Category Archives: Guest Posts

Guest Post: A WRNO Worldwide Transmitter Site Visit

Many thanks to SWLing Post contributor, Dan Brown (W1DAN) for the following guest post:

A WRNO Worldwide Transmitter Site Visit

by Dan Brown W1DAN

The opportunity to visit a shortwave transmitter site does not come to me often. It did during the summer of 2009, so I jumped at the chance. Along with friend Bob K5IQ, we visited the WRNO Worldwide transmitter in New Orleans and were guests of Chief Engineer Larry Thom. He kindly showed us the transmitter site, talked of the interesting technical story of the rebirth of the WRNO Worldwide transmitter site and displayed some of his ingenious technical adaptations to create a smooth running plant.

Larry smiles as Bob Is amazed at the innards of the WRNO HF transmitter!

Originally put on the air as the first commercial shortwave station by local New Orleans radio owner Joe Costello in 1982, and purchased by Dr. Robert Mawire of Good News Outreach in 2001, the now non-profit religious station is fed from Fort Worth Texas studios. The transmitter, still in the New Orleans suburb of Marrero, primarily operates at 7505KHz and can be heard evenings from 1200 to 1400UTC (8PM to 10PM EST).

The plant’s main feature is an Electronic Corporation (Elcor) SW50/3S fifty kilowatt transmitter (see Figure 1). Built in Costa Rica, this transmitter feeds a TCI 516-3 log periodic antenna that was a mainstay of the Joe Costello rock and roll days of WRNO Worldwide. The transmitter is plate modulated and uses time-tested circuitry such as vacuum tubes, relay control and crystal oscillators as compared to solid-state modulators and microprocessor control. The system sends effectively a 3 megawatt signal around the world.

Figure 1. Larry describes the Elcor transmitter. In the foreground is the control cabinet with the control relays out front for easy access.

Interestingly, Larry incorporates baking thermometers to measure the exhaust air temperature. Cheap and efficient! In order to get the transmitter to work properly two interesting adaptations were required. The first was the transformation of the output impedance from 50 ohms to 75 ohms. This was done using a custom Elcor transformer as shown in Figure 2.

Figure 2. Elcor custom RF transformer

This impedance transformer feeds a TCI high power BALUN (BALanced to UNbalanced transformer, but here run in reverse), as the TCI antenna requires a balanced feed. The BALUN is a commercial TCI unit and is shown in Figure 3.

Figure 3. TCI BALUN takes unbalanced RF from transmitter and feeds the 300 ohm balanced TCI Antenna. How big is your BALUN?

Another interesting adaptation became necessary, as the transmitter would often trip the main breaker when it was placed on the air. This problem was due to the high inrush current that would occur when the high voltage power supply was energized. Larry went to Grainger supply and bought high power heating elements and time delay relay. He inserted this in the primary three-phase feed to the power supply. Now, when the supply is switched on, the heating element provides a series resistance (and heats up for a moment) to absorb the inrush. After a short time, the relay would jump the element out to allow full current to feed to power supply (see figure 4).

Figure 4. Heating elements on the upper right inside wall of the power supply limit inrush current.

Another small problem with the transmitter was the drift of the master oscillator. Larry had Elcor build a synthesized oscillator for the transmitter to reduce the drift (figure 5).

Figure 5. Larry with new synthesized reference oscillator module

WWL-AM has their 50Kw transmitter on 870KHz near the WRNO Worldwide transmitter. Due to this proximity they send a hefty signal into the WRNO antenna and thus into the transmitter. Here these two signals can mix together to form a soup of audio in the WRNO transmitter tank circuit. A notch filter was constructed to reduce WWL-870’s AM signal (Figure 6).

Figure 6. WWL 870KHz notch filter

During the visit, Bob and I listened to Larry’s stories and snooped around the building. We spotted a Vintage Radio Labs “Globe King” 500A that is slated as an emergency backup transmitter (Figure 7). It is rumored that this classic redesign of an older transmitter marketed in the 1990’s was a poor copy of the original 1950’s era World Radio Labs Globe King transmitter. Larry states that this transmitter is serial number 1. Only a few were built.

Figure 7. A Vintage Radio Labs “Globe King 500A” backup transmitter (SN1?). The crystal is for the old frequency of 7355 kHz

Figure 8. Bob K5IQ dreams of calling “CQ DX!” on a 50Kw rig and a 14db antenna

Figure 9. The Official FCC-approved Reader’s Digest reference modulation monitor!

Figure 10. The audio and control rack. Audio is fed via a T1 line from Texas to the Telos ISDN decoder, then to the Optimod 9000A audio processor (an original from the Joe Costello days). The remote control is a Burk unit that allows the studio folks in Texas to control the transmitter.

Figure 11. The Marrero, LA transmitter shack heard ‘round the world!

An article I wrote on the re-birth of WRNO Worldwide for the August 2007 Monitoring Times magazine, and the fact that I was on vacation in New Orleans prompted this visit. It is always fun to visit a transmitter site to see how things are done. Thanks to Bob K5IQ for driving!

WRNO-Feedline WRNO-Feedline-B

Figure 12. View from the balanced feed point of the TCI 516-3 log periodic antenna 1ith 14db gain aimed at 20 degrees

Here are a few web-links of interest:

Wow–many thanks for sharing your tour of WRNO with us, Dan! My-oh-my how I’d love to have that 14db gain log periodic at my disposal! Great facility!

