When I learned that Arizona QRP Club AZ ScQRPions released a new QRP Transceiver kit designed by N7VE (Dan Tayloe) I placed my order without even thinking twice. N7VE pushes the performance envelope of HF design to new levels (think the famous Tayloe Detector) and this little transceiver kit is no exception.
The Ft. Tuthill 80 boasts the following performance and is considered exceptional regardless of receiver topology:
- Tuning range: 50 kHz segment of the 80m CW band. This can be extended to 80 kHz by using the other half of the main tuning capacitor.
- Current Drain: Approximately 25 ma @ 12v.
- Supply voltage range: 12 to 13.8v
- Receiver bandwidth: ~600 to 700 Hz bandwidth.
- MDS receiver sensitivity: ‑116 dBm in a 700 Hz bandwidth
- Third order distortion (IP3): +25 dBm
- Blocking Dynamic Range (BDR): ~100 db (limited by the cw filter response)
- RIT tuning range: Greater than +/- 1.5 kHz from the transmit frequency (total RIT range ~ 5 kHz)
- Receiver Type: DC receiver: Both sidebands (USB/LSB) are heard at the same time
- Power Output: > 2.5w output at 12v
- TX harmonic output: At full transmit power, all output harmonics exceed FCC specifications of ‑45 dBc
The BDR is around the same as a ICOM IC756 Pro III for comparison…pretty damned great, and even more so considering this is a Direct Conversion receiver! I am really excited to get this thing on the air!
Here is a picture of the 3.5″ by 3.5″ board stuffed with some of the ceramic capacitors and a few diodes.
The instructions are clearly written with plenty of illustrations. I have deviated somewhat from the instructions however, as I did not have a device to match .1μF capacitors for the filter section. The matching is optional, but I figured with such a fine performing receiver I had better do it correctly. Both my old Fluke and even older Radio Chalet multi-meters are sans capacitance measurement, so I placed an order for the sexy LC meter from AADE–I have had my eye on that device for a long time and now it fit into my evil plans.
I skipped ahead and would the three toroidal transformers and two toroidal inductors. I find winding toroids is only semi-tedious and only difficult the couple times when I lost focus/turns count. I also prepared the final transistors and heat-sink as instructed. I am likely to delay mounting the trimmers and integrated circuits until I match and install the .1μF caps in order to leave enough working room. The manual states about a 6 hour build time; I will be taking mine in stages.
I will post pictures of my progress as I stuff the board.