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In this episode, Martin Butler (M1MRB) is joined by Chris Howard (M0TCH), Martin Rothwell (M0SGL), Frank Howell (K4FMH) and Bill Bares (WC3B) to discuss the latest Amateur / Ham Radio news. Colin (M6BOY) rounds up the news in brief and in the episode's feature is a discussion with Phil McBride VA3QR, new President of Radio Amateurs of Canada.

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• FAA Update to 5G and FAA
• ARRL Surveying Field Day Participants
• New EMC Rules for Electronic Devices to Benefit Radio Hams
• Physics Professor Awarded NSF Grant for Workshop
• Comreg Amateur Radio License Negotiations
• RSGB Construction Competition
• ARRL Foundation to Create club grants program
• Spanish Radio Amateurs can Continue using 2.4 GHz

Colin Butler, M6BOY, is the host of the ICQ Podcast, a weekly radio show about Amateur Radio. Contact him at [email protected].

AmateurLogic.TV Episode 165 is now available for download.

Emile talks GMRS Data modes. ID-52A power on screen with Tommy Dirt. George has the new ARRL Handbook 2022 edition. And an update on Energizer Ultimate Lithium batteries.

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George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

AmateurLogic.TV Episode 164 is now available.

New Year’s Eve 2021-22 Live Stream.

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George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

 

The first time I was involved with a crystal radio DX contest was about 20 years ago when I built a well-performing crystal receiver for the Yahoo Crystal Radio Group's annual DX contest. It was a great learning experience and taught me much about circuit losses and how to overcome them. I originally built several sets but was unable to hear anything other than local stations until I eventually figured things out ... the system was only as good as its weakest link or links!

Fast forward to more recently when I obtained and wrote about the Heathkit CR-1 Crystal Radio, a simple but very well-designed tuner that has become popular with collectors. Using the CR-1 re-kindled my interest in the DX contest activity of years ago and when talking with two other amateurs that had an interest as well (one had also been in the earlier contests sponsored by the Alabama Crystal Radio Group), we decided to bring the contest back once again. The Facebook Crystal Radio DX Contest Group was formed last fall, a set of rules drawn up and the contest date set for the first week of January of this year. This gave interested participants plenty of time to build something they could use in the contest.

I spent all of December designing and constructing a new contest radio, hopefully one with enough selectivity to get around the 15 local flamethrowers (10-50kW S9++ signals) that plague the band for me and eventually drove me from crystal radio activities.

The new radio makes use of several 'traps' to null strong signals ... two are in the antenna line while one is loosely coupled inductively to the detector tank circuit. The two inline trap coils are wound with Litz wire on ferrite toroids (R40C1) while the third is a basket-wound Litz coil (660/46) on a 4" diameter form.

The antenna tuning stage also uses the same ferrite material but in the rod / bar form. I wound a low-end as well as a high-end coil for the tuner using the same high-count Litz as on the big trap coil. The low-end coil is wound on a bundle of three rods while the high-end coil uses a single rod.

Antenna tuner

The detector stage uses another Litz coil with this one being solenoid-wound on a 4" diameter form. Both the antenna tuner and the detector use excellent quality hi-Q ceramic insulated air variable capacitors (18-360 pfd). All components that handle RF are insulated from the plywood bases in order to reduce losses. Moving a capacitor from the plywood to the insulated standoffs makes a noticeable difference, something learned the hard way years ago but actually measured while using the new radio.

Detector stage

 

The detector also has provisions for comparing various diodes as not all diodes are created equal ... not even all diodes with the same number! When testing and comparing diodes of the same type such as the popular 1N34 germanium, every once in awhile one of them will turn out to be noticeably more sensitive than the others. In my built-in B-A-C diode test module, the hottest diode is always mounted in middle-position A, making it easy to quickly compare by switching to the left for B or to the right for C. So far the best one I have found is the vintage Russian D18 germanium diode but an old 1N34 removed years ago from a 1950s-era Heathkit has given it a good run for the money! I've still several hundreds of early germanium diodes, pulled from old diode matrix boards years ago, to test against the D18 as well as numerous Schottky diodes.

