Tag Archives: Software Defined Radio

Tropical Band DXing at home with Elad FDM DUO and Wellbrook ALA1530 active loop

2-jungleRecently I have spent a little more time listening out for Tropical Band stations from my shack in Oxford UK, attempting to emulate some of the very nice signals I have previously recorded out on DX’peditions. The obvious problems with this (and they are numerous) include the relatively weak signal strength of many tropical band stations, the ubiquitous blanket of QRM, resulting in generally poor SNR, lack of space for a large antenna……need I go on?! Fortunately, the Elad FDM DUO has proven to be a very senstive and selective receiver, capable of, at times, incredible SNR, coupled with almost limitless signal conditioning options and SSB, SYNC, ECSS etc. Throw the Wellbrook ALA1530 active loop into the mix (not literally!) and you have a very powerful Tropical Band receive set-up. The Wellbrook is able to null most (although not all) QRM in my shack and that really can make the difference between simply observing a carrier and actually hearing audio. Clearly one cannot expect to hear DX at home under heavy QRM as well as you might outdoors, however, the following stations were logged in the past month or so, with respectable signals, with the ALA1530 indoors:

Video links also follow below, thanks for reading/ watching.

Direct link to Oxford Shortwave Log video; Radio Logos 4810 kHz, Peru

Direct link to Oxford Shortwave Log video; Radio Cultura Ondas Manaus 4845 kHz, Brazil

Direct link to Oxford Shortwave Log video; AIR Bhopal 4810 kHz, India

Direct link to Oxford Shortwave Log video; Rádio Educação Rural 4925.2 kHz, Tefé, Brazil

Direct link to Oxford Shortwave Log video; Radio Mosoj Chaski 3310 kHz, Bolivia

 

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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The RTL-SDR V.3 dongle on shortwave: Gary details setup and reviews

Many thanks to SWLing Post contributor, Gary Wise (W4EEY), for the following review of the RTL-SDR dongle:


RTL-SDR-RTL2832U-e1471375714199

Based on your blog post on the Version 3 release of the RTL-SDR dongle I had to buy one. I ordered mine from Amazon for $25, and it came in two days. I have an earlier version of this unit that was VHF and above only. What intrigued me about the V3 was the possibility of HF reception in the Direct Sampling mode (without an up converter). So I had to try it.

I used the RTL-SDR Quick start guide at RTL-SDR.com/qsg. While I did not see any mention of Version 3, I hoped that the software that was linked would be adequate. As I am using a Windows 7 laptop, I downloaded the Zadig driver installer, along with copies of SDR# and HDSDR.

Getting the dongle going was pretty straightforward. And right away I was receiving VHF and above signals. The I/O driver defaults to Quadrature demodulation and this was what is used to receive VHF. But what about HF?

It took me awhile to figure out that you select Direct Sampling in the setup screen for the driver. In SDR# software this is found by clicking on the gear wheel icon.

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Under sampling mode select Direct Sampling (Q branch).

In HDSDR you select the EXTIO icon.

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Here you select the Q Input under Direct Sampling.

Note that with both you must use the Q input.

With the telescoping antennas included with the dongle, I received very few signals (of very poor quality). But I had read that the unit can only receive HF with a substantial antenna, so I moved the laptop to my hamshack.

I use an ELAD antenna distribution amplifier for my HF receive antennas.

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It was easy to use a spare output from the ELAD ASA15 to drive the antenna input of the RTL-SDR V3.

Wow, what a difference!

First up was international shortwave. Here’s a shot from my Alinco General Coverage receiver on 9955 kHz this morning using my 260′ beverage antenna (pointed toward Europe). S9 on the Alinco S Meter.

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And here’s the same signal on SDR#.

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There was a delay in the audio coming from the PC versus from the receiver, but other than that, reception was identical. Audio quality was very good.

I then moved to the 20M Amateur Radio band. USB audio demodulation.

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The little dongle worked! It is not what I would call my first choice in receivers, but it will demodulate AM and SSB just fine.

