Category Archives: Ham Radio

Share a photo of your shack or listening post for a chance to win a Grundig G2

The listening post and ham radio shack of Giuseppe Morlè (IZ0GZW) from Ponza Island, Italy.

[UPDATE: We have a winner! If you didn’t win, fear not! Follow this link for future contests.]

Want to share your shack or listening post with the world on the SWLing Post? Want a chance to win a Grundig G2? If so, keep reading…!

This month, we’ll be collecting photos of our readers’ listening posts, radio shacks or favorite listening spot. And we don’t care if your listening post or shack is filled with gear or consists only of one radio in a public park; we’re just glad you’re listening, and we’d love to see how.

The fact is, I’ve always been interested to learn what sorts of receivers, transceivers, and accessories our readers––many of whom are also shortwave listeners and/or ham radio operators––have in their shacks or use at their favorite listening spots. After some consideration, the notion to show other readers how we listen became the basis for a fun contest. Fred Osterman at Universal Radio championed the idea, offering his encouragement in the form of a prize.

In exchange for a photo of your favorite listening post, along with a brief description of your equipment––see details below––you’ll be entered for a chance to win a Grundig G2 portable radio/recorder and player by random selection.

Again, many thanks to our good friends at Universal Radio, who will kindly make this excellent prize available to anyone in the world. That’s right; excepting applicable import taxes or duties, for which you’re responsible, Universal will ship your prize to you for free, no matter where you live!

This contest is open to everyone, save Universal Radio employees, their families, and those of us here at the Post.

How to enter…

Simply send an email to [email protected] that includes:

a photo of your listening post or shack,
your name, as you’d like it to appear in the SWLing Post,
your call sign (if applicable),
your shipping address, and
a brief description of your favorite shack gear as seen in your photo. You, too, can make an appearance in this photo if you like.

Again, the winner will be chosen at random, which means that everyone will have an equal chance of winning. By submitting an entry, you’re consenting to have your name and photo posted on the SWLing Post; after all, that’s the idea. Of course, your information stays with us and will never be sold or used for any purpose other than this contest.

Your entry must be submitted by November 1, 2015…Can’t wait to see (and share with our readers) how you’re listening!

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Alternative sites for Dayton Hamvention proposed

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Yesterday, the Dayton Daily News published an article about the problems with the aging Hara Arena, home of the Dayton Hamvention.

Here’s an excerpt from the article:

Fears about Hamvention leaving town because of Hara Arena’s economic struggles has local officials scrambling to propose alternative sites for the economy-boosting event.

Hamvention, the world’s largest gathering of amateur radio enthusiasts, injects millions of dollars into the local economy each year. It has been held at Hara Arena since 1964.

But the arena has struggled financially, and an Iowa-based consultant firm recently asked the city of Trotwood to buy the venue, which Trotwood officials declined. The venue’s owner says the arena is on better financial footing today.

A series of emails obtained by this newspaper through public records requests show that local officials fear Hamvention could pack up and move out of the region and highlight their efforts to keep the event in the Dayton region.

The Dayton/Montgomery County Convention & Visitors Bureau has worked with city of Dayton staff on a Plan B to ensure the event remains in the county if it needs to relocate, said Jacquelyn Powell, the bureau’s president and CEO.

“I want to make it clear that this isn’t the first year that we’ve looked at Plan B options,” she said. “There have been other years where we’ve had this conversation as well.”

The Hamvention board has no intentions of leaving Hara Arena, said Jim Tiderman, general chairman of the Dayton Amateur Radio Association, which hosts the event.

“We do not have any plans whatsoever for relocating,” Tiderman said.

News of Hamvention’s possible relocation was mentioned in an email dated July 7 that was obtained by this newspaper through a public records request.

Continue reading at the Dayton Daily News…

As mentioned in the article, the thought of the Hamvention leaving Hara is not a new one. The Arena leaves much to be desired cosmetically and even functionally–it’s an old venue that requires a sizable investment to maintain.

The Hamvention flea market is, without a doubt, my favorite part of the event.

Earlier this year, I spoke to a long-time DARA representative who assured me that the club wants to keep the Hamvention at Hara for obvious reasons. He did admit, though, that they’ve always had a “Plan B” and even “Plan C” in place, should Hara close its doors.

He mentioned that, each year, Hamvention attendees urge DARA to find a new home, but the fact is Hara is not only the largest venue around, but is the only one on one level. With an aging ham radio population, accessibility becomes a higher priority every year. Those using scooters and wheelchairs would find it frustrating to compete for elevators and lifts in multi-level venues.

As the Dayton Daily News notes, one alternative would be to have two separate locations: one for the inside exhibits and one for the flea market. Selfishly, since I host an inside exhibit table, I appreciate the fact that the flea market is within easy walking distance. It would upset me if they decided to split the venues.

