Category Archives: AM

Radio World: Time to “sound off to the FCC about using all-digital on the AM band”

Many thanks to SWLing Post contributor, Dan Robinson, who shares the following note posted by Paul McClane at Radio World:

For those who want to sound off to the FCC about using all-digital on the AM band — either “fer it” or “agin it” —- the comment deadlines now are set.

Comments are due March 9, reply comments are due April 6.

As RW has reported, the FCC recently released a notice of proposed rulemaking to establish rules governing all-digital broadcasting by AM radio stations in the United States.

Read the NPRM here. The NPRM number is 19-123.

Click here to read at Radio World.

As we mentioned yesterday, this proposal is certainly in the final stages at this point.

Final step for proposed rule to allow AM broadcasters to use all-digital transmissions

Many thanks to SWLing Post contributor, Paul Evans, who notes:

The Federal Register has today published the proposed rule for AM stations to go digital. This is close to the final step.

https://www.federalregister.gov/documents/2020/01/07/2019-27609/all-digital-am-broadcasting-revitalization-of-the-am-radio-service

Comments before 2020-03-09, replies by 2020-04-06.

Thanks for the tip, Paul!

Mike reviews the Retekess TR608 AM/FM/AIR/SW receiver

Many thanks to SWLing Post contributor, Mike S, who shares his assessment of the Retekess TR608. Mike writes:

For this model, the company marketing electronics under the Retekess brand seems to be using a different supplier compared to the previous digital-radio-plus-memory—card-player products. The result is a more traditionally styled multiband DSP radio which runs on (gasp) traditional AA batteries. Its feature set takes inspiration from the Radiwow R108 and original CCrane Skywave, but with mixed results (albeit at a fraction of the price). It delivers decent performance for its price class but more serious listeners would be advised to spend a little more on a more established model.

Pros

    • Usual set of features: sleep timer, alarm, scanning, auto memory fill.
    • Uses replaceable alkaline or NiMH “AA” cells.
    • Decent sensitivity across the board.
    • Full shortwave coverage.
    • Frequency display is large and contrasty.
    • Dial light is effective and can be disabled. Display is readable without it, even in dim light.
    • No annoying keypad “beep”, so no mad rush to discover how it can be disabled.
    • Speaker can play reasonably loud without distortion.
    • FM reception is solid with good frequency response and stereo reception through headphones; this also activates a display indicator.
    • MW/SW reception is NOT plagued by digital hash bleeding through from the processor as with most other models in this price range!

Cons

    • Significantly larger than expected.
    • Unfortunately the added cabinet space is not utilized for a more wide-range speaker; audio is tinny.
    • Clumsy mounting of one spring in the battery compartment on my sample makes it almost impossible to insert the third AA battery without risking damage.
    • Many keypad buttons are so tiny and almost flush with the cabinet, that they are difficult to press.
    • Lens over LCD display is molded and unpolished with moiré distortion at some viewing angles.
    • Air band reception marred by birdies, bleed-through from other bands, and lack of squelch.
    • Volume control defaults back to level “10” under some circumstances (the manual warns about this).
    • Confusing 2-level LOCK function requires close attention to almost microscopic indicator on LCD.
    • No battery level indicator.
    • Although the manual advises that batteries can be charged using the 4.5V coaxial socket, no charging indicator is obvious.
    • Rotary knob, used for both tuning and volume adjustments, has no detents and so can easily spin off target.
    • Assigned function (no indication) depends on whether the tuning or volume buttons on the keypad were the last to be used.
    • No fine tuning outside of pre-programmed increments.
    • MW selectivity is a bit too wide for congested night reception.
    • MW reception occasionally exhibits weird artifacts; ghost images, sputtering audio on marginal signals, and “processed” sounding voice audio. Don’t know if these are DSP or AGC related, or a mixture of both. I have observed the same thing with the Eton Mini and other inexpensive portables using marginal DSP implementations.

SHOWSTOPPER ALERT: MW band channel assignments marred by 9kHz-centric firmware bug. Even after changing to 10kHz channel spacing (undocumented), the CPU still “thinks” in 9kHz assignments for direct input. Entering FREQ-1-0-1-0-FREQ should get you to 1010 kHz; but it actually lands on 1018 kHz because that is the nearest channel in the 9kHz band plan. You are now stuck in frequency step hell, as the up-down frequency keys still operate in 10KHz mode but do not know they are now off bandplan. UP/DOWN yield 1028/1008, not 1020/1000. The only way to recover is to enter a MW frequency that is the same in both bandplans, or to power off and double-reset the step rate resulting in all memories being lost.

Thank you so much for the review, Mike.  It sounds like this little receiver isn’t ready for prime time yet. The issues with frequency steps on the mediumwave band is certainly a show-stopper for anyone in North America. Indeed, it sounds like mediumwave reception, in general, is mediocre at best. At least the receiver isn’t plagued with internal noises.