I did not try it on CW as I ran out of time.

I also tried the HDSDR software, which worked equally as well (but I think I prefer SDR# for ease of use).

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All in all, if you have or can put up a good antenna for HF, the little $25 dongle is in, my opinion, worth trying out.

73,

Gary
W4EEY

Click here to purchase the new RTL-SDR–$24.95 shipped on Amazon.com.


Thank you, Gary, for not only giving a quick evaluation of the RTL-SDR’s HF performance, but for describing how to setup HF reception via SDR# and HDSDR.

Over the years, I’ve gotten probably hundreds of emails from readers who would like to try their hand at SDRs, but were cautious about investing. For many years, a 3rd generation SDR would set you back at least $300-400. At $25 shipped, the RTL-SDR V.3 is an SDR receiver that is accessible to anyone who can afford a fast food meal or a few cups of Starbucks coffee. My how times have changed!

Once I get a few transceiver reviews off of my table, I might do some side-by-side HF comparisons between the RTL-SDR and a few of my other SDRs. 

Thanks again, Gary!

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mySdrPlayback: new version adds a DGPS decoder

mySdrRecordingWaterfall

Many thanks to Chris Smolinski, at Black Cat Systems, who recently announced new mySdrPlayback features:

I’ve released a new beta of mySdrPlayback, which is a Mac app that lets you easily go through SDR recording files. It works with recording files produced by SdrDx and SpectraVue, as well as Perseus.

This version adds a DGPS decoder that decodes from every DGPS channel in parallel, looking for messages. Makes it super easy to DX DGPS stations, just record overnight, then run the recordings through the app in the morning, and you get a list of all of the decoded messages from the various stations.

Click here to view the information and download page at Black Cat Systems.

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Brazilian DX heard in Oxford UK, with venerable Sony ICF-2001D

Hi there, I thought I would share some Brazilian shortwave catches with you, obtained using my Sony ICF-2001D receiver and 200 metre experimental longwire. The first is Radio Bandeirantes, Sao Paolo on 9645.4 kHz. This is a station that I’ve only heard once or twice previously, but was received with excellent signal clarity and strength recently, using my deployable longwire antenna. I would rate this station as moderately difficult to receive with reasonable discernibility. The second is Radio Novo Tempo from Campo Grande, on 4894.9 kHz. This station I would rate as difficult to hear with discernible audio. The key is always signal-to-noise, thus moving yourself out of the ubiquitous blanket of QRM most modern environments endure will usually achieve this and of course coupled with sufficient space outdoors to erect a larger antenna will hopefully also improve signal strength. My final video on this post is Radio Nacional Brazilia on 6180 kHz. I would regard this station as quite easy to hear well; their effective TX power towards Europe is around 2 MW, however, outdoors, this station can literally boom in, with what might be perceived as local-AM signal strength. I hope you enjoy watching the videos and seeing/ hearing what’s possible with a modest set-up. As for the Sony ICF-2001D? Well the design is more than 30 years old, but in my opinion at least, still one of the very best portable shortwave receivers ever manufactured. Thanks and 73.

 

Direct link to Oxford Shortwave Log for reception video of Radio Bandeirantes

 

Direct link to Oxford Shortwave Log for reception video of Radio Novo Tempo

 

Direct link to Oxford Shortwave Log for reception video of Radio Nacional Brazilia

 

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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Radio Fana 6110 kHz Ethiopia; excellent SNR with Elad FDM DUO

FanazaThe Elad FDM DUO makes for a fantastic receiver, in both standalone mode and via the FDM-SW2 software. Thus far it has been demonstrating this by outperforming the Sony ICF-2001D in many of my reception tests using an experimental longwire antenna. Bear in mind that whilst this might not be such a surprise, the Elad without the FDM-SW2 software driving it has no SYNC, which is often invaluable for Tropical Band DXing. To make the point further, here is a wonderfully clear signal from Ethiopia, with, in my experience at least, exceptional signal-to-noise.