The fact is, no decision has been made yet. DARA still plans to host the 2016 Hamvention at Hara Arena and has no intention of moving anytime soon. That is, as long as the owners of Hara Arena can keep it afloat.

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TASS: An Arduino-based antenna switch

Video: “The very particular world of amateur radio”

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Many thanks to SWLing Post reader, Nick, for sharing this 2013 video produced by the BBC. Here is the description from YouTube:

“In the face of the internet, mobiles and instant messaging you might expect the hobby of amateur radio – or HAM radio as it’s also known – to be on the decline.

But in the last three years, the number of amateur radio licences has risen by over 8,000 – with 80,000 currently issued in the UK.

Using designated frequencies, amateur radio enthusiasts communicate with people over the world. Many prefer the relaxed approach of ‘rag chewing’ or chatting at length with people, who often become friends – while at the opposite end of the spectrum ‘contesters’ compete to make as many contacts as possible in a given period.

The hobby is also a public service, with Raynet (in the UK) stepping in during emergencies when regular communication networks fail. Amateur radio enthusiasts are currently contributing to relief efforts following Typhoon Haiyan in the Philippines.”

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Guest Post: Joris’ home brew Si4835-based receiver

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Many thanks to Joris van Scheindelen (PE1KTH)–an SWLing Post contributor from the Netherlands–for the following guest post:

High Tech AM-FM DSP Receiver From

The old mode AM is still an interesting mode for amateur radio communication, also in amplitude CW.

Building your receiver is not difficult and quite fun. The semiconductor industry makes interesting integrated receiver chips today that will be useful for an AM receiver. Not only for broadcast reception but also for amateur AM reception or as part of an AM transceiver.

Silicon Labs also makes Si4734/35 receivers; these need a CPU to control the receiver, but are of interest for amateur use because the frequency can be tuned in 1 KHz steps and the audio channel bandwidth in 7 steps. There is no need for the transmitter to be on the receiving channel…

Si4835 AM-FM receiver

Looking for a small SW broadcast receiver design, and pocket size, I came to the excellent range of modern DSP receivers in a single chip from Slicon Labs.

I made a test bed set up has been made for the Si4835 AM-FM receiver.

The target specification was:

minimal components,
no micro-controller,
low power,
backlash free mechanical tuning,
good sensitivity,
earphone,
robust housing,
a short and small antenna system for outdoor use,
and minimal controls.

The Si4835 makes miniature design possible on a PCB (see photo Figure 1).

The red Dip (band) switch was replaced by a rotary switch in the final receiver design (Figure 4).

The receiver power is minimal 2 x 1.2 = 2.4 volts or a one cell LI-ION accu.
5 volts is the maximum for the Si4835 chip; current consumption is 30 mA.

Fig 1. Testbed setup for the Si4835.

The receiver has an RF pre-amplifier transistor and the LF amplifier is the TDA7050T.
All receiver functions are in the chip; the schematic is very simple and can be built with minimal components (see schematic appnote AN555 Fig 2. below).

Only an LF amplifier has to be added to complete the receiver.

Fig 2. Receiver schematic Si4835 in the AN555 application note.

The Si4835 receiver has the following frequency bands–they are divided in sub bands 800 or 900 KHz wide (See Figure 3). The frequency step tuning is 10 kHz on AM, following the international broadcast raster standard.

Fig 3. Si4835 receiver sub bands.

This means there are 80 or 90 receive channels in the sub bands and make finding the BC stations on the scale more easy. The 10 KHz scale steps are linear. The frequency stability is locked to the 32 kHz X-tal via the synthesizer so there is no frequency drift. The AM LF audio channel is 5 kHz wide set by the DSP filter. Volume control can be done width 2 up-down push switches or by a LF potentiometer..

Fig 4. The experimental pocket aluminium receiver housing on PCB2.

Receiving results

I have been testing many hours and I am surprised about this little receiver.

The receiving results are excellent on FM and AM and signals of 2 -3 uV are well received.

Also the audio quality is good–especially on FM. As can be seen in the frequency table the 40 and 20 meter band are in the range. Clear AM phone amateur transmission has been received when the transmitter was tuned on the 10 kHz raster in 40 meter band on AM.

Also AM modulated CW signals can be received bud not un-modulated carrier CW–they sound “plop…plop”.

The 5 kHz wide LF channel is a bid too wide so many CW signals pass through the audio at the time, but if AM modulated that should not be a serious problem.

The broadcast stations in the SW bands (when the daytime conditions are good) up to 20 MHz are good and strong.

Conclusions

The Si4835 receiver can be a fine broadcast receiver for outdoor work and if an AM transmitter is tuned in the 10 kHz raster this receiver can also used for amateur phone reception.

Addendum: The Si4734/35 is a better amateur AM Receiver

The Si4734 and Si4735 are a better receiver choice for amateur AM purpose because the frequency tuning can be done in 1 kHz steps. Also the BW of the LF channel can be adjusted to 1 kHz wide.

