Category Archives: AM

Guest Post: Backpack Shack 2.0 – a homebrew wideband magnetic loop antenna

19 Replies

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

Backpack Shack 2.0

by TomL

Like Audiophile speakers, it could be said that “antennas are forever”.  They tend to not become obsolete like all of our favorite electronic gear (a good one is worth the trouble).  And antennas don’t care if the signals are digital or analog formats.  They are “Digital Ready” (LOL)!

The flimsy “Backpack Shack” prototype broadband loop antenna created over a year ago had found a permanent home on the porch for general listening.  I started itching to make a new one that was even more portable.  To paraphrase an old saying, “The best antenna is the one you have with you!”

The new design criteria were:

  • Retain the broadband design of the amplified loop on a sturdy form
  • Shrink the size to fit into a backpack without heavy stand or long pole
  • Build a modular platform that would allow quick setup
  • Be something durable that can last me 20+ years of use
  • Allow the loop to be rotated and tilted by hand
  • Be easy to hook up to any kind of radio
  • and later on, Enhance the design as a true Ferrite Sleeve Loop

The Backpack:  The existing photo backpack was slightly too bulky.  Found on Amazon was an Adidas Excel II XXL backpack on special sale with plenty of tall compartments and minimal padding. It is surprisingly roomy and comfortable to wear with springy shoulder straps and padded mesh backside!

Sturdy Basic Form:  The Backpack Shack loop was originally built on 14-inch quilters loops (three of them) in a parallel configuration.  I thought to simplify the whole thing and just use one wide loop.  But what should I use for a sturdy form?  The quilters loops were too flimsy and PVC pipe was too heavy.  I stumbled upon a nice company called FlexPVC which allows sales to the public of various kinds of PVC pipe.  Their Thinwalled Air Duct PVC looked promising.  It is thinner than regular PVC but having standard inside dimensions and comes in custom-cut lengths.  I decided 10-inch diameter would fit best inside the Backpack.  FlexPVC even sends you a small booklet of the U.S. Constitution and the Bill of Rights with your order!  🙂

Thinwalled PVC form

The “length” as they call it would be my form width for the copper strip.  I thought 3-inch would be nice but decided 4-inch was better.  Supposedly, the aperture + the width of the “radiant element” is the main design consideration for loop performance.  So, I figured that as wide an element as I could get away with was better.

Stable Mounting:  Now, how to mount this thing!  I eventually went back to my photographic web links and found nice rig equipment for video cameras.  The typical construct is made of 15mm tubes of aluminum or carbon fiber (CF) and fit into adapters that allow attachment to other adapters or clamps.  Non-metallic CF seemed ideal, so, I ordered a whole bunch of items from eBay to experiment piecing together two 10-inch CF tubes mounted inside the PVC form. Then, I attached two 15-inch CF tubes to the bottom of the PVC with something called a “Cheese Rod” that has multiple holes.  Those two tubes are attached to another “Cheese Bar” which is attached to a second Cheese Bar on a cheap two-axis tripod head.  This is a simpler photo version with quick release plate that locks pan-tilt separately and only cost $16.

Cheese Rod attached to bottom of PVC

Pan-tilt head assembly with Quick Release plate

For the base, I had an unused Sirui T-2005X 5-Section Aluminum Travel Tripod going to waste, so it was pressed into service. Very good tripod: can hold 26 lbs. (forged aluminum, not cast aluminum), legs can flare out for stability, and folds to 14.5-inches.  Now, everything could come apart and fit into the Excel II Backpack!

Critically, the video rig standardization in the DSLR industry allows me to pick and choose parts from any cheap manufacturer but end up with a system that looks and feels coherent, is both sturdy and light, and can come apart if needed.  Also, the pan-tilt photo head is really easy to work to get maximum peak or null out of the loop when mounted to a camera tripod.

CF Problem:  CF tubes have no internal threads like that of  aluminum tubes.  So, I attached two, small 3/8-1/4 inch tripod adapters to the ends of a 3/8-inch oak dowel inside each CF tube destined for the inside of the PVC (ridiculously, I used up almost a whole bottle of super glue to get these 4 tiny pieces to attach to the oak dowels).  This is definitely a weakness of my design but I could not figure out any other way to get the CF to mount inside the PVC form.  Then, added to this is something wonderful I found at Ace Hardware called “speed nuts” to help push ipwards against the incoming stainless steel socket head screws of exact length. With jam nuts, internal lock washers, wing nuts, and strategic use of Thread Locker Blue, I finally had enough confidence that this thing would hold together!!

Speed Nuts pushing upward against incoming screws

Super-glued 3/8-1/4 inch adapter on end of oak dowel inside CF tube

Bottom assembly (Cheese Rod, Cheese Bar, and 15mm Clamp screwed together + wires to a BNC connector)

Ferrite Sleeve Loop:  Halfway through this project, I became determined to use the ferrite bars and rods I had purchased from eBay mid-summer 2017 to turn this antenna into a real Ferrite Sleeve Loop but with a broadband design (At that time, I ended up purchasing the very last quantities of 62x12x4mm ferrite bars from the Lithuanian eBay seller, just because they were becoming scarce plus some other 8mm ferrite rods).  The Thinwalled PVC is 5mm thick, perfect for this type of application.  The video equipment could handle the extra weight.  I had just enough ferrites to line the inside of this PVC form with two bars side-by-side all the way around the inside (plus some shorter ferrite rods at the top and bottom).  Some quick setting JB WELD Kwik Weld epoxy made quick (and permanent) attachment of these ferrites to the inside of the PVC.  Now, the bars stick out from the PVC form by about ½-inch on each side, so I do have to be careful it does not get abused and chip off any of the exposed ferrite.

