June 2010

Over the past year+ the DVMS and Grid Pirates Contest Group have been rebuilding their V/UHF and microwave station atop Mt. Weather @ 1800′ in northern Virginia grid square FM19bb. Although this is the second year of operating from the site, it is the first year we began using some of our own newly erected towers and antennas. We’d previously been borrowing most antennas and tower space from an existing single op station at the location. In late 2009 we planted 4 new tower bases, 2x Rohn 45 and 2x Rohn 55, which in time will become the supports for all bands 50 MHz through 24 GHz. Currently only two of the towers are built, one Rohn 45 holding 50 and 432 MHz antennas and one Rohn 55 holding 144 MHz antennas. A few pictures can be seen below, but plan to read more about our construction project coming soon in another article. You can see many more of the photos from the site build out by clicking here. Click on any other thumbnail image below to see a larger more detailed image.

tower / anchor holes Rohn 45 & 55 tower sections Rohn 45 base planted Lots of concrete! Concrete poured and ready to set

Although the fall season put us ahead of schedule with planting and securing the tower bases and anchor points, the wet spring provided by mother nature unfortunately put a big crimp in our tower erecting plans. The original plan was to bring in a crane early in the season, but that was delayed and delayed again and finally fell through due saturated ground which lasted all the way through late May. Therefore we had to fall back on gin polling up all the tower sections one at a time. The 140′ Rohn 45 went up fairly smoothly for 50 and 432 Mhz and except for some minor issues with the TIC ring rotator, that project was relatively straight forward. In the pictures below you can see the final product 2x 5L beams SSW, 4x 5L beams NW and a 7L rotatable beam for 50 MHz. There are also 4x 12L beams to the NE and 4x 22L beams rotatable for 432 MHz.

50 & 432 MHz arrays 50 & 432 MHz arrays view from 144 tower 50 & 432 MHz arrays

The 50 Mhz antennas and switch box worked perfectly with low SWR and good receive signals. 432 MHz had several issues, mainly due to operator error, e.g, forgetting to plug in various coax jumpers and misc. wiring issues related to the switch controls. Once those were ironed out the 432 MHz system tested perfectly.

The 190′ Rohn 55 tower for 144 MHz was more of a hassle and only made it to 140′ with only half of the planned arrays. We had assembled 2 sets of 90′ of tower with the plan of using the crane to erect them, but when that fell through we had to disassemble that in its entirety and start from scratch pulling each section up by itself. Below you can see the interim product of our efforts which is 8x 6L beams to the NE, 8x 6L beams to the NW and 8x 6L beams to the SW, with a pair of FO12’s rotatable at the top. Eventually all fixed arrays will consist of 16x 6L beams in the 3 mentioned directions with the FO12’s at 190′.

144 MHz tower 144 MHz tower 144 MHz tower

It was just a week before the contest that we were able to begin mounting all the 144 MHz antennas to the various tower legs. It had taken us several after work evenings to strip the 48 antennas off the old 40m tower and repair the various damages caused by wind and ice over the winter. Fortunately all the rotator, hard line, coax, switching relays, etc. all functioned once everything was hooked up. Plugging the antennas into the rigs / amps showed good receive signals and low SWR.

Running out of time prior to the contest meant we ended up falling back on our generous single op station’s 222 MHz rig, amp and antennas and continue to borrow his 50 MHz fixed NE array (8x 6L) as seen below. Also a last minute decision would be to cram 2x 50 MHz, 144 MHz and 432 MHz positions all in one bus vs. splitting them into two buses. This saved on some RF and network cabling runs as well as helped during the contest when it came to passing or getting a fellow op’s attention.
222 station w/ FM 222 beam (top) 50 MHz NE array
Friday night before the contest was dedicated to getting radios (now all K3’s vs. TS-850’s), amps, computers (now all P4’s vs. P3’s) and the network all connected. We still had to network 222 MHz at the house to the bus. We did learn though you can push CAT5 to 450′ (150′ >limit) and still run RoverLog and Internet connections with no noticeable network degradation. With setup time running short we unfortunately weren’t able to perform any inter-station interference testing between the new towers and antenna arrays. That would have to wait until the contest itself. Big mistake.

Saturday morning of the contest, folks started rolling in, first our fearless captain and leader Terry W8ZN (ex-K8ISK, ex-WD8ISK), who without the K8GP operations would never happen, arrived to get things kicked off. Joining him is Chuck W4XP and soon to follow is Rich K1HTV. Immediately K1HTV is put to work replacing 50 MHz relays in the antenna stack switch box. This would be just one of many issues with the new array and switching box over the weekend. Gene W3ZZ shows up with Gary NW5E in tow, arriving the night before from Fla.