Also on board the detector module is a Selectivity Enhancement Circuit (SEC) that increases selectivity by unloading some of the diode's effect on the detector coil, similarly to tapping the diode further down the tank coil. It uses a small butterfly capacitor seen to the right of the main tuning capacitor in the photo above. I found it extremely effective when needed and is well worth the addition to a high-performance tuner.

The detector stage is followed by an impedance-matching transformer for the sound-powered headphones. This stage also houses a 50uA meter to measure diode current / signal strength levels.

 

 

The meter can be switch-bypassed to prevent needle-bounce on stronger signals. It is particularly helpful when using the traps to null a signal to the minimum level.

 

 

The three traps utilized have been very effective in eliminating what I had originally perceived as an impossible DXing situation.

Here are the daytime-power signal strengths of my 15 line-of-site blowtorch stations that, without trapping, very effectively block most sections of the band. Anything over 50uA is ear shattering and problematic, usually requiring the use of all 3 traps:

             KVRI 1600 50uA
             KRPI 1550 100uA
             CJVB 1470 40uA
             CFTE 1410 350uA
             CHMB 1320 100uA
             CJRJ 1200 400uA
             CKWX 1130 300uA
             CKST 1040 90uA
             CKNW 980 150uA
             KGMI 790 100uA
             CHMJ 730 450uA
             CBU 690 650uA
             CISL 650 200uA
             CJWW 600 100uA
             KARI 550 100uA

Overall I was very pleased and surprised at the good performance of the new radio. During the contest period I identified and logged 92 unique stations in 16 states / provinces. More than one station was logged on 9 different frequencies as the propagation varied from night to night.

Highlights of the DX Contest were hearing WHAS in Kentucky (2,007 miles), WJR in Michigan (1,970 miles), KXEL in Iowa (1,556 miles), WCCO in Minnesota (1,423 miles) and CBW-990 in Winnipeg, smack up beside local blowtorch CKNW-980! Additionally, hearing Washington state 250 watter KFLD-870 and 250 watt KWBY-940 in Oregon were great surprises.

I found the use of a spotter radio (Sony ICF-2010) to be very useful in locating signals to target and to zero-beat with an RF signal generator. The generator’s tone-modulated signal can then be tuned in and the xtal radio and antenna / detector stages optimized. 

From here, any pest signals are then tuned to and individually nulled using the traps while watching the signal meter. Antenna and detector stages are then re-tweaked before disabling the generator and listening for the desired signal. 

Often it is heard immediately following the above tuning procedures but if not, monitoring the frequency for several minutes often allows time for the weak signal to fade up to audible levels. 

Comparing programming audio with what is heard on the spotter radio will confirm hearing the correct signal as will comparing audio to the station’s own live-feed on the internet.

Due to the larger and much better antenna (inverted-L 70’ x 100’) on the crystal radio, I would often hear good audible signals on it and not on the spotter (something that I found surprising) so often times it was productive to just tune around the band on the crystal radio, tweaking stages as required.

I’m looking forward to further improvements of the tuner as well as to the next DX Contest whenever that will be scheduled ... hopefully you can join in as well!

                    FREQ UTC    STN    LOCATION    MI      

Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

Hello and welcome to the first short-topics episode of 2022. In this episode, the hosts discuss a new appointment at the ARRL, an inexpensive four-band QRP transceiver, a new direction for Solus, the new release of Pipewire, three popular video rendering projects, WSJT-X, WFView and much more. Thank you for listening and have a fantastic week.

73 de The LHS Crew

Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Ham College episode 84 is now available for download.

Extra Class Exam Questions – Part 22.
E5C Coordinate systems and phasors in electronics: Rectangular Coordinates, Polar Coordinates, Phasors.

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George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

It's time once again for The Weekender. This is our bi-weekly departure into the world of amateur radio contests, open source conventions, special events, listener challenges, hedonism and just plain fun. Thanks for listening and, if you happen to get a chance, feel free to call us or e-mail and send us some feedback. Tell us how we're doing. We'd love to hear from you.

73 de The LHS Crew

Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].