In Fig 5. from the programming APP note you see the code 0X3102 AM CHANNEL_FILTER it is possible to adjust the audio width by sending this code to the Si4734/35.

Fig 5. From the programming APP note

The LF bandwidth can be set on 1, 1.8, 2.5, 2, 3, 4 and 6 kHz wide.

This is excellent for modulated CW and AM phone discrimination in the audio channel.

The disadvantage is the need of an CPU and LCD display, “away from a minimalistic design”.

See also the note 1 and 2 improved 100 Hz rejection. See data sheet of the Si4734/35.

It look like that this receiver is a good receiver for building a modern AM-(AM)CW receiver or in a transceiver application. Tuning can be done digitally.

Think about this receiver [and the Si4835 chipset] when you intent to build a high tech AM – T/RX.

73 ‘ Joris van Scheindelen PE1KTH

What a fantastic home-brew receiver, Joris! I love the simple design of your receiver and the fact that it’s quite portable. Thanks so much for sharing your notes and documentation.

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Dave unveils the Sproutie MK II regenerative receiver

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My talented pal, Dave Richards, has built yet another home-brew regenerative receiver––which he dubs the Sproutie MK II––and wow, it’s a thing of beauty.

Dave tells me has been working on this receiver for many months, and upon viewing the following photos of it, it’s clear to see why he took his sweet time. As in his original Sproutie, a vintage HRO dial has taken pride of place as the centerpiece of his rig; it looks stunning.

But the Sproutie MK II is not only painstakingly-crafted on the outside; like Shaker furnishings, wrought for the eyes of God both outwardly and within, the interior of Dave’s receiver is equally well-crafted.

Okay, maybe that’s a little over the top…but if you doubt me, just join me in admiration of this board:

As for performance? Of course, with such a clean interior, the Sproutie II performs like a champ. Dave posted a few videos showing how his new receiver commands the airwaves and aptly handles AM, SSB, and CW.

That’s an amazing piece of kit you’ve created there, Dave! Hats off to your incredible craftsmanship.

Check out Sproutie II on Dave’s blog, where you can read a full account of how he designed and built this gorgeous regen receiver.

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A photo tour of the 2015 WCARS hamfest

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A few weeks ago, on July 25th, I made my way to Waynesville, NC, to the WCARS hamfest. This is a much smaller hamfest than, say, the Shelby Hamfest I recently attended.

In the past, however, I’ve found some real gems among the tables of this small hamfest.

I took a few photos but should note they’re not at all a representation of what was available at the hamfest, rather the things I found of interest (ahem…vintage gear).

This Hallicrafters SX-100 was on one of the first tables I noticed in the main building. I have an SX-99 and have always thought about “upgrading” to an SX-100. The seller was asking $150.

My buddy, Mike (K8RAT) believes the Omni D is one of the best CW rigs ever made. He purchased one–in excellent condition–with matching power supply at a hamfest in Ohio for $200. I believe this one, and another OMNI D at the WCARS hamfest were selling for $300+.

I would have loved a little radio/TV combo like this when I was in middle school. The two inch black and white CRT screen reminds me of the devices everyone carried to open doors and communicate on Space 1999.

I still find the IC-R70 and IC-R71 appealing. Maybe it’s that classic Icom green.

This National NC-173 really caught my attention. The seller had kept this radio in excellent cosmetic condition.

Indeed, the temptation was too much! I purchased the NC-173 and took it home. After turning it on, though, I felt voltage on the chassis (50V, in fact) and no audio. I contacted the seller, who lives locally, and took it to his home work bench. He happily refunded my money and then began looking for the fault. My life has been so hectic, I haven’t gotten back to him yet, but he was holding it for me should I want to purchase again. I may very well go back and purchase it. Hey, if it’s good enough for Thor Heyerdahl, it’s good enough for me!

While none in working order necessarily, these ARCs were being sold for about $25 each. I probably should’ve gotten at least one.

The seller wanted over $700 for this Clansman manpack transceiver and accessories, if memory serves. Someday, I’ll snag one of these.

I did come home with this beautiful 1946 Phillips Model 46-350 with roll-top dial cover. The 46-350 was a very popular model for Phillips after WWII; over 220,000 were produced. Original sales price? $49.95

The seller–an avid antique radio collector–sold this 46-350 to me for $25. I feel like I got a deal, too: the receiver is amazing and the audio is beautiful. The chassis shows wear, but I like that (gives some chronological context–!). The inside is in great shape for a radio that’s almost 70 years old.

This Model 46-350 has become my bedside radio; one my sweet wife didn’t object to at all. When not listening to a local AM station, or one of the night time clear channel stations, I tune to my (very) locally transmitted 1570 kHz which typically relays the UK 1940s Radio Station.

I also brought the following items home from the WCARS hamfest: