Category Archives: Radios

Jeff designs an SDR “Go Kit” around the Softrock Ensemble

Jeffrey Fritz (WB1AAL) contacted me with details about his SDR (Software Defined Radio) “Go Kit” and has kindly allowed me to post it.

Jeff writes:

As a reader of the SWLing blog, I know that you are very interested in SDR. And you probably know that a “Go Kit” is a portable ham radio system in a case that can be moved at a moment’s notice and set up at another moment’s notice virtually anywhere.

I have a VHF Go Kit made up for emergency events. It is complete with waterproof carrying case, Aden PCS-7000H two-meter transceiver, a Kenwood VHF tuner, a Kenwood SW-100 VHF SWR bridge and two antennas (a 2-meter J-pole made out of twin lead and a two meter mag mount.) But what if there is a need to monitor the HF bands during the same event?

Now that I own a Flex-1500 SDR transceiver, the Softrock Ensemble SDR receiver that I bought a while ago has become somewhat redundant. It is still a serviceable radio and works fine, but it can’t hold a candle to the amazing Flex-1500. While I could turn it into a panadapter or sell it on eBay, eHam, etc., I had a better idea.

To monitor the HF ham bands, I could use something like my Grundig G3 shortwave radio in my Go Kit. While it is portable, battery operated and will tune LSB and USB, listening to SSB or even CW in an emergency situation with the G3 can be a bit of a chore. (Think of the old boat anchors with their main tuning and fine tuning band spread dials, but now make both dials tiny and you’ll get the idea.) Instead, why not build a 12-volt battery supply with common, easy to obtain batteries? I could connect it to the Softrock Ensemble and then via a USB audio interface to a battery powered laptop. Add a pair of headphones and we are in business.

That is just what I’ve done.

I’ve attached some photos of my most recent project–done this past weekend actually. [Check out photos above and below] It’s an SDR Go Kit. One of the attached photos shows the laptop and the Softrock Ensemble SDR receiving 40-meter band SSB while entirely being operated on battery power. There is no power switch. You simply pull the DC jack out of the Softrock Ensemble SDR radio when it isn’t in use. Simple as it gets! The other photo shows the battery pack built into a (ahem!) Preparation H Pad holder pack. (Now, I am not saying who used this!)

Ah but what will battery life be like with 8 C cells in series driving the receiver? It’s too soon to say because I just put it together an hour ago. But here’s a guess:

The Softrock Ensemble draws 18 mA at 12.6 volts (my measurement.) An Alkaline ‘C’ battery can supply up to 8,000 mAh, so doing some math and assuming fresh batteries, the battery pack should run the radio for roughly 400 hours. (Hopefully my math is correct!) If so, then I think that the laptop batteries will give out long before the life span of the C Cell is reached!

73,

Jeff, WB1AAL

Jeff, this is an excellent use for the Softrock Ensemble. I imagine it will run for a very long time drawing only 18 mA. I have a “Go Kit” for QRP ham radio purposes and one for SWLing during travels. You’ve inspired me to piece together a proper receiver “Go Kit” to be used in case of emergencies.

Readers: If you have a project, like Jeff, that you’d like to share on the SWLing Post, feel free to contact me with details!

The new Tecsun PL-880 sounds promising

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The Tecsun PL-880 (Photo: bbs.tecsun.com.cn/)

Last night, I discovered news of the new Tecsun PL-880 on Jeff’s excellent blog, the Herculodge.

Out of all of the current shortwave radio manufacturers, Tecsun seems to be one of the only companies making new models for the radio hobbyist–models with important features like SSB, bandwidth control, fine tuning steps, capable AGC, etc.

According to a comment Owl left on this post, it sounds like the PL-880 could be a performer:

Two photos of Tecsun’s new model PL880 appeared yesterday. It uses an analog+DSP architecture similar to ATS909X but has made some significant improvements (4 AM bandwidth + 5 SSB bandwidth) and better audio compared to previous Tecsun portables.

http://herculodge.typepad.com/herculodge/2013/08/new-tecsun-pl-880-on-its-way.html

I will plan on reviewing the PL-880, once it hits the market. If it’s no larger than my Sony ICF-SW7600GR, it might make for a great travel radio.

(Photo source: bbs.tecsun.com.cn)

Universal Radio: another used RFSpace NetSDR value

Paul reviews the mystery radio

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Many thanks to Paul for providing this review of his mystery radio (see previous posts):

This is a basic AM/FM radio with clock and alarm functions. It runs off three AA batteries (for the radio) or a 1.5 V small cell battery (for the clock). There is also the option of powering it with an AC adapter (4.5 V DC, center positive). The speaker is 8 ohm, 0.5 W. As Ulli pointed out the three AA batteries are a very tight fit. Besides radio and alarm, there is also a headphone jack.

The SET and DIS buttons on the radio are for setting the clock and alarm. In absence of a manual it took a little time to figure out how to do this. The clock LCD tilts up as shown in the photos. Needless to say the viewing angles leave much to be desired. This radio is meant to be used laying on a table; it has a curved bottom and cannot stand up on its own.

In terms of performance, it’s good for powerhouse AM and FM stations. DXing is very limited or next to impossible due to the stiff tuning knob (you need two fingers to move it around; the dimple is not helpful) and the short circular tuning range. It’s hard to tell whether the radio has below average built-in selectivity with the Sony CXA1191S chip, or are problems zeroing in on stations due to the poorly designed knob. In my unit the volume knob was scratchy; this was easily fixed with a little DeoxIt spray.

Among other curious things about this radio is its antenna, which goes out only at a fixed angle – not straight up. It can be moved from left to right at this angle and extended.

Overall this is a basic AM FM clock radio, measuring small (6.25 x 3 x 1.25 inches), and honestly, nothing really special!

Paul, thanks for the review and great photos of your radio. It might not be a performance machine, but it was fun solving the mystery and reading your review of this obscure little radio! -Thomas

Mystery radio identified

1 Reply

Click to enlarge.

Wow, that was quick! Many thanks to Ulli who solved the case of the mystery radio we posted yesterday.

Ulli comments with details:

The radio was a giveaway about 1995.
I opened it :
1 IC Sony CXA1191S 314J22V , 5 Transistors , 3 -band filter , 5.5 cm speakers , 8ohm , 0.5 W.
Today’s AA batteries are a bit too long, the 3 AA not quite fit into the battery tray .
The display with the time can be tilted .
On the back is a sticker :
AM / FM CLOCK RADIO LCD , DC POWER SUPPLY , RADIO DC 4.5 V, 1.5 V DC CLOCK ,
ART No. 05796-07 , CENTRON LABORATORIES LTD .
and on housing :
U.K.REG.NO.2013420 .

Thanks, Ulli!