RADIO advice sought for URBAN prepping

[Lightspeed]

(8 April 2014, 18:25)NorthernRaider Wrote: LS can I snaffle your advice for the article on Urban rad comms?

Feel free NR.

What are you gonna do with it?

[NorthernRaider]

Add it to a basic rough draft combining bits of todays debates about Urban Survival.

[Oggydoggy100]

Hi, I have played around with several different systems regarding Urban Comms & the best I have found for the price is the Mitel UHF 5 watts, available over the counter £145 for two hand held units. They have 15 channels & work fairly well in built up areas. Have tested them in London several times rigged for covert use. You should have a Ofcom license, but that down to the individual. The mittel is also easy to use a rugged construction. The other similiar unit is the ICOM 125 UHF unit, but has only two channels.

[River Song]

OggyDoggy - How did you rig them for covert working?

Seems to me so far that the Baofeng UV5R are still a good buy
but I worry about the distance.

Those mitel ones look pretty good and have a good range.
Price point is not bad.

What is a 'guerilla repeater'?

I can guess the guerilla part and I can guess that a repeater
takes your signal and repeats it. What part does this play in the overall scheme of things?

I'm rather time limited and at the moment I'm still caught up with 802.11 wifi to see whether this can be extended wide area.

Allons-y

[CharlesHarris]

I don't know how agressive they are in UK with regard to locating unlicensed transmitters, but in the US our volunteer Auxiliary Communications Service routinely located weather balloons for NOAA, EPIRBs for the FAA and Coast Guard, as well as tracking taxicabs with unlicensed radios, capturing occilloscope traces of the transmitters which gave positive ID evidence which could be used in court. We were trained by the FCC and the police technology support unit and learned to use and operate their equipment. Computerized scanners, spectrum analyzers and directional antennas at the various public safety radio repeater sites could usually get a position fix on a targeted transmitter within 30 seconds and track it anywhere within a 100 km radius of Washington, DC, Baltimore or New York.

[Lightspeed]

RS: Separate thread started to cover Guerrilla Repeaters.

CH: The premise of this thread is a post collapse of ROL environment. A guerrilla repeater is a good way to remote transmission location away from the transmitting station. Using hard wired or obscure frequency Very Low Power uplink, works well in this respect

[Binnie]

LS All my tests of UV5R indicate a decent range, though but a whip style antenna (i've a Diamond RH771) for that little extra punch.

I gave my UV5R to a licenced ham, he managed to make contact through a repeater 15+ miles away, and the person that repsonded reported a decent copy.

he actually bought one himself for using mobile as he was so impressed with it.

[Scythe13]

I'm sure we could find a way for this to be of benefit: http://forum.survivaluk.net/showthread.php?tid=6805

[Binnie]

i'm already looking into it

[Lightspeed]

(17 April 2014, 09:02)Binnie Wrote: LS All my tests of UV5R indicate a decent range, though but a whip style antenna (i've a Diamond RH771) for that little extra punch.

I gave my UV5R to a licenced ham, he managed to make contact through a repeater 15+ miles away, and the person that repsonded reported a decent copy.

he actually bought one himself for using mobile as he was so impressed with it.

In reasonable conditions, UV5Rs are able to fire-up VHF repeaters at 15 miles range all day long.

The one I am using is non-tweaked, out of the box configuration. Antenna is a Nagoya 777 (?), not as good as your Diamond,but my best VHF range so far with this set up is a little under 60 miles.

In June, if I can get time off on 15th June, I'm planning of giving the UV5r a work out on our 9 element Yagi in the RSGB Backpackers competition. Historically on this event we've achieved 1000 miles + contacts in this configuration, using a vintage 2.5w Yaesu FT290r transceiver. It'll be an interesting test. My prediction is that we'll get contacts 100 miles+ range, maybe more.

Link to RSGB Backpackers competition. http://www.rsgbcc.org/cgi-bin/contest_ru...4backpack2

---

Just a thought.... if you want to listen in to the Backpackers competition, transmissions are mostly horizontally polarised, and mostly SSB

To have a chance of picking up the more didtant FM transmissions it might be a fun project to build a 3 element portable Yagi like the one in the link below. Drilled with roach pole support holes at 90 degrees to one another, the antenna can be used horizontal or vertical polarised.

A 5m fibre glass roach pole is sufficient, and for tuning I have found that cheapo CB swr meters are able to do an acceptable job. Don't be tempted to use a carbon fibre pole as they are conductive to RF ( and lightning) neither of which are good.

Yagi Link: http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=21602

BTW I have made a number of these antennas and they always work well. the advantage compared to a normal whip antenna is very noticable... why have I made a number of them? Because they keep getting pleaded out of my hands by newbie portable stations:-)