W2XS

It's called the OHR HP Transceiver.  HP stands for 
high-performance. It is built around "The Optimized QRP Transceiver" by W7EL 
that has been in the handbook and was the standard for high-performance 
direct-conversion rigs for many years. It's similar to the OHR rig that Tom 
AA2VK had for a while.

Anyway, here's my mini-review (even though you didn't ask):

Pro = Nice and clean-sounding receiver, typical of a good direct-conversion 
receiver.  Low noise and clean, clear signals, even when they are strong. It 
seems to have an audio filter in it and has decent selectivity.  Unlike the 
original W7EL design, this rig drives low-Z earphones with plenty of volume.

Pro = Plenty of sensitivity.  I am hearing plenty of DX and other weaker 
signals.

Pro = Good dynamic range.  When a really strong signal is tuned in, it still 
sounds clear and clean. This is due to the diode mixer that W7EL used in his 
original circuit.

Pro = Nice vernier tuning on the tuning dial.  The 0 to 100 scale is not 
calibrated that well but covers 7.000 to 7.090 which is a good range.

Con = Being direct-conversion, you hear both sides of the zero-beat.  But 
the rig has RIT, so you can move the desired signal one way (up or down) and 
the image signal goes the other way. My first QRP rig was the Heathkit HW-8. 
It was direct-conversion and did not have RIT so it was a bit of a challange 
sometimes.

Con (sort of) = It draws 76 mA in receive. In comparison, the Wilderness 
NorCal NC-40A here draws only 14 mA and the SST-40 draws 19 mA. This 
surprised me at first but I guess you pay the price for a "high-performance" 
receiver circuit, even one that is direct conversion. The K2 draws 300 mA 
normally, and 200 mA in the "battery saver" mode. I have in my notes that 
the OHR400 drew 250 mA in receive, the OHR100a drew 80 mA, and the SWL-40 
drew 23 mA.

Comment - The NC40A seems to be the overall winner in my small collection of 
mono-band QRP rigs. At 14 mA, the batteries will last the longest, and it 
has the built-in keyer and frequency counter. You may have noticed that CQ 
magazine last month did an article on the construction of the NC40A. If I 
had to sell all but one Small QRP rig (not including the K2), I would keep 
the NC40A.  But I don't have to do that yet hi hi

72,

John W2XS
W2XS Projects
