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The evolution of a radio shack…and parting ways with my Elecraft K2/100

[Update: One of our readers purchased the K2/100! Thanks!]

I freely admit it: a lot of radios enter and exit my radio shack––especially portable receivers and SDRs of all stripes. It’s just the nature of doing gear reviews and evaluations. I also keep a fairly robust arsenal of radios here at SWLing Post HQ for future comparison reviews and evaluations as models are upgraded.

But amateur radio transceivers that I personally use at home and in the field––? These come and go much less often.

I feel lucky in that I get exposure to most of the radios currently on the market. Yet I’m also cursed in that I simply can’t turn off that internal reviewer when I use a radio! I’ve become a bit extra-critical, hopefully constructively so, of radio ergonomics, user interfaces, functions, and of course, performance.

I used to have a healthy selection of transceivers in my shack as well, but over the years I’ve found it necessary to distill them down to just a few––almost all of which, if you’re curious, are Elecraft models.

My Elecraft KX1 in the Pelican 1060 case which fit it and its accessories perfectly.

One of the first Elecraft rigs I owned was the KX1, the ultimate handheld field portable 4-band CW radio of its time. I believe I acquired it in 2008. SWLs will be interested to know that I could even tune to broadcasters on the KX1, using ECSS.

The Elecraft K1 (Source: Elecraft)

I loved the KX1 so much, in fact, shortly thereafter I purchased a K1. The latter I ended up keeping for perhaps one year or so.

Soon thereafter, I purchased an Elecraft K2/10 (the “/10” stands for 10 watts).

I should note here, for those who are not familiar, that almost all of Elecraft’s products are available in kit form. The K1, KX1 and K2 are proper kits. You can’t buy them factory built at Elecraft. With that said, I’ve never had the pleasure of building any of these models from kit form because I purchased them second hand.

The Elecraft K2

The K2 has been in production now for twenty years (!!!) and it still has a healthy market and dedicated community. The K2 must be one of the best documented, benchmark performance through-hole kit transceivers ever made. Because of the robust user base and the fact Elecraft still produces it, it’s also one of the easiest radios on the market to diagnose and repair. The thing was designed to be a “hands-on” radio–to be pulled apart and serviced–there’s no mystery meat inside.

I used my K2/10 for many years…and assured myself I’d never sell it.

Grundig G3 shortwave portable (left), Elecraft KX3 general coverage transceiver (right)

Ah, the best laid plans of mice and men…! In 2011 Elecraft introduced the venerable KX3 and I fell head over heels for that radio (just read my review). All of a sudden, my trusted K2/10 wasn’t getting as much air time and started collecting dust, so I (reluctantly) sold it to free up some radio funds.

Then, within weeks of selling my K2/10, someone posted a K2/100–a 100 watt version of the K2–for sale on our local radio club’s email group. No one in the group showed interest. The sale was for a late local ham, now SK (silent key), and his friend who was selling off the equipment really wanted to unload it quickly for the benefit of his family. I expressed interest, and only two weeks after selling my K2/10, I was a K2/100 owner.

I figured this must be the universe intervening because, had I not sold the K2/10, there’s no way I would have had funds to purchase the K2/100.

After purchasing the K2/100, I sold my only other 100W rig: my beloved Ten-Tec OMNI VI+. I had been the owner of the OMNI VI+ for more than a decade and it was a radio I dreamed about in the 1990s. Still, it took up way too much table space in my modest little shack and, yet again, I needed to consolidate.

Activating PK01 (The Appalachian Trail) with the KX2 during the amazing National Parks On The Air event.

Fast forward a few years to the day before the 2016 Hamvention: Elecraft announced their new field portable radio, the Elecraft KX2. The Elecraft team gave me early access to the KX2 and once again, I was head over heels for this new rig. When I started my review of the KX2, I already knew I wanted one, so didn’t even bother reaching out to Elecraft for a loaner––I just bit the bullet and purchased it. Click here to read that review. Shortly after making this purchase, I sold my KX1.

If you’ve been keeping track thus far, you’ll note that I currently have: an Elecraft KX3, an Elecraft KX2 and an Elecraft K2/100.

