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Which Freqs work best in built up areas
19 November 2015, 21:47,
#11
RE: Which Freqs work best in built up areas
Your mileage may vary, but if I recall correctly, PMR446, like FRS in the US, is limited to 500 milliwatts transmitter output with a fixed antenna on the radio, typically a short helical coil, with less than unity gain.

Public safety band UHF portables, have detachable antennas, transmit at about ten times the RF output of an FRS or PMR radio, and have more efficient, base-loaded, flexible quarter-wave whip antennas, which are more efficient radiators and have better range. A 5-watt UHF portable, such as a 70cm ham rig, with efficient antenna, transmitting direct unit-to-unit simplex, not through a repeater, provides reliable communications vertically ten floors, and horizontally ten city blocks or more, depending upon ground clutter and elevation.

73 de KE4SKY
In
"Almost Heaven" West Virginia
USA
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19 November 2015, 22:14,
#12
RE: Which Freqs work best in built up areas
Your correct on LEGAL PMR 446, .5 power fixed antenna etc, however the ubiquitous Uv5R family ham sets have the PMR channels programmed in as well as 2 meter and 70cm bands, so ........ erm...... after TSHTF all betts are off if you get my drift.

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20 November 2015, 00:06,
#13
RE: Which Freqs work best in built up areas
Understood.

I have old analog public safety radios in VHF and UHF which are programmed for 2m and 70cm ham, for which I am licensed, as well as VHF marine, the old analog fire and police "EMAC mutual aid" channels, itinerant business, General Mobile Radio Service etc. 128 channels on each radio.

The backup HF-SSB is an military Motorola Micom-X 2-18 MHz, 200-channels, 200 watts, which has a computer interface for digital modes, or can do SSB, AM or CW. It has the MARS and SHARES allocations in it also, because while no longer an Office of Emergency Management reservist, my FCC license endorsement remains active until it expiring when I turn age 70.

73 de KE4SKY
In
"Almost Heaven" West Virginia
USA
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20 November 2015, 09:28,
#14
RE: Which Freqs work best in built up areas
I already have three of the UV5s |I had 6 but got rid of them as excess to requirements along with a recently donated Yuasu ham transmitter which looked like something off star trek, gave em to a lad in Felling.

So I was planning on getting rid of the last three UV5s as well and just using modern CBs, but I think I will keep the UV5s as they appear to be more suited to urban areas, and they are still far more physically compact than hand held CBC. I may get ONE of the 8 watt versions of the UV5 and set it up as a base station, I've already got a 447 tuned antenna in my loft cut to 160mm length.

Sooner or later someone will tell me I can get PMR446 and 27 CB on one hand set Smile

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20 November 2015, 10:41,
#15
RE: Which Freqs work best in built up areas
Could you please simplify your response chaps as to be honest I'm lost with all the jargon. For instance one of those Boefeng sets---how far would you expect to be able to recieve and send in a city?
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20 November 2015, 10:51,
#16
RE: Which Freqs work best in built up areas
TH think of the UV5s as short range at crowded street level perhaps a few hundred yards, to perhaps a few miles on a good day line of sight, You see the sort of radio used by building site workers on new estates, quarrymen, security guards in HUGE malls, anti shop lifting patrols in central London. Its very difficult to quantify but the more tall steel and concrete around you the shorter the range. I can easily get 4 miles in the rural area with UV5s on PMR 446 frequencies (no licence needed) but only a few hundred yard in the middle of Durham city centre. BUT using the SAME radios on HAM frequencies ( licenced) technically if repeaters are available in the area you can send / receive over great distances. According to the Comms gurus if you put a much better antenna onto a UV5 instead of its rubber duck thingy you can reach miles rather than meters for the same power outputs. oh and UV5s are only bout £35 each but CB hand sets are about £80 and physically much bulkier.

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20 November 2015, 11:13,
#17
RE: Which Freqs work best in built up areas
So a better antenna on a UV5 would also "up your" send recieve distance in a city?
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20 November 2015, 11:14,
#18
RE: Which Freqs work best in built up areas
Is PMR446 effectively what many of us would call a walkie talkie?
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20 November 2015, 11:31, (This post was last modified: 20 November 2015, 11:36 by NorthernRaider.)
#19
RE: Which Freqs work best in built up areas
Yes if you go to Tandy or Argos and buy budget walky talkies, usually in pairs, 8 channels, very low powered, crap electronics, tiny antenna, usually no encryption or hailing or anything fancy in the UK they are called PMR and FRS in the US ( Merkins use different frequencies I believe) .

BUT, the 8 analogue PMR channels also have 8 or 12 more channels allocated to the band for digital PMR whatever the F... that is.

Now both LS and HAL have told me how very handy that rarely used 400Meg frequency band is, IF you use it with better quality gear such as Business spec radios like the Intek MT50-50 a professional PMR446 site radio.

http://www.amazon.co.uk/Intek-MT-5050-MT...B00307DWIW

BUT you get much more bang for your buck as a PREPPER if you utilise the PMR 446 part of the Baofeng UV5 family of radios which come with PMR freqs as well as 2m and 70 cm bands already installed. Cos they are good quality they can be tweaked, tuned and fitted with better antenna and have more power at touch of button (where legal). THEN if you get a Ham licence which most preppers excluding me (opsec issues) chose to do you have an effective hand held Amateur radio and PMR radio all rolled into one.

Naturally being great respecters of law and order non ham owners would only LISTEN to PMR channels on Baofeng sets and not broadcast on them. ( though after TSHTF all bets are off)


0 1666.665250 (none) Tone tone (off) 0.000000 FM Low
1 446.00625 P1 (none) 88.5 88.5 23 23 NN (None) FM High
2 446.01875 P2
3 446.03125 P3
4 446.04375 P4
5 446.05625 P5
6 446.06875 P6
7 446.08125 P7
8 446.09375 P8 Calling
9 446.10625 P9
10 446.11875 P0
11 446.13125 H1
12 446.14375 H2
13 446.15625 H3
14 446.16875 H4
15 446.18125 H5
16 446.19375 H6
17 446.20625 H7
18 446.21875 H8
19 446.23125 H9
20 446.24375 H0
12.5KHZ steps

Cos I don't have a ham licence and don't want one, I actually very easily even for me used the Free downloadable CHIRP program to remove all the 2 and 70cm freqs from my hand sets to prevent accident use or intrusion onto amateur bands, I did this out of respect for Ham licence holders whose efforts created and maintain their vital hobby. I basically have a PMR system on steroids set aside for when TSHTF . I bought a bearcat scanner to neb on other radio users, end up listening to Radio 2 most of the time Smile

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7 January 2016, 07:01,
#20
RE: Which Freqs work best in built up areas
I missed this thread while traveling and it didn't pop up as an unread when I got back...

Anyhow, late but maybe of use.

UHF VHF(UV5r type walkie talkies) and CB Radios will have very hit and miss range in cities, especially from street level in heavily built up areas.

Answering the OP: A UHF/VHF walkie talkie would be (is) my choice as it is easier to carry and operate, being much smaller and less attention grabbing. Using a earphone with inline mike is pretty much identical to a mobile phone's. As Charles pointed out UHF and VHF signals tend also to be more effective at getting into and out of buildings.

So, hang onto the UV5rs NR (and get an SSB capable CB as well).
72 de

Lightspeed
26-SUKer-17

26-TM-580


STATUS: Bugged-In at the Bug-Out
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