My 200 metre longwire is still very much a work in progress. I am in the process of building a termination resistance box, receiver-end termination suitable for high and low impedance inputs and earthing straps for metre-long copper pipes that will remain in-situ. When I have completed these tasks, I will record a video because I know some of you are interested in the details. For now though, it just remains an experiment – 200 metres of wire and very late nights/ early mornings!  Recorded at the ‘DX woods’ in Oxford UK at 03:23 hrs UTC on 31/07/16. Thanks for watching.

Direct link to Radio Fana reception on the Oxford Shortwave Log YouTube channel

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

 

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Creating a global network of inexpensive remote SDRs

U_Twente_SDR

Many thanks to SWLing Post contributor, Mark Fahey, who replies to Ivan’s preliminary review of the V3 RTL-SDR dongle:

With Shortwave SDRs (the receiver dongle) now costing less than $20, the time has come for us to set up a global group of receivers that we can all log into at will!

RTL-SDR-RTL2832U-e1471375714199Have a look at SDR.hu – here you can put your SDR dongle on line and share it with anyone and they have full control of the receiver just as if it was in their own shack.

Imagine receivers scatted around the world – South America, Tropical Asia, Africa! The cost is now virtually nothing, all that is needed is the dongle, antenna (doesn’t have to be anything special – even a long wire or whip) and a small low cost CPU (Raspberry Pi for example).

Anyone else interested in this dream? Lets get together, get some receivers setup and then talk about our experience in a kick-ass presentation at the 2017 SWL WinterFest in PA!

Also… I am very soon to receive my KiwiSDR matched to a BeagleBone CPU. It will be online at SDR.hu and four remote listeners will be able to tune the full shortwave bands independently, its like my own Twente setup! Heaps of others are getting receivers online in the next few months with KiwiSDRs, this is going to be totally amazing!

I agree, Mark! While there is already quite a network of remote SDRs and receivers in the world, the barrier of entry keeps getting lower and lower. It’s hard to imagine that $25 can buy an SDR that natively covers the shortwave and mediumwave bands!

There’s only one other requirement for an online SDR that Mark didn’t mention: a decent Internet connection. Sadly, this is the only thing keeping me from hosting a remote SDR here at my home. I considered purchasing a KiwiSDR like Mark, but my upload speed (0.2-0.3 mbps) is so terrible and so unreliable that I could only host one listener at a time at best. You can bet that as soon as my ISP upgrades our service, I’ll launch a web SDR as well.

Of course, I’m willing to bet that most SWLing Post readers have more than enough bandwidth to host a $25 remote receiver! Let’s make Mark’s vision a reality!

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Ivan’s preliminary review of the new RTL-SDR dongle on shortwave/mediumwave

RTL-SDR-RTL2832U-e1471375714199Many thanks to SWLing Post contributor, Ivan Cholakov (NO2CW), who shares the following video review of the new RTL-SDR dongle on the shortwave and mediumwave bands.

Ivan notes:

This is daytime reception comparison. Nighttime could be a different picture. [The RTL-SDR dongle] tunes and frequency is 100% on spot.

Using SDR Sharp you have several AGC settings to play with and find the best combination. The best setting seems to vary with band and signal strength.

The [SDR receiver] comes with a short (20 cm) and long (120cm) telescopic antennas. Neither one is usable for HF or Medium wave.

When ordering the radio you have to get a USB extension cord for the dongle. When plugged in directly into a laptop and then antenna coax it can become bulky. You also will most likely need an SMA adapter to BNC and SO 238.

I hope this helps.

Click here to view on YouTube.

Many thanks for sharing your video, Ivan! For a $25 SDR, I’m pretty impressed so far! I’m also very curious how it will hold up to stronger nighttime signals and, especially, adjacent signal interference. I imagine it may be prone to overloading as well. Please keep us posted!

Have any other Post readers tested the new RTL-SDR dongle on HF? If so, please comment! 

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