Dave W6OAL on the formation, purpose and history of the Consortium. “The RMVHF+ Group sometime circa 2004 started tossing around an idea about a beacon for use in determining if ones radio was working and also let it serve as a propagation tool, and a somewhat distant signal source for the tuning of receivers and preamps. Here in Colorado we have a lot of mountain tops but most are on private or Forest Service land. Many of the prime locations are already taken and space on existing towers and in weatherproof facilities are costly. Ken – WØETT- one of the cadre of net control stations for RMVHF+ Net mentioned that his family cabin, south of Jefferson, CO on a 9500’ hill not far from Tarryall Creek and north of Tarryall Reservoir might be a candidate. We organized a road trip to the “interior” (of Colorado) to research the facility and its possibilities for use in our endeavor. Our conclusion was that a two meter beacon in the approximate middle of the state of Colorado would not only serve the Front Range but be of service to others around Colorado. It might possibly be able to be heard out of state so that others out of state could be assured that there is really VHF life in that great state surrounded by Utah, Wyoming, Nebraska, Kansas, Oklahoma and New Mexico called Colorado. The beacon consortium was organized WØETT – site owner and manager, W6OAL – Engineering and procurement, WØAH – adviser. When Doug – WØAH left the area the consortium was a gang of two for sometime. In the last few years Doug’s spot was filled by NØPOH – adviser and photographer.”
Originally, Ken – WØETT, supplied the location for the beacons at his family’s cabin located in the South Park Area near Jefferson, CO at 9500’. He also paid the electric bill! The engineering, construction and maintenance is the product of Dave – W6OAL. The South Park beacons operate on 144.282, 222.055, 432.360, 1296.225 and used Ken’s WØETT call sign. The newest beacon is on 903.075 (Hear the 903 beacon at NØPOH’s QTH DM79op) in Fort Collins under the auspices of another new consortium member Art – WØBA. This beacon operates under Art’s WØBA call sign. These were available to anyone that needed a distant signal source for propagation study or receiver/preamp tune up. The first beacon was the 144.282 beacon that was set up around 2004. As time and resources permitted Dave designed and built the beacons for 222.055, 432.360, 1296.225. Over time Dave has refined various aspects of the beacon transmitters and ID keyer configurations.
THE FIRST SOUTH PARK SITE
On a trip up to South Park, Dave reinstalled the rebuilt 222.055 beacon, while Ken winterized the cabin and I was able to take photos of the beacons, antennas and the surrounding horizon looking in the various compass directions from the beacon site. The antennas at South Park are all Olde Antenna Lab’s Big Wheel Antennas. From the top down a pair stacked for 1296 (Hear the 1296 beacon at NØPOH’s QTH DM79op) followed by the 432 (Hear the 432 beacon at NØPOH’s QTH DM79op), 222 (Hear the 222 beacon at NØPOH’s QTH DM79op) and 2 meters (Hear the 2 meter beacon at NØPOH’s QTH DM79op) The antennas are omnidirectional in nature and if you want to learn more you can read Big Wheel Antennas The site affords some excellent scenery and some great views to the front range and the western slope.
While up at the site Dave began reconfiguring the beacon cart. He removed a shelve that was no longer needed and began reinstalling the rebuilt 222 MHz beacon. The beacons resided on a utility cart in the kitchen of the cabin; the top shelf had the kitchen’s microwave oven… This microwave device was not part of the Beacon Consortium’s purview. It was used by Ken and his relatives for normal cooking purposes! You’ll note the refrigerator and stove too. According to Fred – WAØSIK, the cavity seen behind the cart wasn’t helping with the interference that he was experiencing at his cabin a few miles away so we uninstalled that also, then running the two meter beacon directly into the flex line. The 222 beacon was connected up and viola we have power through the Bird. All that remained was neatening up the the units on the cart and sliding the cart back into place against the wall. You’ll note that the hard-line all exits from behind the cart, it is snaked behind the kitchen cabinet and makes it’s way out of the cabin on the other side of the kitchen. The Beacon Cart after installation.
The Hardware
Dave W6OAL picks up the history behind the current beacon hardware and antennas with the first beacon on 144.282 “We have all heard the horror tales of folks using ham band transceivers as beacons and having miserable luck with them falling apart as they were not designed to operate in that sort of grueling service. However, the Colorado 6M beacon used an IC-551 or several of them over the years and they too came apart after so many years but Glenn WØIJR (now SK) and Karen KAØCDN respectively kept the Colorado 6M beacon on the air for at least 26 years of which I am aware. While a research effort was in progress we went on a search for a 2M transceiver that we could press into “beacon” service. Jesse – NØSWV answered the call with a Kenwood TS-271(?). This would serve our purpose for the time being and then be replaced. The consortium along with the RMVHF+ membership had questions and concerns, decisions needed to be made as to what polarization should the antenna system employ and should it be an omni (vertical or horizontal) or a beam and if a beam in what direction should it point. We arrived at the conclusion that a horizontally polarized omni would service the greater amount of people since VHF SSB is predominately horizontal.
Antennas sometimes spring forth from the Olde Antenna Lab of Denver on occasion, the Big Wheel; a proven performer in horizontal omni service was chosen and just happened to emerge from that facility. An ID’er had been ordered from Dave – WW2R, his product a PIC device programmed with ‘VVV de WØETT/B DM79ch’ would suffice for keying the beacon transmitter for the time being. A 12 volt battery and small charger were purchased and it was time to make another trip to the ‘Interior’ and put our RMVHF+ Two Meter Beacon on the air! A mast was already adorning the cabin so with 50 feet of ½” Heliax, the Big Wheel was mounted at about 35 feet. Coax egress into the cabin was via a hole in the wall which had to be then well filled with “Good Stuff” to keep the critters from dwelling in the cabins’ interior. A tea table on which the microwave oven was in residence was commandeered. The rig, battery and charger were set in place. The rig set to 144.282 MHz (a frequency that was deemed appropriate via a research of beacons presently on the air in adjoining states). The ID’er was plugged into the CW port of the rig and hooked to the battery. The battery hooked to rig and the charger hooked to the battery, I believe the rig ran about 30 watts. We were in business. We asked that reception reports be sent to Ken – WØETT so that we could ascertain the usefulness of the ‘beacon’ and who it was servicing. To our liking, reports were coming in from a multitude of folks along the Front Range. The beacon remained in operation for about 8 months until it developed a problem, at which time plans were being formulated for phase II of our beaconing endeavor. Beacon Engineering made a consorted search effort to find simple transmitter boards in the 2 meter band that were not going to cost us an arm and a leg. Hamtronics has been around for many a year and the products from them were dubious in the early years but as of late the FM transmitter (and receiver) boards looked pretty nice and were in kit form. Discussions with the owner of Hamtronics brought forth even more confidence in their products along with quotes of affordable cost. So, a 2 meter FM transmitter kit was ordered. The output was two watts and Hamtronics also offered a 30 watt power class ‘C’ amp kit and one of those was also ordered. Since the beacon was going to be operated on CW only, class ‘C’ was just fine. The crystal for our beacon frequency, 144.282 MHz, was ordered and would take about 6 weeks to be delivered. Looking over the board it was soon evident that the reactance modulator was not going to be needed so those parts were set aside. A lot of experimentation ensued in an attempt to find a place in the circuitry that could be broken and the keyer relay or transistor switch inserted. It is a cardinal sin to attempt to key an oscillator as the ‘chirp’ produced in doing so is so bad that no one would want their call sign attached to such a noise. How about a multiplier stage? When accomplished it was found that the note was also fairly bad so that was abandoned. How about the input to the driver stage of the power amp? That seemed like a likely spot to break – ah shucks, bleed through as the exciter stage (oscillator and multipliers were going to have to be working full time). Well then how about breaking the driver and power amp Vcc (12 volt) line. This seemed to work just fine except for the fact that locally the signal could be heard all the time and would be heard even if lead shielding were employed. A relay was considered to do the keying but after a bit of consulting with my good friend Tom – KØKHE who suggested, ‘Anything mechanical is prone to fail, and at the most inopportune moment.’ A PNP switch was designed and employed which worked just fine. Then the ‘afterburner’ was built and the exciter/PA being keyed by the WW2R Keyer was left to run into a dummy load on the bench for weeks. Then the units (exciter and power amplifier) were packaged up and ready to go. It eventually found its way to the ‘interior’ and replaced the ailing Kenwood 2 meter transceiver, relieving it of ‘beacon service’.”
Dave continues with the next beacon to hit the “interior” 432.360. “The 2 meter beacon was being enjoyed by many members of the RMVHF+ Group and non-members alike. We were receiving suggestions about creating a 70 cm beacon to be used for the same purposes as the 2M beacon. In that time frame, as we were contemplating a 70 cm beacon system, Bill – KØRZ was pulling down his 70 cm beacon and offered us the ‘brick’ oscillator from it, (Frequency West unit oscillator, very stable). This was taken into consideration in the design. In order to suppress any harmonics, a cavity filter was created. ‘Brick’ oscillators operate on a minus voltage in the range of -18 to -24 VDC. We found Jameco Electronics offered an entire line of DC to DC converters which we purchased a 12 – 24 VDC model. Both the input and output of these converters floats so there was no problem obtaining our needed -20 VDC for the heart of this beacon (the oscillator). The ‘brick’ had an output on the order of +17 dBm so with even a 6 dB loss through the cavity filter allowed us plenty of drive to operate a small power amplifier. Our research efforts brought us to Down East Microwave Inc. (DEMI) and their 25 W, 70 cm, PA. Since the ‘brick’ had previously been used in beacon service the frequency was already established and 432.360 MHz was where the beacon, frequency-wise was to reside. Another WW2R ‘keyer’ was purchased for this beacon which keyed the ‘initiate’ line on the DEMI PA and again letting the oscillator run full-time.
As the 70 cm beacon was being constructed and taking shape on the workbench a ‘FlatPAC’ power supply from VICOR became available from Mike – K6AER at cost that would allow us a 30 amp source at 12 VDC from the 120 VAC mains of the cabin. Thus, eliminating the need for the battery and charger arrangement presently in place. The 70 cm beacon was bench checked for several weeks and a 70 cm beacon antenna was created. The Big Wheel worked so well and garnered so many kudos and reception reports that what else could the 70 cm beacon antenna system be but another Wheel. This time a Little Wheel accompanied our trip to the ‘interior’ to change the input power scheme and install the 70 cm beacon and antenna. Upon departing the South Park area this time both 2m and 70 cm beacons were operational. Signals along the Front Range were strong.” “Someplace between the creation of the 70 cm beacon and the contemplation of the 23 cm beacon it came to pass that parts came together for a 33 cm beacon. As I recall the heart of that system was a Down East Microwave Inc. (DEMi) crystal oscillator on 903.075. Then came a PF0011 10 W PA device that was mounted on a DEMi board and the system enclosed in some sort of enclosure. Again a WW2R IDer was used to key the PA and a Wheel antenna was mounted on the Mast with the other Wheels. Since there are not all that many folks on the 33 cm band we didn’t get much feedback on its operation or usefulness. I could hear it here at my place (DM79QL) with a 47 element Loop Yagi at 60’. The beacon site is about 64 miles from me on a heading of 260° and I was able to copy it S-2 to S-3 on occasion. My not being able to hear it all that well I knew the rest of the Front Range was going to be having trouble with it.
As my old friend Art – WØBA (ex-WA6OYS) got settled into his Fort Collins digs I approached him about having the beacon at his QTH and received an affirmative. So the 33 cm beacon now resides at DN70KM and services the Front Range much more adequately that in the South Park area. The configuration of the beacon from the original has gone through several iterations and may be ripe for another. The obstacle of having a beacon at ones home QTH is that when one wants to use that band the beacon has to be turned off in most cases. Which isn’t much of a hardship but more of a frustration, in that, if one wants to monitor that band they can’t with a beacon blaring away. “Obstacles” but they can be overcome with perseverance so the 33 cm beacon lives and is very welcome to us that frequent the 33 cm band (902.1 MHz USB). At some point in time this beacon may go back out to the South Park area and sport an antenna system that is a bit more directional than the Wheel (Omni) antenna. Since most to all of the 33 cm activity is along the Front Range it seems judicious to place as much signal as possible toward the area where the activity is centered. I hope all of you that have used the beacon and those that will in the future find is a useful entity. The 23 cm beacon came along as parts became available and time to do the design and construction materialized. The items we call ‘brick’ oscillators, basically unit oscillators ranging in frequency from 2 GHz to 12 GHz or so are quite prevalent in the electronic surplus market and used more often than not by hams venturing into the more rarefied ether (UHF/Microwave bands) and such was the case in the development of the 23 cm RMVHF+ Beacon. The basic oscillator of the ’bricks’ run at around 100 Hz. A very rich comb of harmonics is generated in these oscillators and in our case the 12th harmonic of a 108.0188 MHz crystal was employed placing the beacon output on 1296.2256 MHz. Since as stated the basic oscillator put out a comb we thought it judicious to have our frequency of interest well filtered. A very high “Q” cavity filter with low insertion loss was created at OAL. The oscillator/cavity combination was run on the bench for a couple of weeks to age the crystal and insure stability. Down East Microwave, Inc. has been very good to us and for us in their offerings of VHF/UHF power amplifiers. The low required drive power has made them ideal for our beacon design and construction. And so was the case here with our 23 cm beacon. Their 2330PA (23 cm, 30 W output) fit our bill perfectly as out of the cavity filter we had on the order of +17 dBm (50 mW). The spec on the 2330 was 50 mW for a minimum of 30 W output power. A DEMI 2330PACK was ordered, built, tested and integrated into our 23 cm beacon system. A very nice feature of the DEMI product line of amplifiers is the availability of a key line which allows the amplifier to be keyed externally and allowing a bias point to be set if the amplifier is to be employed in SSB or CW service. Our beacons are all CW and therefore we bias them to cut off or class “C” operation where the key line simply initiated the power amp. This, for us, is an excellent feature as the oscillator runs all the time and is not “CW keyed” as chirp would result. So, the initiate line is keyed with a keyer and produces PA output only when keyed. All the parts were gathered together and secured to a platen (substrate of sorts), taken to the beacon site and placed in operation. The antenna system of the 23 cm beacon is a pair of stacked Wheel antennas. The antenna system is fed with ½” Heliax allowing very little loss between exciter/PA and antenna. The beacons are all powered by a Vicor FlatPAC AC-DC Switcher power supply giving us 12 volts at 30 amps. The FlatPAC is powered from the mains in the community and at present without an UPS. We do however, have an UPS on the Freakin’ Beacon keyer as we found in the past a power glitch would take out the keyer, attached to the FlatPAC, down and beacon operation would cease as the keyer would sometimes not reset itself. Art – WØBA to the rescue – in his stash he had several UPS called NAVPAC’s a product by NEWMAR that when site power was interrupted the NAVPAC would supply 12 V with a 4 AH capacity. The keyer requires very little power so power could be off for days and the keyer would continue to operate; however, we have not experienced power loss at the site for more than a few minutes, an hour at most.
