Experimenting with the BK1198 receiver IC (and Digitech AR1458 conversion)
The BK1198 is an IC that is basically a multiband AM/FM/shortwave receiver-in-a-chip. Its phasing method allows selectivity without the usual frequency conversions and IF transformers or filters
required by a superhet. Hence receivers using it are cheaper and smaller to project. There are two versions, with the larger 22 pin version having extra features including FM stereo. Full information
about the IC does not seem available. However partial information is. That's enough for some interesting experiments.
An unofficial datasheet is here. Jaycar, who stock the IC, also have a handy sheet available
here.
Review of Digitech AR1458 receiver (which includes a BK1198)
The BK1198 is a surface mount chip. To experiment it you can either buy an IC and carrier board (link above) or purchase a ready-made receiver with one. For example the
Digitech AR1458. Even if you don't intend to buy one click on the link to see the circuit in the downloads.
An AR1458 is reviewed below.
First experiments getting the AR1458 to receive shortwave
Below are my first attempts to get the AR1458 to receive shortwave, using some of the data linked above. I demonstrate reception of unknown frequencies.
More shortwave and SSB reception
Here I have another attempt. First station received was WWV/WWVH on 5 MHz. I compare reception with another receiver. Then I try 7 MHz amateur SSB reception with an
external beat frequency oscillator. I use a regenerative receiver but it could be an RF signal generator. Maybe even a Nano VNA. This is very rough and you'll likely
get better results with (a) an external tuning potentiometer with larger knob for easier adjustment, (b) another potentiometer for fine tuning (for even easier adjustment),
and (c) a front-end preselector filter and possibly RF attenuator.
Disclosure: I receive a small commission from items purchased through links on this site.
Items were chosen for likely usefulness and a satisfaction rating of 4/5 or better.
