Newsletter Field Day Edition 2017, The Radiogram, page 2 - Official eNews of the Wireless Society of Southern Maine

WSSM at the South Portland Fire Department Open House

South Portland, ME
by Tim Watson, KB1HNZ

On Saturday, October 14th, WSSM members, including Rory McEwen KB1PLY, Charlie Shepard W1CPS, and Tim Watson KB1HNZ, set up a display table and a portable HF station during the annual South Portland Fire Department Open House.

The event, which took place at the Western Avenue Fire Station, featured fire trucks on display, including a fully extended ladder unit, an ambulance, demonstrations of the jaws of life, food, activities, and more.

The Cumberland County Emergency Management Agency (CCEMA), and several local businesses also had displays. There were lots of kids having fun, climbing in the trucks, and the many families were enjoying the beautiful fall day.

The WSSM team setup an HF radio, using a BuddiPole antenna, for on-air activities, and made a good demonstration of the hobby for the curious onlookers. There were also some other radios on display, including an Icom IC706MKIIG, which is used during SOTA and other portable operations, as well as some of the other equipment used, including SLA batteries of various sizes. Intro to ham radio handouts and club information was also available.

The highlights of the day occurred when mascots from two of the local sports teams stopped by to play a little radio.

WS1SM #1 in Maine for 2017 Field Day
ARRL Field Day

by Tim Watson, KB1HNZ

SCARBOROUGH, ME - The 2017 Field Day results are in, and WS1SM took first in Maine for the fourth consecutive year! Congratulations to everyone on our team for a job well done!

WS1EC Participates in Maine and New Hampshire Simulated Emergency Tests
CCEMA Bunker, Windham, ME
by Tim Watson, KB1HNZ

WINDHAM, ME - On Saturday, October 28th, the WS1EC and WX1GYX teams took part in the Maine Simulated Emergency Test (SET), and on the following Saturday, they were at it again, for the New Hampshire SET.

The scenario for the Maine SET was an ice storm similar to the 1998 Ice Storm. Among the concerns would be power outages, loss of land line and cell phone communications, and loss of repeaters. Our plan, in addition to communicating with the state EOC via HF, included establishing communications between the CCEMA Bunker and all of the FEMA/Red Cross shelters in Cumberland County, and relaying weather reports from each location to NWS Gray. At the end of the day we were successful in contacting each of the shelters, State EOC, NWS, and the Red Cross chapter in Portland.

The reason for such an aggressive plan was to identify which shelter locations would require something more than an HT to reliably contact the CCEMA Bunker during a real activation. During the exercise, we were able to identify three locations that need more than 25 watts and an antenna with gain, to reliably communicate.

Eric Emery KC1HJK operates from NWS Gray during the New Hampshire SET

For the New Hampshire SET, on November 4th, WS1EC played a slightly lesser role, but WX1GYX at NWS Gray was very involved, maintaining a presence on HF, and receiving and relaying messages and weather reports via Winlink for much of the exercise. The New Hampshire SET was based on a hurricane, similar to the 1938 storm, and many of the traffic received was true to the theme, and included hurricane-related damageand wind reports.

The SETs were used primarily as a training exercise for participants, as they offered good practice of sending and receiving formal messages, using NBEMS and Winlink, and providing familiarity with the ham stations at both NWS Gray and the CCEMA Bunker.

Multiband Antenna Traps

Ham Radio Projects
by Frank Kamp, K5DKZ

These devices are called Traps, but they are actually more like frequency sensitive switches. They are parallel resonant, high Q, tuned circuits which provide a very high impedance at their frequency of resonance.

An example of their use can best explain their operation. Take, for example an 80/40 meter trap dipole. The center section of this antenna is a normal 40 meter dipole of conventional length. One end of each trap is connected to the ends of this dipole. The other end of the trap is connected to additional lengths of wire (typically 21 feet) to allow the complete antenna to resonate on 80 meters.

The resonant frequency of the traps should be the frequency you wish to use in the 40 meter band. The additional 21 foot lengths of wire should be adjusted so that the antenna resonates at your choice of frequency for the 80 meter band. Note that each leg of the dipole is only a little over 50 feet long making it about 20 percent shorter than a full sized 80 meter dipole.

On 40 meters, the traps have a very high impedance, effectively disconnecting the two 21 foot lengths of wire needed for 80. On 80 meters, the traps act as loading coils permitting the antenna to be shorter than a conventional 80 meter dipole.

