[NJARC] TRF radio?

[Aaron Hunter]

Dave

TRF stands for "tuned radio frequency".  In other words, the incoming 
radio signal is tuned and amplifed through one or more stages and then 
detected for audio.  It does not have the mixer - oscillator stage for 
converting the signal to a desired radio frequency for better 
selectivity.  A crystal set is a simple TRF radio.

TRF sets are best for local stations as weaker adjacent stations are 
drowned out by the stronger ones.  This circuitry was used mostly by the 
early (20's) battery sets because of cost and battery drain.  Superhet 
sets required a license fee, more tubes and more battery drain . Plus 
TRF sets were easier to build..  When RCA bought Victor in 1929, the 
first sets put out in the Victor name were TRF sets.  I haven't figured 
this out since RCA held the patent and these were not inexpensive 
radios.  Possibly an earlier Victor design pushed into production?

TRF sets were built throughout the tube era because of cost.  Without 
knowing what you have, I suspect your Airline is a set from the 30's or 
40's, possibly know as a "farm" radio, used where electricy had not 
reached their area.  These sets used less power than their earlier 
counterparts of the 20's   You can always build or buy a battery 
eliminator and enjoy the set without worrying about batteries. 

Some sets required a 6 volt car battery.  These batteries can get messy 
and ruin a good rug.  Some sets were large enough to house the batteries 
or the set would sit on a "radio stand" built to hold the radio and 
batteries.  Sometimes the speaker was built into this stand.  Or the 
batteries can simply be put in the basement and wires run up through the 
floor.  If you're like me, you'll be on the lookout for a 32 volt Delco 
generator set.  Used for recharging the batteries that powered the house 
lights  and the radio on the farm.  Makes for a nice farm or car show 
display.

Aaron

Mstang6T5 at aol.com wrote:

>Visit our web site - See http://www.njarc.org
>_______________________________________________
>Hi all,
> 
>I'm a novice member who needs to tap into the NJARC knowledge  base. What is 
>a TRF radio? What type of tubes do they use? And  what may be the current draw 
>on the tubes?   I'm  currently looking at an Airline battery set, the owner 
>thinks it maybe a "TRF  radio" but is not sure. Thanks for the help. And have a 
>Happy New year!
> 
>Dave LeMay :-)
>
>
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