and consider what is going on then? Wow! talk about over reacting. I wasn’t saying you were wrong, or incorrect, or that I disagree - just commenting that physics disagrees with reality. Neck - wind in!