The 80/40 meter trap dipole example will work on all bands (80, 40, 20, 15, and 10), but will work most efficiently on 80 and 40. If this sounds to good to be true (shorter antenna with multiple band performance), there are some compromises to be considered. On 80 meters even a full sized dipole cannot provide an SWR of less than 2:1 across the entire band. On 40 meters, we have the same problem to a lesser extent. A trap dipole exhibits an even narrower bandwidth than a full sized antenna. Still, if your use of these bands can be served with a 200khz to 250khz bandwidth, a trap dipole can be a good solution.

Another compromise of a trap dipole is the requirement for the traps. Conventional traps are constructed of high voltage transmitting type capacitors and heavy B&W miniductor stock. They are not particularly difficult to make, but the parts are expensive and they are subject to drift in frequency when exposed to adverse weather conditions. However, there is a method of building traps that is very inexpensive, can withstand full legal power limits, and is relatively stable under even the most adverse weather conditions.

The 1988 ARRL Handbook alludes to this method of trap construction but does not give any specific data. I have built a set of traps using this method and would like to share the information with anyone interested in homebrewing a trap dipole.

My traps were built to be used in an 80/40 meter dipole as in the example given. The same method of construction can be used for other frequencies with the turns reduced to cover the higher frequencies.

The method of construction alluded to in the handbook uses a coil of coax to form the tuned circuit of the trap. The shield of the coax forms the coil. The center conductor of the coax on one end of this coil is connected to the shield at the opposite end. This allows the capacitance between the center conductor and the shield to act as the capacitance that resonates the assembly.

Aside from the low cost, this method reduces resistive losses in the coils to an absolute minimum. The shield portion of the RG62AU coax I used is electrically equivalent to using quarter inch copper tubing. The capacitor formed by this assembly is capable of withstanding several thousand volts of RF allowing the use of high power on 40 meters. Although I used RG62AU, RG58 or RG59 would serve as well. RG8 may also be usable, but it's stiffness might require a larger diameter coil form and may result in a heavier assembly.

My traps were wound on two 6.5 inch long pieces of schedule 40 PVC pipe 1.25 inches O.D. I found that 20.5 turns would resonate at 7.285 mhz, my chosen 40 meter frequency.

Each end of the PVC pipe was prepared by drilling two opposing holes in it about 0.25 inches in from each end. Solid number 12 copper wire was inserted through these holes and bent around thePVC to form a loop with the wire inside the pipe. These terminations were used to attach the antenna wire as well as provide a tie point for the coil of coax.

Each trap will require 80.5 inches (6.7 feet) of coax. Start with seven feet and trim it up to the frequency you want in the 40 meter band. Each length of coax is prepared by stripping about 2 inches of outer insulation from each end. The shield is unbraided and twisted at each end. The center conductor at one end is stripped of insulation for a length of about 1 inch.

Start your winding by drilling a hole just large enough to pass the coax through the PVC pipe. This hole should be located about 0.5 inches in from the end of the pipe. A close fit of thecoax through this hole will help secure the winding until the holes are filled with epoxy.

Insert the end of the coax that has the center conductor stripped through the hole and wrap the shield of the coax around the number 12 wire at this end. Solder the shield to the wire. Use a 50 to 100 watt iron and do it quickly so that the heat will not travel up the braid to melt the insulation to the center conductor. Let the soldered connection cool completely before starting the winding.

Now wind about 22 turns of coax onto the pipe. I estimate that 22 turns will resonate at the low end of the 40 meter band. If you are interested in the higher portion of the band, stop at 21 turns. Remember, you can always cut off coax to raise the frequency, but if you get too high in frequency, your best bet is to start over with a new length of coax.

Mark the pipe at the end of the winding and drill another hole in the pipe at this location to pass the coax. The close fit of the coax into this hole will keep the windings in place.

Prepare a length of wire. Hookup wire #20, #18, #12, is adequate. Cut the wire to 6.5 inches in length. Strip off 1.5 inches of insulation from each end of the wire. Solder one end of the wire to the center conductor of the coax at the end where you started your winding. Pass the wire down through the center of the pipe and twist it's bare end to the coax braid where you finished the winding.

Pull the hookup wire through the center of the pipe so that the soldered bare end of the coax center conductor is pulled down away from the soldered coaxial braid at the end of the coil where you started the winding.