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Paul’s review of the Kaito KA108

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Many thanks to SWLing Post contributor, Paul Dobosz (K8PD) who shares his review of the Kaito KA108. Paul originally wrote this for the Michigan Area Radio Enthusiasts and has kindly allowed us to post it here:

Kaito KA-108 Review

by Paul Dobosz (K8PD)

Kaito just introduced a pocket sized DSP based MW/SW/FM receiver with some interesting features missing in other SW receivers its size. I just got my hands on one for the first time a couple of months ago and am getting familiar with its features, performance, and quirks. I first saw the KA-108 at the Consumer Electronics Show in early January when I visited the Kaito booth and spoke with Walter about their newest radios. There are no schematics included with the KA-108 and I haven’t cracked open the case but based on the functionality, size, and price point it appears that the KA-108 utilizes the now common DSP based receiver architecture found in most of the new portable radios.

First of all, a brief run down on the features and functions of this compact little radio.

Compact Size – 5.5” x 3.25” x 1.1” Weight 9 oz
Frequency Coverage – MW: 520 – 1710 KHz, FM: 64 – 108 Mhz, SW: 2300 – 23000 KHz
Memories – 400 (100 MW, 100 FM, 200 SW)
Power – BC-5 Rechargeable LiPo 3.7V battery
Other Features
- Timer/Clock radio dual alarm function
- MP3 Timer record & playback to/from a Micro SD card
- Standard USB port that accepts a thumb drive.
- Exceptional Bass Response for travel sized radio
- “Auto Store” feature will scan and store frequencies
- Battery charging via micro USB (no wall wart to carry)
- Audio “line In” can be used as computer or MP3 speaker

Most radios have their good and not so good points and the Kaito KA-108 is no exception. Here is a rundown on the LA-108’s “HITS & MISSES”

The HITS

This radio is small and lightweight which makes it an ideal travel radio. The control layout features a full keyboard for frequency entry as well as up and down keys that will search for signals when held down. The fit and finish are excellent and the keys have good positive tactile feel. There are two rocker switches, one for volume up/down and the other for band/mode selection. The radio comes with a decent user manual and quick start guide. The manual’s English is a little awkward in places but is fully understandable.

The backlit LCD display is brightly lit with large white numbers on a blue background. It is easy for older eyes to read, even without glasses. The signal strength meter is actually fairly useful which is rare for radios at this price point.

The standard frequency step is matched to channel spacing for the band in use with exception of the FM band which tunes in 100 KHz increments instead of the US standard 200KHz steps when the frequency range is set to the North American band. The FM band can be set up to tune all the way down to 64 MHz if desired but since TV has migrated from analog to digital the usefulness of that coverage is minimal for North American users. AM is 9 or 10 KHz step capable with a frequency range to match all parts of the world. In addition to the standard frequency steps, the thumbwheel encoder can be used to fine adjust the frequency between the standard increments in 1 KHz steps.

The MP3 playback is very pleasant to listen to. I tested it with several different genres of music with consistently good sound quality. I haven’t tried the recording function yet but it is definitely a nice feature, especially in such a compact package. The KA-108 has a standard USB input (not mini or micro) behind a sliding door on top of the radio for external memory devices like thumb drives. MP3s can be played and audio recorded to/from this port as well as the Micro SD card slot aside of it. I’m also hopeful that the USB port may be capable of upgrading the radio firmware in the field. If not, that’s another feature that Kaito should definitely consider for future versions of the KA-108. (More on that later)

One feature I really like is the rotary tuning thumbwheel encoder on the side of the radio. It has a light detent feel that allows you to manually tune the radio in 1 KHz steps to easily allow you to move to one side of a signal. Frequency entry via the numeric keyboard is straight forward and intuitive with exception of the non-standard location of the zero key to the right of the bottom row of the numeric keys.

The FM reception is excellent with bass response that makes you wonder how such a mellow sound comes out of such a small box. Despite the 1.5” speaker, the audio has lots of bass and lacks the “tinny “sound of most travel portables with small speakers. It plays loudly without distortion.

MW reception was typical for a radio with limited space for a small ferrite antenna and I was able to hear the usual SWBC stations and time/frequency UTE’s on the HF bands. SW reception using just the 20” whip was just OK with easily listenable strong signals found on most of the active SW bands 2MHz and above. The KA-108 is AM only on the HF bands (no SSB or CW). There are some quirks with the MW and AM reception that I’ll cover in the MISSES section of this review

The MISSES

I never thought I would complain about a portable receiver with a “too tight” a bandpass filter but the KA-108 is a first. The bandpass filter for MW &SW are extremely narrow which when coupled with the KA108’s exceptionally strong bass response, reduces the intelligibility of the received audio on the MW and Shortwave bands. I have been able to mitigate the situation a little bit acoustically by covering a portion of the speaker grille with my hand or placing a small tube in front of it which seems to attenuate the bass and improve the overall audio response but the audio is still lacking in the higher frequencies that make things like music and the human voice more intelligible.

