Yearly Archives: 2018

Make your own 3-D printed crystal radio

Did you know you can build your very own working 3D-printed radio – without any soldering, electronics experience, electric cord, or even batteries?

Digital Trends reports that’s exactly what talented Houston, Texas-based 3D-printing and electronics enthusiast Sage Hansen has created. And he’s willing to show you how to do it, too.

Called a crystal radio receiver, or sometimes a “cat’s whisker receiver,” this is an incredibly simple type of radio receiver that was popular in the earliest days of radio. The only power it requires to work is the received radio signal, which is used to produce sound. It is named after its most important component, the crystal detector or diode.

“AM radio was one of the first ways of transmitting audio to a very broad audience in the early 1900s, but it is still very popular today,” Hansen told Digital Trends. “It starts with the radio station converting their audio sound waves into electromagnetic waves, which can travel great distances.

Each radio station uses a specific frequency that is constant, but the sound waves are mixed so they amplify and modulate the base radio wave. What makes the crystal radio so exciting is how simple the circuit is, and how it can be made out of normal household items.

Watch the video and read the full story at
https://www.digitaltrends.com/cool-tech/3d-printed-working-radio/

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Dean seeks input for his holiday radio adventure

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Many thanks to SWLing Post contributor, Dean Denton–our intrepid 13 year old DXer–who seeks a little input from the community. Dean writes:

I am going on holiday in July this year, to Fuerteventura in Islas Canarias, near west Africa.

This will be the first time I will be going on holiday, you will probably know the feeling. Because I am a hardcore radio-fan, I will of course bring my Tecsun PL-660, and I will be posting clips on my YouTube Channel, EuropeDX.

Please could you give me, some vital tips when going on holiday when DXing?

The Canary Islands are in close proximity to North West Africa, so I will be DXing: Morocco, Mauritius, Algeria, Western Sahara, Senegal and others.

To those who are reading this post, I am compiling a list of tech that I am bringing with me. Please help add to this list, off of your experience of being abroad.

Here is the list:

Shortwave Radio, Tecsun PL-660, for the immersion.

Tecsun AN-200 Loop antenna, for pulling AM stations.

Travel adapter, we all need one.

Portable MP3 player, to listen to music

A Portable Digital TV, for watching movies on USB.

An action camera w/lapel microphone, for capturing videos.

FM Transmitter, to show the locals what music is!

4G Mobile Data Router, internet is a basic human requirement.

Please suggest more!

I think that the AM and FM DXing will be breathtaking. The Canary Islands are located where I will be able to pick up African radio stations, but also Transatlantic Brazilian and American stations. Due to the high pressure and high temperature, FM Tropo is not rare in the Canary Island’s climate. Enabling this, it will spark my YouTube channel.

Thank you for reading this, and I hope the SWLing community help me. If you would like to contact me, email me at europedx(at)gmail(dot)com.

Yours,

Dean.

Thanks, Dean! You’re talking my favorite topics: radio and travel!

I know we have a number of readers who live in the Canary Islands. No doubt, you’ll get to experience some serious radio fun across the bands.

In terms of tips, I would suggest you assume your accommodation could be plagued with radio noise and you may be forced to find an outdoor spot to do all but your FM DXing. If you know where you’re going to stay, check it out on Google Maps and see if there’s an obvious safe spot to play radio outdoors. Of course, it helps if your accommodation has an outdoor space like a balcony, patio or garden.

Looks like you’ve got a pretty good checklist there. Here are a few additional items I typically take on a holiday DXpedition:

Earphones/Headphones (never leave home without them!)
A small back-up radio (if you have one–something like a Tecsun PL-310ET)
A copy of the World Radio TV Handbook (though I don’t take the WRTH if space/weight are too tight–I rely on apps with offline schedules like Skywave Radio Schedules [Android] or Shortwave Broadcast Schedules [iOS])
Extra set of AA batteries for the PL-660
Small headlamp or flashlight for night time outdoor listening
Notepad and pencil for logs

SWLing Post readers: How do you plan and what do you take on radio holidays? Please feel free to comment and share your advice!

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Georges’ review of the XHDATA D-808

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Many thanks to SWLing Post contributor, Georges (F6DFZ), who writes:

After the first information from your wonderful website, I immediately ordered the XHDATA D-808 receiver from Aliexpress for €62 including shipment to France.

I got it very quickly, shipped from Amazon UK!

I did a few tests on SSB. MDS is outstanding, the minimum signal from my HP generator at -127 dBm (0,1uV), is strong even on 28 MHz. Selectivity is also good, and the opposite sideband rejection is audibly also good. However I was unable to measure it because the S meter give the same indication over a few kHz around the signal of the generator. I suspect the opposite sideband rejection to be done by the DSP chip at AF, but I cannot confirm this.

Reception is very good on FM, and the AF from the loudspeaker is reasonable. On headphones, it’s very good. RDS works as it should and sets the clock of the receiver.

I did only a few minutes test on LW and MW, and it seemed OK, even if I don’t have a lot of experience on these bands.

SW AM listening was very good; good audio, great selectivity. I suspect that the bandwidths given are AF bandwidths as even the most selective were not too much muffled. If it was IF selectivity, the AF bandwidths would have been half the values and much muffled.

SSB and CW reception are also very good even if the DSP chip has a long attack time and hence gives distortion during the beginning of each message.

About SSB: I think that this receiver is better than the [Tecsun] PL-880 and comparable to the PL-660.

