EC Report for March 2016
This month’s schedule was rather relaxing; it was a clone of last month: 4 Monday Night EmComm Nets, 1 EmComm l meeting, 1 EmComm and Coffee, and two public service events, plus a Radio Workshop.
We are still holding Radio Workshops to assist our members and nonmembers alike solve problems and get assistance with anything Amateur Radio related. The last workshop was held April 12th. We worked on getting our laptops brought up to speed with the latest updates for FlDigi and some of the logging programs. Also Richard (KE6SHL) worked on the SATERN computers to get them ready for Field Day, which will be on the fourth full weekend in June. The computers do not want to talk to each other on the network at this time.
At our next workshop we will continue to work on the logging system as well as training our people to use the programs. So if you are interested in coming to the Citadel and working Field Day come and join us.
Our next workshop will be Tuesday May 3, 2016 at 18:30 Hr.
Public Service Calendar 2016
Most of you know we help CARP doing Public Service events. We use them for training; they help keep us sharp handling traffic and working under a net condition. I am including the calendar of events as it is now.
2016 Public Service Events:
- May 7 – Kirch Flat Ride
- September? – (date TBD)
If interested in volunteering at any of the above events, contact Rob Mavis
“Easy Digi Kit” interface project with Lew Roberts (KI6YWX) has been suspended. He has gathered the parts that were still on order and has handed them off to Dan Pruitt (AE6SX) for distribution. Contact Dan and you can pick up your parts. Lew is in the process of putting the final instructions on paper and will email them to us when he gets settled. At that point we can setup a build session at The Salvation Army Citadel and omplete the project.
Last month Greg (KJ6OUI) demonstrated what he called a Tiger Tail at the CARP meeting. The Tiger Tail is actually a counterpoise for the hand-held radios rubber duck antenna. It is just a bit of wire that hangs down and makes the antenna a vertical dipole, this is supposed to give you a 3 Db gain. I made one and it works well. I have barrowed some information off the internet that may help you understand how it works:
HT Antenna Modification for Increased Performance!
Edited and re-written from an article entitled
“Getting the Most from Your Hand-Held Transceiver”
C. Edward Harris, KE4SKY, AEC Fairfax ARES
Also see the HT performance mod by N6JSX at the end of this article for lots more ideas!
When limited to “barefoot” operation, with a “rubber duck”, HT antennas are not very efficient nor adequate for communications. They fail miserably as an effective radiator due to their design! They are nothing more than an extended dummy load acting as an antenna!
The following modification will help you to make the most of your HT by increasing the factory antenna’s efficiency and the cost is just a piece of wire!
FACTS ABOUT HT ANTENNAS
The National Bureau of Standards tests of Public Safety high band and amateur 2-meter antennas indicate that a “rubber duck” has -5db, “negative gain” compared to a quarter wave held at face level. In terms of effective radiated power (ERP), this means that a 5 watt HT with rubber duck, radiates only 1 watt. Operating an HT on your belt results in another -20db attenuation, reducing ERP to 50 milliwatts! That’s 1/20 of one watt!
UHF results are no better…
Due to the design of the factory installed HT antenna, you are effectively missing half of the antenna!
MODIFY THAT HT ANTENNA FOR BETTER RESULTS
Get ready to use that scrap of wire you have in your junk box!
A simple, inexpensive and effective method to improve a “rubber duck” antenna is by adding an external counterpoise or “tiger tail” thereby adding the other “half”.
It should be noted that if your HT is under warranty, the internal modification may void that warranty…you have been warned!
Adding the other missing “half”:
You can easily build one from a quarter-wave piece, (about 19.5″ on 2m, 11.5″ for 220 and 6.5″ for 440), of stranded insulated wire, crimped and soldered to a battery clip or use a small spring tension clip that will fit the BNC antenna connector with the wire attached to it. Use a clip or other connection that fits tightly but can be removed if needed. It must make both a good mechanical and electrical connection.
Another method would be to attach the end of the wire by soldering it to a grounded portion of the circuit board inside the HT, although this may not be practical with some models, or any point that is at ground potential on the HT such as the “ground” side of an external speaker/headphone jack, the BNC connector at the antenna, or the Negative side of the battery terminal. The preferred location is at the factory antenna base at the BNC connector. If you have some other type of metal antenna connector the same applies.