Tuning 1-2 KHz off of the carrier frequency with the thumbwheel helped improve things a little bit similar to the way you might use IF shift on a high end tabletop receiver. I also noticed that stronger stations that have a signal that spills further down the filter’s skirts had better audio response than those that lacked sufficient strength to spill over the filter response curve. I am hopeful that Kaito will offer a firmware upgrade to open up the bandwidth. If the USB port used to play thumb drives has hooks into the radio’s CPU then it might be possible to open up the bandwidth and improve the MW and SW audio without cracking open the radio case to re-flash the CPU or make a hardware change. The bandwidth issue is the largest single miss for the KA-108 in my opinion

I found a few buzzes and whistles on the MW band and you can hear the CPU clock oscillator strongly at 12MHz. I haven’t looked inside of the radio yet but I would imagine that some of the MW noise can be tamed with a bit of internal shielding.

I also found the AGC setting to be a bit too abrupt, jumping up and down in almost a step function with a signal whose level was fluctuating quite a bit. That’s another minor software adjustment to consider for the next edition.

Due to the KA-108’s small size, the whip antenna is rather short (only about 20”) which means the front end must have a lot of gain leaving it more vulnerable to overload. I was able to receive a the stronger SWBC stations while sitting in the middle of my house but I also heard another faint signal under the SW stations. The interfering signal turned out to be a local 1KW AM station on 145o KHz whose transmitter is about 4 miles from my home. It was present in the background while listening to SWBC and was heard standalone on its 2nd and 3rd harmonics which were most likely generated internally due to the high gain front end. The short SW antenna does create the need for higher front end gain but should be accompanied by a high pass filter behind the SW whip antenna or at least a 10dB attenuator. Either or both of those features would reduce AM BCB intrusion while listening to SWBC.

In the coming weeks I’d like to do some parametric measurements on the KA-108 and will also see how it behaves with a longer antenna and antenna tuner with low pass filter ahead of it. That should be a good test to see if a simple filter can eliminate the AM intrusion. Improvements to widen the AM/SW filter bandwidth and reduce the AM overload should be high priority improvements for the next version of the KA-108.

Summing It Up

I found the KA-108 easy to operate as I’ve explored the AM/SW/FM and MP3 operating modes and it’s a nice sized radio for casual listening when I’m at home or to take with me as I travel for use as an alarm clock, music player, and radio in one compact package.

The KA-108 has potential with a few software and hardware tweaks. Fixing the MW/SW bandwidth is #1. A simple high pass filter that rolls off just above the AM broadcast band behind the SW whip antenna is #2. I can live with a few buzzes and tones but why not fix them with a little inexpensive shielding while adding the other fixes.

The KA-108 will never match the performance of tabletop or lunchbox sized portables, but if you’re looking for a nice little radio that will almost fit in your shirt pocket with nothing more than a micro USB cable to tote along for battery charging, and a radio that sounds twice its size, this radio fits the bill. I hope that Kaito will address the issues I’ve noted with future software/hardware revisions to improve the performance of the KA-108 and maybe even offer a way for current owners to field upgrade their radios.

That’s a thoughtful and fair assessment of the Kaito KA108, Paul. It’s a reminder that, with a few strategic tweaks, the KA108 could be a great little portable. Thank you for sharing your review with us!

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Edward restores a Star-Lite Town & Country FM-820 portable receiver

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Many thanks to SWLing Post contributor, Edward Ganshirt, who writes:

This is a “mystery brand” radio that I picked up at a swapfest for a buck, I never heard of a Star-Lite Town & Country FM-820 by the HOKUYO MUSEN KOGYO CO in Japan. This portable behemoth is not “lite”, It is heavy (13 pounds).

The only thing I came up with is Sam’s photofact that refer to radio. (I am not about to buy a service manual for something that is not broken). There is a Chrysler Town & Country station wagon, which is also a behemoth that swamps out all Google searches. This set appears to be made in the mid sixties. I was told that is was on a fishing boat as evidenced by its condition it was very dirty with a lot of corrosion on the bezel and missing a tuning knob.

I fabricated a tuning knob on a lathe, which was a 2-piece affair. The outer knob is tuning and the inner knob is the fine tune. It cleaned up well and I had to repaint the bezel. The auto parts store said that the Chrysler of that area did not use metal flake paints but they matched a touch-up spray can of a Toyota millennium silver.

This radio has 8 push-button bands: long-wave, AM, short-wave 1.6 to 26 MHz, and FM along with tone controls. The sound is surprisingly good it is a 6-cell battery only (no AC). It has reasonably good short-wave drift-free performance. The paint job looks good, there is a rusty chrome bumper next to the push-buttons. I decided to to restore this part. It is ok for your 1960’s Town & Country to have rusty bumpers.

While you would not take your Panasonic RF9000 your Transoceanic or Grundig, This radio is my “beater” to take to the beach.

Does anyone know about the Star-Lite brand?

Thank you, Ed, for sharing this. I am not at all familiar with this make and model of radio. I must say…I’m most impressed that you were able to fabricate a tuning knob! It would have been a challenge to find a replacement knob otherwise.

I bet she plays well, too–looks like a decent ferrite bar inside and a substantial telescoping antenna.

And you’re right, Edward, it is ok for your 1960’s Town & Country to have rusty bumper! Now take that girl to the beach! 🙂

Post readers: please comment if you’re familiar with the Star-Lite brand!

