Tag Archives: Mods

Dr. Phil’s radio articles: portable SDR and pocket DX

SWLing Post reader, Dr. Phil, recently contacted me regarding a collection of articles he’s written about DXing and radio modifications.

His site actually has a number of useful articles that I’ll plan to convert to future posts, with his permission.

I asked Dr. Phil for links to two of his most popular publications. He replied:

My two big recent articles are shown below. One is about “Pocket Radio DX”: using under-$20 radios to DX (started in 2003). Click here to download as a PDF.

The other is about using an $18 NooElec TV-tuner as a MW and shortwave receiver. Click here to download as a PDF.

Brilliant! Thanks so much for sharing these, Dr. Phil!

I actually have a Sony ICF-S10MK2, which I consider to be a capable and useful little AM/FM receiver for the sub $20 price. I’ve also been very tempted to purchase an RTL-SDR dongle, so I may go ahead and bite the bullet on one of the NooElec SDR dongles.

Two strategies to improve Sangean ATS-909X sensitivity

26 Replies

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?

Modify An Icom IC-735 To Work DRM

1 Reply

The original IC-735 brochure. Click to enlarge.

Are you a ham radio operator and/or SWLer that would like to dabble in DRM (Digital Radio Mondial) but don’t have a purpose-built receiver? A friend recently brought to my attention a clearly-outlined DIY photo instructional for a modification you can make to the classic Icom IC-735 ham transceiver to add a 12 Hz downconverter and I.F. output jack.

If you’re handy with a soldering iron, view the PDF instructional created by Matthias Bopp (DD1US) for making this modification. The downconverter (along with many other DRM items) is sold by German firm, SAT-Schneider–follow this link to purchase it online for just 25 Euros.

logo_drm Though the IC-735 is primarily a ham radio transceiver, it has general coverage and makes for an exceptional shortwave broadcast receiver as well. In fact, I have an IC-735 in my shack and use it primarily for SWLing. This unit was produced by Icom in the 1980’s; many are available now in the used market for around $325-450US. A great value for the money, especially if you also happen to be a ham.