Andy K1RA arrives and incorporates the latest Roverlog 22,000+ call LUP file on all station computers and begins ensuring all network connections, rig control, rotator control and WSJT software and sound cards function and perform as expected. A PC is already blue screening, so a quick reimage is performed to get it back online. On site is a commercial WiFi provider from which we normally get our internet connection but we soon discover its radiating all over the 50 MHz band. Opening the door to the barn (see picture below) where the ISP houses its equipment reveals the culprit on the floor. This sits right under the fixed NE 50 MHz array. We pull the plug with much dismay to the ISP and are relegated to using spotty Verizon EVDO cell modem and laptop gateway for a connection to the net.
W8ZN finds RF noise
Other op’s start rolling in, Ed K1TR flew in from NH into Baltimore Washington and makes the drive up the hill. Mike N2NAR and Bill N4SV arrive providing support and finally Ty K3MM pulls in to round out the weekend’s crew.

Although we’d tested 222 MHz earlier in the week with no issues, pre-contest testing reveals receive and transmit problems. Searching through the racks and cables of the single op station (see below) is a chore. We finally narrow it down to a relay we are able to jumper. At this position we also set up a triband rig for FM which turns out to be relatively productive over the weekend. We have several hundred watt solid state amps and small vertical beams at about 40′ above the house.
racks-o-stuff racks-o-stuff

146, 223, 446, FM amps triband FM rig

With a bit of extra time still left before the contest Rich K1HTV requests a low, rotatable 50 MHz beam for working ESkip. We happen to have a small 3L beam and in remembrance of our operations at Spruce Knob, WV we pull up one of the 30′ Rohn 25 bus towers and slap the antenna on top and patch the rotator control and feedline into the bus. It will turn out this antenna will be much more than a ‘nice to have’.
Bus and 3L 50 MHz beam 3L 50 MHz beam Bus and 3L 50 MHz beam
As contest time approaches the skies begin to turn grey. As usual in the D.C. area a chance of afternoon thunderstorms loom off in the distance. Rich K1HTV and Gary NW5E take their positions at the two 50 MHz stations, Ty K3MM takes 144 Mhz and Ed K1TR rounds out the end of the table in the bus with 432 MHz. Chuck W4XP, Gene W3ZZ and Mike N2NAR fill in at the 222 MHz and FM rigs in the house. Terry W8ZN and Andy K1RA standby in the wings to perform triage just incase anything breaks down. And as it is no contest without Murphy, things start to deteriorate quickly.
Rich K1HTV & Gary NW5E (50) Ed K1TR (432) & Ty K3MM (144) Gene W3ZZ (222)
50 MHz starts off with an ESkip opening to the south to EL8x/9x and EM9x, but almost immediately we find 50 Mhz generating S5-7 broad band hash across the 144 MHz station. So much for testing for inter-station interference before the test. We just have to grind our teeth and give 50 MHz ‘hand signals’ and deal with many repeats on 144 since more pressing issues are about to arise. Its only after the contest that we determine T-ing a quarter wave length piece of coax at 50 MHz on the 144 MHz receive line all but eliminates most of the noise issues.

After about the first hour and a half Ed K1TR reports he’s lost both the 432 NE array and the preamp. Fortunately a spare preamp is built into the box. Unfortunately it means climbing the tower to switch some jumpers and taking 50 MHz off the air too since the two employ the same tower for their antennas. Ed will have to do without the NE array since changing the relay isn’t as easy. Fortunately 50 Mhz can switch over to the low 3L beam and since ESkip is hopping that antenna proves to be a real winner running stations from EM0x/1x/2x/3x/4x/5x/6x, DM3x/4x/5x/6x/7x and EN1x/3x/4x. Its about 30 minutes to change and test the 432 preamp, but no sooner then we finish up it begins to pour, thunder and lightning.
Something goes awry in the 50 MHz switch box. Fortunately its at the bottom of the tower, but we’ll have to wait for the storm to pass to get it. Its back to the 3L beam on the bus. During the down pour 144 loses its rotator indication, though we can still turn the antenna we are doing it blindly, or have to poke our heads outside the bus to see where we are pointing.

