Monthly Archives: December 2016

Chris tracks down sources of radio noise

spectrum-waterfall-sdr

Many thanks to SWLing Post contributor, Chris Smolinski, who shares this guest post from his blog, RadioHobbyist.org:


Yet Another !&*%$! Noise Source

by Chris Smolinski

The past few days, I have noticed higher than usual noise levels, generally on the lower frequencies, and particularly on the longwave band, including the 285-325 kHz DGPS band, where I run nightly SDR recordings, to later process the data and decode and detect DX DGPS stations using my Amalgamated DGPS app.

Thinking back to what new electronics devices have been added to the house, two came to mind, a new cable modem, and a new ethernet switch. The switch is up here in the shack, so it seemed to be a likely candidate. The switch is a D-Link DES-1008E 8-Port 10/100 Unmanaged Desktop Switch. It uses a mini USB port for power, using either the included AC adapter, or power from a USB port. When I installed it, I decided to not use the AC adapter, but rather a USB port on my UPS, figuring it was better to not add yet another potentially noisy switching power supply to the mix.

The test was easy, I just unplugged the power to the switch. Sure enough, the noise vanished. Great, the switch is a RFI generator. Or is it? As another test, I plugged it into a port on a USB hub. No noise. Hmm… so it seems that the noise is indeed from the USB port on the UPS. I did not notice any increase in the noise floor when I got the UPS a few months ago, but It’s something I should look into again, just to be sure. The UPS is a CyberPower CP1350PFCLCD.

Here’s a waterfall from the SDR, showing the DGPS band, 280-330 kHz. You can see where I changed the power to the switch from the UPS USB port to the USB hub, the bottom part of the waterfall is when the switch was still powered by the UPS (click to enlarge it):

pmuv3bc

I still have a noise source just above 305 kHz to hunt down.

Update

I decided to see what I could do to improve things, and reduce the noise floor.

Here is the baseline, after no longer powering the switch from the UPS:
qormmpg

First, I relocated the AFE822 away from the computer and rats nest of assorted cables behind it, powered from an HTC USB charger:
kljq7ef

The squiggly noise around 305 kHz vanished!

I then switched to an Apple USB charger / power supply, as their products tend to be a bit better made:
goyrdt4

Another improvement, the overall noise floor is a bit less now.

But can we do better? I then switched to an older USB hub for power to the AFE822, that I thought might be better filtered:
k0e8eaw

I then changed to a linear supply plugged directly into the AFE822. I don’t notice any obvious improvement? Maybe it even looks like a little more noise? Difficult to tell. You can see a DGPS station popped up on 304 kHz while I was switching things around, between the last two tests, it was likely Mequon, WI.

ocsavij


Thank you for sharing this, Chris! I find a wideband spectrum/waterfall to be such a useful tool for tracking down sources of noise. Not only can you “see” the noise, but you can measure its bandwidth and identify what portions of the dial it affects.

Follow Chris at RadioHobbyist.org.

Spread the radio love

Pacific Beat: ABC decision to halt shortwave broadcasts criticised

Radio-Australia-Banner(Source: ABC News)

ABC decision to halt shortwave broadcasts criticised

A decision by the ABC to halt shortwave broadcasts early next year has been criticised by a former manager of Radio Australia.

The shortwave transmissions to Asia and the Pacific will cease from January 31st next year, as alternatives such as FM and internet become more prevalent.

Former head of Radio Australia and subsequently a consultant on international broadcasting in the Pacific, Jean Gabriel Manguy, tells Bruce Hill the decision is short sighted.

Click here to listen and read on Pacific Beat’s website.

Spread the radio love

Radio Australia to end shortwave broadcast service on January 31, 2017

radio-dial

Like many SWLing Post readers, I’m a huge fan of Radio Australia’s service on 9,580 kHz. For ages, listening to their news headlines over shortwave has been a part of my morning routine. I’ve been listening to Radio Australia since I was 8 years old.

I’m going to miss this friend on the shortwaves.

(Source: Australian Broadcast Corporation Press Release)

ABC Exits Shortwave Radio Transmission

The ABC will end its shortwave transmission service in the Northern Territory and to international audiences from 31 January 2017.

The move is in line with the national broadcaster’s commitment to dispense with outdated technology and to expand its digital content offerings including DAB+ digital radio, online and mobile services, together with FM services for international audiences.

The majority of ABC audiences in the Northern Territory currently access ABC services via AM and FM and all ABC radio and digital radio services are available on the VAST satellite service.

ABC International’s shortwave services currently broadcast to PNG and the Pacific. Savings realised through decommissioning this service will be reinvested in a more robust FM transmitter network and an expanded content offering for the region that will include English and in-language audio content.

Michael Mason, ABC’s Director of Radio said, “While shortwave technology has served audiences well for many decades, it is now nearly a century old and serves a very limited audience. The ABC is seeking efficiencies and will instead service this audience through modern technology”.

