All:

I had a great time at the AMSAT-DC meeting on Saturday. I greatly appreciated the contributions, ideas, and questions from all the participants. HUGE THANKS to Pat Kilroy and to NASA GSFC for hosting!

Since I went on quite a bit about cheap antennas, here are some links to design & construction info and some related information.

Cheap Antennas for the AMSAT LEO's (WA5VJB) http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf Construction suggestions, tuning, diplexer design. Also discusses performance of Arrow antenna.

Cheap Yagi for 70 cm (search Amsat.org or internet for the companion 2M design) - uses foam board! http://www.amsat.org/amsat-new/information/faqs/crow/JulAug06AmsatJournal.pd...

Controlled Impedance "Cheap" Antennas (WA5VJB) http://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf The original cheap yagi article. Designs for 2M, 220 MHz, 70cm, 902 MHz, 1296 MHz, including AMSAT and FM sections on 70cm. Great ideas for terrestrial as well as satellite ground station antennas.

The 6 element 2M antenna I had with me on Saturday is VJB's 2M design and I've used it with reasonable success on 2M terrestrial (tropo, E-skip) and meteor bounce (FSK441 using WJST software). It's probably about as large as I'd want to use for a VHF rover station or portable installation. It's larger than necessary for use with LEO satellites; a much lighter boom & 3 or 4 elements are more than sufficient. There have been several published handheld designs that are 2 elements, and the Arrow (even with alleged performance issues) is a 3 element design.

WA5VJB Herringbone Log-Periodic for satellites: http://www.cq-vhf.com/vhf_highlights/2012_vhf/2012_spring_vhf/2012_spring_vh... Interesting design, simple, very portable (designed for hand-held).

DK7ZB's designs. http://www.qsl.net/dk7zb/start1.htm Huge wealth of information here! Probably better performance than the WA5VJB designs, but more demanding of precise construction. Most of his designs are in metric units but some have English measurements as well. There are several standard inch dimension rods that are close enough to metric sizes to work. And you can get metric-dimensioned components , too. Many examples of ingenious construction techniques in the photos. His area of interest in terrestrial weak-signal communications; many of his designs are VERY optimized for 144.2 MHz and 432.2 MHz, particularly the lower impedance designs. So stick with the smaller 50 ohm designs for satellite use.

The 2M/70cm-Yagis Ultralight page is probably most useful for satellite antennas. http://www.qsl.net/dk7zb/PVC-Yagis/PVC-details.htm Many of the designs are available from SOTABeams (UK) http://www.sotabeams.co.uk and as kits from Attila Kocis DL1NUX, Nuxcom, http://www.nuxcom.de. Some satellite-specific ideas & info: http://www.qsl.net/dk7zb/Cross-Yagi/crossyagi.htm

Using electric fence post insulators as element mounts (especially for aluminum booms) http://www.qsl.net/dk7zb/images/Elementhalter/elementholder_fence.htm DK7ZB and WA5VJB both assume the antenna elements are insulated from the boom. If you use an aluminum boom (recycled antenna pieces, ¾"x ¾" extrusions from Lowes/Home Depot), you have to mount the elements above the boom or with insulated plugs through the boom (and worry about boom correction factors). These insulators are a good alternative. And I don't understand why the Europeans get all the cool design small parts. Less exotic looking ones are available on Ebay & Amazon (and probably at farm/horse supply stores, Tractor Supply, etc.). I purchased a big bag of them off Ebay and plan to experiment with this approach.

Antenna element materials: WA5VJB recommends welding rod (cheap, elements may require splicing with hobby tubing to get lengths for 2M), #10 solid copper wire ($$), solid aluminum guy wire (old versions - Radio Shack discontinued the product several years ago), hobby tubing/rods (can get $$). Several online vendors sell a variety of aluminum rod and brass rod, some will cut to custom length at small additional cost if you are as inept as I am with hand tools! Watch shipping charges if you go over 48" in length. On the 6 element 2M antenna I displayed, I spliced the 2M driven element for that reason. The local big box stores generally don't stock small enough diameters/long enough lengths but it's worth a look. Or hit Timonium or Manassas and see what's in the flea market.

Internet Vendors: http://ww.speedymetals.com http://www.onlinemetals.com (I think I ordered from them) http://www.mcmaster.com/#standard-aluminum-rods/=m17g2q [Thank you to Sambudra for reminding me of M-C] McMaster-Carr sells the rod stock in 6ft lengths; I haven't checked if they have oversize shipping charges. They sell a lot more than just metals.

The above designs can make circularly polarized antennas. The 2nd set of elements is mounted at 90 degrees on the boom and is offset by ¼ wavelength (free space, I believe). It's fed in parallel with the 1st set. Since both antennas are 50 ohm designs, there are at least 2 solutions to deal with the parallel impedance:

1. Make a matching harness from coax of carefully cut and assembled lengths. 2. Purchase or build a power divider (both Directive Systems and M2 Antennas sell them), use IDENTICAL lengths of 50 ohm feedline to the antenna feedpoints.

Note - According to the Directive Systems website, the company has been sold and is in the process of moving to HAYMARKET VIRGINIA this week! http://www.directivesystems.com

RF Connection (therfc.com) in Gaithersubrg MD is an excellent local source of feedline, connectors, couplers, and associated parts. He can also make custom harnesses (those phasing lines). Attends all the local hamfests, so good way to save on shipping large amounts of coax across the country.

I did not discuss omnidirectional antennas. The quadrafiller helix and Lindenblad were mentioned at the meeting, and Pat had a Lindenblad on display. These antennas have a reputation as difficult to build. A passive Lidenblad design was published in QST (or maybe AMSAT journal) a few years ago and looks much easier to build. No idea how well they actually perform. The local RF noise level is high enough that higher-gain antennas may be a requirement around the DC area.

WB4APR has recommended for years using a low-moderate gain yagi elevated 15 degrees (some folks go for 20). Rotate in azimuth and don't worry about elevation - most passes are not close to overhead and the satellite spends very little time there. And when it is close, the shorter range and path loss make up for the loss in antenna gain (at least for smaller antennas - a very tight EME array is a different matter!)

Preamps - besides the wideband RX-only model AMSAT sells, there are several sources mentioned on Saturday. Advanced Receiver Research's product list is here http://www.advancedreceiver.com/page2.html

Hope this is of use to folks and look forward to the next meeting & meeting you on the air locally, and on the birds!

73 Steve, KS1G FM18 Herndon, VA