Soviet ferrite bars and rods, 400 ui (initial permeability).

Note: Using Gary DeBock’s Performance estimate (diameter * length), this calculation predicts that this FSL 10.75-inch loop should perform similarly to Gary’s 10-inch models using 140mm long Russian ferrite bars (mine probably performs less than his since I am not using carefully tuned (to Mediumwave) litz wire on higher permeability 1500 ui ferrites like he does).

See:  Summary of Gary DeBock Ferrite Sleeve Loop designs

But, “*WHY* do FSL antennas work?!?!” is still the very intriguing question….   🙂

See:  Graham Maynard report on Ferrite Sleeve Loop antennas

Preamplifier:  I believe one advantage of building a portable, table-top loop antenna like this is that all the connections are short.  This allows me to use a Preamp right at the connection point of the loop. Indeed, this was critical since passive testing (no Preamp, nor ferrites) found that this loop is somewhat deaf at the MW frequencies and uninspiring on the SW bands. This was true even when connected to Antenna A of my SDRPlay RSP-2 and the internal Low Noise Amp cranked all the way up.  So, I ordered the DX Engineering RPA-2 Preamp. This adds to the weight somewhat since I also needed a 12V battery supply using a 10-cell holder of NiMH AA batteries and 2.1mm plug.

See:  Short discussion about Preamp placement to antenna

The question arises that I “should” impedence-match the output of the loop before anything else to  increase “maximum gain”.  Well, for one thing, a tuner or matching balun would just introduce loss as soon as the wire comes out at the base of the antenna. The slight net increase in gain does not seem worth it; the signal/noise ratio rarely changes when introducing a device that is meant specifically for matching a transmitter to a load.  Receiver circuits don’t care as long as there is enough signal to process.  That is what the Preamp is for.  The Preselector is for rejecting out-of-band (i.e., increasing signal/noise ratio + eliminate overloading the electronics).

See:  Good discussion why antenna tuners don’t matter

Preselector:  Now that the signal level was satisfactory, I added on the Cross Country Preselector, which I like very much since it is passive, lightweight, and well made.  I had looked at other amplified preselectors but found the schematics showing the preselector came first in the path.  I needed the preamp first, so that is how I ended up with separate units.  In fact, the reverse configuration performs with worse signal/noise ratio because of the loss inherent in the preselector.  In this case, it is definitely needed to amp the loop first with a high quality preamp (high IP3 rating)!

Automatic Bypass:  The Cross Country unit has a great feature in the “off” position as an automatic bypass.  This feature is very important since I do not need a Preselector in the circuit all the time.  The bypass feature also allows the RSP-2 to monitor a large swath of spectrum without having the Preselector cut the bandwidth.  The DX Engineering RPA-2 Preamp also has a circuit bypass when the power is off – very nice feature!  So, I can keep all the antenna wires connected if I don’t want to use either device on a certain band – necessary for my broadband antenna design and use with an SDR.

Modular Portability:  Another advantage of a table top loop is portability.  Because of the modular design, I can put this into checked baggage (except for the AA batteries and laptop) and have it available for DXing in unexpected places.  It could be useful when traveling and I cannot string wire into a tree but want something better than a whip antenna on a small radio.  Everything fits into the bag and can be setup on a balcony, inside a car with a sunroof, or on a park picnic table.

A third advantage is that a short antenna could be clamped to one of the tubes and then connected directly to Antenna B of the RSP-2 for listening to higher frequencies (like a Comet W100RX). This expands the usefulness of this project as a platform for multiple antennas!

Finished Loop and accessories assembled together

Performance:  Good on MW and very good on Shortwave.  It is not in the league of Wellbrook antennas but it is useful as long as the RSP-2 LNA is kept down around  -7 on MW and -4 on SW, else it overloads.  The photo gear makes it easier to use than the original loop.  I found that one side has a slightly larger receiving lobe than the other which is OK in practice.  The null is very sharp and takes a little finesse to null out an offending station by almost 20 dB on MW and 15 dB on SW (the photo head can lock in place).  It is handy to have the pan-tilt arm point directly at a station to maximize the null since the arm is mounted perpendicular to the loop.  I will look for a clear plastic bag to cover the antenna and electronics to use in wet environments.

A larger loop would work better but this one is to use wherever I can.  Also, my work laptop is noisey and shows birdies and spikes here and there on the bands, so I added a large ferrite bead to the USB computer end which helps.  But I don’t have to use an SDR, I just have to change a connector and radio.  It was expensive and fun to build – I guess I am just LOOPY!

Happy Listening,

Tom Lebryk

Appendix I, Field Recordings 27-Jan. 2018 between 21.26-22.36 UTC:

Note 1:  All Transmitter locations referenced from web site short-wave.info at time of recordings

Note 2: My location in a shelter at Dick Young Forest Preserve (41.84334, -88.38133)

Note 3: Moderate but declining solar wind with no flares, Kp Index = Calm (1)

9.420 MHz – Voice of Greece booming in like it was next door:

9.640 MHz – China Radio International (weakly) in Spanish from Kashi-Salibah western China:

9.620 MHz – HCA, Kununurra Australia beamed at Korea:

9.395 MHz – WRMI booming in:

9.445 MHz – All India Radio clear as a bell, quite nice to hear!

9.490 MHz – KNLS World Christian Radio, Madagascar in Chinese:

9.600 MHz – Vatican Radio, Tinang Philippines in Chinese:

9.610 MHz – Voice of Turkey, Emirler Turkey (endless string & flute music):

15.000 MHz – WWVH, Hawaii (halfway, I checked on WWV at 10 MHz to make sure it was on the air, weird propagation, defintely not due to my antenna!):

Appendix II, Parts List:

  • 1 FlexPVC 4-inch Custom cut X 10-inch diameter Thinwall Air Duct PVC
  • 1 pair each size of 15mm CF rods 10-inch and 15-inch
  • Video Camera Rig parts: 2 Cheese Bars, 3 Rod Clamps, and 1 Cheese Rod
  • 1 cheap Neewer pan-tilt photo head with quick release plate
  • 10 screw adapters for tripods 3/8-to-1/4 inch
  • 1 copper sheet roll cut to size (or Aluminum foil instead)
  • 4 Flat Speed Nuts 1/4-20 from Ace Hardware
  • 1 Oak Dowel 3/8” diameter from a local hardware store, cut as needed
  • 1 DX Engineering RPA-2 Modular Receive Preamplifier
  • 10 AA Powerex Precharged NiMH batteries for the Preamp + 10x AA snap battery holder + CCTV 2.1mm snap plug
  • 1 Cross Country Preselector
  • 1 SDRPlay RSP-2 with SDR Console software on Lenovo laptop
  • 1 Belkin USB printer cable with large ferrite bead looped through 3 times on computer end
  • 1 Sirui T2005X travel tripod
  • 1  Adidas Excel II XXL backpack (gaudy Solar Orange color!)
  • Velcro brand 7/8” x 23” One-Wrap velcro strips

Plus shielded cables, BNC and SMA adapters, Thread Lock Blue, tie wraps, rubber bands, super glue, JB WELD Kwik Weld epoxy, speed nuts, jam nuts, acorn nuts, wing nuts, internal lock washers, nylon nuts and screws, and 1/4”-20 socket head screws of various lengths as needed.

What a brilliant project, Tom! What I love is the fact that you consider your unique requirements prior to starting a project and base your design on your specific needs. Additionally, you see each design as an iteration. Fantastic job! No doubt, you’ll log numerous hours with this antenna in the field!  Thank you for sharing your detailed design notes, process, list of materials and even audio clips with us.

Spread the radio love

Doctor Vlado repairs the Panasonic RF-2200 (Part 1)

33 Replies

Panasonic RF-2200 at Hamvention

Last year, at Hamvention, I picked up a Panasonic RF-2200 for $70. It came with the original box, manual and was in superb cosmetic condition.

The seller told me that over the years he exclusively used the radio to listen to a local FM station.

At that price, I didn’t hesitate to make the purchase even if this would have simply been a non-functioning parts radio for my other RF-2200.

After I brought the radio home, I unpacked it and gave it a quick test.

FM worked brilliantly. Mediumwave and shortwave, however, were essentially deaf. I made the assumption that the ‘2200’s switches and pots likely needed cleaning with DeoxIT. The next day, I was leaving for a two month trip to Canada though, so I packed the RF-2200 back into its box and set it to the side of my shack table.

Fast-forward to yesterday…

While digging around my shack, I re-discovered the boxed RF-2200. Since I was planning to visit my buddy Vlado (the best radio repair guy in the world) yesterday evening, I thought I’d take the RF-2200 and do a proper contact cleaning. Several of the RF-2200’s switches and pots cannot be easily cleaned without removing the chassis.

(Click photos to enlarge.)

Vlado is familiar with the RF-2200 and since it’s not the easiest radio to work on, I asked for his expert hands on the job. Within seconds of handing him the radio, he plugged it in, tested the switches and pots, then removed the back cover (disconnecting the battery compartment leads) and then the front cover (disconnecting the speaker leads).

The magic behind the RF-2200’s classic analog dial:
Vlado offered a word of caution to anyone operating on their RF-2200: as you can see in the photo below, the dial string snakes around the front of the radio and is very close to some key components. You must exercise caution when having a soldering iron tip near the string, or using lubricants nearby.I didn’t realize this, but by the time Vlado started taking apart the RF-2200, he had already determined that even though the contacts needed cleaning, this wasn’t the source of the audio problem for the MW and SW bands.Vlado expertly pulled out the pot for the FM/AM/SW selection–not an easy task–began cleaning it, testing it and re-soldering contacts.

Vlado determined the pot was actually in good shape, thus started testing the rest of the circuit.

After a few minutes of performing tests and getting intermittent performance, he determined that at least one, if not more, of the RF-2200’s caps need to be replaced. Of course, neither one of us was terribly surprised. At this point though, it was getting late and I had an early wake up time in the morning, so I left my RF-2200 with Vlado.

Am I worried about this prognosis?  No, not in the slightest…

Doctor Vlado is on the job!

Vlado will have the RF-2200 back on the air in no time, working as well as it did when it was new. He’s actually performed a similar RF-2200 repair for an SWLing Post reader and I’m willing to bet this repair job is relatively simple compared to most he encounters (including the Icom IC-7200 he recently repaired after it was hit by lightening!).

I’ll try to post a “Part 2” update with photos of the RF-2200 repair.  Follow the tag: Panasonic RF-2200 Repair

Spread the radio love

A follow-up review of the PK Loop C-LOOP-HDSW6-18 antenna

20 Replies

In 2016, I purchased portable shortwave magnetic loop antenna designed and built by Paul Karlstrand in Australia. I posted a “preliminary” review of this antenna in 2016 and since then have taken this loop on many travels.

SWling Post contributor, Ron, recently noted that Jay Allen reviewed one of Paul’s inductively-coupled mediumwave magnetic loop antennas. Jay gave it good marks on performance as it compares favorably with the Grundig AN-200, Select-A-Tenna M, and Terk Advantage AM–even having a performance edge due to it’s larger loop diameter. (Note that Paul makes a number of loop sizes–click here to download PDF of catalog.)

In Canada last summer, I used the PK Loop on a number of field radio listening sessions.

But what really sets the PK Loop apart from its competitors is its durability. PK’s Loops are built to be incredibly rugged. I routinely throw my PK Loop antenna in bags/packs and–unlike most of my other radio components–never worry about how it’s padded or protected. There’s little to damage unless you’re intentionally abusive to this antenna. My Grundig AN-200 antenna, on the other extreme, has exposed coated wires around its loop that I’m constantly concerned about harming in transit.

Following up…

Ron’s message reminded me that I never followed up after posting a preliminary review of the PK Loop C-LOOP-HDSW6-18 in 2016.

Shortly after publishing the review, I had a fantastic opportunity to evaluate how well the PK Loop would perform in a typical hotel room. My buddies Eric (WD8RIF), Miles (KD8KNC) and I stayed overnight in a hotel on Wright-Patterson Air Force Base during our mini National Parks On The Air DXpedition.

My Elecraft KX2 connected to an external random wire antenna.

The hotel room was indeed dense with RFI.

We hooked my Electraft KX2 to both the PK Loop and to a simple random wire antenna.

Without a doubt, the PK Loop was much better at mitigating radio noise than the wire antenna we hung on the inside of the hotel window.

Unlike most modern hotels, however, this one actually had operable windows, so we tossed the random wire out the window and made another comparison. In this case, the external wire antenna consistently outperformed the PK Loop, no doubt because it had the advantage of being outside the radio noise cloud within the hotel’s walls. It goes to show that outdoor antennas–even if simply hanging from a room window–will almost always outperform comparable indoor antennas.

A late evening listening session on the condo balcony.

Last summer, I also spent two months in a condo near Québec City. The condo was dense with RFI–the PK Loop made the experience much more bearable.  The loop couldn’t completely eliminate all of the persistent wideband noise, of course, but it did reduce noise to a level that I could enjoy some of my favorites like RRI, VOG, VOT, REE, WRMI, RNZI and even weaker stations in North America like the BBC and DW.

Even the shortwave version of the PK Loop can null out QRM to some degree by rotating the loop perpendicular to noise. I became quite adept at this by the end of our stay.

Summary

Since I purchased the PK Loop, it’s been a constant travel companion and I highly recommend it. I don’t believe you’ll find a more durable or effective portable mag loop antenna on the market.

PK Loops are built by Paul Karlstrand in Australia who has a stellar reputation with his customers. For those of us living outside Australia, there will be additional shipping costs, but they’re negligible and Paul has been exporting these loops for many, many years. I believe I received my loop within a couple of weeks of ordering it.

Click here to view a PDF catalog of Paul’s loops and products.

As an added convenience, Paul also has an eBay store where he sells the following antennas:

This year, I plan to purchase PK’s largest mediumwave loop, the model HDXLTAM that boasts a 20″ diameter. Please comment if you have experience with this loop or any of Paul’s loops!

Spread the radio love

A review of the Sangean HDR-16 AM/FM HD Radio

30 Replies

It’s funny that, while I’ve written dozens and dozens of radio reviews over the years, I’ve never written even a single review that included an HD radio.

Well, the time to begin is now: HD radio, here we come.

Those readers living outside North America may be scratching their heads, asking, “What exactly is ‘HD radio?’” To answer in clear terms, I’ll turn the question over to Wikipedia:

HD Radio is a trademarked term for iBiquity’s in-band on-channel (IBOC) digital radio technology used by AM and FM radio stations to transmit audio and data by using a digital signal embedded “on-frequency” immediately above and below a station’s standard analog signal, providing the means to listen to the same program in either HD (digital radio with less noise) or as a standard broadcast (analog radio with standard sound quality). The HD format also provides the means for a single radio station to simultaneously broadcast one or more different programs in addition to the program being transmitted on the radio station’s analog channel.

Got that?  In brief, HD radio is digital radio broadcasts that occupy the same FM/AM spectrum currently allocated for analog broadcasts.  Wikipedia adds:

[HD radio] was selected by the U.S. Federal Communications Commission (FCC) in 2002 as a digital audio broadcasting method for the United States, and is the only digital system approved by the FCC for digital AM/FM broadcasts in the United States.

For my own part I had mostly ignored HD radio, assuming there would be few stations to listen to from my rural home location. That is, until recently, when I purchased a car that has built-in HD radio reception. I was impressed by the number of commercial stations I found that I can receive via HD radio. In truth, only a handful of the mainstream HD station offerings had any appeal for me, but I really took notice when I received a commercial-free jazz station via the HD2 channel of my favorite NPR member station, WFAE.  Having been a jazz fan since I studied music in college, I was intrigued: could a portable HD radio receive this distant HD station reliably?  I had my doubts; moreover, I really didn’t want to purchase a radio, then be obligated to send it back if it didn’t receive anything.

Instead, I contacted Sangean.  The company was more than happy to send me a loaner radio for review. I requested the HDR-16––at the time it was Sangean’s most affordable HD portable, one about which a number of SWLing Post readers had expressed their curiosity.

Overview

The Sangean HDR-16 is a simple radio with a modern design. The chassis is a glossy black hard plastic and feels substantial. It has a useful fold-out carry handle and substantial telescoping whip antenna. The front face features a 16-character two-line backlit display, five function buttons, five dedicated preset buttons, and a dedicated power button. On the right side of the radio you’ll find a dedicated (two function) tuning knob and smaller volume/tone knob. The left side of the radio features an “aux-in” port, a “rec-out” port, an earphone jack, and a 7.5 volt “DC-in” port.

Features

  • HD Radio digital and analog AM / FM-Stereo reception
  • 10 Memory Presets (5 FM, 5 AM)
  • PAD (Program-Associated Data) Service
  • Support for Emergency Alerts Function
  • Automatic Multicast Re-Configuration
  • Automatic Simulcast Re-Configuration
  • Auto Ensemble Seek
  • Real Time Clock and Date with Alarm and Sleep Function
  • 2 Alarm Timer by Radio, Buzzer
  • HWS (Humane Wake System) Buzzer and Radio
  • Snooze Function
  • Tone & Bass Control
  • Information Display for Channel Frequency, Call Sign, Radio Text, Audio Mode, Service Mode,   Signal Quality and Clock Time
  • Easy to Read LCD Display with Backlight
  • “Battery Low” LED Indication
  • Auxiliary Input for Additional Audio Sources
  • Record Output for Connecting to Hi-Fi System or Recording from Audio Program
  • I/O Jacks: DC In, Line-Out (Rec-Out), Aux-In, Headphone and HD / FM Rod Antenna

Audio

The HDR-16 sports two 2.5” front-facing speakers that deliver crisp audio that can be customized with simple treble/bass EQ settings. I found increasing the treble just a bit and the bass quite a lot produced the best audio for music broadcasts.  Even the default audio settings are pretty good, however. The HDR-16 doesn’t have the rich fidelity of the Eton Field BT or the Tecsun S-8800, but it does offer stereo sound that is room filling and pleasant. Sangean obviously took audio fidelity seriously when designing the HDR-16.

The left side features AUX in, Record Out, Earphone and a DC power port.

Note that the the HDR-16 sounds especially good in spoken word/news broadcasts.

Operation and Ergonomics

The Sangean HDR-16 is a very simple and intuitive radio to operate. I sorted out all of its functions simply by following button and knob labels, but even the most tech-challenged person in your family could give the owner’s manual a single read-through and operate the HDR-16 with ease.

But let’s get one gripe out of the way…perhaps a case of simplicity gone too far:  the HDR-16 only has five station preset buttons. Five! Actually, it offers a total of 10 memory allocations: five for AM, five for FM. Still…even in my rural market, I can easily program ten station memories on an FM radio, especially since HD Radio channels offer that many more new options. But the HDR-16 forces me to curate my presets down to a mere five stations per band. In my view, this strict limitation is an unfortunate design oversight.

Performance

The HDR-16 is an AM/FM radio that receives both legacy analog broadcasts and HD/digital broadcasts on both bands.  I’ll break down performance by mode and band below.

HD performance

Digital FM

Of course, what I was most eager to explore was FM HD reception from my home. After unpacking the HDR-16, I placed the radio on my kitchen countertop and initiated an HD Seek scan via the dedicated button on the front panel. Couldn’t have been easier.

The HDR-16’s scan/seek functionality is impressively quick.

I quickly found there were a number of commercial radio stations––about four, to be exact––that I could instantly receive with little to no effort. Mind you, I live in a relatively rural market in a mountainous area. No doubt, if I initiated an HD radio search in LA or New York City, the dial would be chock-full of terrific stations.

All of the HD radio stations I received were either local, or powerhouses from neighboring markets. I was disappointed to find that I could not receive my most desired station, WFAE HD2.

I then moved the HDR-16 to a south-facing window and tuned to WFAE’s FM frequency of 90.7. I found I could easily receive the analog station and its RDS information, but still had no option to listen to HD2. After tinkering with antenna position and placement in our kitchen window, a sweet spot for reception was found, and voila! WFAE HD2 came in fully decoded, without any drops.

Recalling the days when I used to tinker with the rabbit ears on a TV, once I found that sweet spot, I carefully left the HDR-16 alone and didn’t move it further. As a result, over the course of the afternoon, I had nearly 100% copy from WFAE HD2.

I knew WFAE was a fringe station and checked their propagation map for HD radio. My location was actually outside of the fringe reception area.  I looked up GPS coordinates of the WFAE 90.7 MHz transmitting site and found it is exactly 101 miles/162 km from my home.

Obviously, the HDR-16 is a sensitive HD radio on FM!

Via the 1/8″ stereo AUX in jack, you can use the HDR-16 as amplified stereo speakers for your favorite portable music device.

Turns out, FM HD reception is pretty flaky when dealing with fringe stations, though.

Over the course of the next weeks, I tried the HDR-16 in different positions and locations.  There was only one spot in my house where the HDR-16 could get reliable reception of WFAE HD2. When I started the evaluation, it was August; our trees were still had a canopy full of green leaves. Sangean kindly allowed me to hang onto the HDR-16 to see if reception improved in late fall when all of the leaves were off the trees. As I write this review, we’re in winter, and the tree branches are bare. But curiously, reception of WFAE’s fringe signal is about the same as before. Nor have I noticed any difference in the reception of other commercial stations.

The HDR-16 accepts four C cells.

My conclusion is that the HDR-16 is a true performer on the FM band in HD mode. I have no other HD radios with which to compare it, but based on what I know about HD radio, this rig certainly exceeded my expectations.

Digital AM

The HDR-16 can also receive AM HD signals. There are far fewer AM HD broadcasters on the air, however. In fact, one of the first in our region dropped their HD coverage last year due to a lack of listeners.

With that said, I’ve read that a number of HDR-16 owners who live in the vicinity of AM HD broadcasters love the fact they get a digital audio quality signal on the AM band. One SWLing Post reader recently told me he even gets the occasional night-time AM HD DX signal with an HDR-16.

There are no local AM HD stations near me, and despite my best efforts, I never decoded an AM HD broadcaster in the evening. Perhaps if I did a little research and planning, then inductively coupled the HDR-16 to a MW mag-loop antenna, it would increase my chances.

Analog performance

FM

I’ve done almost as much analog FM listening on the HDR-16 as I have HD listening.

The HDR-16 can hold its own with most of my portable radios, in that it can receive all of my benchmark FM stations, and even some fringe analog stations.

RDS decoding also seems to be quite effective, even with fringe stations.

AM

AM (mediumwave) performance is surprisingly good. Perhaps my expectations were low, but I expected analog AM reception to be an afterthought. Or perhaps to have acceptable AM HD reception, Sangean had to put some extra effort into overall AM performance. Honestly, I don’t know, but what I do know is I’ve been pleased with the HDR-16 on the AM band. The AGC is pretty stable, noise relatively low, and sensitivity better than on other similar digital radios.

Many of my shortwave portables, like the PL-660, PL-310ET, and PL-880, could outperform the HDR-16 on the AM band, but frankly performance is on a level that it’s going to please most radio listeners. I’ve even had luck getting solid copy from one of my favorite AM DX stations, CFZM (740 kHz) with the HDR-16.

Should you purchase the HDR-16 for AM/MW DXing? No; there are better radios for this exclusive function. But for what I would consider a “bonus” band on a digital radio, I’m very pleased.

Summary

Every radio has its pros and cons. When I begin a review of a radio, I take notes from the very beginning so that I don’t forget some of my initial impressions. Here’s the list I’ve developed over the time I’ve spent evaluating the HDR-16.

Pros:

  • Excellent FM HD radio reception
  • Excellent FM analog reception
  • Very good AM broadcast band reception for a modern digital portable
  • Good audio from internal stereo speakers
  • Nice carry handle that tucks away
  • Both auxiliary-in and -out jacks for audio
  • Dedicated earphone jack
  • Design is compact, sleek, yet sturdy
  • One of the more affordable HD radio options currently on the market
  • Easy access to bass/treble tone controls through volume multi-function
  • HD seek functions work on all but the most fringe stations

Cons:

  • No ability to internally recharge C batteries
  • No external antenna jack to improve FM HD reception with directional antenna
  • Limited to just 10 memory presets (five for AM, five for FM)
  • Fringe HD stations may continuously flip between digital and analog, annoying when HD station content and analog broadcast content are quite different Update: I recently tried to have the receiver replicate this behavior but it did not, so I’m striking it from the cons list!

Conclusion

Can I recommend the HDR-16? Absolutely.

If you’re looking for an AM/FM HD radio that’s well-rounded, simple to operate, and provides quality audio, I don’t believe you could go wrong with the HDR-16. The HDR-16 has proven to me that it’s a worthy FM HD receiver as it’s sensitive enough to snag fringe HD stations with some reliability. I’m certain I could design a small FM antenna and get 100% copy from my favorite HD station 101 miles from my home.

I think the HDR-16 would be a safe purchase for anyone, as it’s easy to operate, relatively compact, and makes the process of seeking HD stations a breeze.

I’m especially pleased with the HDR-16’s AM analog reception. It pleasantly surpassed my expectations and makes it easy to recommend the HDR-16. The HDR-16 is one of the few HD portables that also includes AM HD reception.

If you’re looking for a well-rounded HD and analog portable, grab the HDR-16. If you’re looking for a mediumwave DX machine, go for a benchmark mediumwave radio instead, like a GE Super Radio, C.Crane CC Radio 2E, CC Radio EP Pro or even a “Holy Grail” vintage Panasonic RF-2200.

I like Sangean’s high gloss finish (though it does show fingerprints rather well!).

I’m very tempted to purchase the HDR-16; I’ve found it difficult to justify, though. Living in a rural location, I have fewer HD stations to choose from––all but one are commercial, chock-full of advertising, and lack any real variety and diversity. I am very pleased with WFAE’s jazz station on HD2, but it’s hard to justify a $100 purchase just to receive one station over the air. Especially since I can easily stream WFAE HD2 from my Sangean WFR-28, Como Audio Solo, or Amazon Echo.

But if I lived in an urban area, with the accompanying diverse radio market, I wouldn’t hesitate to buy the HDR-16.

Here are some retail options for the HDR-16––at the time of this writing, almost all retailers price it at $100–Amazon, New Egg and some eBay vendors offer free shipping:

In closing…I should add that there’s another tempting Sangean HD radio coming just around the corner: the HDR-14. It’ll be priced lower than the HDR-16, and is even more compact, suggesting that it might make an excellent portable for the traveler. I will certainly review the HDR-14 when it’s available, as I’ll be very curious if its equally effective at snagging fringe HD FM stations.  Note that the HDR-14, unlike the HDR-16, has only one speaker, so I doubt audio fidelity will match that of the HDR-16, which should be a better choice for home and local use.

Spread the radio love

Pacific Island Results from Gary DeBock’s Hawaii Ultralight DXpedition

2 Replies

Clearing the southern coastline of Maui en route to the Big Island. (Photo by Gary DeBock)

Many thanks to SWLing Post contributor and intrepid Ultralight DXer, Gary DeBock, who shares this DXpedition summary with recordings:

Kona, Hawaii DXpedition– Pacific Island Results

by Gary DeBock

From December 17-20 a Mini-DXpedition was conducted in Kona, Hawaii with a 5 inch (13cm) “Frequent Flyer” FSL antenna and a 7.5 inch (19cm) loopstick C.Crane Skywave Ultralight radio.

The FSL antenna was a new type designed to easily pass through TSA security checkpoints at airports, and provide inductive coupling gain roughly similar to that of a 4 foot air core box loop. South Pacific island reception was generally good from 0630-0800 UTC daily, but usually became problematic after that when powerful Asian stations tended to drown out the exotic Pacific island stations as sunset progressed over Japan, Korea and China. By 0900 daily only the most powerful Pacific island stations on 621, 846, 1098 and 1440 had much of a chance of surviving the Asian signal onslaught, and even some of those were drowned out. During a similar visit to Kona, Hawaii with identical gear in April (DXing at the same motel) the Pacific island stations were generally stronger, and had no co-channel competition from the Asians from 0800-1030 UTC. As such the South Pacific results during this trip were slightly down from April, although there were still plenty of strong signals to record.

The new 846-Kiribati on Christmas Island was a star performer as the strongest island DU station, with local-like signals shortly after the Hawaiian sunset each evening. Despite this it had an intermittent transmitter cutout issue, with the signal failing to transmit at odd intervals (including one stretch with six signal dropouts within one minute, as documented in an MP3 linked below). In addition 846-Christmas Island’s programming had a variable time delay with that of distant 1440-Kiribati in Tarawa, with both a 19-second and 35 second time delay noted. This may be related to the transmitter cutout issue, with the time delay changing after a major dropout. DXers looking for a parallel with 1440 should keep this programming quirk in mind. Although both 846 and 1440-Kiribati signed off at the usual 0936 UTC time on the first couple days of the trip, they had both switched to a 1009 UTC sign off on the last couple of days. Whether this is a permanent programming change is unknown, but the loud 1000 Hz audio tone is still being broadcast before power is cut, resulting in a very easy way to distinguish the stations at sign off time (even in heavy domestic QRM).

846 and 1440 weren’t the only exotic DU’s with transmitter issues. 621-Tuvalu came down with distorted audio on December 18th, a problem which got worse and worse on the remaining two days. By the last day it was sounding very garbled, making a bizarre combination with 621-Voice of Korea’s buzzing Japanese service transmitter. Whether 621-Tuvalu has repaired its garbled audio is also unknown.

540-2AP was somewhat weaker than it was in April, while 558-Radio Fiji One was MIA during the entire trip (probably because of Asian QRM). Efforts were made to track down 630-Cook Islands but only a weak UnID was recorded. 801-Guam was possibly received during a Pyongyang BS/ Jammer fade, but 990-Fiji Gold was given a golden knockout by 990-Honolulu. 1017-Tonga showed up for a couple of good recordings, but got slammed by Asian co-channels after 0830. Efforts to track down 1035-Solomons ran into heavy 1040-Honolulu splatter, while 1098-Marshalls became the only Pacific island station to have stronger signals than in April. Its overwhelming signals after 0700 daily were one of the bright spots in Pacific island reception. Finally the new 1611-DWNX in Mindanao, Philippines was received at a strong level at 0855 on December 19th, apparently with a major boost from sunset skip propagation.

540 2AP Apia, Samoa, 5 kW Christian worship music at a good level through the T-storms at 0751 on 12-17, but not nearly as strong as in April:

Click here to download audio.

621 R. Tuvalu Funafuti, Tuvalu, 5 kW This station had very strong signals until around 0800 on most evenings, when it usually began to be pestered by Asian QRM (China, N. Korea and NHK1). It also came down with a garbled audio issue on December 18th, which continued to get progressively worse until I left Hawaii. Sign off time is still around 1006, but by that time it ran the gauntlet of powerful Asian co-channels during the December propagation.
Local employment offers read by the usual lady announcer at an S9 level at 0750 on 12-18. This was the last undistorted audio signal recorded from the station during this trip; after this the audio went “south”:

Click here to download audio.

Guest speaker in Japanese-accented English, followed by local island-type music at 0835 on 12-18– the first sign of audio distortion:

Click here to download audio.

Full Radio Tuvalu sign off routine at 1003 on 12-18, but with China QRM initially. Tuvalu’s signal prevails during the national anthem, but the audio distortion is quite noticeable. The carrier apparently stays on for over a minute after the audio stops:

Click here to download audio.

630 UnID While trying for the Cook islands (Rarotonga) I came across this weak Christmas music with English speech at 0742 on 12-17, although this could just as easily be a west coast domestic station playing the “exotic” to fool a hopeful DXer. Walt says this station is a notorious underperformer:

Click here to download audio.

801 UnID (Guam?) Apparent Christian female vocal music received during Pyongyang BS/ Jammer fade at 0931 on 12-18, but no definite ID clues:

Click here to download audio.

846 R. Kiribati Christmas Island, 10 kW This newly rejuvenated station had awesome signals, and was overall the strongest Pacific island station received. Of all the Pacific island DU’s it faded in at the earliest time after sunset, and maintained its strength even during strong Asian propagation — as long as it managed to transmit without its signal dropping out. Unfortunately this seemed to be a pretty common occurrence while I was in Kona. Island-type music at typical S9 strength at 0735 on 12-18:

Click here to download audio.

This segment at 0620 UTC on December 17th features 6 signal dropouts within one minute:

Click here to download audio.

This segment at 0944 UTC on December 18th is even worse– 9 dropouts in 90 seconds:

Click here to download audio.

After a prolonged 846 transmitter dropout it seemed like the programming time delay between the distant 1440-Kiribati on Tarawa Island and the new 846-Kiribati on Christmas Island would change. On December 17th I recorded two different time delays– 19 seconds, as in the following recording (the MP3 starts out on 846 at 0635, switches to 1440 at the 1:02 point, then switches back to 846 at the 1:34 point, with a 19-second time delay evident between the 1440 and 846 programming (846 lags behind):

Click here to download audio.

Later on the same evening there was a 36 second time delay between 1440 and 846, with this MP3 starting off on 1440 at 0645, and switching to 846 at the 11 second point:

Click here to download audio.

1017 A3Z Nuku’alofa, Tonga, 10 kW Female native language speech at a very good level at 0858 on 12-19:

Click here to download audio.

Somewhat weaker through the T-storms on 12-17 at 0734:

Click here to download audio.

1098 R. Marshalls (V7AB) Majuro, Marshall Islands, 25 kW This station was very strong in Kona with its island music every night, and rarely had any Asian co-channels.
S9 Island music and native language speech (and possible ID) across the 0700 TOH on 12-17:

Click here to download audio.

Equally strong island music and native speech at 0813 on 12-18:

Click here to download audio.

1440 R. Kiribati Bairiki, Tarawa, 10 KW Somewhat weaker than its rejuvenated 846-Christmas Island parallel (which has variable programming delay times, as explained above), this home transmitter could hold down the frequency until around 0800 every night, after which it was usually hammered by JOWF in Sapporo. Despite this it often put up a good fight until its new sign off time of 1009, and it continues to use the loud 1000 Hz tone right before the power is cut (an awesome aid for DXers hoping to ID the station through heavy QRM).

Typical island language speech and strength level at 0830 on 12-18, just as it is starting to get jumbled by JOWF (a Japanese female “Sapporo desu” ID is at 25 seconds):

Click here to download audio.

Full sign off routine at 1005 on 12-19, including the National Anthem and the 1000 Hz tone before the power is cut. The tone gets through the JOWF QRM like a DXer’s dream:

Click here to download audio.

1611 DWNX Naga City, Mindanao, Philippines, 10 kW (Thanks to Hiroyuki Okamura, Satoshi Miyauchi and Mauno Ritola for ID help) Received at 0855 on 12-19, this station was a mystery until the Japanese friends matched the advertising format with that of a new, unlisted station which just came on the air in the Philippines. The propagation apparently got a major boost during sunset at the transmitter:

Click here to download audio.

73 and Good DX,
Gary DeBock (DXing at the Royal Kona Motel with a 7.5″ loopstick C.Crane Skywave Ultralight+
5 inch (127mm) “Frequent Flyer” FSL antenna.

Demo video of the “Frequent Flyer” FSL antenna:

Click here to view demo on YouTube.

Thank you for sharing your Hawaiian DXpedition with us, Gary! Your mediumwave DX catches with modest equipment reminds us all that when HF propagation is poor, there is still so much signal hunting below 2 MHz!

Interested in Ultralight DX? Check out archived posts in our Ultralight DX category.

Spread the radio love

The Minerva Tropic Master: a portable WWII era morale radio

11 Replies

If you’re a regular here on the SWLing Post, you’ve no doubt discovered that I’m a fan of vintage radios.

Lately, I’ve been attempting to let go of some of my vintage gear to give my favorite rigs proper shelf space and dedicated antenna time. To keep temptation at bay when I visit flea markets or hamfests (like Hamvention and the one in Shelby, NC) I now focus on WWII era radios; specifically “morale” radios that were used for troop entertainment. I’ve two morale sets: the Scott Marine Radio Model SLRM (technically, a commercial version of a Navy set) and the Minerva Tropic Master.

I purchased this Minerva set off of eBay a couple years ago. I got it for $50 or $60, if memory serves (the seller originally wanted $180 + shipping!). He claimed it worked, but after I asked him a few questions prior to making an offer and learned that “working” meant the speaker prodeced a noise and the backlight worked. I made a low offer and he accepted.

Last year, I took Minerva over to my buddy, mentor and boat anchor doctor, Charlie (W4MEC). Charlie discovered the radio had many issues and several poorly implemented repairs. Still, in a few short weeks, when parts arrived he brought the girl back to life.

With front cover closed.

The Tropic Master is a portable eight tube receiver that covers both the AM broadcast band and shortwave bands from 5.5-18 MHz. It can be powered by AC or DC. It was “tropicalized” to withstand extreme heat and humidity. The internal speaker produces mellow, full-fidelity audio and the volume can be increased to room-filling.

To give you a taste, this morning I tuned the Tropic Master to my in-house AM transmitter on 1570 kHz which was being fed audio from The UK 1940s Radio Station (my favorite Internet radio station). This particular clip features Jay Lawrence’s excellent show, From Stateside:

Click here to view on YouTube.

The Tropic Master is portable and even has a fold down handle on top of the chassis. Though substantial, it must be the lightest of all of my vintage metal chassis radios.

Tuning isn’t exactly precise, but it does the job and is a pleasure to use. It’s quite sensitive on both shortwave and mediumwave. Last night, she was tuned to the Voice of Greece on 9420 kHz–I probably listened to two hours of Greek music while her eight tubes warmed the shack.

Who could turn down a radio with this speaker grill?

If you ever find a Minerva Tropic Master at a flea market or hamfest, I say adopt one! It’s a beautiful receiver and like all good vintage radios has a story and history of its own.

Post readers: Any other Tropic Master owners out there or do you have a morale radio? Have you ever spotted a Tropic Master in the wild? Please comment!

Spread the radio love