Around 5pm the 432 MHz amp HV P.S. blows a fuse (20 ohm resistor) and its off the air. Fortunately 50 MHz secondary and 432 share a common HV type connector so secondary 50 MHz goes off the air to get 432 back on again, though it takes another 30 minutes of 432 being off the air before this is completely switched over.

The storms subside around 630p and its Terry W8ZN off to pull the 50 MHz switch box and attempt a repair. 144 MHz goes off the air and Andy K1RA climbs the 144 tower to replace the rotator with Bill N4SV and Mike N2NAR providing ground support. Another 30-40 minutes go by and new rotator is back in line and antennas are realigned. 144 is back on the air again, but to our dismay we learn we missed a crucial 144 MHz ESkip opening to the southwest costing us some possible 10 additional new grid squares and several dozen new QSOs!

By sunset Terry has repaired the 50 MHz switch box and replaced it at the bottom of the tower. No joy though, there is still an issue, and it appears that its at the top of the tower. We come to find out the 7L 50 MHz rotatable is not pointing where the TIC ring rotator control box says it is. Lightning has caused the controller to lose it sense of south stop and in turn caused the rotator to go well past south, killing the internal pot (and more). Terry yet again tells 432 to call it quits and gets up the tower with little remaining daylight to pull the motor off the TIC ring. 45 minutes lost before 432 is back on the air. Terry fixes the motor in about 30 minutes and the plan is go back up the tower with spot lights and head lamps a shining after 432 slows down. Terry goes to sleep around 9pm for a bit, but nobody wakes him until 5am. Throughout the rest of the evening 50 MHz runs up many ESkip contacts from the Caribbean, southwest, mid to northwest and west coast and has now spent almost the entire contest using a 3L beam at 30′. After midnite ESkip dies out and both 50 and 144 MHz go into WSJT mode working many skeds and random QSOs and 222 and 432 plug away through the night with little to no tropospheric enhancement.
Gary NW5E (50) Ty K3MM (144) & Ed K1TR (432) Gene W3ZZ (222)
On Sun. morning Terry and Andy head up the tower to pull the 7L 50 MHz beam and of course this means 432 has to go off the air again. The lightning and subsequent TIC controller failure and over rotation the day before has ripped and shorted the feed of the antenna. Terry pulls the antenna off the ring rotator and swings it against the tower so Andy can repair some 10′ below. Its another hour+ before its back in place and aligned properly. By mid morning everything is working relatively well. Terry also fixes the HV P.S. fuse to get secondary 50 MHz back on the air though ESkip on the band is nowhere near as good as Sat.

By mid day on Sun. our 144 MHz K3 with built in transverter was dying about once every 5 minutes, no TX or RX. It appears it was overheating and it appears the local oscillator is no longer working. A power reset brings it back to life, but after a while we go back to an external DEM transverter that carries us through the rest of the contest.

Except for ESkip on 50 MHz on Sat., which was much better than last year and lasted well past midnite, the 144-432 MHz propagation was moderate. There was no great tropo or enhancement. We saw DX contacts down to FM03/04/05 in the south, FN34/44/25 to the north and EM79/84/85 and EN61/71/72 to the southwest and west but not in any large numbers. Below are several maps showing grids contacted and QSO densities for the 144-432 Mhz bands over the entire weekend.
k8gp-jun10.log.144.png k8gp-jun10.log.222.png k8gp-jun10.log.432.png
Sunday night provided nice clear skies and Andy K1RA captured a few long exposure pictures of the 50/432 and 144 MHz antennas and towers, under lit from several spot lights mounted on top of the bus. There will be no tear down at 11pm like on Spruce Knob, no early wake up call at sunrise to pack buses and head down the hill. We’ll all be in our own beds by midnight local Sun. night.
nite 50 & 432 MHz tower nite 144 MHz tower nite both towers
We wrap up the weekend with the following band by band breakdowns and overall totals:

Band   QSOs   Pts  Grids
50      807   807   204
144     465   465    71
222     118   236    41
432     220   440    44
Tots:  1610  1948   360

Claimed Score: 701,280

Many lessons were learned and much more work is planned for the future. We hope to continue to grow the station and refine the operation as time goes on. 73 and thanks for all the QSOs!

K8GP Grid Pirates Contest Group
June VHF 2010 ops:
Rich K1HTV, Andy K1RA, Ed K1TR, Ty K3MM, Mike N2NAR, Bill N4SV, Gary NW5E, Gene W3ZZ, Chuck W4XP and Terry W8ZN

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