[ARC5] BC-453 Current Draw - update

[Bill Cromwell]

Hi,

We had some animated discussion on this thread and I have an update 
using battery power with my BC-453s. I stated that the radios will 
operate at 45 volts. Some others have examples where individual radios 
may not operate with B+ that low. Trying things with two different 
receivers I get the same result. But as the B+ gets reduced the exact 
setting of the gain control gets more critical. That was noticeable and 
irritating with about 10 or 15 minutes of operating time.

If the gain is set too high loud signals may hurt our ears. The radio 
may overload - exhibited by a dramatic increase in "noise". If the gain 
is set too low the weaker signals will drop out - or even the strong 
ones if it's low enough. Operating with 90 volts the gain control "sweet 
spot" (not too much, not too little) covers a wider, very comfortable 
range of operation. At 45 volts it's really touchy and any variation 
drives the radio into the ditch. The two radios I played with (logging 
NDBs) got better when I added just one 9-volt battery to the pyle for 
~54 volts B+. The sweet spot was tolerably stable. I suppose I will be 
operating my radios at ~90 volts B+. Your mileage may vary.

Probably a stock radio with only 45 volts also lacks adequate headroom 
before some clipping or flat-topping occurs (I didn't break out the 
scope). If we modify the radio by changing some resistor values as 
mentioned by Les and some others these "issues" might resolve. In my own 
mind that engages other problems such as the next radio enthusiast who 
gets the radio and applies 250 volts B+ will be quite unhappy. I do 
expect the radio will outlast me.

73,

Bill  KU8H