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Shortwave Logs from Alaska: June 25 – July 16

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Conditions haven’t been so great lately and combine that with just being a bit tired and worn out means I haven’t DX’ed as much as I’d like. But I have spent a little time at the radio dials and when I do, I usually pull out a few good logs, so here we go:

3325 kHz, July 12 at 1025UTC. NBC Radio Bouganville with an absolutely LOUD, STELLAR signal. Audio was excellent and there was only light fading with no interference or noise. Survivor’s 1984 hit, “High On You” was playing during my recording. They seem to favor 80s and 90s rock or adult contemporary music when they play tunes. Audio of 3325kHz here:

5835 kHz AM (July 15, 1621UTC, 10871.70kHz USB (July 12 2049UTC) & 10861.90kHz USB(2052UTC). Russian Channel Marker. I’m not really sure where in Russia these come from or what their purpose is, as i am not very “up” on the utility type broadcasts on HF. The 5835 kHz beeping is pretty clear and evident, but it sounds like there’s a little interference coming from somewhere or someone else. The signal from the 10871kHz signals is pretty weak but the beeps do make it above the fading/noise, 5835kHz audio

here: https://www.youtube.com/watch?v=DEZMo5DziCI. 10871.70kHz usb audio here: https://www.youtube.com/watch?v=kIhn7MIHMR4 and 10871.90kHz USB audio here: https://www.youtube.com/watch?v=xQ9BeqosLtc

5857kHz, July 15 at 1626UTC. “HLL Seoul” with a weather broadcast by a woman speaking Korean. Poor to fair signal with some noise and interference. Audio here: https://www.youtube.com/watch?v=jBNmrdyDDI4

7260 kHz, July 12 at 1001UTC. Radio Vanuatu in their local language with talk in the local language, a little preaching and some Christian music. The audio quality isn’t too great (sounds like it’s full of digital artifacts) but the modulation level is better then usual. Around 14 minutes and 35 seconds in, a female announcer comes on and talks for a bit then begins reading a sign off message then plays the Vanuatu national anthem. The carrier is left on for 10-15 minutes before being shut off. 7260 audio here: https://www.youtube.com/watch?v=jTnudTRmduk

7485 kHz, July 13 at 1636UTC. BBC Bengla service in Bengali language with a news broadcast. An absolutely stellar, steady signal with almost no noise whatsoever and no fading or interference. 7485kHz audio here: https://www.youtube.com/watch?v=hRDZKSDkSMk

7210 kHz & 9730 kHz, July 13 at 1628UTC and July 15 at 1643 UTC respectively. 7201 kHz is their broadcast in Vietnamese with 20kw via Daclac, Vietnam. Vietnamese music is heard at fair levels but with lots of noise and fading. Pretty decent considering what and where it is. As for 9730kHz, it’s The Voice of Vietnam in what appears to be the Russian language. A poor to fair signal with fading/noise and what appears to be interference from another station. 7210kHz audio here: https://www.youtube.com/watch?v=_xUpmAbpOW4 and 9730kHz audio here: https://www.youtube.com/watch?v=x2CE2QCgiD0

9515 kHz & 9640 kHz, July 11 1644UTC to 1652UTC. The 9515 signal is a bit stronger with slightly fess fading and noise. both are broadcasting the KBS World Radio english service with talk about travelers and tourists. 9515kHz audio here: https://www.youtube.com/watch?v=V0k77cY4DLA and 9640kHz audio here: https://www.youtube.com/watch?v=KhBxIPGHMh8

9526kHz, July 15 at 1645UTC. Voice of Indonesia with Arabic language speech and music. Fair to good signal with low modulation and some noise/fading but comparatively speaking, this is a VERY GOOD signal for what is usually heard on 9526 kHz! And yes, they are about as close to 9526 as can be. Zero beating them in USB with my PL880 produces a whine/noise till I’m right at 9526 kHz. One website, Eibi’s schedule says that are at 9525.9.. I suspect they may be even closer then that! 9526 kHz audio here: https://www.youtube.com/watch?v=U4WdKewnyWM

9665kHz, July 16 at 1715UTC. The Voice of Korea is heard here all day everyday but the audio is usually noisy and fairly poor(usually overmodulated) but this is a case of not only good audio but a pretty solid signal! 9665kHz audio here: https://www.youtube.com/watch?v=cMBLYV4icBQ

9770 kHz, July 11 at 1653UTC. KBS World Radio in Korean with men talking and a pretty steady, GOOD signal. Fair amount of noise and light fading. Audio of 9770kHz here: https://www.youtube.com/watch?v=tyXb3sg-1-o

9890 kHz, July 11 at 1729UTC. The Voice of Korea signing on in Arabic. Starts off as usual with a dead carrier, the interval signal and announcers mentioning the name of the signal. Noisy signal, but a much better signal then I’ve ever had from VoK on 9890kHz and the first time I’ve heard them here with log worthy audio! You can somewhat hear another station under them in this recording, and normally, that staion is usually on top VoK on this frequency. 9890 kHz audio here: https://www.youtube.com/watch?v=ftVaztXipTg

10005 kHz, July 12 at 1705UTC and July 16 at 1718UTC. For the 2nd and 3rd time in 6 months, I’ve heard the Chinese Firedrake jammer on 10005 kHz. The first time several months ago, it was so strong it was interfering with WWV & WWVH. These last two times it was fairly weak but what made it even more interesting both times is I heard time pips underneath the jammer. If you listen closely in the two following clips, you can hear the tips and you can clearly hear a longer louder tone signifying the minute mark. July 12th clip: https://www.youtube.com/watch?v=t3X3iIs41PE. July 16th clip: https://www.youtube.com/watch?v=dClTJkpat30

