Sunday, April 23, 2017

Restoring an Ameco R5 All Wave Receiver

This is a neat little shortwave receiver I acquired through my friend Joe. He picked it up in some of his trading, and it was in unknown condition when he gifted it to me. I've always had a "soft spot" for Ameco stuff, and this came from the Aerotron facility in Raleigh NC sometime in the late 1960's. Here's a few pics of it before I got started with the repairs...

Considering the age, it was in pretty good condition, and just needed some minor TLC on the cosmetics, the bigger challenges were waiting inside :-) I sat about to discover the various issue with this rig, and make repairs to get it operational. This one had been "tinkered" in a bunch, from the looks of things. It seems it was actually the R5K, which I learned from Rodger WQ9E. was a version offered as a kit with the RF stages pre-assembled. Initially, it was totally dead, due to problems in the low voltage power supply. Stuff all around the band switch area was connected to the wrong terminals, circuits bridged together, etc. I spent a bit of time working through the schematic and correcting all of that, replaced a shorted 1000uF electrolytic immediately after the rectifiers, cleaned the controls, etc...typical stuff.

I ran through the initial alignment, and got it working, more or less. The receiver was full of images in the lower SW bands and easily overloaded when connected to my full size 160m dipole. It's kind of odd to me that the AGC is defeated when in the CW mode. The instructions say to run the RF gain as low as possible when receiving CW of SSB signals.

After the first jaunt of repairs and troubleshooting, I found the following problems that still needed attention:

- The BFO didn't work. I couldn't detect any oscillation in the BFO circuit, but I decided I'd had enough fun for one day and tossed in the towel.

- There were no dial lamps, I needed to figure out what it was supposed to have, but that shouldn't be too tough.

- I found an oddity with the AF gain control...even when all the way down, some audio was still passed to the audio amp. It's as if the low side of the volume control wasn't completely at ground potential. The low side of the control is connected to the circuit board ground. If I short the high side or wiper to chassis ground, I get a weird & loud AC buzz. I can measure about .004 vdc between the metal chassis and the circuit board ground, even though they are clearly connected together. I decided that I needed to look into that more.

- Knobs... whew, it had one of every type knob ever made on it :-) . I've got to do something about that, and fabricate a bottom cover (missing that) for it.

I parked the radio for a while, until I could get motivated to come back to it for more work. After a bit of a break, I cam back for more fun. I'm pretty sure this was surely was a kit receiver. In addition to tracking down problems via the schematic and finding a bunch of things being incorrectly connected, I found an interesting problem in the BFO circuit... I was poking around the non-functional BFO circuit, and decided to test the BFO transistor. It was good, but for come reason I decided to verify the transistor leads as tested on my old B&K transistor tester to the pads on the board, and found it had been incorrectly installed in the radio. Once I rotated the transistor so the leads corresponded with the correct pc board connections, it worked. Yipee, one more perplexing problem solved! Now that it is "sorta working", I shot a few videos on put them on Youtube...

This is a short video of it receiving an AM shortwave broadcast around 6.5mhz...

This is a short video of it running with the BFO operating...

This is a short video of it receiving a little SSB on the 75m ham band...

This is a little video of it receiving a bit of CW on the 80m ham band...

 The next time I returned to the project, I found and repaired these other issues:.

- A PCB trace was burned out on the bottom of the board from a 1000uF filer cap that was shorted. I bridged the trace and replaced the cap...

- A tap on one of the LO coils was disconnected. That was corrected easily...

- A 10pf cap, originally intended as the coupling cap from the antenna port, was bridged totally across the preselector assy L101/102/103 at the band switch. This coupled the antenna downstream of the preselector, and the radio was all noise.

- A 5v reg had blown and another was tacked in under the board. I connected it correctly, but left it on the bottom of the board. I need to move it topside where it's supposed to be, but that's a non-issue right now.

- It goes without saying that the entire alignment was totally jacked up I found the instruction and service info on the web and went through a complete alignment. Wow, that made a huge difference!

- No dial lamps for whatever reason, just empty sockets. Easy fix. I located some bayonet style lamps in the shop and got those installed.

- I couldn't turn the volume down below a fairly loud level. I checked and the lo side of the pot was at ground, made no sense. After a quick measurement, it became clear what the problem was... The 5k volume pot wiper wouldn't go below 300 ohms when totally CCW. Weird, I have never seen that happen in over 40 years of repairing radio gear. I replaced the pot and all was OK.

