Andy Flowers, K0SM. The Rochester VHF Group. Elections. VHF software for you cell phone or PDA. Inside This Issue:

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1 News! The next regular meeting of the Rochester VHF Group will be Friday, May 11, 2007 at 7:30pm NOTE: This meeting will be held in Ogden, NY just off Rt. 531 at the Ogden Town Hall! MAPS are in the back of the journal. Topics: Elections VHF software for you cell phone or PDA Inside This Issue: The Chairman Speaks! Andy Flowers, K0SM Fellow VHFers, Thanks to all of you for a great season. I also want to thank everyone from both the RVHFG and RDXA who came out for the banquet this last month. The May meeting is the last one before the summer recess. We have elections coming up at the May meeting. So far we have the following candidates: Chairman: K0SM Vice Chairman: K2TER Secretary: N2KXS Treasurer: KC2IQV The floor will also be open for nominations at the meeting before the vote. After that I ll be giving a short presentation on some VHF-related software tools that you can have on your cell phone or PDA, including a grid-square calculator and a satellite tracking program. This will be a hands-on demonstration, and if you have a web-enabled cell phone or PDA you will be able to try out the software on that as well. Chairman s letter: 1 -Andy Flowers K0SM/2 The Rochester VHF Group Vice Chairman s letter: 2 Secretary s report: 3 Antenna range report: 4 Published by Rochester VHF Group PO BOX Rochester, NY Editor: Andy Flowers, K0SM The VHF Journal is published by the Rochester VHF Group monthly except June- August. The subscription price is included in the membership dues. If you elect to receive the PDF version by downloading it from our website, dues are US$10 per year. In this case, you will be notified by the day it is available for download. If you choose to receive the hardcopy Journal by Postal delivery, the dues are US$15.00 per year. Articles and comments should be submitted to journal@rvhfg.com

2 April Meeting The Vice President Speaks! Bill Rogers, K2TER John Stevens (WB2BYP) did a great job is assembling an antenna range testing system. I know he put a lot of effort in to planning, acquisition and verification of the equipment that we used. Dean Keyser (WB2QCJ) provided many of the reference antennas which were essential as well. I think we did the best we could with the conditions we had. I think the weak link was the delayed feedback system we employed to peak the antennas. John and company moved the antennas around to find a peak while we sat indoors and read off the spectrum analyzer strength readings over the radio. I consider this a learning experience and look forward to an effort in the summer to provide the same service under better conditions. See John s write up in the journal and Stay tuned! Awards Banquet If you didn t attend the banquet you missed out on an evening of lively conversation and a good meal. I encourage you to attend next year! Thanks to Dave Hallidy (K2DH) and his spouse for organizing the banquet and securing the facilities, it s greatly appreciated by all of us. June Activities The Rochester Hamfest is coming up. We always need help to man the booth, please contact an officer of the club to volunteer for a 1 hour slot. This is our main activity related to sustaining and growing membership, so this hour of your time is vital to the club s future. Tom (KV2X) and I will be roving in the June VHF Contest. Mark (K2QO) will also be roving with 10 bands. Are you going to be on? Are you planning a large effort? Let the group know at the meeting or on the RVHFG reflector. Field Day I plan to be operating the VHF+ station (all bands 50MHz through 10 GHz from my rover) for W2RFC again this year. I think VHF+ is underutilized for field day and there are a lot of additional points that can be made if you take the time to put these bands on the air. There is a lot of 6M activity as well. I encourage those operating from home stations, especially those with microwave equipment, to make a presence on the upper bands. You may find that this will spur more VHF+ activity in coming years. In closing, I would like to say that it was my pleasure to serve as the club vice chairman this year. I would like to thank all who contributed to the successful club meetings and presentations we had. We couldn t have done it without you! Looking forward, we are seeking topics for next year s programs. I have heard there may be an evening of 24, 48, 76GHz equipment and one on Big Amps. What else do you want to see? What would you like to present? Please let us know. Bill K2TER

3 Secretary Report Judy Stonehill, N2KXS Rochester VHF Group Meeting Minutes for April 13, 2007 The meeting, which was held at Town of Ogden Highway Facility, was convened at 1940 local by the Chairman, Andy, K0SM. Attendees introduced themselves with their names and calls, and talked about their ham-related activities during March. OLD BUSINESS The group was reminded that tonight, April 13 th, is the last day to buy banquet tickets and that the banquet will be held on Saturday, April 21 st at the Pineview Family Restaurant in Spencerport. Contributions of door prizes for the banquet are requested. Sponsors for RVHFG awards are still being accepted. Jeff, N2JQR, reminded everyone to send him the summary sheets of their VHF contest results. Paul, N2OPW, told the group that RDXA is planning to set up for Field Day. VHF operators are needed for 6 meters, 2 meters, 440, and up to help operate during the contest, June 23 rd and 24 th. Paul, N2OPW, requested that a link to the AMSAT website be put on the Rochester VHF Group web site. It was moved by Dave, K2DH, and seconded by Jeff, N2JQR, that the Treasurer s report be accepted as printed in the Journal. The motion was approved by the attendees. Chuck, KC2IQV, moved that the Secretary s report be accepted as printed in the Journal. The motion was seconded by Dave, K2DH, and approved by the attendees. Members in attendance included: K0SM, K2TER, N2OPW, K2DH, KC2IQV, AF2K, WO2P, W2DYY, WB2BYP, NQ2O, W2CNS, N2JQR, KB2TAK, N2KXS, and W3OAB. NEW BUSINESS The annual election of officers will be held at the May meeting of the Rochester VHF Group. Anyone interested in running for office should let Andy, K0SM, know. He needs to know before the April RVHFG Journal deadline. The meeting was adjourned at PROGRAM John Stevens, WB2BYP, among others, provided measurement equipment and source antennas to demonstrate the concepts and methods behind an antenna range. A range for 2M and up was set up in the parking lot. Several very interesting antennas were brought to the meeting and tests were run to acquaint people with the measurement devices and processes used with this technique.