You’d think I was an Elecraft fan, but that’s not entirely the case. Elecraft KX series transceivers simply suit my operating style and meet my performance expectations. Why?

excellent ergonomics
benchmark performance (just ask Rob Sherwood)
general coverage SW broadcast reception
accessible, friendly customer service
regular updates and upgrades
and brilliant portability!

Recently, I’ve come to realize that although I still love the K2/100 in so many respects, I reach for my KX3 and KX2 more often…even though the K2 is my only 100-watt transceiver.

For this reason, I’ve decided I must sell the K2/100 so that I can fund the purchase of the (rather pricey) Elecraft KXPA100 amplifier. With the KXPA100, both my KX3 and KX2 will have a 100-watt linear amplifier at their disposal. Integration is seamless, and the amplifier is quite portable. With the KXPA100, I’ll be able to run a “full gallon” on Field Day on two radios I know like I know the back of my hand (especially the KX2!).

It has the latest firmware and includes all modifications. It’s fully-loaded, too–here are the options:

KPA100 K2/100 Internal Integration Kit
K160RX 160M and 2nd RX port
KDSP2 SSB Adapter (which is now discontinued)
KNB2 High Performance Noise Blanker
KSB2 SSB option

The only option it lacks, as far as I can tell, is the K60XV (60M and transverter adapter).

I’m hoping to sell the K2/100 for about $900 shipped (unless you, gentle readers, advise otherwise).

My K2/100 will be on view at the Winston Salem, NC hamfest this weekend, where I plan to hold down a table with my buddy, Vlado (NC3Z). I doubt I’ll sell it there, so will likely post it online later.

Here’s the thing, though…I look at this awesome little radio and wonder why I’m selling it! And then I close my eyes….take some deep breaths…and remember that it’s all about consolidating the shack and maximizing the potential of the KX3 and KX2.

And, who knows? Maybe the universe will intervene once again, and I’ll own another K2 in the future.

Post Readers, weigh in: What radios have you bought and sold? Any regrets? Which have been, or are still, your favorites––and why?

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Tom notes $14.99 closeout pricing on Sennheiser MM 50 iP ear buds

Alan Roe’s updated A18 season guide to music on shortwave

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Many thanks to SWLing Post contributor, Alan Roe, who notes:

I have now updated my Music on Shortwave listing for A-18, and attach version 2.1.version 2.0.

Alan, thanks so much for keeping this excellent guide updated each broadcast season and for sharing it here with the community!

Click here to download a PDF copy of Alan Roe’s Music on Shortwave A-18 v2.1

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TX Factor Episode 21

Gary pulls apart and examines the XHDATA D-808

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Many thanks to SWLing Post contributor, Gary DeBock, who shares the following report of the XHDATA D-808:

XHDATA D-808 AM-LW-FM-SW-AIR Portable- Tech Report

by Gary DeBock

The XHDATA D-808 portable is an AM-LW-FM-SW-SSB-AIR band model which has already been the subject of many excellent reviews. Until recently the model was not marketed to North American purchasers, but recently a couple of Chinese sellers have started soliciting North American buyers via eBay listings.

My own interest in the model was in comparing its AM Band performance to that of the best performing Ultralight radios– specifically the CC Skywave and Skywave SSB models. Although the D-808 is slightly larger than the 20 cubic inch limit for Ultralight radios, its size and weight make it very convenient to take along as a “travel portable,” specifically as an SSB-enhanced model capable of checking transoceanic station carrier strength on exotic ocean beaches. The Skywave SSB model can also do that– but at a $169.99 list price, compared to the $112.86 (plus $10 shipping) cost of the D-808. In addition, none of the published D-808 reviews seemed to have any information about internal components like the loopstick, or Si4735 DSP chip.

My first test was to compare the stock Skywave SSB model with the D-808 in fringe AM station reception. The Skywave SSB model has a reputation of being one of the most sensitive Ultralight radios, but the D-808 clearly outperformed it on both low band fringe station (550-KARI) and high band fringe station (1700-City of Auburn TIS) reception. The D-808 couldn’t quite hang with a 7.5″ loopstick Skywave model, but that only made me curious about how the same modification could enhance the D-808. So… it was time to disassemble the D-808, and find out why its loopstick was such a superior performer.

