A Message from Walter KA4KXX -- On Bias Setting, the Joys of Al Fresco Rigs, Lawn--Sign Radio Base

 

Dear Dean KK4DAS:

...

3) Note that a rule of thumb I have used successfully in adjusting RF Power MOSFET

bias is to increase the voltage in 100mV steps, measuring the RF Output Power 

each time, and stop as soon as you start to see significantly diminishing returns.

4)  Although I did mention a plexiglass cover (the idea was from the Electroluminescent 

Receiver in photo below) in a 2017 entry I made on my QRZ page, I never built one, because I  have found a cover of any kind to be unnecessary and even detrimental based on operating portable outdoors in a public park with my rigs once every month for 10 years.  

From these experiences I have enjoyed the wonderment and respect I have received 

from fellow hams as well as passersby who have universally admired my creations. 

If the truth were known, my homebrew Alfresco transceivers might be the most 

photographed radios in all of ham history!  

Therefore, the only box I bring to my ham radio outings is for my lunch, because nobody

really gets excited about photographing just another box.

However, I do use plastic carrying cases per the photo for any rigs I carry 

in the trunk of my car.  If it rains, the top of the carrying case can be used as a 

temporary cover, so I know contacts can be made in a light rain because I have done it.

[Of course, credit card hams are not capable of operating portable even on a cloudy day

or their $$$$ radios would suffer from high humidity disease and need to be sent 

back to the offshore factory for $$$ refurbishment!]

5)  Lastly I will mention that I have never used any type of wood for a radio base because

wood is too heavy (and 1/8 inch aircraft plywood is too expensive), and the strength of

wood is not necessary to support a measly 5 pounds of electronic parts. 

Instead, per the photo, I have used Coroplast yard sign material (usually two sheets

with the channels crosswise then taped or glued together with the top covered using copper tape) common school science fair poster board, or good heavy duty cardboard such as from a TV set box.

Either light or heavy-duty double-sided tape and 4-40 or 6-32 nuts, bolts, and washers (sometimes oversized) are used to hold everything on board.  Occasionally L brackets, standoffs, hot glue, and foam or balsa wood support pieces are also utilized. 

In summary, keep up your good work as the new star on the Soldersmoke Podcast and 

please be certain Bill pays you as much as Pete.

72,

Walter

KA4KXX