XPost: rec.radio.amateur.moderated

KB6NU's Ham Radio Blog

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Would paralleling diodes make a crystal radio work better?

Posted: 09 Apr 2022 05:00 AM PDT https://www.kb6nu.com/would-paralleling-diodes-make-a-crystal-radio-work-better/?utm_source=feedburner&utm_medium=email


On the amateur radio subreddit, some guy posted a link to his ePay store
where hes selling fancy crystal radios. Since theres a rule that you cant
post ads, his post was quickly removed, but not before I clicked on a link
and got a look at his work. Honestly, some of it looked pretty interesting,
but there was one thing he was selling that I questioned.

One of his products is a little board with four germanium diodes in
parallel (see below). Im going to guess that these are 1N34A diodes. When I asked him what the purpose was for connecting four diodes in parallel like that, he replied, To decrease the Diode Resistance so it improves the Diode performance in a Crystal Radio (his caps, not mine).



Now, its true that connecting resistors in parallel will decrease the total resistance, but lets look at a typical crystal radio circuit:



This circuit uses high-impedance headphones or a high-impedance earphone because there is no powered amplifier. The only power comes from the
received radio wave itself. This means that very little current will be
flowing in the circuit, so theres really not much to gain by decreasing the Diode Resistance.

So, to answer my own question, no, I dont think that paralleling diodes in
a crystal radio circuit would make it work noticeably better.

The post Would paralleling diodes make a crystal radio work better?
appeared first on KB6NUs Ham Radio Blog.


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VK5DR, Codec 2 developer, wins 2022 Amateur Radio Software Award

Posted: 08 Apr 2022 10:37 AM PDT https://www.kb6nu.com/vk5dr-codec-2-developer-wins-2022-amateur-radio-software-award/?utm_source=feedburner&utm_medium=email

Little known fact: I gave the ARSA committee the idea for this logo.

Earlier this week, the Amateur Radio Software Award (ARSA) committee
selected David Rowe, VK5DGR, and his project, Codec 2, to receive the 3rd annual Amateur Radio Software Award. The award recognizes projects and
their developers for technical innovation, impacts on amateur radio and community involvement. The award includes a $300 grant.

Codec 2 is a foundational project for digital voice communication on HF and VHF. It provides a royalty-free and open source codec suitable for digital voice application in amateur radio. Codec 2 enables other software and
hardware projects to utilize digital voice communication without the
barriers of licensing, usage fees and vendor lockdown.

In describing the project, Rowe said, As well as speech compression
software, the Codec 2 library also includes a variety of modems integrated
into the FreeDV protocol to support robust open source digital voice over
HF radio. We are working on improving the quality, and lowering the SNR required for HF digital voice.

With Codec 2, David has made significant contributions to amateur radio by helping to move the community beyond the vendor controlled digital voice ecosystem and enabling other innovation previously prevented by patents.
David Rowe and key contributor Mooneer Salem, K6AQ, created FreeDV, a
program for digital voice communication over HF, as a reference
implementation. Codec 2 is also used by the M17 team for digital voice in
their VHF/UHF/GigaHertz communication protocol and applications.
About the Award

The Amateur Radio Software Award is an annual award and is intended to recognize software projects that enhance amateur radio. It aims to promote amateur radio software development that adheres to the same spirit as
amateur radio itself: innovative, free, and open.

The ARSA committee is solely responsible for determining the winner of the award. The committee this year included:

Claus Niesen, AE0S (since 2020)
Kun Lin, N7DMR (since 2020)
Rich Gordon, K0EB (since 2021)


For more information about the award, visit the ARSA website.
Special Event Station

ARSA is sponsoring special event stations K3A, K3R, and K3S from Friday,
August 26th through sunday September 5th, 2022 to promote innovative, free,
and open amateur radio software. During the event, we will honor the 2022
award recipient. As part of the special event, we encourage people to
submit nominations for the 2023 Amateur Radio Software Award.

The post VK5DR, Codec 2 developer, wins 2022 Amateur Radio Software Award appeared first on KB6NUs Ham Radio Blog.

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