11665 kHz, July 13 at 1647UTC. RTM Wai FM with an overall very good reception, good audio and steady signal. Only a slight bit of fading. This is by far the best I’ve ever heard this frequency here! 11665kHz audio here: https://www.youtube.com/watch?v=iw4oVv1hzOI

11735 kHz, July 11 at 2033UTC. Zanzibar Broadcasting Corporation with music and talk in Swahili. This is about the usual kind of signal I get from them, fair to the low side of good with some fading and noise. At times, there signal is even steadier, stronger and less noisy then this. They are listed as being on till 2100UTC but I’ve heard them sign off anywhere between about 2045 and 2058UTC in mid song with no announcement of any kind. In this nearly 19 minute recording, they sign off at 17 minutes and 33 seconds in. Some type of RTTY/data broadcast has recently appear in the last few months on 11735kHz causing interference, severe at times, with Zanzibar on 11735kHz. Audio here: https://www.youtube.com/watch?v=gZiG_nslSi0

12015 kHz, July 11 at 1703UTC & July 13 at 1652UTC. In the July 11th clip, you can hear CRI & VOK fighting it out together, with the two trading places back and forth. If either has a silent carrier, you can clearly here one of them. In the Jul 13th clip, Voice of Korea is on the frequency alone. 12015kHz audio here: https://www.youtube.com/watch?v=OyKCnQ8DLCQ and https://www.youtube.com/watch?v=LF3PNWT69Fw

12035, July 12 at 0859UTC. The Voice of Mongolia. The signal is incredibly weak and this is a good catch if their beam is headed straight south from the transmitter site in Mongolia. Their interval signal pops up out of the noise a few times and you can hear a male announcer say the name of the station in Mongolia before the English language service begins at 0900UTC. Audio of 12035 kHz here: https://www.youtube.com/watch?v=DH3ibgLLAg4

13605kHz, June 25h, 1058UTc. All India Radio with fair signal but lots of fading and noise, this is better then what I usually get from AIR. 13605 audio here: https://www.youtube.com/watch?v=d03wQHXB-dA

13710kHz & 15435kHz, 1705UTC & 1705UTC. Radio Saudia/BSKSA. The 13710 signal was a bit better strength wise with chanting/Arabic music. The 15435 signal had men talking, like a news or interview program and was a bit weaker. 13710 audio here: https://www.youtube.com/watch?v=0t3YP8RCZY8 and 15435 audio here: https://www.youtube.com/watch?v=xr3tgnRBSn4

15235 kHz, July 14 1649UTC to 1710UTC. Channel Africa, first their news service in French followed by the English broadcast. Signal is good with some fading but very steady and listenable. 15235kHz audio here: https://www.youtube.com/watch?v=rtFZxeh468k and here: https://www.youtube.com/watch?v=HD5lToK7Pdc

15275 kHz, July 16 at 1724UTC. Deutsche Welle in French, a very noisy signal with lots of fading. Sounds like a news or interview program with a man and woman speaking. Any DW signal is pretty rare here! Audio here: https://www.youtube.com/watch?v=lChqqJH2crc

17730 kHz, July 13 at 1658UTC. Eye Radio, broadcasting to South Sudan. A very very weak signal with tons of noise and fading. I can barely make out a man speaking before the carrier drops at 1700UTC, which is Eye Radio’s sign off time. Audio here: https://www.youtube.com/watch?v=W-CphVmuJSA

17740 kHz, July 16 at 1732UTC. Deutsche Welle in French with a signal even noisier and worse than 15275kHz. It very well may have been the same broadcast as what was on 15275kHz that I heard minutes earlier. Any DW signal is pretty rare here! Audio here: https://www.youtube.com/watch?v=lChqqJH2crc

17775 kHz, July 13 at 1706UTC. KVOH which a preacher speaking in Spanish. Weak and noisy but steady signal. This may be the first time I’ve heard KVOH here and I consider this a good catch since they beam to Mexico and Central/South America. Audio here: https://www.youtube.com/watch?v=aqegTkffahA

17850 kHz, July 13 at 1702UTC. Radio France Internationale with a weak, noisy, fading signal. Women talking in French during a news broadcast. Audio here: https://www.youtube.com/watch?v=ujnbGMo8Tww

17850 kHz, June 25 at 1048UTc. Radio Thailand, they are a somewhat regular visitor but this is a bit better then usual signal. However, there is a lot of fading and noise. Audio of 17850 kHz here: https://www.youtube.com/watch?v=XOuoZM00XmI

Paul Walker is an avid Shortwave DX’er located in Galena, Alaska working at “Community Radio For Alaska: KIYU” as Program Director and is a regular contributor to the SWLing Post. Be sure to check out Paul’s YouTube channel and SoundCloud channel where everything he logs is recorded and posted. Click here to read his other contributions on the SWLing Post.

