Posts Tagged dx

An Interesting AM BCB DXer’s catch

KVCK, at 1450 AM, broadcasts a monophonic signal using the standard monophonic AM modulation scheme. The music feed to the station from its content provider, however, is stereo, and KVCK routes only one channel of that feed to its transmitter. So for any content that provides fully panned mix to the missing channel, no sound reaches the listener.

This problem has existed for decades, the station has been notified many times about it by email and in writing, yet it persists. The solution should be as simple as a stereo-to-mono cable or mixer, or, if the content is provided digitally, by a software setting or a call to the content provider.

That this has never been corrected comprises an interesting mystery with regard to KVCK, and makes it an unusual DX catch for BCB DXers.

Here’s a 20-second fragment of Marvin Gaye’s "Heard it Through the Grapevine"

First, here’s how it should sound. Pay attention to the ladies in the chorus from 13s to 20s:

Full mono, both tracks combined properly

Now, here it is from KCVK, on the afternoon of September 28th, 2016… listen again at 13s to 20s:

One track only (incorrect mixing at station or content provider.)

KVCK is like one of those double-struck pennies from the US mint. Very rare, and not a very good product — but interesting!

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New OSX and Windows version of SdrDx – 2.11

SdrDx 2.11 adds visible memory markers, an enhanced internal database, better panning window width by window width, a number of fixes and performance improvements, and additional documentation.

  Screen shot:

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New OSX and Windows version of SdrDx – 2.08

SdrDx 2.08 supercedes the UDP interface in 2.07 (UDP still present in case you’ve coded for it) with a TCP server interface that is capable of supporting multiple clients. It turns out there’s a rather serious bug in OSX that prevents UDP connections from being opened with more than one client, so TCP is better for now.

As with the UDP interface, I’ve included a basic TCP client example written in Python.

In addition, beginning with SdrDx 2.08, the program will let you know if and when upgrades are available to you in the program’s title bar, as long as you have an Internet connection when you start it.

The TCP interface now has many additional commands as compared to the previous version’s UDP command set, and so far we’ve got an alpha version of an iPad client that displays waterfall, spectrum, demod envelope, allows tuning and other control, and plays back audio — all using the new TCP interface. In addition, during the beta period, tuning control for a screwdriver antenna was implemented using the TCP interface and Python.

I have a multi-VFO (26 of them, A-Z) application I’ve made available (OSX only so far) that works with the new TCP interface as well, giving you copious radio-like VFO control over SdrDx. Each VFO remembers frequency and all related display settings, so you can frequency hop like a little radio bunny. (cough) Sorry. :)

SdrDx 2.08 provides for frequency offset, which in turn allows it to be used more easily with up-converters such as those that might be part of a FUNcube installation.

There are various other changes, mostly small tweaks and bugfixes. Enjoy!

Screen shot:

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Online Docs for SdrDx

I am pleased to introduce online documentation for SdrDx. This marks a sea change, where we move from a text file, buried in the distribution, to a system where everyone is looking at the same document, one that is easier to read, to look at and in general to deal with. It includes a table of contents, an index, visual cues for user interface elements and so on.

The link is on the SdrDx page, and the next release of SdrDx will take you there directly.

Comments and corrections are welcome, of course.

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New version of SdrDx – 1.10

Please see this post for the latest details on v1.10.

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New Version of SdrDx (Mac / OS X version of CuteSDR)

Please see this post for the latest details on v1.07.

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