Amateur Radio From Loudoun County VA

October 2000

The LARG Radio News - DE K4LRG

The Loudoun Amateur Radio Group, P.O. Box 1004, Purcellville, VA 20134

President Ray Houff (K4AJA) (540) 338-7297
Vice-Pres. Dennis Boehler (KF4TJI) (703) 777-9427
Secretary Carol Boehler (KF4TJJ) (703) 777-9427
Treasurer Tom Garasic (NA4MA) (703) 753-0568
Editor John Unger (W4AU) (540) 338-4620
Training Bill Buchholz (K8SYH) (540) 338-6928


The October LARG Club meeting, scheduled for October 21, 2000, will be replaced by the next LARG balloon launch. In the event of the balloon mission being scrubbed, we will hold a meeting in the Conference-Training Room at the Leesburg Police Station. If you are not on the LARG email reflector, you should check on 147.480 Saturday morning for the status of the balloon launch / meeting. Also, check on the launch communications frequency of 144.945. If the balloon mission is scrubbed, our club meeting will be at the Police Station on Plaza Street at 8:30 a.m. The facility is located on Plaza Street between East Market Street and Edwards Ferry Road. Talk-In is on 147.480 MHz. You can join other LARG members for breakfast (~7:30) before the meeting at the Bob Evans Restaurant located Leesburg Corner Shopping Center.

Balloon Committee News - Since the regular October club meeting will be superseded by the scheduled balloon launch, we thought it would be a good time to bring you all up to date on the activities of this committee and its preparation for the launch. The great progress this committee has made is due mostly to the hard work or its chairman, Tom, WB3AKD. We will have four teams operating during the flight (NOTE, if you don't see your name on one of the Teams' rosters and want to be or think you are on that team, contact the Team Leader): Mission Control will operate from Craig's, N4OHE, mountaintop QTH and will attempt to plot the position of the payload from bearings obtained from the tracking team and will record the telemetry from the payload instruments. Mission Control will also coordinate the other teams as necessary and function as a communications relay station.

The communications frequencies will be 144.945 FM and 7.185 +/- LSB and 7.015 +/- CW; the HF frequencies will be used mainly to communicate with the launch team.

The Mission Control Team consists of John, W4AU, Larry, KG4CGR, Jacob, KF4VLQ, Craig, N4OHE, and Tom WB3AKD.

The Launch team is responsible for the final assembly of the payload, parachute and balloon, filling the balloon, and releasing it when the other teams are ready. This is a fairly complicated procedure that Norm, AI2C and his team executed flawlessly on the last flight in April 1999. This year's team will again be led by Norm, AI2C, with team members Bill, WB4ACC, Mary, KF4UUY, and Bob, KF4VBM.

During the flight, the tracking team will provide bearings to the VHF beacon signal so that an approximate track of the flight can be maintained allowing the recovery teams to move toward the touchdown point at the termination of the flight. This phase of tracking is a vital part of the flight operations as the signal is difficult to detect when the transmitter is on the ground and a successful recovery depends on getting the recovery teams close to the landing location without losing the signal.

TheTracking Team will be led by Denny, KF4TJI, and also includes Carol, KF4TJJ; Tom, WB9RXJ; Charlie, K4LJH; Mark, N3GMW; Erik, KD5CTJ; Art, KD4CSO; Larry, KC1YC; Chester, WB9LAZ; and Bob, W4POF. Armed with Small beam antennas, attenuators and portable receivers, the recovery team has perhaps the most difficult task of trying to locate the payload once instrument package has landed and the flight has terminated.

They also have the task of recovering the payload, once it is located. This task could involve tree-climbing, bush-whacking and, certainly, a lot of walking. Gary, NC4S, has the lead for this team, which also includes Tom, NA4MA; Angie, KF4AVR; Paul, N4PD; and Nancy, KE4RTP.

We will use modulated CW (Morse Code) at 15 wpm as the data downlink for the balloon on the tracking frequency of 145.650. The message takes about a minute and a half to transmit and will be as follows (each # is a digit): DE K4LRG/BALLOON BK BARO ##### MB BK NEG BATT ###### MV BK POS BATT ###### MV BK AIR TEMP ##### K BK BUS TEMP ##### K AR

The instrument package for the balloon will consist of a 50 mW FM transmitter, which will transmit the continuously modulated CW message detailed above, relaying data from sensors in the payload. During tests last week, signals from the transmitter and flight antenna were copied from above Round Hill to Leesburg; so we should have no trouble hearing signals from the payload package.

The software used to generate the CW transmit code and the numeric to Morse translation code for the message was originally written by Paulson Macintyre, and modified to accommodate the mission-specific data. Bob Bee , W4POF, has contributed to the airframe and developed a switch arrangement. Tom, WB3AKD assembled the payload and designed the electronics. John Steinberger contributed several Motorola HT200 transceivers for use in this and future flights. Charlie, K4LJH,designed original twinlead J-pole antenna used.

Club News - Paul, N4PD, reports that he is again on 80 meters, having put up a new dipole last month. With the help of Craig, N4OHE, and Charlie, K4LJH, John, W4AU, added about 15 feet to his tower and KT-34A height with a IIX ladder mast; watch out for those big signals from Hamilton! As AI2C says, "Higher is better...". Many LARGers now have much-improved signals on 2 meters due to antenna work done over the summer. Tune into our Sunday night nets and see how many great signals are now on the air from western Loudoun County.

Calendar of Events:

Every Third Saturday 8:30 a.m. Club Meeting - 10/21/2000 - Leesburg Police Station
Weekday Mornings and Evenings Commuter Net, 147.480 MHz Simplex
Every Sunday 8:00 p.m. Club Radio Net, 147.480 MHz simplex