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Video: Dan listens to RNZI’s Sunday Night with Grant Walker on a Hammarlund SP-600

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Many thanks to SWLing Post contributor, Daniel Hawkins, who writes:

One of my favorite Radio New Zealand International programs is Sunday Night with Grant Walker. This program is heard on RNZ in New Zealand from 8:06-10:00 p.m. and is run at the same time on RNZI. Sunday Night features hit oldies and one interview. Each program highlights oldies from one year. Last Sunday was 1977 and the week before was 1955. My video from last Sunday includes a favorite that I haven’t heard for many years.

The RNZI broadcast of Sunday Night is 0806-1000 UTC Sunday on 9700 kHz. That’s 1:06-3:00 a.m. Sunday, PDT. Definitely a show for night owls. West Coast reception is nearly spectacular for the distance: 6,600 miles from my location in Davis, CA, USA. The radio used for the video is a Hammarlund SP-600 JX-21, built in 1956 or 1957. Yes, the tuning dial is a little off on this band. I’m using the 8 kHz selectivity setting with fully advanced AVC. The antenna is a 106’ outdoor random wire. The speaker is antique as well: a 10” Jensen PM-10C with matching transformer connected to the 600 ohm audio output on the SP-600.

DanH

Click here to view on YouTube.

Wow! Thank you for the program recommendation, Dan! I, too, have an SP-600–there are few valve receivers that can rival it for both audio fidelity and sensitivity. What a beauty of a rig you have there!

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Guest Post: Patrick compares four receivers

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Many thanks to SWLing Post contributor, Patrick Canler who writes to us from France and shares the following guest post which he translated into English:

The number of receivers on the market is quite large, and all are sold to be the “best”. I have thought it useful to compare materials using them in the shack as a neophyte SWL; going beyond the features in the brochures to talk about everyday utility. This article does not pretend to do “scientific” testing of the four receivers–skills and special equipment are needed and some specialized laboratories already do it.

The four receivers cover thirty years of electronics manufacturing; four different brands with their own technology and specifications. Over such period, technologies and innovations have evolved. One of the questions I had was: “Does efficiency give any receiver an advantage?”.

The Contenders:

NRD-535 from Japan Radio Company.

A reference of the 90s! It received 5 stars from WRTH (which publishes annually the almanac “World Radio and TV Handook”). The NRD-535 has conventional construction with an electronic card per function and discrete and analog filters.

This is a home station receiver, weighing in at 10 kg. The NRD-535 ceased to be produced in 1996, and its value second hand is growing due to its reputation.

AR7030 from AOR

Designed by the engineer who developed the LOWE receiver line, the AR7030 is also famous for its reception. It uses special ergonomics and a hybrid of software menus and conventional controls. Quite small, it is easily transportable, due its design that already uses SMC but keeps the analog filters.

IC-R75 ICOM

Modern device, classical format and renowned–the R75 is the only receiver tested that is still in production [Note: it was recently removed from production]. It uses CMS, combines analog and DSP filtering (the DSP option is present on the device under test). Its ergonomic design is intuitive and so too are controls and menus.

1102S RADIOJET Bonito,

The 1102S RADIOJET is the only unit in this comparison that is produced in Europe!
The Radiojet includes the latest developments in technology, its performance is simply stunning on the data/spec sheet. The application includes many tools (spectrograph, digital filters, IF and AF recorders, decoder, list of broadcast stations, etc.). It brings together all the SMC receiving electronics in a small box that can fit in a pocket.

The commands and tools are assigned to a software (highly evolved) that runs on the PC which is connected the SDR. The power of the PC also brings graphics, memory, recordings etc.

Why these four rigs?

In the beginning, and it was it which led me to be SWL, I acquired the RADIOJET based on its announced characteristics: sensitivity of “secret services”, adaptable to all cases with filters, graphics tools–“Star Wars equipment” is not it! Later I learned about 50 MHz and at the same time I was struggling to exploit the Radiojet SDR.

A good opportunity to purchase an ICOM R75 brought me back to conventional radio ergonomics. As time passed, I felt my listening skills improved with these 2 receivers and the receiver syndrome grew! A Kenwood R5000 joined the others for its VHF potential and HF reputation.

Then I discovered an NRD-525 on Ebay at a fair price point (rare)–it joined the group of receivers. The latter two were sold and replaced respectively by an AOR 7030 and by NRD-535. I really enjoyed the 525, but the 535 is even better.

In use, the RADIOJET and R75 have always posed problems with settings and sound quality. Kenwood reassured me about the fact that we could get some nice reception without fighting against the controls. validated by the AOR, the NRD 525 & 535. Perhaps I did not understand the manipulation of digital filters???

Now to the shack!

The four receivers are placed side by side, but arranged so as not to disturb each other (eg. the display of the ND535 disrupted the RADIOJET).

The antenna is a 25m random wire oriented East/West with 9:1 balun and its own ground. The passage from a receiver to the other is done by a conventional antenna switch.

All the tests were performed in one evening for constant conditions, there was a fairly present QRM which, was not too bad for comparison purposes. The tests were made in SSB or AM. Preliminary tests had shown that the results in digital modes (PSK31, JT65, ..) relied more on the decoder performance of the PC rather than the receiver. The tests increased from the lowest frequency detected this evening (Europe 1-163 kHZ) to the highest (Foreign Broadcast =15,545 MHz).

