AmateurRadio.com

Series Seven Episode Eighteen of the ICQ Amateur / Ham Radio Podcast has been released. The latest news, Martin (M1MRB & W9ICQ) and Colin (M6BOY) the history of Amateur Radio Exam passes and Martin (M1MRB & W9ICQ) interviews Bill Meara N2CQR.

• Sotabeam End Fed Tuner Kit
• Schedule for RSGB Convention released
• The first Greek microsatellite is a fact!
• Yaesu FT-991 KW/50/144/430 MHz Transceiver
• Southend & District Amateur Radio Special Event
• New Zealand's Prohibited Equipment Notice updated
• Western Australia gets Summits on the Air
• 90th Anniversary of first UK-NZ contact

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

This was designed to be printed on 4X6 Glossy stock and then laminated. You can jam in your portable ops bag, in case you're always forgetting the US QRP frequencies like I do.


Feel free to save the JPG as an image on your own computer and print it out, if you like. I also have it as a doc file if you'd like to edit to suit your needs. An e-mail request will get it sent to you.

72 de Larry W2LJ
QRP - When you care to send the very least!
Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

How did I miss this?  I've had my September QST for over a week now (we Lifemembers seem to be the last to receive our QSTs!), and I must confess .... today was the first time I've given it a leaf through.  I was surprised and gladdened to read a really nice op-ed piece by good friend Jim W1PID on page 101.

Jim shared his thoughts on the changing face of Amateur Radio in celebration of the ARRL's 100th anniversary, but yet focused on the things that remain the same through the changes. The joy, the excitement, the satisfaction, the fun.

Good article, Jim and I'm glad the Newington Bunch had the good sense to publish it!

72 de Larry W2LJ
QRP - When you care to send the very least!
Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

Has anyone any idea of the likely UK price of this new radio?

It would be excellent if they released one of the low powered versions (normally available in Japan) for UK and Europe too. I think the lower powers are for some Japanese licence classes? It is a lower powered version I quite fancy. 10W or 30W max.

My FT817 units have been excellent buys as have the VX1 and VX2 handhelds. You could call me a Yaesu fan.

I want to concentrate on operating for the next few years. My stroke currently gives me little choice as building and real field experimentation are out of the question, sadly, for a while.

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

Mike Tuggle's Lyonodyne 17 Crystal DX Tuner

The use of integrated circuits can be interesting in that one IC can be used to build a full superhet. The use of an IC means that the set will not qualify for the 1AD nor for the 2AD bonus points."

The challenge was too hard to resist for many and the contest was popular for several years running. Some of the inventive entries for individual years may be seen here. The contest logbooks  also make for interesting reading and demonstrate the capability of some of these simple radios.

Although the contest has not been run for the past few years, there is still much interest and discussion of "1AD" radios on Dave Schmarder's "RadioBoard" forum.

Mike's LF tuner is a prime example as he uses it daily and continues to post some amazing DX to the Yahoo "ndblist" Group. His furthest ndb catch in North America with the regen has been "YY" in Mont Joli, Quebec.
Now, "YY" is a good catch for me, from B.C., but Mike is listening from Kaneohe, Hawaii !

You can read about Mike's original design here, while his latest version shown below, incorporates a dedicated LF antenna tuner.

LF Regen (Courtesy Mike Tuggle)



LF Regen Schematic (courtesy Mike Tuggle)

A recent posting to the ndb list by Roelof Bakker(PAØRDT) of mini-whip prominence, described his recent construction of his own LF regen, based largely on Mike's design but with a few interesting changes.

Courtesy: Roelof Bakker, PAØRDT

Roelof has also published a nice write-up describing the project which sparked a lot of "must build" discussion within the group.....even enough to make Mike get out his soldering iron and build the European-version!

As old and as simple as they are, regenerative receivers still hold much fascination amongst radio builders and dollar-for-dollar are amazingly good performers, especially on LF.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

A fellow SKARS club member picked up a nice condition Kenwood/Trio TR9500 70cm all-mode transceiver (circa 1980) from the Hamfest last year for not a lot of money and he hoped to use it for the UKAC contests unfortunately it proved to be faulty.

From the description of the fault and studying a downloaded service manual I suspected a relatively simple fault and saw an opportunity to acquire it and offered to buy it for the price he had paid. However I have decided to be more charitable rather than mercenary and have offered to give it a look over and repair it for him if I can.

The fault as described was the rig receives okay but on transmit there was a carrier on FM with no audio and a very quiet SSB signal. A faulty microphone had been ruled out and someone had suggested a bad connection internally. Due to the compactness of the unit and the difficulty in dismantling no one had felt confident to attempt any further inspection. I wasn't so sure this was the issue so at the last meeting I picked up the rig and currently have it on the workbench.

TRANSMITTER CIRCUIT
The microphone signal is amplified with the microphone amplifier Q1 (2SC2240(GR)), which is commonly used for both SSB and FM transmission modes and is incorporated in the carrier unit (X50-1720-XX). The amplified signal is then fed to both the SSB and FM circuits.

Looking at the block diagram of the carrier unit and the above functional description in the service manual I suspected the microphone amplifier Q1 to be faulty.

I want to confirm the fault first and so I connected up a dummy load and RF power meter and using the FUNCube Dongle SDR I could observe and monitor the output signal. Sure enough on FM there was a nice carrier at 10W with very faint audio, on SSB there was a small visible signal again with very little modulation. Whistling, blowing and tapping of the microphone could be seen on the waterfall... just!

I connected a switch to the Morse key input and confirmed the rig transmitted in CW with no issue.


On the block diagram there is a switchable tone burst oscillator for repeater access and the output of this is joined to the output from the microphone amp. Encouragingly the tone burst can be clearly seen and heard in the transmission again pointing to an issue with the microphone amp.


To get to the carrier unit PCB it was a simple matter of removing the bottom cover. The PCB is held in a metal frame mounted with five screws and can be lifted out, as pictured above. But before I did that I checked the continuity to the microphone socket and the 8V supply to the amplifier circuit and both were fine (see diagram below)


The poor quality image from the scanned service manual shows the bottom of the carrier unit, this is the side of the PCB visible without needing to remove it. The microphone connector is in the top left, putting an oscilloscope on the microphone input (pin1) a signal was observed, however the output (pin8) had an almost identical signal with little or no amplification. Injecting a low level audio signal from the a generator on this pin could be seen and heard in the transmitted signal. This observation together with the tone burst seemed to confirm the other audio circuitry was functioning normally and the microphone amp wasn't.

Actually removing the carrier unit PCB proved a bit tricky as it has a number of small and very secure connectors with ageing and delicate wiring, but I did manage to extricate it and a visual inspection didn't show up any obvious issues such as broken tracks or joints.


This is the detail of the microphone amplifier section from the schematic. Using a meter I have checked the continuity of tracks and have checked all the resistors for shorts or open circuits and they all read the correct values. The capacitors all look okay and checking the signals either side of C3 the C7 coupling capacitors show they are functioning correctly. This left Q1 a 2SC2240(GR) transistor as the likely culprit and I have ordered a replacement which should arrive in the next few days. I am hoping this will make it spring back to life.
Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].