Now you will need a grid dip meter to check the resonant frequency of the trap. Don't rely on the grid dip meter's calibration. Use a frequency counter or your communications receiver to verify the frequency. (My homebrew grid dip meter doesn't even have a calibrated dial. Only it's coils are marked as to frequency range covered.) I found that by inserting the coil of the grid dip meter about 1/8th inch into the end of the PVC pipe an easily recognizable dip could be obtained. For your final frequency check you may want to reduce the coupling between the dip meter's coil and the trap. In my case I found a 50khz shift in frequency as I reduced the coupling. The dip obtained at the reduced coupling is the more accurate one. Also, make certain that your dip meter is on the right frequency range and that you have the receiver tuned to the fundamental frequency and not a harmonic. My grid dip meter had enough output to register an S9 +20db at the receiver with the receiver's antenna disconnected. Use the receiver's S-meter to zero in on the dip meter's output when determining frequency or zero beat as you would on an AM signal.

Your first frequency measurement should fall somewhere in the low end of the 40 meter band. If it doesn't, and if you did get a dip on the meter, you may be too low in frequency. If so, cut off about two inches from your winding and try again. In my case, I found that a one inch reduction in coax length resulted in an approximate 50khz frequency shift.

As you cut more and more coax from the winding, you will need to drill additional holes in the PVC for proper termination of the winding. The PVC is easily drilled. This cut-and-try method requires a little patience, but it is very repeatable. My first trap took me two hours to build. The second was done in 15 minutes.

The coax winding is tight and close spaced onto the PVC form. After your final frequency check, trim the finished end of the coax winding and solder the braid and the short length of hookup wire to the #12 copper wire termination that you installed in the pipe at that end.

That completes the trap. Now all you have to do is build another one and solder the antenna wires to the copper wire terminations at each end of each trap.

Note that the number of turns required will only hold true for RG62AU coax. Other types of coax may well be used, but the turns required may vary.

Initially, I was a little concerned as to whether or not the end terminations I used would hold the strain of supporting the traps. The terminations have held through the weather conditions we have experienced in the last two months. However, I would not recommend using anything less than schedule 40 PVC pipe.

First published in the "Ham Distribution Net BBS" in December 1993.

Introduction to D-STAR
Digital Voice and Data
by Tim Watson, KB1HNZ

For December's meeting topic, Eric Emery KC1HJK, will make an Introduction to D-STAR presentation. As a preview, we'll take a closer look at what D-STAR is all about.

D-STAR, which stands for Digital Smart Technologies for Amateur Radio, is a digital voice and data protocol designed for amateur radio. It was developed in the late 1990's by the Japan Amateur Radio League (JARL) in an effort to find new ways to bring digital technology to amateur radio. The original study was funded by Japan's Ministry of Posts and Telecommunications, and administered by the JARL.

Digital Voice (DV) and Digital Data (DD)

D-STAR involves the transfer of both voice and data via digital encoding over the 2 m (VHF), 70 cm (UHF), and 23 cm (1.2 GHz) amateur radio bands. There is also an interlinking radio system for creating links between systems in a local area on 10 GHz, which allows emergency communications oriented networks to continue to link in the event of internet access failure or overload.

The Digital Voice portion of D-STAR uses Advanced Multi-Band Excitation (AMBE) to compress the voice for transmission. AMBE is implemented in the proprietary AMBE-2000 or AMBE-2020 chips which are found within every D-STAR radio. Voice audio is encoded as a 3600 bit/s data stream, with 1200 bit/s FEC, leaving 1200 bit/s for an additional data "path" between radios utilizing DV mode. On air bit rates for DV mode are 4800 bit/s over the 2 m, 70 cm and 23 cm bands. In addition to digital voice mode (DV), a Digital Data (DD) mode can be sent at 128 kbit/s only on the 23 cm band. A higher-rate data protocol, currently believed to be much like ATM, is used in the 10 GHz "link" radios for site-to-site links.

There are only a handful of D-STAR repeaters in Maine, and some areas have no coverage at all, but that doesn't mean that you can't get on the air and have fun with the mode. If you have a D-STAR capable radio and no repeater nearby, you can make use of a D-STAR hotspot, such as a D-VAP dongle, or SharkRF, and if you have no radio at all, you could use a DV Dongle to access the network.

For more information about D-STAR, including links to additional resources, click here to visit our Intro to D-STAR page.

DX News
October 18 - March 20
by Tim Watson, KB1HNZ

The Summer seemed a little quiet as far as DXpeditions go, with a few interesting ones such as Greenland OX3LX, in late August and Fernando de Noronha PY0F in September, but it began to pick up in October, with several announced DXPeditions, including the HD8M activation of the Galapagos, the much anticipated 3C0L DXxpedition to Annobon Island, and OJ0JR (Market Reef). Some current DXPeditions include J5T (Guinea Bissau), which is about to end on the 26th, and the TO2SP expedition to St. Barthelemy, which is about to end on the 30th.