With pricing around $29.99-$39.99 it’s certainly a bargain radio. But I’m sure you’re thinking what I’m thinking: you pay for what you get.

The Retekess TR608 can be purchased on eBay or Amazon.com (affiliate link).

Video: “Tribute to a Century of Broadcasting”

Many thanks to SWLing Post contributor, Bill (WD9EQD), who writes:

You probably have already seen this, but from The ARRL Letter, November 21, 2019:

Art Donahue, W1AWX, of Franklin, Massachusetts, has posted his “Tribute to a Century of Broadcasting” video in recognition of the centennial of formal radio broadcasts. The video features a complete scan of the AM broadcast band (530 – 1700 kHz), with station IDs for all 118 AM radio channels.

Following is ARRL Link:

Radio Amateur’s “Tribute to a Century of Broadcasting” Video Debuts on YouTube

Following is YouTube link to the video:

It was a lot of fun to watch the video, hear the on-air id checks, and compare what he heard to the list of stations that I have heard.

Thanks for sharing this, Bill–I missed reading about this in the newsletter.  This goes to show you that the AM dial is chock-full of stations here in North America. Those who complain that it’s “dead” simply aren’t listening.

Sangean DT-140 & SR-32: New Sangean AM/FM radios


Many thanks to SWLing Post contributor, Michael Schuster, who writes:

The Sangean SR-32 from the 2020 catalog.

Attached image [above] is extracted from a PDF of the 2020 catalog, it shows the
upcoming Sangean DT-140 and SR-32.

Wondering if the SR-32 (from the almost-defunct “slide rule” series) uses DSP-as-analog tuning like its larger sibling with speaker.

Thanks for the tip, Mike!  Yes, I’d be willing to bet that the SR-32 is DSP-based. I might have to check these out further.

It’s also nice to see that they also feature both the ATS-909x and ATS-405 shortwave portables in the 2020 catalog!

Click here to download the Sangean 2020 catalog (PDF).

Coastal DXing with the AirSpy HF+ Discovery and a homebrew passive loop antenna

Last week, we packed the car and headed to coast of South Carolina.

The trip was a bit impromptu but through the creative use of hotel points, we scored a two bedroom ocean front unit with a fantastic little balcony.

The vacation gave me an excuse to test the new passive loop antenna my buddy Vlado (N3CZ) helped me build recently.

The loop design came from AirSpy’s engineer and president, Youssef Touil.

This passive mag loop takes advantage of the new AirSpy HF+ Discovery‘s exceptionally high dynamic range. Youssef had reported impressive results, so I had to build one.

Vlado had a length of Wireman Flexi 4XL that was ideal for this project. The only tricky part was penetrating the shielding and dielectric core at the bottom of the loop, then tapping into both sides of the center conductor for the balun connections.  Being Vlado, he used several lengths of heat shrink tubing to make a nice, clean and snag-free design.

The results were truly exceptional. I spent most of my time on mediumwave from the hotel balcony because I was determined to catch a transatlantic signal.

Check out the spectrum display from my Microsoft Surface Go tablet:

Our ocean front hotel was inundated with noise, but I still managed to null out most of it and maximize reception using the passive loop. I simply suspended the loop on the balcony rocking chair–not ideal, but effective and low-profile.

Want to take a test drive?

If you’d like to experience this portable SDR setup, why not tune through one of the spectrum recordings I made?

Click here to download the spectrum file [1.7GB .wav].

The recording was made on November 17, 2019 starting around 01:55 UTC–I chose it at random and have yet to listen to it myself. You’ll need to open this file in AirSpy’s application SDR# or a third party SDR app that can read AirSpy .wav files.

Stay tuned…

I’m writing an in-depth report of the HF+ Discovery, my experiments with this setup and AirSpy’s soon-to-be-released passive loop antenna for the January 2020 issue The Spectrum Monitor magazine. Spoiler alert: I am truly impressed with the wee little AirSpy HF+ Discovery. It’s a powerhouse!


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FCC proposes allowing AM stations to go all-digital

(Source: Radio Insight)

The FCC approved today the adoption of a rulemaking allowing AM stations to transition to all-digital operation.

Hubbard Radio’s “The Gamut” 820 WWFD Frederick MD has been operating in all digital mode since July 16, 2018 in collaboration with HD Radio owner Xperi. The new rulemaking will allow AM stations to go all-digital and establish operating parameters for doing so.

The FCC today also is opening a comment period on the removal of the programming duplication rule adopted in 1992. The rule limits AM or FM stations from airing more than 25% of total hours in an average broadcast week of duplicative programming. The rule applies to commercial stations in the same service (AM or FM) with substantial contour overlap that are commonlyowned or subject to a time brokerage agreement.[…]

Click here to read the full article.