Details

Written by: G Wolfe - KI0KK

Published: 23 February 2016

I have built most of my transmitting equipment since getting into ham radio in high school. Several things influenced me to build this amplifier. My interests are in HF and 6M operation and combining those bands into a common/single amplifier as are these bands so combined in modern transceivers seemed like a logical extension of the concept. This is not common in commercial amplifiers. This amplifier represents an hundred years of developments and refinements in high power amplifying equipment and was developed with the ARRL Centennial celebration in mind. It has some features that you just don't find in commercial amplifiers today.

The use of high power on the 6M band while living in a compact suburban setting has been practically unthinkable until recent years with the advent of underground utilities, and now, particularly with the removal of VHF TV broadcast to UHF HDTV.

The basic design begins with the choice of a triode in the usual grounded grid circuit. The several good reasons for this choice are that it is simple, it does not require grid supplies and protection circuitry, linearity is excellent, and input power is not wasted in a dummy load as is required at the input to the grid in grounded cathode operation. In fact, with the grounded grid amplifier the drive power shows up in the output.

Beyond these basics, features are added at the input and output of the amplifier to make it more flexible in operation. There are separate inputs for HF and VHF. Likewise there are separate outputs. Several transceivers can be connected - or one transceiver with two outputs - and separate outputs are provided to the antennas The bandswitch position determines which connections are used when the amplifier is keyed. Two TX key lines into the amplifier are provided for.

The amplifier has some novel switching to accommodate the combination of HF and VHF functions. It has parasitic stabilization as described in my QEX article of September 2003. Geared drives and dials provide means for accurate logging and quick resetting the amplifier when moving between bands. A fast overcurrent shutdown circuit provides protection to the amplifier and power supply. A warm-up timer protects the tube from premature operation.

Details

Written by: Jim Cessna - AC0KN

Published: 11 October 2017

Our September 16, 2016 the Tech Demo presentation waas Setting up an Amateur Radio Station by George McCarville WB0CNK. George will give all of us, and especially the newly minted ham, an understanding of what it take to successfully create “the Shack.”

The components necessary in bringing the operating position to life; power, grounding, the desk, lighting, temp, and out of the family traffic mainstream. And, the components necessary in bringing the radio-world to life; antenna, feedline, tuner, rig, mic, earphones. Last, but not least, a comfortable chair.

In addition to watching our presentation, the new Hams will also want to pick up Bob Heil’s book titled, “Heil Ham Radio Handbook.” It gives, in plain simple language, everything a new Ham needs to know about setting up a station. It’s well worth the price of $15 at Associated Radio.

Details

Written by: G Wolfe - KI0KK

Published: 07 October 2017

Kit Building Expert Joe Eisenberg K0NEB presents at SFTARC Tech Night - 1/20/2017

Joe Eisenberg made the trip from Lincoln to present "Kit Building" for the SFTARC Tech Night meeting. Joe is well known in the local Kansas City/Lincoln area and around the world as being the "Cat in the Hat" person at ham events. He is also the Kit Building editor for CQ magazine.

From Joe's QRZ page he explains his adventure in ham radio and the electronics hobby.

"I have been licensed since 1969 and am currently the Kit Building Editor for CQ Magazine. There is nothing better than sitting down at the bench with parts sorted and ready to be stuffed into a circuit board! My Elmer was Leo Meyerson, W0GFQ, who started me in radio at an early age in Omaha, Nebraska. I am available to speak on Kit Building for your hamfests, conventions and meetings. I can also put on group kit building events as well. Building a kit as a group can be a fun and educational experience. See you on the air!"

During his presentation Joe mentioned a number of companies that you can get kits from and here are some of the ones highlighted:

Nightfire Kits (vakits.com)
QRPme.com
Velleman
Elenco
4sqrp.com
QRPkits.com
Elecraft
qrpguys.com
hamgadgets.com
banggood.com

There are many good suppliers so get that soldering iron going and try some of them. Some of the most interesting kits include CW keyers, component tester (R,L,C) and low speed scope. Some of the kits are based on the Arduino processor and others aren't.

Some of the kit building equipment that was suggested is a good soldering iron preferably one that you can control the tip temperature. Xtronicusa.com is a local company in Lincoln that has a good one. The right kind of solder is important and he mentioned 63/37 0.031 or 0.025" rosin core, no clean as a preferred one that he uses. If you are mounting surface mount parts you might use solder paste and cure it with hot air or a heat plate that has temperature control so its not too hot for the parts. Also to store kits or parts Joe mentioned the Plano 1354 Tackle/Tool Box is available from many stores and in a variety of colors. It has several drawers to hold parts or boards.

Joe finished the presentation with some of his video creations of picture taken at various ham events and then set to music. The final days of Hara Arena in Dayton which has been the home for the Dayton Hamvention event for more than 50 years is changing location and there was a nice video remembering the arena location.

Many thanks to Joe for a fine presentation and sharing of his knowledge.

Details

Written by: G Wolfe - KI0KK

Published: 07 October 2017

For those who have struggled with RFI at the home station here is my solution to the interference.

Over the past few years I have had an annoying set of evenly spaced tones that interfered with my 2M, 6M and UHF reception at home. The noise could be heard for about 100 ft from the house and then dropped off quickly. RF suppressors on the cables did not reduce the noise source.

My final solution proved to be replacing my 4 port Ethernet switch which was located near my radios. The low cost plastic case switch (LinkSys 10/100 5 port SW) was replaced with a another low cost switch with a metal case (Netgear FS10). I still have some interference on 6M but I also have another Ethernet switch downstairs that may be an additional source for 6M interference.