QRPHB Check In

Despite my rare posts — and sadly lacking much time for QRPHB, this blog enjoys reasonable traffic and I gratefully enjoy email from readers all over the world. Thank you !

Although home brew radio electronics remains a passion for me, component-level hobbyist radio electronics lies past its prime. Digital devices pushing ever higher frequencies = the new frontier as hardware plus software radio excites newer generations of builders. Craving simpler times, where we get to bias transistors and perhaps implement long-obsolete parts, some of us enjoy more nostalgic creativity — and prefer making radio gear from solid state parts. 

Although I enjoy them all, it seems that many nostalgic ‘transistor plus resistor’ or tube RF circuits enthusiasts rarely seem to move beyond their comfort zone of LF - HF?  I recall reading many wonderful VHF and UHF hardware projects in Ham Radio-related magazines in the 1980s into the 2000s. Where did this interest go?  I do feel inspired by the modern-day Low Frequency Experimental Radio buffs who “get it done” despite the many challenges they face.

Perhaps ironically, we modern time solid-state builders enjoy an abundance of cheap, digital-based bench test equipment like never before.

QRPHB promotes hobbyist diversity and seeking knowledge. Like you, I’ve got many geeky ideas and interests and have way more questions than answers. We also champion inclusiveness – tribalism is tearing apart society. Whoever you are, whatever your hobby interests — this is a safe space to read, think and to question for all.

Lately, guitar amplifier-related hits dominate the blog. Please see a snippet of data from the past week below:

Above — Unique visits to QRPHB plus the 2 topped rank blog posts from Oct 3 to today, Oct 10 (well most of today). Guitar amplifier interest beats out RF by far. I only got 2 comments, but garnered 18 emails. I answer all emails and enjoy engaging with others about our geeky hobby pursuits.

I’ve got many ideas to share and also much to learn about making jazz guitar amplifiers.

Here, once again, a small group of enthusiasts choose to make solid-state analog devices in a very tube dominated, plus digital guitar amp world. I think the best future home brew jazz guitar amps will involve digital, plus analog circuitry (and perhaps might include a single 12AX7) to give you that boss, sweet, bluesy guitar tone! In the distant future, after learning how, I will add sound bites on YouTube so you can hear my amps in action.
 
Behind the scenes at QRPHB live some amazing family members doing some cool but very geeky things. 1 particular area of interest for us is indoor air quality — specifically using data to test the effectiveness of our indoor air quality interventions such as filtration.  

Above — Stuart's air quality system lying on the sand with a local admirer. Not many builders get wildlife inspecting their projects.

Above — A close up of Stuart's indoor air quality monitoring system. I feel amazed that we can measure particles below 5 microns --- let alone 0.3 µ

Here are a couple of  URLs:

https://www.waveshare.com/wiki/Pico-Environment-Sensor

https://www.adafruit.com/product/4632

I’m also interested is radio astronomy and space weather.  I like and support the GRAPE project:

SPACE WEATHER

Grape Version 1: First prototype of the low-cost personal space weather station receiver

pdf file for free download at
https://www.sciencedirect.com/science/article/pii/S2468067222000347

ABSTRACT

Crowd sourced data collection among the international community of amateur radio operators and shortwave listeners has great potential for addressing problems of under-sampling in the geospace system.

Quantitative Doppler measurements of high frequency (HF) time standard stations, used in bottom side ionospheric sensing, have been accomplished using existing radio hardware belonging to volunteers in distributed campaigns. However, typical shortwave receivers cannot be put to ordinary use while these measurements are being taken, do not have standardized signal chains, and are generally too expensive to be purchased for the sole purpose of taking Doppler measurements.

Here, we provide documentation for a low-cost intermediate frequency receiver, the Grape Version 1, which is designed specifically for measurements of North American time standard stations. Grape receivers can be easily constructed and deployed by amateur scientists in order to gain a deeper understanding of variations in radio propagation in their local environment. When compared over long periods and across distributed networks of stations, the resulting data yield insights on greater spatial and time scales. At the time of writing, several of these receivers have been deployed across the United States and are actively collecting data. These receivers form the first iteration of the Low-Cost Personal Space Weather Station network.

Gibbons, J., Collins, K., Kazdan, D., & Frissell, N. (2022). Grape Version 1: First prototype of the low-cost personal space weather station receiver. HardwareX, 11. https://doi.org/10.1016/j.ohx.2022.e00289