The D-808’s 3 7/8″ (98mm) loopstick is shown adjacent to the 2 3/4″ (70mm) loopstick of the CC Skywave models. The D-808 is much easier to disassemble than the CC Skywave models, though, so enhanced loopstick transplants should prove to be quite popular in the D-808.

The D-808 loopstick is 3.7/8″ (98mm) long, while that of the CC Skywave SSB model is only 2 3/4″ (70mm) long. Other reviewers have noted the excellent performance of the D-808 on the AM band, and this is probably one of the main reasons. The SSB mode operates very similar to that of the Skywave SSB in providing a quick check of carrier strength on weak AM band targets– the LSB mode can be set to +55, and the radio tuned to different frequencies to check fringe station carrier strength. This can provide a real-time check of propagation changes during time-limited propagation openings for live ocean beach DXing with Ultralight radios or other portables (or with the D-808 itself, if desired).

The D-808’s Si4735 DSP chip was initially used in the Eton Traveler III Ultralight radio model, which was fully reviewed in the 2015 Ultralight Radio Shootout (where it won top honors for MW sensitivity). The D-808 augments that capability with a significantly longer loopstick, plus multiple DSP filtering selections. As such, the D-808 in stock form should be a very superb performer.

The Si4735 DSP chip has markings of “3560, DCUL, .738” and provides a wide range of AM bandwidth choices for the Medium Wave DXer (6K, 4K, 3K, 2.5K, 2K, 1.8K and 1K). These perform very well, and as with the other DSP-enhanced portables, the narrowest bandwidth (1K) provides the most sensitive AM band reception.

In construction very similar to that of the CC Skywave, the D-808 separates into two main circuit boards, connected together by a plug-in ribbon cable. One strange quirk is that the Si4735 DSP chip is located on the RF board (close to the center right edge). The Si4735 DSP chip is also used in the Eton Traveler III Ultralight radio, and although that model lacks the multiple DSP filter selections of the D-808, is has been the subject of highly successful 7.5″ loopstick transplant modifications– proving that such enhanced Medium Wave and Longwave loopsticks will perform very well in the new, Si4735 chip- powered D-808.

Disassembly of the D-808 model is fairly straightforward in comparison to the CC Skywave models, and the technician doesn’t need to memorize a detailed reassembly protocol in order to perform a routine loopstick transplant operation. Neither C.Crane nor XHDATA are likely to show any sympathy to someone botching up an antenna transplant, so you need to be confident that that your skills are superior to those of the company technicians before taking the plunge. In the CC Skywave and CC Skywave SSB models various parts fit together like a puzzle, but the D-808 isn’t like that. It should prove to be a fairly popular model for enhanced MW and LW loopsticks.

Those considering a purchase of the D-808 should be advised that its type 18650 Li-ion 3.7v battery is not commonly available at most stores, and that Postal regulations supposedly forbid shipping these batteries through the mail. One of the eBay sellers (harelan ecommerce) did manage to ship me two of the standard XHDATA type 18650 batteries through the mail (along with two new D-808 models) but if your seller won’t do this, you can still purchase the batteries on eBay. Some of the 18650 batteries sold on eBay have a flat positive terminal which won’t contact the D-808 cabinet’s positive battery connector terminal, but in such a case you can simply insert a #8 lockwasher in between the two, and the arrangement will be very secure. From that point on you can simply recharge the battery with a USB terminal connector.

Thank you for sharing this technical overview of the XHDATA D-808, Gary! I’m looking forward to the antenna mods you’ll no doubt make to this compact DX machine!

Click here to read other posts about the XHDATA D-808 and here to read posts by Gary DeBock.

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How to build SM0VPO’s 20 meter magnetic loop antenna

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The completed 20 meter loop antenna.