4 Results of Antenna Measurement 13 April 2007 at the Rochester VHF Group Well.How do we explain this. I think we have rediscovered the difficulties in making ad-hoc antenna measurements. In no particular order of precedence, I ll start the conversation with a few truisms about antenna measurements. 1) You can have sophisticated instrumentation available to you, and still be constrained by a reflection-rich environment. That fact will limit your ability to make anything meaningful below perhaps 903 MHz. Find a grassy knoll with nothing but sky and lossy turf in the view angle of the source and test antenna. 2) You should have good representative gain standards on all bands that you think you will test on, and a wide variety of test antennas so that when odd results are encountered, you can make some sense out of them. EIA dual dipoles and representative can waveguide antennas on each band, ready to re-substitute and recalibrate the system would have been a great assistance. 3) Feedback mechanisms between the measurement instrumentation and the HHA (Ham Held Antenna) are necessary to assisting finding the peak of the pattern, as well as the optimum height above ground. An audio tone as a function of signal strength would be nice. 4) Making measurements in the cold evening may lead to accepting sub-optimal results. (It got pretty cool out there ) My vote Lets try this again this summer and refine the technique! Here are some of the results for 903, 1296 and I left out the 432 measurements because we had such varied results that it was clear that no trustworthy data was resolved on that band. 903 MHz Antennas RVHFG Antenna Measuring 13 Apr 07 Test Ant Est Gain (dbi) Sig Level Source Output Level Est Path Loss to (db) dipole Ant # Callsign Description AUT Level Comparitive Predicted Gain (dbi) Notes 1 kv2x m^2 18 el The upper box represents the setup where we calibrated using a unit dipole and recorded a specific power on the analyzer, given a fixed transmit power attenuated over the path length of the parking lot. We then substituted the AUT (Antenna Under Test) and observed the new and hopefully larger signal attributed to antenna gain.

5 In this case we see an increase of 14.4 db on Tom s 18 element yagi, which is plausible, but we could have used a few more antennas on this band for comparison MHz Antennas RVHFG Antenna Measuring 13 Apr 07 Test Ant Est Gain (dbi) Sig Level Source Output Level Est Path Loss to (db) emc horn Ant # Callsign Description AUT Level Comparitive Predicted Gain (dbi) Notes 1 k2dh coffee can feed horn fashionably weathered 2 nq2o 10 element HB yagi k2ter m^2 22 el wb2qcj wide flange horn Polarad Model CA-L Serial NO KMc 5 wb2qcj log feed dish wb2byp Septum Feed pol On 1296, we used a similar technique with the test antenna being a ridged horn with a previously predicted amount of gain. Again we see there are plausible results with the bigger or larger aperture antennas yielding higher gains. The septum horn at the bottom of the list was circularly polarized so it differed from the other horns of similar aperture by 3dB. Doing this again I would like to also calibrate with a circular reference to compare horns with polarizers MHz Antennas RVHFG Antenna Measuring 13 Apr 07 Test Ant Est Gain (dbi) Sig Level Source Output Level Est Path Loss to (db) horn Ant # Callsign Description AUT Level Comparitive Predicted Gain (dbi) Notes 1 wb2qcj wide flange horn k2ter 2304 looper Polarad Model CA-L Serial NO KMc Harris special 3 wb2byp septum pol wb2byp septum pol k0sm 16 turn helix wb2qcj log fed dish asn101a

6 On 2304 MHz, we used the same horn for calibration and inserted the predicted gain into the calculation. Again we see some plausible results and comparative examples of higher and lower gains associated (hopefully ) with larger apertures and boom lengths. We attempted a run at 3456 and had only the one antenna and were running out of time. We rigged for as we had a few more antennas on that band, but experienced difficulty in achieving enough signal given the limits of the generators and increased path loss. Lessons learned were to bring more antennas and have some additional output power available at the higher bands to ensure adequate dynamic range of the measurement system. Stay tuned We are going to do this again, hopefully over the summer with a little more daylight, maybe a few picnic tables, more antennas, liquid refreshments and add some bands to the mix. Thanks to all who helped measure, brought antennas, provided suggestions and encouragement. John Stevens wb2byp@ieee.org Source antennas providing a signal from 432MHz 10 GHZ A hefty wide-band UHF antenna. Rumor has it that it was designed for rovers that had to drive through trees.

7 Things of note about our Meeting Location: 1) It s VERY convenient from ANYWHERE in the Rochester area. From downtown, it s under 10 minutes. From the eastern towns it s under 25 minutes. From the south of Rochester (Geneseo) it s only 45 minutes. 2) It s a VERY nice building. A brand-new building, modern facilities, and PLENTY of parking 3) It has access to internet connections and a video projector, and has seating for up to 70 people. 4) In other words, it s a tremendous location. BIG thanks go out to the Town of Ogden and Jeff Tewksbury (N2JQR) for allowing us the privilege of using this facility.