Minutes of the 2003 Annual Meeting of the
Communications & Electronics Section of the NSS

Brian Pease, Secretary/Treasurer
August 4, 2003, 12:30 PM

Attendance:

33 people put their names on sign-in list either at the luncheon/business meeting or at the Program session. This compares with 37 last year. We now have a total of 58 "official" members. We had 13 known hams this year compared to 8 last year for a total of 15 hams. We had 2 people who did not list an email address each year for a total of 4. All of the officers were present.

Minutes from 2002:

The 2002 minutes were unanimously approved

Treasurerís Report:

Brian Pease (Sec/Treasurer) reported that we have $1525.07 in a Peopleís Bank money market passbook account opened in the Sectionís name on 10/15/02. The initial balance was $1562.00. There were 2 withdrawals; $21 to reimburse for back issues not received; and $22 for our NSS web space.

Old Business:

The Section is now operating under its new Constitution and Bylaws, which are posted on our website.

Brian said that he has not completed the project of contacting everyone who has in the past paid for paper copies of Speleonics not received.

New issues of Speleonics will be posted on our website in PDF format and not mailed to the members. Any requests for paper copies will be handled on a case-by-case basis.

Henry Schneiker said that he would continue to convert the backissues of Speleonics to PDF format for posting on our website.

Paul Jorgenson solicited articles for Speleonics. He needs more articles. He does have my Diver Comms article.

New Business:

Bart Rowlett said that he could provide server space for the Speleonics PDF files, which are already causing us to exceed the basic cost of our NSS hosted website. Before we need to pay again, Gary Bush will simply change the links to the Speleonics issues on our website and remove the files from the NSS server. This will save a lot of money in the long run, especially once all of the back issues are available. Henry and Bart made a motion to move the files, which passed unanimously.

Brian suggested that the section should have some sort of project to spark interest in the section. Bart suggested that we have a workshop at the Michigan Convention in 2004, including field demonstrations in a nearby mine. He volunteered to look into this. He would like to advertise the workshop on the Speleonics email list.

Henry Schneiker made a motion to have me check into the possibility of putting the sectionís money into a larger NSS fund to earn more interest than the current money market account. The motion passed 5 to 4. During the convention, I talked with Roger McClure, who manages ~2.2 million in funds for the National Speleological Foundation, including NSS funds. He said that could be done, but that $1500 is much too small to bother with.

Elections:

John Lyles declined to run for Executive Chair again. Bart Rowlett volunteered for the job. The other officers agreed to serve again. Since there was no opposition for any office, I was directed to cast a ballot to approve the slate. The officers who will serve until the 2004 convention meeting are: Bart Rowlett, Executive Chair; Brian Pease, Secretary/Treasurer Chair; Paul Jorgensen, Publications Chair; Gary Bush, Communications Chair.

 

 

Program Session:

Programs started at 2 PM.

Brian Pease presented his paper Thru-The-Earth 2-way Voice Communications with Cave Divers, which described how commercial acoustic voice communications equipment, used by divers to talk to the surface, was converted to communicate thru-the-earth. The equipment works on 32.768 kHz Upper Sideband. The conversion involved replacing the acoustic transducers with antennas and filter/matching networks. The diver unit has a 25-ft trailing wire antenna while a 1-meter square loop is used on the surface. It is intended to be used along with Brianís 3496 Hz real-time diver-tracking device, which allows the surface voice operator to remain more or less directly over the diver. It is not designed to work over long horizontal distances. The system was used to maintain continuous 2-way voice communication while divers explored 3 different Florida Spring systems at depths to 200 ft.

Brian also described his ongoing efforts to create a compact high-power 3496 Hz beacon, mainly for underwater use. His existing design, which was originally developed for dry caving, operates on 12 Volts about Ĺ Amp to allow the use of small batteries. He showed a 4-lb ferrite core antenna that uses a commercially available rod assembled from torroid cores. He also showed his breadboard class-E amplifier circuit that uses a series-tuned loop antenna with a separate energy storage capacitor and RF choke. This circuit is driven by a 50% duty cycle square wave rather than the 1/16 duty cycle of the current circuit, and has no large switching transients. When the new circuit is used with the new ferrite antenna, the magnetic moment is about 12 Amp-turns-meter squared with a 6-Volt battery. More work is needed before the circuit is ready for field-testing.

Henry Schneiker gave a history and update of the white LED Action Lights produced by his company, HDS Systems. His first model used 24 Nichia LEDs with a constant-voltage boost converter for the two highest settings, and a resistor for the lowest setting. This light used a single lithium D cell. The second model used 24 LEDs with a constant current boost regulator, but never made it into production due to the unavailability of an inductor in production quantity.