The highest frequencies, up to 30 MHz, were deserted in phone, at least for my installation.
The procedure was:

Signal is detected from the spectrograph SDR: it typically “sees” almost inaudible signals.
The candidate frequency is tuned on all four receivers
I listening to all of the signals on all receivers, seeking to get the maximum performance, using all possibilities (notch, passband, IF Shift, integrated amplifiers, attenuator, etc.)
Results are reported in the table below.

One can notice rather quickly:

that age is not a handicap
the number of functions is not always an advantage

1102S RADIOJET
Performance and capabilities above the rest (on paper) and requires being connected to a PC. At the present time, on an old Celeron 2Gb ram, the RadioJet’s application never saturated the CPU. The band spectrum display allows one to find the QSO, to filter theoretically perfectly, but it does not always equate to the understandability of the signal or give a pleasant audio. And the number of software features and functions complicates the signal manipulation. The sound is still a little metallic, perhaps due to the signal processing software. Its small size makes it a unbeatable mobile receiver for travel, functions are incredibly useful for those who master the RadioJet application.
AOR AR7030
Inherently simpler at face value–the AR7030 is ultra easy to use. It makes it easy for the user to find and tweak a candidate signal. It’s intuitive and has essential functions only. It has well-designed electronics. The AR7030 is also best receiver tested for handling strong signals without overloading (broadcasts stations or nearby hyper-kilowatted amateur radio operators) which seems to prove that it is designed for these stations. Its limit is the lack of adaptive notch filter types to clean the noise, which is still quite present when the QRM is there. (The newer version 7030+ has added features to help). Finally, it is the smallest stand-alone, portable and with 3 options of antennas connections.
ICOM R75
The R75 climbs up the frequency band all the way to 50 MHz, the only receiver tested with this frequency range. It enjoys an excellent reputation, and can be equipped with a DSP (digital signal processing) on audio. The DSP provides adaptive noise reduction and automatic notch, but has a relative effectiveness which is not always successful in clarifying the signal. Sometimes it adds an unpleasant “rattling”. In use, the interface is pretty intuitive–mixing commands by buttons and menus. Twin pass band tuning (PBT) is effective and allows for IF Shift and/or notch. The speaker is (very) small and gives an aggressive/harsh sound. This receiver is relatively small in size and lightweight. It has a mobile stand and is designed for a 12-14V power supply.
JRC NRD-535
The NRD-535 is the oldest tested–indeed, it was already discontinued before the other receivers were in production. A solid and reliable construction, good ergonomic with conventional front panel controls, good sensitivity, and a decent sized speaker have earned it status as a benchmark in its time. Very sensitive, it extracts the signals and, once found the right filter, gives it pleasant audio. Some signals are not completely cleaned but it does rarely less than others. The NRD-535 is designed for home use: it is heavy, almost 10 kg, and is contains several circuit boards which should not be too exposed to excessive shocks, especially considering they’re over 20 years old.

Summary

My ranking is as follows:

JRC NRD-535 for its ease of use and ability to dig out a usable signal from the QRM.
AOR AR7030 for its simplicity, portability and the fact that it extract good sound/audio quickly, even if a little noisy at times.
Bonito RADIOJET for its small size and its extensive feature set. It is ultra-mobile with a laptop.
ICOM R75 does the job and covers a wide frequency range. But lags in performance relative to the other receiver tested, with a “nasal” sound and a DSP that does not keep its intended promises.

About digital filters: the SDR and ICOM have them, the possibilities are extensive and allow adaptive filtering that others do not with analog filters. By cons they give a dry sound and sometimes add “snap” under whistles. Listening is overall less pleasant in comparison.

Receivers Advantages + / Disadvantages –

Bonito RADIOJET
+ Top technology, visual and many new features over the others on this point
– Complicated, metallic sound, emphasizing the sometimes painful receiver interaction with a computer mouse

Icom R75
+ Great value at the present time
– Audio and imperfect signal cleaning

AOR AR7030
+ Simple and effective
– Ideal companion if it had a notch filter: noise is present

JRC NRD-535
+ Effective sensitivity and clean audio
– Older technology, less portable

Note that this is a personal opinion: a computer geek will certainly get the most of performance and possibilities from an SDR like the Bonito RadioJet.

The NRD-535 shows its age, will one day reach the end of its useful life despite its robust construction. ICOM can cover up to 6m remaining mobile and has a good filter possibilities (DSP). The AOR is easy, fast and gives a correct listening, general purpose. It is the only one to pass the VLF.

The ideal then?
* RADIOJET for sensitivity,
* The RADIOJET for tools/features and functions
* AR7030 for the lower bands
* Icom for the higher bands
* NRD-535 for ergonomics
* AOR for portability

Personally, I use the NRD-535 for DXing (due to superior audio), the AR7030 for digital modes,
the RADIOJET to visually search for signals, and to sometimes clarify the signal even better and because it’s ultra-mobile and always in my PC case.

73,
Patrick F61112

Thank you, Patrick!

I should mention that I think you did a fine job translating your article into English for us! I would not be as successful writing an article in French!

I’ve never owned a JRC of any sort. If I ever found an NRD-535 for a good price, I would purchase one without hesitation. I’ve never spent much time on the AR7030 either. It’s simple “Lowe-like” front panel is quite appealing for field use. I found that the RadioJet audio is quite nice when paired with a good set of headphones.

