Making Choices Count when Selecting an RF Output Device.

You are either selecting to purchase a new portable appliance box radio or contemplating homebrewing same. So, how do you decide which homebrew topology or which appliance box to buy?

I am reminded of a management training class I took back in the dark ages, and the subject was how to select an employee based on a set of interview criteria. 

Our instructor started off by saying (at that time) hiring a new employee cost about $5000. There are the hidden costs of screening candidates, training, getting them up to speed on processes and the final integration into the work team. There was a loss of productivity and impact to the work group as team members pitched in to help integrate the new employee as a fully functioning team member. The message was to make your choices count. 

A hypothetical hiring of a new executive secretary was our test case. Each of us was asked our input and mine was that if it were my executive secretary then it was important to have that new hire understand how I make decisions and that giving a quick answer may not be the best answer. It was important to be honest and where a critical question was being asked to defer the answer to me and not guess.

Our flamboyant Marketing VP had a rather simplistic answer commensurate with his daily job. His answer he said was easy: Pick the best looking one with the biggest boobs. Works every time was his follow-on comment. In all honesty he wasn't the only one to think of that solution. Since "wokeness" has been deprecated I guess it is ok to say that today.

But that serves as a lesson that choices are frequently made without a thorough and sound evaluation. A choice the majority made a year ago is what we all live with today.

So, the decision has to involve performance and functionality. The bottom line is how will my signal be heard and that is all about the output stage!

For the appliance box you want a good output and not fall off the cliff beyond 20M. You also want to be able to copy strong signals and have a reasonable power draw on both transmit and receive. It also has to be stable and not drift.

There are some "iron men" in the ham ranks and maybe you are one. The approach you take is CW POTA with the use of old technology like vacuum tubes!

Let's assume you are homebrewing a simple one or two tube CW transmitter for your POTA Tool and looking back at the past there seemed to be a cycling between a 6L6 or 6DQ6B as found in homebrew examples or the Heathkit AT-1 (6L6) and DX-20 (6DQ6B) and even the DX-40 (6DQ6B on steroids).

So I asked copilot and the answer was the 6DQ6B based upon identical operating conditions (power supply, output network, operating frequency, class of operation). Although the 6L6 has a greater plate dissipation it is the peak current handling, as is the case with CW, that gives the 6DQ6B the edge with more power output.

OOOPS, I forgot most hams today only do solid state, so the question is really the choice between an IRF510 and a RD06HHF1. Copilot suggests that the RD06HHF1 is the better choice and explains that basically the IRF510 is not specifically designed for RF service and the RDo6HHF1 will give better performance with a greater efficiency.

I often hear that as a nation we should relax for things could be worse. Well, some see the Las Vegas odds are betting on worse. Winter is coming and many will face winter weather and the added cost of keeping warm and balancing between staying warm or eating. It is an either or... not both.

Them that know can make things go.

[BTW the 6DQ6B in other Heathkit transmitters uses a higher plate voltage and tighter Pi Network and that is how they soup it up to give more Pout.]

73's

Pete N6QW