The ABC, working alongside SBS, is planning to extend its digital radio services in Darwin and Hobart, and to make permanent its current digital radio trial in Canberra. Extending DAB+ into the nation’s eight capital cities will ensure ABC digital radio services can reach an additional 700,000 people, increasing the overall reach of ABC digital radio to 60% of the Australian population.

ABC Radio is also investigating transmission improvements to address reception gaps in the existing five DAB+ markets. It aims to ensure a resilient DAB+ service in every capital city, with enhanced bitrates and infill where necessary.

“Extending our DAB+ offer will allow audiences in every capital city in Australia equal access to our digital radio offering, as well as representing an ongoing broadcast cost saving owing to lower transmission costs,” added Michael Mason.

ABC International’s Chief Executive Officer Lynley Marshall said the reinvestment from closing international shortwave services would maximise the ABC’s broadcast capabilities in the region.

“In considering how best to serve our Pacific regional audiences into the future we will move away from the legacy of shortwave radio distribution,” Ms Marshall said. “An ever-growing number of people in the region now have access to mobile phones with FM receivers and the ABC will redirect funds towards an extended content offering and a robust FM distribution network to better serve audiences into the future.”

Once international shortwave ceases transmission, international listeners can continue to access ABC International services via:

Audiences can access further information via the reception advice line 1300 139 994 or via ABC Local Radio (Darwin & Alice Springs).

For more information
Louise Alley
P: +61 2 8333 2621
[email protected]
(ABC Radio queries)

Nick Leys
p: +61 3 9626 1417
[email protected]
(ABC International queries)

FAQs
Domestic and International

Spread the radio love

WRTH 2017: Available to pre-order

2017-wrth-coverMany thanks to SWLing Post contributors Andrea Borgnino and Tom Ally who’ve notified me that WRTH 2017 is available for pre-order!

Here’s a description from the WRTH website:

The Features section for this 71st edition includes articles on Remote Receivers, a Pacific Radio Adventure, The Mighty KBC radio station, CKZN St John’s, the International Radio Disaster Relief Project, and a reminiscence by Vagn Fentz. There are equipment reviews of the Icom IC-7300, Reuter Elektronik RDR55D, SDRPlay RSP, Wellbrook ALA1530LNP, and Bonito AAS300, as well as other articles, information and maps.

The remaining pages are, as usual, full of information on:

  • National and International broadcasts and broadcasters
  • Clandestine and other target broadcasters
  • MW and SW frequency listings
  • National TV by country
  • Extensive Reference section

Click here to pre-order your copy!

Spread the radio love

Oxford Shortwave Log: transatlantic MW DX catches with 200 metre Beverage – part 2

verdad-final

Hi there, here is the second set of reception videos for my transatlantic MW DX catches using the 200 metre Beverage antenna. Most of the signals originate from the United States and Canada, however, there is also a catch from Mexico – XERF La Ponderosa – which is a personal first and another from Bogotá, Colombia – Verdad Radio. I hope you enjoy them. Please do not hesitate to contact me if you would like further details regarding the Beverage design and/or construction. in the meantime, thank you for watching/listening and I wish you all great DX!



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.

Spread the radio love

Oxford Shortwave Log: transatlantic MW DX catches with 200 metre Beverage – part 1

worspectrum

Hi there, a few weeks ago I posted a couple of medium wave DX catches with the Elad FDM DUO and newly constructed 200 metre Beverage antenna. Since then (and following my trip to Brazil) I have uploaded several more catches, some of which I would like to share with you. It has become evident that the Beverage’s low-gain but high SNR properties resulted in a huge increase in the sensitivity of my entire set-up and as a result. I have achieved numerous personal firsts on the medium wave band, coupled with many other signals that I can only describe ‘best-ever reception’. If nothing else, this endevour has underlined the importance of utillising the best antenna possible for your particular circumstances. We’ve all read at some point, how, in many respects, the antenna is more important than the receiver – and these catches demonstrate how absolutely true that statement is. All of the reception videos were captured using the Elad FDM DUO running on a home-brew battery-pack and connected to the Beverage via a 50 Ohm input transformer.

Below is the first set of reception videos, most of which are signals from East Coast of the United States. However, there is also an absolutely booming signal from WGIT Puerto Rico into my QTH in Oxford UK. Part 2 will follow almost immediately, but in the mean time thanks for watching/listening and I wish you all great DX!


elad

 

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.

Spread the radio love

Guest Post: The Story And Restoration Of My Hallicrafters SX-42

halllicrafters-sx-42-front-panel

Many thanks to SWLing Post contributor, Arthur Smith, who shares the following guest post:


The Story And Restoration Of My Hallicrafters SX-42

by Arthur Smith

As a junior high student way back in 1978, I had a natural interest in radios. My dad was a ham radio operator, electronics engineer, and designer. We always had cool, exotic radios and electronic gadgetry around the house. He was also in the Korean War, in the US Army Corps of Engineers, with access to a wide variety of equipment. He often told me the story of how he became interested in radio at an early age, and how he saved up for expensive radio gear, with a little help from my grandparents. Back in 1946, Hallicrafters was THE brand to own, and their postwar designs from Raymond Loewy, were catching the eye of many enthusiasts. The SX-42 was being hyped up in Hallicrafters ads as the ultimate radio to own, one that could tune the shortwave and ham bands, and beyond. I don’t know the complete story, but prior to acquiring his SX-42, my dad also purchased an S-38 and S-40. Never satisfied with “good and better”, my father wanted “the best”. All 15 tubes and 50-plus pounds of boatanchor.

