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last updated 11 Nov 2004

DX & Records
DX is an old telegraphy code that means long distance. 446MHz, even with just 500mW, can travel long distances from good high locations, and is sometimes helped along by special atmospheric conditions (see 'Tropo helps' on the Technical page) - so there is no reason why we can't enjoy this fascinating aspect of PMR 446.

Please make sure you've read the Calling page on this website, first.

There are...

Distance records up for grabs! The amateurs do it, why don't we? Calling all amateurs... next time you head for the hills when there's a good lift - take the PMR446 and monitor channel 8 tone 88Hz! Give a shout on the VHF/UHF calling channels and say you're listening on PMR446 too... we might get some surprising contacts! 500mW ERP during good tropo will easily cross the channel, why not claim the first? This MUST be done with straight unmodified equipment (no extra antennas) to qualify, otherwise it's meaningless PMR446-wise - you might as well be using an amateur band. That's not to say don't have whatever fun you like with these things, that's up to you but I obviously can't be seen to encourage such a thing. A "PMR446 distance record" simply wouldn't make sense with anything other than straightforward gear, although there could be an interesting second category where anything goes with antennas and orginal type approved electronics. I just wouldn't want to see anyone causing interference and spoiling the service by hogging channels for miles around. Be sensible with this, please!


(If you have a 446 site, please promote 8/88 with this, or another banner)

Record Rules
To count as a record, genuine 500mW FM radios in the 70cm band (with integral antennas) MUST be used. This includes approved PMR 446 radios, FRS, and other countries' equivilants.

What could be achieved is proved by the following contact, which would be the current record if proper 446 radios had been used at each end. The Dutch were using amateur transceivers and external antennas, so this cannot count as a true 446 record - but it shows what could be done :

England to Netherlands, 535.8km (333 miles) :
'Delboy' : "Tues Aug 05, 2003,
This morning at 08:15 (BST) I made a long distance contact from Blyth, Northumberland to Chris located in Amsterdam at an approximate distance of 322 MILES! (later corrected - Spoddy) The conversation, which took place on channel 1, lasted for about 10 minutes and was witnessed at this end by David (M0DAD). I had noticed that 70cms was absolutely packed with German and Dutch stations which I was able to work with only 1 watt from my home location, so I took my Motorola T6222 to the top of our local pit heap and made the contact."
"Hi Delboy you want our exact location for the distance we are about 20 km near Amsterdam, a town called Almere that's the newest town of the netherlands before Almere it was a sea but now it's made into land they called it the Flevopolder, it's in between Amsterdam and Utrecht, I think exactly in the middle of our country"

National Records
Here are the best records so far, as reported from around the world.

In Spain, the record is 326km (202 miles). A Google translation : "The best location had Somiedo, at the top of the Calvitero, to more than 2,400 meters of altitude, in the limits of Salamanca and Cáceres. Desder could there speak with the Tips of Europe, where was Pedro, of the Radius Bierzo Club, in a difficult contact that served to them to exceed the 326 kilometers, establishing a new mark. Also it connected with Tordesillas, the Radius Bierzo Club and the rest of links of the zone Center: Juan Francisco (of U.R.B.), who left from Alburquerque, in Badajoz (to about 159 kilometers), with several Portuguese operators (like Pedro Coast) and with Excalibur and Alfa Charlie, that were in the Mountain range of France (to about 42 kilometers)."
A previous Spanish record was between two 2100km (7000ft) mountains 279km apart (174 miles), on 446 (no date known), Jose Manuel Vidal.

Poland, May 2004, Simon CZ001 / 007Mobile : "with a standard tti freequency 122tx and with a height of 869metres made a contact some 224km or 140 miles from my spot on the Polish border to a station in the far south west of the country on the German Border, his weight 800m a.s.l. A record for these small radios here in the CZ. Also made was 11km,14km,51km,95km,105km and then the 224km contact.

Andy in Jersey (British Isles) :
" Wed Aug 06, 2003; Good tropo this morning, luckily I had the morning off, so I headed up to the north coast cliffs at 7am (must be mad!). Plenty of fun on 2m and 70cm, and I scanned a very quiet 446. Then, at about 9:40am, I heard a "CQ DX" call on ch1 (no tone) - I couldn't believe it! I got straight back to Steve G7SYO who was 10 miles from Taunton Somerset. I used my trusty unmodified Vivanco on NiMH power, he had a BT Freeway. A good, but slightly scratchy contact." Between IN89WG & IO81HA is 214km (133 miles), "... which would have been a record at one time - d'oh! Still, it's my personal best on 446, and will probably be the first confirmed GJ-G contact."
Andy's previous 'first Jersey - England contact' will never be proven :
"Today 24th August 2002 at half 5 in the afternoon, I made contact with someone in Dorset, which has got to be at least 100 miles from here. This was due to special conditions today - ham radio stations are booming in from all along the UK south coast. This must be the first GJ to G contact on 446! My 446 radio is a Vivanco, running on NiMH batteries. I heard someone saying hello a lot on channel 8 tone 8, so I called back. It was a bit of fun, I thought they'd be somewhere else on the island so I was delighted to hear that they were indeed in Dorset as their accent suggested. Before we got a chance to find out exactly where they were, my batteries ran out! No chance of a QSL or anything, so you'll have to take my word for it, but I'm happy I've proved it's possible."
( http://www.network54.com/Hide/Forum/message?forumid=103662&messageid=1030217408 )
Actually the mimimum distance is to Portland at IO80sm : 88 miles, but several miles further would be more likely.