A few days ago, SWLing Post contributor, Robert Gulley (AK3Q), pointed me to an excellent website by Harry Lythall (SM0VPO) which is chock-full of various homebrew radio projects. In particular, we both were impressed with Harry’s 20 Meter Loop Antenna–it’s such a simple project and requires no special order components. In fact, all of the components (save, perhaps, the antenna connector) can be purchased at a DIY store.

I reached out to Harry and he has kindly allowed me to republish this project as a guest post:

20m Loop Antenna

by Harry Lythall – SM0VPO

Introduction

I recently saw that my 80m (3.5MHz) loop (or frame) antenna has been really popular, and that there are loads of other radio amateurs who have taken my design and “ran with it” to produce variations that all have some great improvement. There have been many in-depth tests and simulations, all with exceedingly good results and reports. This is exactly what I am aiming for with my homepages – free information for all and my designs being improved upon. That way we all win 🙂

One small point all variations have in common is the need for an expensive tuning capacitor and a very restricted RF power level. Of course, you can throw money at the problem, but for me this hurts. I got to thinking that there must be a way of adjusting the design a little and finding another technique to tune the antenna, and to make the best use of the little radio transceiver I have in Sweden, given the limited space.

My limited space apartment.

As you can see there is not much opportunity for grand antennas. And to add to this, the equipment I have in Sweden is also limited to a single 5-Watt unit.

My limited equipment – only 5-Watts.

The Design Thoughts

Today I have no area of land to use for antennas. I have a glassed-in balcony on the 4th floor of an apartment block. I really like the 20m (14MHz) band so I will concentrate on that. I am not really interested in the CW end of the band, except perhaps 14.070MHz for the digimodes. So my requirements are:

As efficient as possible (useable)
Small size, also portable so I can use it for field use
No expensive components, everything available locally
No TVI, QRM or interference to stereos or computer sound
Total price less than $2

The antenna I have created is based on my original 3.5MHz loop (or frame) antenna. This time I built it out of scrap components. I cadged (tiggade) some plastic conduit tubes from an electrical contractor at work. The same guy also gave me the remnants of a roll of 2.5mm C.S.A. multi-strand mains cable. That was all I needed.In my junkbox I found no tuning capacitors, but WAIT!! Why do I need to tune the antenna? Once it is tuned I should not need to tune it again, just set the centre-frequency to 14.175MHz. If I can get the Q-factor to around 100 then my useable 3dB bandwidth should be more than 150kHz. That will give me 14.10MHz to 14.25MHz.

Ok, I need a 1-off, preset tuning capacitor. Why not use a Gimmik Capacitor? Just twist two bits of wire together and cut it short to get the resonant frequency I want. So I need to get the coil wound so that there is sufficient cable length and self capacitance to give a resonance of about 14.5MHz without any extra capacitance what-so-ever. That means I need just a few pf. That sounds like a good plan.

Construction

The 15mm Diameter plastic tube I “aquired” were 80cm long. After much trial and error I found that exactly 3 turns, with 2.5cm spacing, gives about 14.9MHz self resonance. The wire support holes are exactly 4cm spaced, beginning 1cm from the end of each tube. The two tubes are fixed into a and X using zip-straps (tie-wraps, buntband). The feed loop is 1/2 turn.

Note the size and position of the feed loop. Also the Gimmik capacitor.

One problem I had with the original loop antenna was that of RF coming back down the cable braid. Using on old FT-101ZD it was possible to feel the RF on the microphone with your lips. The cure for this is to use a balanced feed and at least 5m of RF cable.

I robbed the ferrite ring for the balun from an old ATX computer PSU and made a triflar wound torroidal transformer. That is to say, twist together three lengths of 1mm x 7-strand insulated hookup wire together. Use this to make a 7-turn coil and connect the three coils in series, with four connections. Feed connections (numbered in the picture below) 1 and 3 are connected to to the antenna feed loop. Connect the coaxial cable braid to connection 2, and the coax centre to connection 4. My balun is self-supported on the connection leads.

The 1:1 Balun I used.

The coaxial feed cable was found to affect the resonance slightly, so I fed that through an extra bit of tube to make it stay in one place. It works fine.

