After stopping the "Expanded Rockmite" i looked about on the web for my next project. I then came across VE7BPO's excellent website http://www.qrp.pops.net/
On this website is Todd's Cascoder 7. A superhet receiver built in stages on seperate boards with discrete components. Todd warned of this being a simple receiver but this one works great IMHO. I believe he is being a bit humble!
I built a 2 watt audio section and modified it to limit current. My reasoning was for richer audio since i plan on this being a home or picnic table rig and current is not a top priority. I also added a capacitor at the input to the ladder filter and grounded the bfo crystal (bypassed the crystal). This gave the receiver a low tone audio floor and made it easier for me to listen.
Construction is Manhatten style with circular drill bits from ebay.
I finally added a PC board cage around the VFO board. And found it necessary to modify the VFO a bit to get into the 40 meter band on my version.
Finally before mounting in a box, i added an extra capacitor & switch to cover two bands 7025-7055 and 7095-7125. Also added a 10 turn bourn pot for the VFO.
Future goals for this project;
S Meter
Audio Filter
Noise Blanker?
RF Att Switch (Todd has this on the Schematic)
Possibly a speaker with switch to turn up audio power and down for headphones.
5 watt Transmitter
Marker Generator
Box all up in a Ten Tec Enclosure & play with a bit likely modifying further. Then remove all, paint and label the Enclosure. Then reassembly for final.
A 40 meter rig that i built, can fix, modify at will, play QRP field or home. Very Cool!
On this website is Todd's Cascoder 7. A superhet receiver built in stages on seperate boards with discrete components. Todd warned of this being a simple receiver but this one works great IMHO. I believe he is being a bit humble!
I built a 2 watt audio section and modified it to limit current. My reasoning was for richer audio since i plan on this being a home or picnic table rig and current is not a top priority. I also added a capacitor at the input to the ladder filter and grounded the bfo crystal (bypassed the crystal). This gave the receiver a low tone audio floor and made it easier for me to listen.
Construction is Manhatten style with circular drill bits from ebay.
I finally added a PC board cage around the VFO board. And found it necessary to modify the VFO a bit to get into the 40 meter band on my version.
Finally before mounting in a box, i added an extra capacitor & switch to cover two bands 7025-7055 and 7095-7125. Also added a 10 turn bourn pot for the VFO.
Future goals for this project;
S Meter
Audio Filter
Noise Blanker?
RF Att Switch (Todd has this on the Schematic)
Possibly a speaker with switch to turn up audio power and down for headphones.
5 watt Transmitter
Marker Generator
Box all up in a Ten Tec Enclosure & play with a bit likely modifying further. Then remove all, paint and label the Enclosure. Then reassembly for final.
A 40 meter rig that i built, can fix, modify at will, play QRP field or home. Very Cool!