For more information about upcoming announced DXpeditions, click here for the latest 425 DX News, by Mauro Pregliasco I1JQJ.

Upcoming DXpeditions

10/18 - 11/30
11/02 - 12/01
11/04 - 11/28
11/07 - 12/04
11/13 - 11/26
11/15 - 11/30
11/16 - 11/30
11/23 - 12/12
12/03 - 12/08
12/15 - 12/17
01/01 - 01/31
01/10 - 01/23
01/13 - 01/21
01/21 - 01/27
01/25 - 03/14
02/01 - 02/07
02/23 - 03/16
03/02 - 03/15
03/02 - 03/19
03/10 - 03/17
03/10 - 03/20

H44MS
3XY3D
3B8HC
5H3DX
J5T
9X2AW
TO2SP
3B9HA
XW4ZW
6V1A
RI50ANO
6Y6J
ZF2PG
J88PI
3Y0Z
P29VXG
3D2EU
XR0TD
YJ0GB
TX5X
9M0W

Solomon Islands
Guinea
Mauritius
Tanzania
Guinea Bissau
Rwanda
St. Barthelemy
Rodrigues I
Laos
Senegal
South Shetland Is
Jamaica
Cayman Is
St. Vincent
Bouvet I
Papua New Guinea
Rotuma
Easter I
Vanuatu
French Polynesia
Spratly Is

By DL2GAC, from Malaita I (IOTA OC-047); 160-6m; SSB
By F5OZC, from Kassa I (IOTA AF-051); 80-10m; mainly CW
By HB9ARY, from Pointe aux Sables; 80, 20, 17, 15, 12m; focus on 80m CW
By NK8O; 40-6m; mainly CW; QSL via NK8O direct and eQSL
By I1HJT and others; fm Bubaque I (IOTA AF-020); 160-10m; CW, SSB
By DF2QO, from Kigali; CW, SSB, RTTY, FT8; QSL also OK via M0OXO
By SP3CYY and others; 160-10m; CW, SSB, RTTY
By G0CKV; focus on low bands; holiday style expedition
By K4ZW; focus on low bands; QSL also OK via K1SE
By 6W7JX, and others, from Goree I (IOTA AF-045); HF; CW, SSB
By UA1OJL, from Belligshaisen Station; HF; QSL also OK via RN1ON
By JA3HJI and others; 160-6m; CW, SSB and digital
By K8PGL, from Grand Cayman I (IOTA NA-016); 160-10m; SSB
By GW4DVB, from Palm I (IOTA NA-025), FK92ho; 40-6m; mainly SSB
By Ey8MM and others; 160-10m; tentative dates
By JA1XGI, from Rabual, New Britain I (IOTA OC-008); 160-30m; CW
By 3D2AG and others; 160-10m; CW, SSB, and digital
By DH8WR and others; 160-10m; CW, SSB, RTTY, FT8
By G7VJR, from Epule, Efate I (IOTA OC-035); HF; multiple modes
By W0ZRJ, from Tahiti (IOTA OC-046); mainly CW, some SSB and JT9
By YT1AD and others; 160-6m; CW, SSB, and digital

SKYWARN Recognition Day is December 2nd

2017 SKYWARN Recognition Day is December 2nd, from 0000-2400 UTC.

SKYWARN Recognition Day was developed in 1999 by the National Weather Service and the American Radio Relay League. It celebrates the contributions that volunteer SKYWARN radio operators make to the National Weather Service. During the day, SKYWARN radio operators visit NWS offices and contact other radio operators across the world.

For more information about SRD, click here.

QSL Corner

In this issue, we'll take a look at QSL's from the 2016 H44GC DXpedition to the Solomon Islands, ET3AA from Addis Ababa, Ethiopia, and the 2015 C37N DXpedition to the Principality of Andorra.

If you received an interesting QSL lately that you'd like to show off, please send a digital image to kb1hnz@yahoo.com, and we'll highlight it in an upcoming issue!

	H44GC - for multiple QSOs with K1GJY: 09/30/2016 0209 UTC 17m SSB 59 09/29/2016 2316 UTC 15m SSB 59
	ET3AA - for a QSO with K1GJY: 12/01/2016 1603 UTC 15m SSB 59
	C37N - for multiple QSOs with K1GJY: 10/25/2015 1933 UTC 20m SSB 59 10/24/2015 2004 UTC 15m SSB 59