Feeder cable secured in the support tube.

Testing

Testing is very easy. I used my GDO-2 to check the middle-turn of the loop for a dip. Twist the two tails together to form the Gimmik capacitor and adjust the length of the twist until the centre-frequency is 14.175MHz. With the GDO you can get it within about 100kHz to 200kHz, but then you can check the VSWR using your HF radio. You can also sweep the band for maximum noise and get a very close approximation.

The Gimmick capacitor.

The centre frequency of my 20m Loop antenna is 14.175MHz, and the VSWR is better than 1.05:1 (I can hardly see any movement on my meter). The Q-factor is somewhere approaching 100. The useable bandwidth is just a little narrower than I would have wished, but the antenna certainly works well and meets all the other criteria. But the slightly less useable bandwidth criterion is at the expense of better performance, and it still allows me to use 14.070MHz, although it is a little quieter down there.

The completed antenna.

Conclusion

No-matter how you play with the figures, the best indoor antenna cannot replace a full-size dipole antenna. But the indoor antenna can give some extra features, such as just reaching out your arm and trimming a little, which you cannot do with a long-wire antenna up a tree out in the garden, especially when it is raining.

This antenna gets me on the air on 14MHz, and it has a useable frequency range. The VSWR is almost perfect at the centre-frequency, and this time I don’t burn my lips on the microphone (not that I am likely to do so with just 5-Watts of power). The design uses no expensive components, in fact the only item I bought was the block-connector for the balun. That cost me US$1.50 for a pair of 12-contact screw-terminals. The construction is ridiculously simple and easy to build.

On the air I can hear traffic on 14.070 digimodes, and from 14.130 to 14.220MHz I have a near-perfect VSWR aqnd good clear reception of SSB. I can also rotate the antenna to cut out rubbish, and most of all, using the Gimmik capacitor I don’t need to re-tune it: it seems temperatore-stable. The weight is less than 500g and when I poke it out of the balcony window the reception improves, the VSWR does not change, and I can make myself heard among the big boys.

I hope that you have some fun building and using this antenna. If you have any ideas for further improving it then please use my forum.

Don’t forget to visit my messageboard if you have any questions about this or any other project. I always look forward to receiving feedback, positive or negative.

Very best regards from Harry Lythall
SM0VPO (QRA = JO89WO), Märsta, Sweden.
EA/SM0VPO (QRA = IM86BS), Nerja, Spain.

Many thanks, Harry, for sharing this excellent project on the SWLing Post!

Post Readers: be sure to check out Harry’s website which is loaded with radio projects of all stripes. You’ll easily spend a few hours digging through his tutorials and downloads. Harry also maintains an alternate mirror server located here.

Side note: I’m impressed with the fact that the main SM0VPO website is actually hosted on a bedside Raspberry Pi computer (running the Linux-based Lighttp server). Very cool!

Check out other homebrew mag loop antenna projects on the SWLing Post by clicking here.

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triple j uncovers Australia’s filthiest radios!

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Photos submitted by triple j listeners.

(Source: RadioInfo via William Lee)

The topic of dirty radios cropped up on triple j yesterday, following a conversation between presenter Alex Dyson and listener Ryan from Wollongong.

[…]By the time Dyson and Ryn finished their chat, the triple j textline was bursting with pictures of filthy radios. And since most were from work sites, Joe from Whittlesea helpully pointed out that they’re actually TradieOs™: radios belonging to tradies.

I had a radio that, I believe, might have won this competition! It was a Grundig S350 that I used on site as I built my house. One of my sub contractors borrowed it to listen to music in the attic space as he worked up there. The following day, a crew arrived to install spray foam insulation between our rafters. The crew never noticed the radio until it was too late and the entire thing was covered in foam spray. I wish I would have snapped a photo of it. I scraped off all of the spray foam, but the radio was forever ugly–still worked great, though! I believe I eventually gave it to one of my subs.

Post readers: Care to share photos of your dirtiest radios? Please comment or contact me with photos. If I receive enough, I’ll make a separate feature post!

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