Many of the newer models don’t lend themselves to internal modifications easily. If the “rubber duck” antenna that came with the HT does not come off, then you will have to make the connection inside the HT to a grounded point. Extreme care must be taken to prevent shorting out other components!!!!!! Use insulated wire. You may have to drill a small hole in the case for the exit point of the wire and tie a knot inside to provide strain relief. Each installation will be different. Use your own judgment and at your own risk!
Always reinforce the soldered connection with heat shrink tubing or tape to resist flex and shorting to other components if possible.
When the counterpoise, (the other half of the antenna), is clamped to the outer collar of the BNC connector on your HT antenna, it helps to prevent RF from coupling with your body, so your completed HT antenna “system” acts much like a center-fed dipole instead of an end-fed dummy load!
You just built a directional antenna and did not know it!
In marginal conditions, extending the counterpoise horizontally and pointing your hand to steer the radiation pattern where you need it, produces a dramatically stronger signal than letting it “droop” towards the ground. Experiment with the angle of the counterpoise to get the best results. In effect, you are creating a form of “V” type center fed vertical dipole with a bit of gain compared to just the factory installed antenna.
If you want to buy another HT antenna, rather than add the counterpoise described in this article, then it is recommended that you shop around. Don’t be misled by the cheaper priced antennas. Buy from a reputable dealer that will answer your questions. Try to find an antenna with published gain figures compared to a dipole or 1/4 wave vertical. Don’t expect Yagi or similar performance….have fun and get better performance than you were!
The N6JSX HT Antenna Modification
Easy HT Improvements
by N6JSX 09/2013
We all know OEM (original equipment manufacturer) HT rubber-ducky antennas are a dismal compromise, at best, facetiously called “helical-dummy-loads”. There are a few ways to improve your HT’ing distance and experience. First and foremost consider buying an after-market antenna, like the Diamond SRH77CA-SMA or RC77CA-BNC, or make a more economical full 1/4 wave BNC Brass Whip and add a Tail. I found my 2m Brass Whip to work well on 70cm too.
Second, is to improve the antenna’s counterpoise; an HT body is a very poor counterpoise! A product I saw decades ago, called the “Tiger-Tail”, seemed to have been the answer to this problem but it was just too easy for HAMs to reproduce, killing its sales. The Tail is a 1/4 wave + 5 percent counterpoise wire hung from the HT antenna connector creating a mock 1/2 wave dipole. The trick in making an affective Tail is to insure a good tight fit to the HT connector. I duplicated the Tail by using ring terminals but a problem with ring terminals are those darn BNC posts. I overcame this by filing a small notch inside the ring to fit over one post, twist it around the BNC barrel and slip it over the other post. See photo below.
But with the advent of HT’s going to a SMA connector the BNC post issue disappears making this Tail a much simpler and far easier to attach.
Notice the new notches in the rings! Cool idea!
The Tiger-Tail is a 1/4 wave +5 percent length of wire hung from the HT connector.
Thomas & Betts ring-crimp-terminals:
SMA = 1/4 inch eye for 14-16AWG wire (blue) T&B #14RB-14X
BNC = 3/8 inch eye for 10-12 AWG wire (yellow) T&B #10RC-38X
Black 14-16AWG stranded wire is soldered to the ring.
(I do not crimp my tails but solder the tail wire to the ring terminal.) See Table “A” in the complete download pdf file link below for wire lengths per band.
The hardest part of using this Tail is getting the wire to hang straight. 73~~~ N6JSX
Editor note: You may need to get an adapter to go between your exiting ht antenna and the case connector of your ht. The type of adapter would depend on the type connector at the case of your ht and stock antenna bottom end.
We are now posting events and meetings on the calendar as well as posting articles on the home page. Check us out at fcemcomm.org.
Net Control Staff Needed
We are looking for volunteers to take a turn as net control on Monday nights. This is not a difficult task. We will provide the preamble and net roster. This is a great way to enhance your skills running a net for emergency situations. If you are interested, please contact Gary (KI6OYW) at 559-269-1340 or email firstname.lastname@example.org
Don’t forget the Monday Night EmComm Net at 19:30 hr. on the 147.15 MHz Pl 141.3. We have some good information and camaraderie. On the third Friday of the month there is the EmComm Coffee at YFC on Cedar south of Ashlan in Granite Park at 07:00hr. And last but not least the EmComm Meetings are held on the Fourth Thursday of month. The next meeting will be held May 26th at 1900 hr. at the Salvation Army Citadel at 1854 Fulton St., Fresno.
Best of 73’s
GLEN CAINE (N6HEW)
Fresno County RACES Officer
Fresno County ARES EC