Always ambitious and industrious, he mowed lawns, repaired motorcycles, and did odd jobs for neighbors in his suburban Boston neighborhood. He worked smart, and worked hard. And that fall, bought his SX-42.

halllicrafters-sx-42-front2

The radio, we think, was about $279, which would make it the equivalent of almost $3500 in today’s dollars. He heard the start of the Cold War, and the Soviet Union’s Sputnik. And the birth of Rock and Roll on FM! He graduated high school, went away to the Korean War, serving two Tours of Duty. He came back home, and became an electronics engineer. And a licensed ham radio operator.

Moving ahead to 1978, and yours truly had the radio bug, in the worst way. Not as ambitious or as savvy as my father, a classmate, who was also a ham radio operator, told me about a National HRO he had, with some coils, and maybe needing some work. My Dad came home from work, and I just had to tell him about this great opportunity, which of course, would require his financial backing. At this point, the SX-42 and his other two Hallicrafters were seeing “backup” duty, having long since gone solid state in his post. “Hey, I’ve got an idea!” When a Dad says that, a son usually wants to run. Not in this case. “How about we give you my SX-42?!” Gee, twist my arm. I had loved watching those mesmerizing green back lit dials, S meter, and geared tuning knobs. Unfortunately for my classmate, he had to keep his National. Fortunate for me, I had my father’s SX-42!

That radio logged my first 100 countries, including QSL cards from countries and stations no longer in existence. It heard the fall of the Berlin Wall. And, it was at the heart of my school Science Project, which made Science Fair, featuring an experiment on longwire shortwave radio reception.

halllicrafters-sx-42-open

halllicrafters-sx-42-tubes Years later, the focus became family, a child, and a house. The SX-42 and siblings came with me, but this time, in boxes. After having seen a WW2 vintage Hallicrafters S-20R at a consignment shop a couple of summers ago, I thought how cool it might be to have Dad’s radios electronically and cosmetically restored.

The S-38 and S40 were in a box in my damp basement. While intact, they had a considerable amount of rust. Luckily, I was able to find a gentleman with great electronic and mechanical skills. He brought the S38 back to life, working and looking beautiful. And is working still on the S-40. As for the SX-42, that was upstairs in a box in my son’s closet. Dry and somewhat preserved, but with some corrosion on the control panel. And sadly, that iconic lock knob that switches between main tuning and brandspread tuning, had been lost in the move. I had to find someone who could take this project on.

After an extensive search, I found my man. An engineer with his own business, who was moving into retirement, and shutting his business down. He had restored an SX-42 a few years back, with amazing results. I had to lure him out of retirement! Which I did after a few emails back and forth. And, he was within driving distance! First warning was “do not power the radio back up under any circumstance- you’ll fry the wafers on the bandswitch!” I resisted temptation, as I had read online that these were notorious for failure, usually to some original capacitors that leak over the decades.

After 13 months replacing every capacitor, virtually every resistor, and vacuum tube, the iconic radio was coming back to life, in a great way. The transmission and gears in the tuning was re-lubricated. During the restoration process, a date was found stamped on the chassis of October 25th, 1946. Could it be?

img_7367-02-12-16-06-57-1Hallicrafters had advertised in the Oct, 1946 issue of Radio News that “The first hundred are always the hardest to build.” This, coupled with the fact that none of the chassis circuit had been modified, lead my restorer to believe that my radio was one of the first 100 SX-42’s that Hallicrafters had built!

The front panel was stripped and treated, professionally painted and silkscreened. The cabinet and apron bead blasted, repainted, and clear coated. It came back home with me last month. A month after it turned 70.

halllicrafters-sx-42

As you can see here, the radio looks stunning. And, with all the Hallicrafters Service Bulletin mods implemented, sounds and performs better than I remember. Maybe more importantly, we were able to locate a replacement brake lock knob for the tuning shaft, even with the “Lock” decal and arrow showing to rotate it counterclockwise. It just would not have felt complete without that little knob- and, it works!

halllicrafters-sx-42-frontEngaging a set of what essentially are brake pads, you rotate it once to disengage the main tuning and engage the bandspread tuning. Again, and you’re back to main tuning.

halllicrafters-sx-42-ad

This radio will always remain a truly cherished family heirloom, and will be my son’s someday. Complete with the original owner’s manual, and Darth Vader-like R42 Reproducer (speaker).

halllicrafters-sx-42-front-panel

Hopefully to live on for another 70-plus years, and hear more history along the way.

-Arthur Smith Worcester, MA


Wow–!  Thank you so much for sharing your story with us, Arthur. No doubt, your SX-42 will certainly outlive all of us and will hopefully continue to be passed down through your family. What a wonderful story.

Spread the radio love