From FB group Building Transistor Radios 2018-09-01 There are too many ‘gotchas.’ You have to put up a large sized antenna to gather enough power to run the circuit. That means you cannot use this in a city where the properties are too small, due to lack of space. You go to the country where
(Read More…)
From the FB group Building Transistor Radios Regenerative / reflex designs are not as stable as superheterodyne radios. One problem is the design depends on factors that are not predictable such as gain and feedback, which are not linear. The regenerative reflex depends on the circuit being on the verge of oscillation, which is not
(Read More…)
From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is
(Read More…)
From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is
(Read More…)
From FB group Building Transistor Radios, Jul 30 Hey, if you live in Central Florida, you really do need an optocoupler! I got a Tennelec Memoryscan scanner on sale for a really cheap price back in the ’70s (the company quickly went out of business). I connected it to a VHF/UHF discone antenna on my
(Read More…)
From FB group Building Transistor Radios Jim Glover You asked about performance. There are factors unrelated to either type that affect the performance, one being the type of wire used. If Litz wire is used it has lower losses, and therefore higher Q than solid wire. Same holds true for silver plated wire at HFs.
(Read More…)
From FB group Vintage Transistor Radios OMG, that was so long ago, I could never sort out which one. See, I was born with a soldering iron in my hand, and I fixed so many radios, I could never remember which one was one that I had. Most of the electronics I was given were
(Read More…)
From FB group Building Transistor Radios Then there is the loopstick. It is deliberately made long and thin to capture the RF magnetic fields. The frequencies that loopsticks are better at capturing are those that require long antennas that would be impractical. So the AM broadcast band is where loopsticks do their best. The loopstick’s
(Read More…)
From FB group Ferrite Loopstick Antenna Experimenters Some experimenters in another group looked at schematics and saw that some radios with a RF amplifier between the loopstick and the converter used a third section on the variable capacitor to tune the RF amplifier. This is good, but it makes the variable capacitor more expensive and
(Read More…)
For FB group Building Transistor Radios Darrell Darby (Schematic below) What amazes me is the collector load resistor for the earphone stage is 100k. That’s more than ten times higher than usual, and it’s okay because the crystal earplug is very sensitive. I would squeeze a bit more gain out of it by removing the
(Read More…)