On a forum I found a Finland record :
"FIN 1 / EST Rakke Emumäki KO38EW - Zero Hyvinkää Kulomäki KP20JP 17.07-03 vx-146 209,8km !!!"
Previous Finnish and Estonian PMR-446 DX record 106km. "The operation QTH KO29KL in Estonia was 200 m over sea level in a TV tower http://www.teletorn.ee/index.php?lang=eng . The QTH in Vihti KP20FJ was 100 m over sea level. There was no tropo propagations on that day between Finland and Estonia. We where using Vertex Standard VX-146 radios in both ends." See http://www.radio-tele.com/pmr/dx/dx.htm

On March 30th 2001 a well organized mountain top to mountain top FRS test was done between 4 mountains in North Carolina, USA :
Grandfather Mtn to Hanging Rock. 93 miles
Mt. Mitchell to Pilot Mtn. 110 miles
Mt. Mitchell to Hanging Rock. 123.5 miles (198.7km)
"Stock FRS units made the trip just fine! (462MHz, 500mW) In most cases, the signals were full quieting and broke the factory-set squelch. Over the longest distances, moving an inch or two sometimes made a difference, as did holding the radio arm's length in the air (on Pilot Mountain)."

Distance records in Korea : http://www.wireless.co.kr/shop/community/frsdx.htm - 150km between mountains. Coby in Monte DoBong (to the north of Seoul) to Monte Keyryong (to the south of Daejun). Conventional equipment with no modification and with the original antennas.

Other UK DX
Height certainly helps under normal conditions. In the UK, mountains are not especially huge - Ben Nevis at 1344 meters, Scafell Pike 978m, Helvellyn 950m, Skiddaw 931m, Snowdon 1085m etc. On a perfectly smooth Earth, a 1000m height would give you a horizon of some 112km. Useful, but the best contacts are made with the help of tropo 'lifts'.

On http://www.transmission1.net/pmr446/review-motorola_t6222_review.html it is claimed that a contact was made between Flamborough cliff tops and "Cafe Del Mer" in Sherringham, Norfolk (an ice cream kiosk on the beach).
"Using websearches, OS maps in a local shop, and http://www.mapquest.com/maps .... Flam: 54 07 N, 00 08 W? Sher: 52 56 55 N, 01 13 E? If so, according to http://www.amsat.org/cgi-bin/gridconv Flam is around IO94wc, and Sher is JO02ow. Then, http://www.chris.org/cgi-bin/finddis says "156.84km (97.461 miles), bearing 145.3 degrees".
I would say this is OK to within about 5 miles or so. Looks like it was all over water, via tropo. Nice contact!"

Michael Wills, Saturday 21/6/2003.
"I walked from Winder Hall, slightly NE of the top end of Ullswater to Troutbeck, near Ambleside in the Lake District, leaving at 8.15 am and arriving Troutbeck around 2.15 pm. I was following High Street, the old Roman road that follows the fell tops E of Ullswater. Around Midday I was calling my wife at Cliburn (about 12 miles) from Racecourse Hill on High Street (not far from Kirkstone pass) when I made clear and good contact with Bill (or Bob??) inn Holywell, North Wales. We were both using barefoot unmodified Motorolas, mine a TA200 running on NiMh cells. Contact was maintained for several minutes till I made contact with my wife." ...
"Using 53:16:32N, 3:13:08W for Holywell, and 54:28:54N, 2:55:39W for Kirkstone Pass from http://uk.multimap.com , 'Distance between IO84ML & IO83JG is 135.36km (84.114 miles), bearing 187.1 degrees' - not bad!"

125km during August "DX Weekend" by Simon and Alex, who were astonished when contacting Ned in North Wales.

G7KEH, 120km with standard equipment and using alkaline batteries from Nebo (Wales) to G6GVG in Manchester.

More 'proof of concept' from one-who-knows : "About 17 years ago I worked into central Bristol from the top of Werfa in South Wales on 433.45 simplex with a Pye PF-1. Distance was around 55 miles (88km) and signals were full-quieting both ways. This was during VHF NFD with the Coulsdon club. The PF1 put out 100mW at best and typically about 80mW. 500mW from a PMR446 rig should be easily able to do the same. - Chris Cox, N0UK/G4JEC

So, however much some big-headed Radio Amateurs may scoff, we can see that 100 mile distances can be achieved under good conditions. Why knock efforts to have fun with 446 radios? It is exactly the same sort of activity that interests the amateurs - getting the best out of limited equipment.


To calculate range, it would be useful if 446 DXers adopt the amateur radio convention of using grid square locator codes. A 6 character locator like IO94wc is accurate to about 3 or 4 miles. If you dial in two locators to a site like www.chris.org/cgi-bin/finddis it will tell you the distance and bearing e.g. "156.84 km (97.461 miles), bearing 145.3 degrees".

To work out your locator, first you need your lat and long coordinates. Fine if you can use a GPS, but the easiest way is to use the streepmap website which allows you to enter your postcode and then the rest should be simple... if you have a problem with that, you could try going into a bookshop that sells Ordnance Survey maps (or a library) and have a quick peep at the map to get the figures. You can check/verify the position with websites such as http://www.mapquest.com/maps, http://uk.multimap.com, http://www.streetmap.co.uk, but take care if you're near a grid line to ensure that you end up in the right square. There is a new square every 5 minutes of longitude (East to West) so take care near 05, 10, 15 etc. The 'squares' widths vary from approximately 9.26km at the equator, converging to triangular sections that meet at the poles and are just 13m at the base; at the UK's position on the globe they are about 6km (49N) to about 4.5km (61N) wide. The grid lines are every 2.5 minutes of latitude (North/South), so the sides of each square are always roughly 4.63km spaced, from the equator to the poles.

When you've got your figures, such as 54 07 N, 00 09 W, a website like www.amsat.org/cgi-bin/gridconv will tell you your locator square.