Category Archives: How To

Pete gives Kaito high marks for customer service

SWLing Post reader, Pete Jernakoff (K3KMS), writes:

“I purchased two PL-880 radios from Amazon about a year ago and before the soft muting issue became a hot topic. Both of my radios (8819 firmware version) suffered from this most annoying problem but it wasn’t until I started reading your excellent blog that I learned of the cause.

About two weeks ago, I called Kaito Electronics USA and asked if they could upgrade the firmware on my two radios to the 8820 version. The person I spoke to said (paraphrasing) “Sure! Send them to us any we’ll perform the upgrade for free. All you do is pay for the return shipping.”

So off the radios went to Kaito. About 10 days later I had them back with the new firmware installed. The return shipping was $10. Weak MW and SW signals are now easy to listen to: no soft muting issues at all. Kudos to Kaito for agreeing to perform the upgrade for me. My dealings with them were thoroughly pleasurable.”

Thanks for sharing that great experience, Pete! You’re right–the 8820 upgrade is certainly worth the shipping costs and I’m happy to hear Kaito makes the process so easy.

Don’t know the firmware version of your PL-880? Click here to learn how to display the firmware version.

For more information on PL-880 soft muting, click here.

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Sproutie hears the Shortwave Shindig

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SWLing Post reader, Dave Richards (AA7EE), made a short video of his regen receiver “Sproutie” tuned to the Shortwave Shindig Friday evening.

Dave writes:

“I was quite pleased with the fidelity. Of course, the skirts on a regen are quite broad, even though the nose of the selectivity curve is fairly narrow. The signal was a bit lower in level and noisier at the beginning of the show but by the time it got to this segment, it was a nice strong signal. Sorry – no S-meter here, so that is the best I can do!”

Dave, thanks for sharing this video! Sproutie did a brilliant job tuning in a program from across the continent. I’m also most impressed with Sproutie’s audio. Amazing!

Readers, click here to read a previous post about Dave’s home brew regen receiver, “Sproutie.” Also, be sure to bookmark Dave’s blog by clicking here.

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Pulling Radio Santa Cruz out of the interference

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I recorded Radio Santa Cruz early this morning around 05:00 UTC on 6,135 kHz using the TitanSDR I currently have under review.

Radio Santa Cruz‘s 10 kW signal from Santa Cruz, Bolivia, was very much audible here in North America, though RSC was competing with another station on-frequency at the time. Actually, Radio Santa Cruz was broadcasting slightly off-frequency–6134.8 kHz instead of 6,135 kHz. In this case, the fact that RSC was slightly below frequency helped me delineate the station’s audio from that of a competing station.

In the screen-grab of the narrowband channel from the Titan SDR (above–click to enlarge) you can see two distinct carriers spaced only .2 kHz apart (represented by the two peaks in the spectrum display and two parallel vertical lines in the waterfall display).

Here is what the audio sounds like in normal AM mode when we center on the Radio Santa Cruz frequency of 6,134.8 kHz:

You hear a hetrodyne and garbled noise from a competing station. Not pleasant audio.

If we change from the AM mode to eLSB mode (essentially, the TitanSDR’s version of synchronous detection on the lower sideband) we are ignoring all of the noise in the upper sideband, allowing the desired signal of RSC to pop out.

You can see in the screen-grab above that now only the lower sideband of the RSC signal is highlighted. Here’s a 21 minute recording:

Makes quite a difference!

It’s easy to see competing signals and interference on an SDR’s spectrum display, but if you hear something similar on your portable, try the techniques above to see if it clears up the signal.

If your receiver lacks a selectable synchronous detector, much of the same results can be gained by zero-beating (tuning in) the desired signal in lower sideband mode. Of course, if you have a receiver that lacks SSB mode, the best you can do is tune slightly below frequency in AM, in which case the results will not be as dramatic.

Conclusion? Listening in single-sideband or with a selectable sync detector might be all you need to dig a signal out of the interference.

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Two strategies to improve Sangean ATS-909X sensitivity

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SWLing Post contributor, Moshe, writes:

“I would like to share something I noticed about Sangean sensitivity issue:
As I own the ATS909, I noticed that with fresh set of regular batteries (1.5V) or it’s power transformer, it is very sensitive.
When the voltage of the batteries drops, so does sensitivity! Which means that if one uses rechargeable batteries (1.2V), the radio will be much less sensitive to begin with.”

Many thanks, Moshe! That is a very good reason to keep fresh alkaline batteries for the 909X, or to run it on a quiet power supply. Moshe is correct–fresh rechargeable batteries can’t deliver full voltage.

Several weeks ago, a reader informed me about a modification that increases SW sensitivity by adding a 4:1 impedance transformer.

Click here to download a PDF that documents the 4:1 transformer procedure.

Note that I can’t remember who shared the PDF and am not sure who was so kind to document the procedure with photos. Any additional information would be appreciated.

Have any readers performed the transformer mod on the ‘909X with success?

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Video: Chris reviews the Tecsun 2P3 AM radio kit

SSB for the non-technical

Video: Controlling the Elad FDM-S2 SDR with the HP Stream 7 tablet

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Many thanks to SWLing Post contributor, Guy Atkins, who shares the following video demonstrating how the Elad FDM-S2 can be controlled with the $99 HP Stream 7 Windows 8.1 tablet PC: