Category Archives: Radios

Guest Post: National HRO-500 Unboxing and Initial Tests

Many thanks to SWLing Post contributor, Dan Robinson, for the following guest post:

HRO-500 Unboxing and Initial Tests

by Dan Robinson

It is amazing that in these days of waning shortwave broadcast activity, there are still those occasional time capsules — radios that appear on the used market via Ebay or private sales that are new in the box or close to it. Think of it — after 50 or 60 years, these fine examples of radio history can still be found, complete with their original boxes, shipping crates, manuals and accessories.

We have seen a number of these in recent years. Several years ago, a Panasonic RF-9000, one of the Holy Grails of radio collecting, appeared on Ebay, in new opened box condition. As rare as that was, it’s even rarer to find tube or solid state communications receivers from the 1950’s and 1960’s. Such is the case with National HRO-500s, which were considered high level receivers when they came on to the market in the mid-1960’s.

In 2016, a seller in California advertised a great rarity — a HRO-500 that he said he purchased in 1967, complete with its original shipping crate.

It was said to be in new/unopened condition, which of course raises concerns about the unit itself since it has never been used since leaving the factory. While that radio apparently sold (the asking price was $2500), I was astounded to recently see another HRO-500. It was not in New/Unopened condition, but the closest one comes to it. Among a collection purchased by the seller, the radio was in its original crate, inside of which was the original box with the original National Radio Co fabric cover, with original strips of fiberglass insulation. The manual is still in its plastic wrap.

I decided to do a video for SWLing Post readers, and provide some still shots, as this time capsule of radio history was opened (this was likely only the 2nd or 3rd time it was opened since leaving the factory, the last time by the seller for photography for the Ebay ad.

The good news — many HRO-500s on the used market exhibit failure of the PLL lock circuit. While the PLL lock light on this particular radio does not light up, its PLL does operate on every band. This radio arrived with one metal cap for the MODE knob missing, so I’ll be searching for a spare. And the dial calibration clutch knob appears to be frozen, another minor issue that does not impact operation of the radio.

All in all, this was a fantastic find and I hope SWLing Post readers enjoy the video and stills:

Video

Click here to view the video on YouTube.

Photos

Thanks for sharing your notes, photos and video, Dan!

The National HRO-500 is a gorgeous radio and it looks like you’ve got a prime specimen. I’m so impressed it came with the original wooden crate, exterior box and radio box! Amazing.

We’re looking forward to your assessment of the HRO-500 once you’ve have it on the air a while.

SWLing Post readers: In March, I had the good fortune of visiting Dan Robinson’s home and taking a tour of his impressive radio collection. I took a number of photos with Dan’s permission. I’ve been incredibly busy as of late, but as soon as catch my breath after travels, I’ll post the photo tour. I’ll also post photos from our tour of the NSA museum in Fort Meade, MD. Stay tuned!

eBay find: The Braun T-1000

2 Replies

Many thanks to SWLing Post contributor, David Korchin (K2WNW), for sharing a link to this Braun T-1000 on eBay.

With two days left on the auction and already 73 bids, I believe David is correct in assuming this radio might fetch upward of 900 Euro. Braun models certainly tend to fetch premium prices. The T-1000 is possibly my favorite Braun portable and I certainly wish I had one. I love Dieter Rams’ designs.

Note that shipping seems very modest at 6 Euro worldwide via DHL. I would check on that pricing prior to bidding if outside of Europe. This seller has a 100% rating with over 400 transactions on eBay. Again, thanks for the tip, David!

Click here to view on eBay.

Any lucky SWLing Post readers own a T-1000? I’d love a review!

On Sale: Executive Editions of Satellit and Traveler III

Tecsun S-8800 – The Birdie Problem

17 Replies

[UPDATE: This issue has now been solved. Click here to read our full review.]

Recently, Tecsun announced and released onto the market the new S-8800 receiver. Thomas Witherspoon has indicated that sensitivity, selectivity and audio fidelity are very good for this new unit.

BUT…..in his post on February 12, 2017, entitled Tecsun S-8800 Update, Thomas discovered that his new S-8800 has a serious fault, one that could potentially drive radio enthusiasts mad! In tuning around the dial, he found the radio has many “birdies”. In the same post, he notes that Bertrand Stehle F6GYY also found birdies on 4 spots in the mediumwave band and 63 frequencies across the entire shortwave spectrum. Not good!

In reading the comments that followed Thomas’ post, I noted that a few writers seemed a little confused about what a birdie is and how it differs from radio frequency interference. Hopefully, the following explanation will shed some light.

The term “birdie” is, I guess, derived from the type of sounds that are emitted from a receiver having this problem. It can take on a variety of forms, like a squealing or whistling sound, or perhaps a warbling sound, or a hash noise, or indeed, even a silent carrier. In a particular radio, a birdie could appear on one or many frequencies across longwave, shortwave, mediumwave or into the VHF spectrum. And it will usually be permanently there on the same frequencies every time.

Occasionally, you will find birdies smack bang on the very frequencies where you might want to do some listening. But, unfortunately you can’t really do anything to get rid of these nuisances because the design faults are in the the receiver itself. You can test to see if what you are listening to is a birdie by simply disconnecting the antenna. If the squealing/whistling/warbling/hash/silent carrier is still there without any antenna, then it’s a birdie – an internally generated carrier by the receiver’s own circuitry.

Click here to continue reading the full story.

Rob Wagner, VK3BVW, is the author of this post and a regular contributor to the SWLing Post. He also blogs at the Mount Evelyn DX Report.

Cornell engineers invent two-way radio on a single chip

2 Replies

Many thanks to SWLing Post contributor, Tom Ally, who shares the following news via the Cornell Chronicle:

Engineers devise two-way radio on a single chip

Two-way communication requires, of course, both send and receive capabilities. But putting them in the same device requires a filter between the send and receive circuits to provide signal isolation.

Without a significant filter, communication would be impossible.

“Your transmit signal is [10 to the power 14] times stronger than your receive signal,” said Alyosha Molnar, associate professor of electrical and computer engineering (ECE). “That’s 100 trillion times stronger – that’s a really hard problem.”

But researchers in Molnar’s lab have offered up a solution.

Molnar and collaborator Alyssa Apsel, professor of ECE, have devised a method for both transmitting and receiving a radio signal on a single chip, which ultimately could help change the way wireless communication is done.

Their work is described in “A wideband fully integrated software-defined transceiver for FDD and TDD operation,” published online Jan. 27 in the Institute of Electrical and Electronics Engineers’ Journal of Solid-State Circuits. Doctoral student Hazal Yüksel and Dong Yang, Ph.D. ’15, are co-lead authors.

Separating the send and receive bands is difficult enough, but the problem is compounded by the ever-increasing number of bands in the latest devices. From GPS to Bluetooth to Wi-Fi, each band requires a filter to stop the strong transmit signals from drowning out reception.

Molnar and Apsel have come up with an ingenious way to separate the signals. Their idea lies in the transmitter – actually a series of six subtransmitters all hooked into an artificial transmission line. Each sends its signal at regular intervals, and their individually weighted outputs are programmed so that they combine to produce a radio frequency signal in the forward direction, at the antenna port, while canceling out at the receive port.

The programmability of the individual outputs allows this simultaneous summation and cancellation to be tuned across a wide range of frequencies, and to adjust to signal strength at the antenna.

“In one direction, it’s a filter and you basically get this cancellation,” Apsel said. “And in the other direction, it’s an amplifier.”

“You put the antenna at one end and the amplified signal goes out the antenna, and you put the receiver at the other end and that’s where the nulling happens,” Molnar said. “Your receiver sees the antenna through this wire, the transmission line, but it doesn’t see the transmit signal because it’s canceling itself out at that end.” […]

Continue reading on the Cornell Chronicle.

pantronX Titus II quick update

7 Replies

Many thanks to SWLing Post contributor, Ed, who notes:

I just received a status update on the pantronX Titus II portable SDR from Mike, their chief engineer.

Mike said the self-contained SDR portable will include “SoapySDR as the interface to make it much easier to roll your own SDR app.” Here’s some info about SoapySDR:

https://github.com/pothosware/SoapySDR/wiki

Mike also said, “To be 100% truthful, our biggest push right now is for the international MW & SW broadcasters. They want to go DRM digital is the worst way!”

You might want to share this news with SWLing Post readers.

Thank you for the update, Ed! Click here to view the pantronX website.

The TAR-224 CIA Radio

2 Replies

Many thanks to SWLing Post contributor, @K7al_L3afta, who suggested I post photos of the TAR-224 Radio. Obviously, he knows I’m a fan of this sort of rig!

He discovered the TAR-224 on the excellent CIA online museum where they give a brief description of the unit:

A compact, high-frequency, paramilitary transceiver, the TAR-224 enabled communications with field agents operating behind enemy lines. It saw service in Vietnam as well as during Operation EAGLE CLAW.

31 cm x 18.3 cm x 12 cm
(L x W x H)

A much better description of the TAR-224 can be found at the CryptoMuseum:

TAR-224 was a very compact, self-contained spy radio station, developed by AVCO Corporation in Cincinnati (Ohio, USA) around 1970 for the CIA. It was intended for communication with field agents operating behind enemy lines, and can be seen as a successor to the ageing GRC-109 (RS-1) of the 1950s. It was used for many years until it was phased out in the late 1980s.

The entire unit is completely waterproof, with all switches and controls at the front panel properly sealed, allowing the radio to be stored under harsh conditions for an extended period of time. A plastic lid can be placed over the controls to protect them against dust and dirt. It is held in place by three metal latches at the edges.

[…]The radio coverages all frequencies between 2 and 24MHz. The receiver has a Variable Frequency Oscillator (VFO), allowing continuous tuning of all 4 frequency bands, whereas the transmitter is crystal operated. The unit can be powered by an external 12V source that is connected to a 3-pin socket at the front left, or by a special 12V battery pack that is installed behind a watertight panel at the front left. A plastic grip, at the left of the radio, allows the unit to be carried around easily.

[…]Most TAR-224 units were used by the CIA on special (overseas) missions, but the radios were also used by intelligence services in Europe. It is known to be used on a mission in Angola in 1975. According to CIA communication specialist Teddy Roberts, the TAR-224 was still being used in operational context in 1983, when he trained a unit of US Army Green Barets on its use.

Continue reading…

Evidently, the TAR-224 is quite rare and I was not aware of it. Thanks for sharing, @K7al_L3afta!