7/27/2019 A Broadband Ham Network Crosses the Finish Line

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A Broadband Ham NetworkCrosses the Finish LineA broadband ham network brings long-range videoto the Big Bend 50 Ultra Marathon's finish l ine.

The EquipmentHSMM -MESH nodes are made from readilyavaila ble consumer \ \' i-Fi routers (sec .. ..... ',hs mm -rnesh.org for model numbers that arcsupported by the so ftware ). No internal hardware modification is needed; it 's simple to re-

amphitheater, The netw ork is easy 10 set up,battery powered and far less expensiv e than asatellite link

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The 50lOOon-a Finish Line CamA group of hams from the Austin ARC (JOfJelinski. KC2KG; Pau l Kinney. KD5VRU;Milch London. KD5HCV, and Alan Russell.KE5DTR j got the idea 10 deploya high speed mulumedia mesh (HSMM-MES HInetwork 10 broadcast a live video feed froman Internet protocol vide o ca mera (similar 10those used in security applications ) at the finish l ine for specl alors gath ere d in the remote

Each year in the cool weather of January, BigBend National Park hosts the Big Bend UltraRun . a 50 kilometer (31 mile ) marathon Ihalis lim ited to 150 runners to minim ize environmental impact. Athletes come from aroundthe world to compete,

Lynn Jelinski , AG41UBig Bend National Park is located north ofthe Rio Grande River. which separates theUnited Stares fro m Mexico. Big Bend, whichis I..rgcr th an the state of Rhode leland, is aremote and dramatic wi ldemess locatedwithin the harsh Chihuahuan Desert .

The ChallengeTo support the mara thon. ha ms from the BigBend Amate ur Radio Club, the AustinAmate ur Radio Club and the San Antoni oRadio Club establi shed a race control andsafety 11(1 OIl 1 meters . The race net had beenused during previous race s and had provedvery effective both for coordination of raceactivities and runner safety. However. for thespectators, somethmg was nus smg.The friends and family of race participantscouldn' t watch the ir runners cross the finishhne beca use they we re cordoned o tt i n anamphitheater at Rio Grande Village about 10miles away

Figure 1 _ The equjpment used to estabnsh Ih!! HSMM-MESH nodesare theL inksys router. a 12 V battery-powered UPS. signal mirror. com pass and leather gloves. [Lynn Jel inski. AG4IU. photo]

Figure 2 - From Ihe left are Milch, KD5HCV. Joe. KC2K G, and Alan,KE5DTA. who used a compass to aim the antenna and a sigrtal mil ror 10 COflfi rm the orienlati on.The antenna is seCl,Jred wrth guy wiresattached 10 10 inch steel spikes. The cooler is 10 keep the batterypowered UPS warm during Ihe night. [Paul Kinney. KD5VAU. photo]

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7/27/2019 A Broadband Ham Network Crosses the Finish Line

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= ~ .Finish Une:9.1 M iles

Figure 3 - Alan Russell , KE5DTR (L), and Jo e, KC2KG, a re lookingout from the HSMM-ME SH node location atop Ernst Ridge to the lmts hline 9.1 miles away [Mitch London, KD5HCV photo)Figure 4 _ Paul Kinney, KD5VRU, adjusting the video display a nd dealin9 wilh the bri9ht TeJ(B s sun . [Joe Jelinski. KC2KG, phOlOJ

.9ul y 2013. a n l . o r gDid yo u e njo y th i s ar ticle?Ca st Yol,lr vot e a t =--www.a m.orgic:over-plal!IM-po11

viewed wh at went we ll and what could beimprovedThe major ghtch of th e event was tha t we underesti mated the intensity of the selling Texassun. It was so brightthat it overpowered thevideo projecnor. Despite our havmg erect ed acanopy over the screen , using a projectionscreen with a h ighly reflectiv e surface and ahigh-powered projector, th e finish line vid eoprojection was hard to sec (sec Figure 4 ).Next year we wi ll use a TV screen or a CRTto display the hIe video feed ,Next Year -Audience CamSpectators loved seei ng their runners cressthe fin ish line, but the runners them selvesdidn 't hear (he cheers or share in their exhilaration. Nu t j-ear we plan to place a secondvide o ca mera ill th e audience - an "audie ncecam" - so we can provide a live "ideo feedto the ath letes at the w ilderness finis h line .HSMM-M ESH is up to the tas k!

