SnappyPortableDipoleAntenna

“Snappy”…A Band Switching Portable Dipole  by Clair Cessna, K6LG

Since I enjoy outdoor operating activities, QRP events, Field Day, and others, I needed an antenna which could be thrown in a backpack,  quickly deployed, and easily used on several HF bands.  A segmented dipole was put together, using bullet connector “switches” across insulators to change bands… reducing the necessity of using an antenna tuner.

The antenna is usually configured as an inverted Vee supported in the center at about 16 feet, using a SD-20, 20 foot, telescoping, fishing pole. Alternatively, it can be suspended from a tree branch. The ends are usually near ground level or supported by bushes, trees, rocks, etc.

“Band switching” for the five bands is simply a matter of shorting across selected insulators to adjust the antenna, using the bullet connector shorters (switches.) Since the antenna is usually relatively close to the ground, or can be easily lowered from the ends to clothesline height, one can rapidly walk along, and change the antenna length.

Materials needed for construction: Forty feet of #16 or #22 plastic jacketed speaker wire (Lowes or Home Depot); small sheet of one-eighth inch thick Lucite or other plastic for insulators, ten bullet or spade connectors (Radio Shack), piece of quarter inch thick plastic, two inches square, SO-239 connector.

Cut to the lengths shown below, but add 3 inches to each for connecting through the insulators. Since you will be unzipping the speaker wire later, both sides of the antenna will be the same for each segment. Strip an inch and a half off the ends of each segment and insert the insulators. Solder short leads to the male and female parts of the bullet connectors and solder in place across each insulator, leaving enough slack so they can be easily plugged in or unplugged. (I prefer the bullet connectors since they are easier for my fingers to manipulate.)

Measurements beginning from the center (middle of insulator to middle of next 2” insulator) should be 12‘ 7“, 3‘ 6“, 6‘ 0“,  9‘ 1“, 1‘ 7“. (Remember to add 3″ to each of these lengths for attaching to insulators and bullet connectors.) These measurements are for 17, 20, 30, 40/15M, and cut for the low end of these bands. Notice that for 15M the entire antenna length is used. The 1′ 6” end section is used on 40/15M to facilitate matches on those bands depending on whether the end of the dipole is staked to the ground or elevated in a tree. The antenna is fed with RG-58 coax. No balun is used.

 Generally these measurements provide a satisfactory match.  Of course in the field, antenna height, configuration, and environment may sometimes be different, so, when possible, I carry an MFJ Tiny Travel Tuner to deal with any variations. 

The “Snappy” is a snap to build, and to set up in the field. For band changes, just snap or unsnap the connectors!

de Clair Cessna K6LG 8-22-2011

T-Hunt Attenuator

This schematic was drawn up by Phil – KJ6KE

An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. (From Wikipedia)

This device is used during a t-hunt when the fox transmitter is close by and all the radio can hear from all angles is the beacon.  The signal is diminished to a point where the directional antenna can be used again to find the hidden transmitter.

Field Day 2020

Riverside County Amateur Radio Association Field Day 2020

Here is the picture slideshow from Field Day 2020

  • RCARA Members and visitors pause for a pic along side a VW Bus
  • Moving the supplies and equipment from the parking lot
  • Juan KM6CFH packing in his portable rig
  • A new battery technology was introduced at FD this year.
  • For 2020, there was no line power in out location for even non-radio gear. Battery and solar powered the show this year!
  • Power management in a box with power pole connectors and a built in volt meter.
  • Rick KK6CTT - large battery box and solar panels included an inverter which provided line power for laptops and HT & Cellphone charging.
  • John W7RSO operating under an EZ-UP, socially distanced but racking up the QSO numbers
  • John W7RSO came wearing his FD 2020 hat.
  • APRS Map showing that Alan KM6KPW is at the park
  • An APRS controller with GPS and simple telemetry. This module uses a Baofeng UV-5R type of HT for it's transmitter and receiver.
  • An APRS controller with GPS and simple telemetry. This module uses a Baofeng UV-5R type of HT for it's transmitter and receiver.
  • Steven W7DTH brought out his shelter and portable rig
  • Steven W7DTH displays a clean power distribution module. LED indicators and fuses are a great features.
  • Field Day is great to see what others are using in their portable and mobile rigs
  • Just waiting for the 11:00 AM whistle to start making contacts
  • Our newest Extra class operator making contacts. Congrats to Juan AJ6PH !!
  • Juan finding the balance between sun for the solar panel and shade for the operator
  • Alan KM6KPW ran 10M FT8 on 15 watts QRP power.
  • Alan KM6KPW on the Xiegu working FT8 on 10 meters. The band was like a revolving door
  • John W7RSO brought out the hitch mounted extending mast antenna.
  • A close up of John W7RSO's trailer hitch mast mount
  • Alan KM6KPW brought out a 10 meter dipole that fits into the go bag.
  • Rails to save the face and rear connectors of his mobile transceiver. Lite and solid, nice!
  • All gathered around the picnic table
  • Both the US flag and our ARRL FD mascot on display in front of the pavillion


Updated Q&A from the ARRL about club totals – (PDF or Original Article)

Members operating from home, please remember to include “RIVERSIDE COUNTY AMATEUR RADIO ASSOCIATION” (NOT “RCARA” or “W6TJ”) on your submission.  See the ARRL COVID-19 2020 Waver document for more information

 

 

We may have to be away from each other but that does not mean we have to be out of reach!

Stay Safe and keep making contacts!