n3ajx radio experiments

In a previous post, I briefly described issues I had preserving quadrature output from an Si5351 board.  Allegedly, once a 5351 is programmed to provide a fixed phase offset on a second output,  it should maintain that phase shift across frequency excursions, provided the "even divisor" remained unchanged - No PLL reset needed until the a large enough frequency excursion requires a change in the "even divisor".  PLL resets caused annoying "pops" in the output of direct conversion front ends that I typically use for phasing-type receivers.  I was loathe to include a PLL reset on every frequency change because of that.  So, I (and many others) only do a PLL reset when the required integer "even divisor" was changed.  Many fewer "pops", but semi-random loss of LO quadrature within a relatively small frequency range.  I added a polled front-panel switch to my hardware that I use to manually reset the  PLL when my "ear detector" de...

Some folks have built HF gear using MMIC's (gain blocks) as either IF amps, receive preamps or pre-drivers.  I've used AG303-86's, MAV-11's, MAR-0685's and even a some hamfest SGA-6486's with few problems and with excellent repeatability.  50 ohm input and output, low external component count, relatively low noise figure and low distortion up to about 20dbm output at 1 db gain compression - what's not to like!  The issue I have with these devices is that they're a bit anemic for use use a QRP final amp or as drivers for 5+ watt PA's.  Recently, I bought a couple of SV1AFN's (SV1AFN) 1 watt driver, PHA-202+ boards to fill the need for 1 watt (approx.) gain blocks in a few projects.  This device/board can , indeed, deliver close to 30 dbm (at 1 db gain compression) output for 10 - 13 dbm input.  The down side:  the PHA-202+ is relatively expensive (Digikey's single unit price is around $16.64 (US)),  current consumption is rather high compared ...