Reception is good on the short but sturdy telescopic antenna.

If you connect the receiver to a large external antenna, you will encounter many IMD signals. As there is no built-in attenuator, you will need an external one.

The manual is correct, but very short about the memories.

ATS logs its findings into the first pages, so if you want to keep some memories, log them a few pages away.

The available pages are different with bands, FM has its pages, SW its pages etc…

Unfortunately, memories don’t keep the mode on SW–only the frequency and selectivity. After calling a memory, you will have to choose between AM, USB and LSB.

I was totally unable to light the “Preset” label on the display ?!?

Display and backlighting are very nice.

Somewhat odd, but the squelch seems to work sometimes on other bands than Air band !

Ergonomics are reasonable, quality of construction is good for the price.

Overall, for the price, this receiver is quite outstanding.

Best regards from France .

Georges F6DFZ

Thank you, Georges! Excellent thoughts on the D-808. Your note about squelch control working outside the AIR band reflects what the Digitech AR-1780 does as well–hinting that firmware is very similar.

I fully suspect the D-808 is on the path to being one of the best radio values under $100 US.

Merci bien, Georges!

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XHDATA D-808 and Digitech AR-1780: Comparing size and appearance

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Digitech AR-1780 (left) and XHDATA D-808 (right)

Tuesday evening, I received my long-awaited XHDATA D-808 from AliExpress via the postal service. Yesterday morning, I unboxed it and started charging the included 18650 Li-Ion cell. I haven’t properly put it on the air yet but if you’re interested in some initial reports, check out these previous posts.

Dimensions

I was curious if the Digitech D-808 was identical in size to the Digitech AR-1780–I could tell even from D-808’s initial information that these two radios share a common ancestry.

To my surprise, they are not identical in dimensions! With that said, the differences are very marginal.

The D-808 is 7 mm wider and 2 mm deeper than the AR-1780.

To confirm measurements, I checked out the manufacturer specifications of both radios. Oddly, the specs also indicate that the AR-1780 should be 3 mm taller than the D-808 but I don’t detect this difference. I measure them to be equal in height.

The telescoping antennas are identical in height and number of segments.

Of course, as you can tell from the photos, the D-808 body is light grey in color while the AR-1780 is black.

Batteries

The Digitech AR-1780 uses four 1.5V AA cells while the XHDATA D-808 uses one less common 3.7V 18650 Li-Ion rechargeable cell (included).

External Power

The XHDATA D-808 (left) and Digitech AR-1780 (right).

The XHDATA D-808 has a standard 5V Micro USB port for internal changing. The AR-1780, on the other hand, uses a much less common 7V DC plug.

Right panels are identical.

Having a 5V micro USB port is a huge plus for the D-808, in my opinion! While travelling, I always have at least one micro USB charger.

Backlighting

The LCD display appears to be identical in size and display information, however the D-808 has blue backlighting while the AR-1780 has orange backlighting.

The Digitech AR-1780

The XHDATA D-808

Keypad

AR-1780 (top) D-808 (bottom)

Other than variations in button shapes and color, the only difference between the two radios is the location of the power button.

The Digitech AR-1780 keypad

The XHDATA D-808 keypad

As Guy Atkins mentioned in a previous post, the D-808 keypad buttons are almost flush with the radio body. The buttons on the AR-1780, on the other hand, are more prominent and tactile.

Accessories

The Digitech AR-1780 shipped with no accessories–the only two items in the box were the radio and the owner’s manual.

I was surprised when I opened the D-808 box to find a padded carry/travel bag, USB charging cable and even a compact external wire antenna.

Summary

There are actually few differences between the XHDATA D-808 and the Digitech AR-1780 in terms of physical appearance and function.

All in all, though, I prefer the D-808 package which ships with a carry bag, power cord and external wire antenna. In addition, the D-808 uses a standard and convenient Micro USB port for charging!

In terms of size/weight, the differences are negligible and wouldn’t sway my purchase decision.

Over the course of the next week, I hope to spend some time comparing their performance on the air. Though they appear to be from the same family, will one sibling outperform the other? We shall see!

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ETOW distributes radios to hurricane-ravaged Puerto Rico through amateur radio network

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In November, we posted an update on the Ears To Our World website with information about our most recent work in Puerto Rico.

After Hurricane Maria left the majority of Puerto Rico without power and basic services, at ETOW we waited for the right opportunity (after food, water and medical supplies were rushed in) to send self-powered radios to those still living without power and in need of basic community information.

Once US Postal Service delivery was restored to the island, we turned to our amazing volunteer (and SWLing Post contributor) Robert Gulley (AK3Q) to coordinate the process.

Robert contacted the Lares Amateur Radio Emergency Service (LARES) in Puerto Rico and asked for their assistance. Nelson Santiago (WP3B) with LARES enthusiastically volunteered to venture out into the community and distribute radios to those who needed them the most–families still lacking mains power. The LARES club distributed the radios effectively and efficiently–they also photo-documented everything.

The whole process was simply amazing to watch unfold.

Many thanks to Universal Radio who helped us quickly procure 15 self-powered radios for our initial pilot shipment. As of December, we’ve now sent and distributed an additional 40 radios–totaling 55 units to 55 families.

This whole project became a reality through our network of radio enthusiasts. We’re so grateful to everyone involved. Thank you!

Click here to view photos and read about this project at Ears To Our World.

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