Ham Help Desk

My latest ARRL renewal came with the usual free gift. This time I selected the “Emergency Communication Handbook.” I made a promise to the fifteen or so EmComm organizations that made an appearance during the Haiti tragedy to look at EmComm again with an open eye resulting in the ordering of this book.

Fair enough.

I was glad to order this book to see how EmComm might be done from a well organized perspective. I sat down one evening and opened it up. Here is the first sentence…
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Many hams add power hungry radios to their vehicle power systems. A preferred way to obtain the power is directly from the battery terminals.

I have been adding various gadgets to my Ford Taurus to bring battery power into my passenger area so I can get rid of my cigarette lighter plug for my 2m/440 radio.

Adding a wire to my original battery posts was a problem so I used replacement posts from the car audio market. This turned out to be a mistake.
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Does your transceiver power supply run a little too hot?

Mine sure does, but I found a simple solution that keeps things cool without a lot of whoosh noise.
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The new antenna for 2010 at this QTH will be the popular G3TXQ Broadbeam Hex Beam. What follows is a look at the DX Engineering Hex Hub.
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Regular readers of Ham Help Desk know my general lack of confidence in the volunteer emergency communications efforts.

Thankfully amateurs are documenting good examples of helpful communications on YouTube.

This one will make you proud…

http://www.youtube.com/watch?v=JqaKzIkyBug

Thank you operators. We really needed to hear this positive example.

I am preparing for the Virginia QSO Party and want to add an alternative 20 meter solution for my 43 foot vertical plus get better 15 and 10 meter coverage; I have been working plenty of 15 meter contacts with the 43 foot vertical so I know that band is open. Plus you never know if the sunspots might give us some 10 meter fun too

So…

I have been eagerly absorbing all there is to know about the hex beam style of HF antennas.

If you are the least bit interested in building or buying your own hex beam a must read web site is the G3TXQ study of the hex beam…
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Prayers go out to the folks in Haiti who are living in the aftermath of that earthquake.

Amateur Radio Operators seem to be geared up to provide some form of assistance.

The Salvation Army Team Emergency Radio Network (SATERN) organization is managing nets…

“Full Alert Level DELTA III for Haiti Earthquake Emergency. All nets active. 14.265 MHz Primary Daytime. 7265 and 3977.7 kHz evening and night.”

We can only hope and pray these good intentions result in useful deeds accomplished.

We should all listen in on the net frequencies above to see for ourselves how amateur radio may help the situation. I will be tuning in.

Meanwhile, I will also be sending some cash to relief organizations who are clearly going to need some resources quick.

Continuing our discussion of Single Operator Two Radio (SO2R) station design brings us to the topic of antenna routing.

Previously we discussed SO2R gear arrangements which have two antennas connected to two radios, one antenna for each radio.

If all you have are two antennas for your two radios then there really is no point in putting in a matrix to allow either antenna to route to either radio.

However, let’s assume you do have a pressing need to multiplex the antennas and use this as an evolutionary step in our series of posts.
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Continuing our discussion about SO2R technical discussion brings a focus to the concerns of cross band interference between your two radios.

Having one transmitter spewing energy at full power while trying to listen on the other radio’s receiver is daunting. Unless you have an Elecraft K3, your radio’s ability to perform adequate band pass filtering is probably not sufficient for the 2nd and 3rd harmonics from the transmitter resulting in severe de-sense of the receiver signal chain.

Orienting the antennas to minimize their interaction will help. If you are lucky you may well achieve good isolation between at least some of the cross band combinations.

To help radios avoid this interaction, a few manufacturers have products which provide excellent band pass filtering.
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In my many years as a ham, I somehow missed the whole topic of the Single Operator Two Radio (SO2R) technique for amateur radio contesting. I pulled up a few YouTube videos showcasing the great operators using this technique and convinced myself SO2R is interesting enough to research.

The ability to add a bit more excitement to those late contest constant CQs with an additional radio looking for other contacts, especially new multipliers, is inviting.

There are many resources on the Internet about why to do SO2R. I invite the reader to explore these resources. We will review a couple key concepts on why to do SO2R and then dig in deep to some technical approaches.
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