Joe Jelinski, KC2KG; Paul Kinney, KD5VRU;Loden, KD5HCV, and Alan Russell.KE5DTR, contributed 10 this article.Lynn J elins ki, AG4tU, an ARRLmembe r, wasnrstncensed in 20 00. Lynn and he r spouse,Joe , KC2KG.were membe rs 01 the East CoastWatelWsy Net clurin9 their 11 yea rs operatingmamrn e mobite.lynn helps universities writegrants for research lundln9, Lynn and J oe canbe contact ed at 640 6 Hopkins Dr, Austin, TX76n 4. kc2kgG earthttnk.net

Network PerformanceThanks to careful placement of the nod es.good antennas and the 10 RF noise floor atBig Bend National Park, e were ab le toget 100% copr We placed backup butteriesat each remo te nod e in case we needed the m,but the origina l batte ries lasted for the entire10 hours of the race. The batteries poweringthe video camera lasted for 6 hours andneeded to be changed durmg the race .

di sh antenna at both location s For the 1,8 milepath to the Rio Grande Village. we used a12 dB omnidirectional antennapaired with a12dB Vagi. With these antennas and d ear signal pat hs, we didn't ne ed an RF amplifier.

Prior PlalVling and Testing PayoffOUf gro up spent man)' of our Digitalwednesday meetings planning the operat ionWe s tudied topographical maps , tested thenodes and checked th e cold-temperature performance of the batte ries. Having planned theantenna locations, we performed a microw avepath analysis of the terrain to see how reliableth e path s wou ld be,Once at Big Bend we validated our planningwith on-s ite testing, We set up the network .checked antenna stability and battery inregnry:! days pr ior to the event. In preparation forth e event each of us had c limbed Ernst Ridgew ith heavy bac kpacks nt least three times,clawing for handholds in the rocks whileho p'ing the temperature was too co ld for scorpions and rattlesn akes . Each ascent was theeq uivalent of clim bing 400 stai rs

H o t W a s h ~IIwas dark by the tim e the final runner, whowas b)' then a walker, hobbled across the finish line. Un der the light of the sta rs we re-

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Deploying th e NetworkUsing microwave path analysis softw are, wedetermined we needed IWO nodes, one for a9.1 mile pat h (see fi gures 2 and 3) and anotherfor a I 8 mile path, For the 9,I mile path fromErnst Ridge to the finish line, we used a 24 dB

As the nodes arc powered up , the software enables each node to disc over other nodes withinrange, for m network paths and transfer dataautomaticallyTwo of the nodes, the finis h line cameranode and the Ernst Ridg e relay nod e,we re inlocations so remote tha t they didn' t have e iectricity We chose to usc lightweight (6 Ib)12V batt ery -powered uninterruptable povversupplies (UPS jt o power these nodes I seefi gure I ).The Amateur Radio AdvantageThese routers normally de Ii\ er only hous eholddistance operation, This is where Am ateurRadio comes in, Some of the 802.11 BIG (2 4GHz) channels 0 \ erlap the Amateur Radiobands . If you hold a Technician class or higherlicense )'ou may attach an amp lifier, antennaor both to the node to Increase its us eful rangeRemember, only the operating software tfirmware ) in the Wi-Fi rou ter is changed to convertit to a mesh node.

program the rout er with free softwaredownloaded from the site, The software con verts the standard router to a m icrowave meshnode , (A mesh node operates with in a meshnetwork. Each node in the mesh network canacquire data fro m all external device (such asa video camera ) and also reb)' data acq uiredb)' other nodes. - Ed,) The converted routerwill still use the factory transmn power ofaooUl80mW