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Alexander’s report from Ham Radio Friedrichshafen

2 Replies

The Friedrichshafen exhibition grounds. (Photo: Ham Radio Friedrichshafen)

Many thanks to SWLing Post contributor, Alexander (DL4NO), who shared a few notes with me from his visit at the Friedrichshafen Ham Radio convention. Alexander has kindly allowed me to post his notes here on the SWLing Post. Alexander writes:

The first booth I visited was of Dokufunk (http://www.dokufunk.org/). They collect QSLs and other information about wireless history for scientific evaluation. Its head Wolf, OE1WHC, was a moderator for the Austrian shortwave service which does not exist anymore. But ORF still supports Dokufunk. They have a large archive and even the equipment to digitize large quantities if information. I brought them a package of ham radio periodicals, mostly issues of DL-QTC, the predecessor of cqDL, and got some QSPs (magazine of OEVSV) back. I collect those periodicals to gain and provide access. Seehttp://www.dl4no.de/thema/amateurfunk-zeitschriftenarchiv.htm, catalog at the bottom.

The flea market filled three exhibit halls. If you needed a tube heating for your shack you had a wide choice, from radios to ham equipment to scopes. On the newer side you could get Windows XP packages with the appropriate hardware.

Flea Market Photos Courtesy of Ham Radio Friedrichshafen

A3: Stand mit historischem Radiogeräten

A3: Stand mit Empfängern und Messgeräten (Photo: Ham Radio Friedrichshafen)

A3: Stand mit Empfängern und Messgeräten, hier zwei Schweizer an einer historischen Feld-Telefonzentrale (Photo: Ham Radio Friedrichshafen)

A3: Koffer mit Ham-Radio-Aufklebern aus mehreren Jahrzehnten (Photo: Ham Radio Friedrichshafen)

A3: Alte Radiogeräte (Photo: Ham Radio Friedrichshafen)

A3: Alte Empfänger und Radios (Photo: Ham Radio Friedrichshafen)

A3: Stand mit Empfängern und Messgeräten (Photo: Ham Radio Friedrichshafen)

Yaesu, Icom & Co where there, of course. A large part of Hall 1 had booths for most of the European ham radio societies and other entities. Several attractions for the youths were there: A fox hunt around the hall, possibilities to solder simple circuits and more. The exhibit center even provides a kindergarden.

A1: Hilberling PT 8000A (Photo: Ham Radio Friedrichshafen)

A1: ICOM (Photo: Ham Radio Friedrichshafen)

A1: Wimo, BABY Loop (Photo: Ham Radio Friedrichshafen)

A1: YAESU Funkgeräte (Photo: Ham Radio Friedrichshafen)

Hamradio had lots of presentations. The “SDR Academy” run all over Saturday – completely in English. See http://www.sdra-2016.de. Last year’s presentations are on Youtube. Search for “SDRA-2015”.

My presentation was titled “HAMNET On 70 cm – Possibilities and Limitations”. I should explain that HAMNET is our way to use the 44.0.0.0/8 TCP address space reserved for Ham Radio use. Starting in Germany and especially Austria we use more or less standard WLAN equipment to build a ham radio intranet. User access is mostly on 2.3 GHz and links on 5 GHz. Where we have gaps in the wireless coverage we use Internet wormholes. This way you can access for example packet radio sites in Canada. See http://hamnetdb.net.

2,3 GHz and up means exclusively line-of sight connections. Quite some OMs cannot reach access points this way. The only alternative up to now has been VPN connections through the Internet. I think we could provide relatively fast access on 70 cm. Here in Germany we have two 200-kHz channels for such uses. They were defined in the 1980s for packet radio access up to 76 kbps. This technology is next to dead.

Theoretical calculations show that we could provide up to 1 Mbps and cover up to 50 km if we use modern modulation schemes. You could even improve throughput by making TCP/IP less gossipy. I proposed to use SDR blocks like HackRF or LimeSDR and combine them with a RF frontend (filter, preamp, PA, fast switching). The hardware is more or less readily available, but this is mostly a software topic. While HAMNET relies on standard WLAN equipment with all its limitations for ham radio usage, this system could be completely open. We could it adapt to all our needs and ideas. In the end we could port it back to the microwave bands.

Even if we only work on the lowest protocol levels this will pose quite some challenges. We would need programmers with quite varied expertise from TCP/IP protocols to SDR technology. My presentation was to attract such people. Personally I will not program anything. As a technical writer with a quite wide expertise I might be a bracket for the project and write documentation for it.

A “Peltier Lamp”: The candle heats one side of the Peltier element while the other is cooled by the heat sink. This produces enough electricity to light a LED. (Photo: Alexander DL4NO)

At the opposite end of the exhibit center another fair went on, called Maker Faire. In former times you would have called it “make it yourself”. The exhibits there went from computer modding to 3D printing, knitting and also ham radio. For this I modified my presentation a bit: “WLAN Below 1 GHz – Do You Want To Program For It?” The technology I talked about is near hot topics like Internet of Things or traffic telematics.

Booth of a high school showing the robots they built. (Photo: Alexander DL4NO)

Booth of a high school showing the robots they built. (Photo: Alexander DL4NO)

vy 73
Alexander
DL4NO

Thanks so much for sharing your notes from Friedrichshafen, Alexander. I look forward to attending one year myself! I’m fascinated with the fact that the bulk of the event is indoors–what an incredible venue.

Any other Post readers attend Ham Radio Friedrichshafen? Please comment!

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