So, what is an RFH? That my friend is a Radical Fundamentalist Homebrewer or a person who totally homebrews a rig with discrete parts, no SMD, no chips or Arduinos here. The trouble is that the supply system is doing you in!
A blog reader suggested I go to Digi-Key and search on BF998 which used to be a staple Dual Gate MOSFET, and one often used by W7ZOI. I did that and found out they are not available being obsolete. Aha --click on the link for substitutes and I did that.
Surprise! There is Zero stock, and the subs are also obsolete.
At play here are four factors that will affect our RFH. The first is a demand issue and the basic question who is buying the BF998 DGM for use in production or projects? The answer is a few RFH's or someone who stumbled upon an article in QRP Quarterly by N6QW who designed a two band Direct Conversion Receiver using the BF998. Another user may be looking for a replacement part in an obsolete radio but that is peanuts. No new designs are in process that will use the BF998 or any DGM.
The second factor is cost which the low volume usage drives the price to something above the gag level. What used to cost less than $1 now may hit $10 if you can find it. Just like my recent look at building a LPF with Silver Mica Caps that would each cost $3 or $4. The Polypropylene ones were less than a buck. But there is no less than a buck subs for the DGM's without making one from two J310's.
But then that raises the third problem as more and more common parts are surface mount only which likely is incompatible with the glue down pads favored by RFH's AKA Manhattan Construction. Most current stock of the J310's is now SMD.
The fourth problem is the seismic technology shift to vertical integration of digital electronics into the ham world. Less and less devices that were once the staple of LC VFO's like coils, NPO or COG Capacitors or even through hole J310's are found in rig designs. Today it is an embedded Microcontroller with a Si5351. The fourth problem goes further by addressing the shift in topology from Hardware Defined Radios to Software Defined Radios. The refined SDR approach using DDC has no BF998's or J310's -- it is all software and digital electronics.
So, up front a tip of the cap to the RFH's who can build a rig that puts out a good quality signal and hold its own on today's bands with stations using a GPS synched frequency scheme capable of telling the RFH you are three hertz low. Indeed, it takes skill, knowledge, perseverance and a real sense of adventure to be an RFH. But cutting off the supply of once common and low-cost, through hole parts make Radically Fundamentalist Homebrewing a very difficult task.
In contrast to our DGM, the MC1496, a through hole Double Balanced Mixer, is a 50-year-old part can still be had at less than $2 in single pieces from Jameco Electronics. The SMD version is half that cost. But that does the RFH no good because it is a chip and the cheap one SMD. But his alternative is a homebrew DBM using four diodes and two cores is still a good solution.
Simple End Message: The times are changing and keeping the rigid principle of "homebrew all" has just been made a bit harder. Add in the self-inflicted tariffs and the hobby may shift to the sport of kings!
Them that know can make it go.
73's
Pete N6QW