The new third model, Action Light 3, will be available in the fall. It uses a 1-Watt Lumileds white LED with a reflector to produce a better spot similar to a flashlight. The pattern is a 15-18 degree spot with >90 degree total sidelight beamwidth. The electronics will operate the LED at constant power with several settings, including overdrive, but will automatically dim when the battery gets weak, and start blinking before rechargeables are damaged (1V/cell for NiMH). Temperature is also sensed, with automatic power cutback to prevent overheating. The light will not be able to run continuously at full power without cutting back. Other features include an optional turn-on code to prevent accidental turn-on in your pack and a flashing "find-me" mode. The electronics will start up on 2V minimum, with 7V max. The housing is machined aluminum. The "flashlight" version runs on 2 AA cells (any type) or on two common "123" lithium cells which will run about twice as long as alkaline cells at about the same operating cost. The headlamp version will have a larger built-in battery pack.

He is thinking about a higher power version of the Action Light 3 using the 5 watt Lumileds LED, possibly early next year.

He also said that Lumileds is now sorting LEDs by color temperature as well as by voltage drop, etc, so it is possible to produce lamps that all produce the same light.

In the longer term, he would like to have a light that produces constant illumination at the cave surface, with more light where the walls are dark, and much less while looking at a sketchbook. He would also like automatic switching from a broad beam close up to a spot for distance.

Henry said that he might have a sale on lithium D cells, after first offering them to those who have purchased the original Action Lights in the past.

??????????????????? described his experimental LED headlamp, which uses an Altoids box to hold 4 AA cells, with 3 blue LEDs cemented together on a cable with an inline toggle switch. It will go caving soon.

David Larson showed his new Leica Disto rangefinder, which replaced his Disto Classic, which suffered a broken LCD screen. It is more weather resistant than the Classic it replaced, and uses 2 AA cells instead of 4 AAAs. There is a waterproof barrier between the battery pack and the rest of the unit. The new unit also has a bubble level for horizontal sighting, and a sighting telescope with a sighting ring for use in daylight. It also has a separate on/off switch and is smaller. It will fit in the same small padded Otter cellphone box as the old one. He explained that you want to deal directly with Disto-Atlanta rather than through a dealer, http://www.disto.com . Disto-Atlanta has a fixed-price repair policy of $209 plus the defective unit. Rather than repair the old Classic, they shipped David the new deluxe unit, which retails for $495! There is a stripped-down version available for $375 retail (without the telescope) that is all any caver needs. It might make sense to purchase an old one on Ebay (at a low price), and turn it in for repair if it didnít work properly!

 

Other Things:

Brian showed the PC boards that are available again for his 3496 Hz radiolocation gear for $25/set plus shipping. The double-sided epoxy boards with plated-thru holes were made by ExpressPC. We were able to display his website http://Radiolocation.tripod.com on the screen. Two were sold during the session.

Bart Rowlett has tried the 40-meter Ham band (7 MHz) for thru Ėthe-earth comms in a mine. He used ~2-Watts power and series-tuned 1 meter square loops with matching transformers. He had successful comms on 40 meters, but also on 2 meters (144 MHz), the latter as yet unexplained.

Ted Lappin said that his optical caver detector, described in last yearís minutes, has been successfully tested in a cave where it was installed in a narrow part of the entrance passage. The detector and the in-cave logbook differed by only 1 person after a considerable time.

He also said that Eagle Software http://www.cadsoft.de has a free limited version of their software available for doing schematics and laying out small boards. It includes a library of parts.

It was also mentioned that Proto Express has a cheap prototyping service.

An excellent L-C meter that can accurately read a wide range of values down the small uH and pF range for a reasonable price can be found at http://www.aade.com .

David Larson showed a nice backup light based on the common waterproof/tiltable 4-AA cell all-in-one headlamp. It uses the 1 Watt Lumileds LED, with a custom plastic focusing lens, which also used the original reflector, and simple resistor ballast. It gives a definite spot beam. His cost was $29.95 plus $3 shipping! The manufacturer said that they were raising the price to $39.95 so they could make a profit, but their website http://www.electrolumes.com ??????? still lists the cost at $29.95!

He also showed the Waterproof Inova 724 multi-LED light, which uses the 123 lithium cell. It has many different modes including red and white at various brightness settings, blinking and Morse code.

Henry Schneiker suggested that we look into what the optimum digital modulation scheme for cave radio might be. Ray Cole said that for a narrowband (31 Hz) typing-speed mode, PSK31 is probably the best, either normal DPSK or the QPSK mode with Forward Error Correction (FEC). The PSK31 signal can be generated with an efficient switching amplifier, which increases the bandwidth, but is no problem for us. Other FEC schemes could be used to reduce reception errors.

For truly error-free transmission, we would have to use a packet mode such as Pactor, which repeats each packet until it is received error-free.

Charles Cicciarella said that he has a need for a caver-hardened EKG (Holter) monitor that can handle shock, mud, and water. He is not aware of any such device.

 


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