- Cleaned all controls & band switch

- I sorta found better knobs and replaced the goofy collection of knobs... Surprisingly enough, most of the knobs I found were a decent match to photos of the radio I found online. I'm still going to wath for a junker for those, but for now, I'm pretty happy.

- I repaired a problem with the BFO adjustment coil and repaired that, and found a small knob for the BFO coil shaft.

A pic of the receiver RF stages where I found several parts in the wrong place, stuff bridged over, and some wiring totally incorrect.

Burned trace on the board, low voltage regulator tacked in on the bottom of the board incorrectly, and other goofiness :-)

Knobs switched, front panel cleaned up, and looking much better!

Here's a few pics of the nearly completed radio, less the bottom cover that I have to cut and fit, next. It plays well, and is a fun little shortwave receiver. It was originally designed to possibly be paired with a simple transmitter for ham radio use, but it really wouldn't make a good station receiver for CW or SSB, though it does perform well on AM.

Here's an advertisement by Allied Radio from 1969 for the Ameco R5 Receiver, from the 1969 Allied Radio Catalog...

Lastly, here are a few more videos of the completed unit...

- Receiving a SW station around 4mhz

- Receiving some SSB on the 75m ham band, around 3650 khz

- Receiving Radio Havana Cuba at 5040 khz

This was a fun project, and a great little SWL radio to have in the shack. Thanks to my friend Joe for this great find and awesome gift!


Thursday, March 16, 2017

Hallicrafters SX-42 in da house!

I picked up an old Hallicrafters SX-42 at the Charlotte Hamfest. I had one of these back when I was a novice in 1974, and sold it in the early '80's. I've regretted it ever since. It's not that it was a great receiver, but I do have a soft spot for it. I was fortunate enough to get a spare parts rig and the matching R-42 speaker with it.

The SX-42 was Hallicrafters 'Top Of The Line' received in 1947. It sported crystal phasing and allowed for up to 6 increasingly tight stages of selectivity. By today's standards, it's a poor receiver for single signal CW operation. It is, however, an AWESOME receiver for AM signals from the ham bands or SWL. It operates from 535khz to 108 mhz in AM, CW, and FM. My intention is to pair it with an AM transmitter for use on the 160 meter band.

I got it fired up fairly easy, with very little work. I plan to totally recap it, implement the service bulletins to protect the band switch and fix other things, and bring it back to new cosmetically. Here are a few videos of it in operation, fresh out of the mothballs (spider webs)...

Receiving on 3.875 AM...

Receiving on 1.885 AM...

Receiving on 94.7 FM broadcast...


Wednesday, February 22, 2017

AM Rally : Aprtil 1-3 !!!

The AM Rally is coming, April 1st through 3rd. This event will be a great opportunity to work folks on rigs from Vintage through SDR... All technologies welcome! It's more of a social event than a contest, but will be loads of fun for all interested in the AM mode. Be sure to check out all the info online at http://amrally.com/ and check in on the air and enjoy the camaraderie between all operators of this neat, high fidelity vintage mode, with whatever you have to operate AM on! See you there!


Saturday, January 28, 2017

160 Meter CW Contest this weekend 1/28/17

Wow, I love this contest. I'm not a really serious contester, I almost never turn in my scores. I enjoy contesting, just the same. It's a great opportunity to pick up new states and countries needed on a certain band or mode, test new antennas and equipment, etc. This contest is very simple, and the rules can be found here:


When I hear folks say things like "CW is Dead", I can't help but be amused. Here's a couple of pics from the lower 25khz of the band, on the band scope of my Icom IC-756...

I worked a couple of hours this morning before work, and made a BUNCH of contacts all over the USA and Canada on my new 160 meter "low-pole", low altitude zig-zag dipole. I put this temporary antenna up to keep me on 160 over the winter, while working on my tower rebuild. It's only about 65' up, in a sort-of inverted-V configuration, with the last 30' of each side about 6' up and "zig-zagged" from tree to tree in the woods to get the full length in. I've worked into Europe, Africa, South America, and all over North America with this silly set up.

Anyway, I hope to work you on 160 this weekend. I can hardly wait to get back home from work and get back on!

73 de WB4IUY

Wednesday, December 28, 2016

Digital modes - Check your gain and ALC...

Many of us work the digital modes like the various PSK's, Olivia, Hell, ect using a sound card interface of some sort. They work pretty darn good in transmit more, if you pay attention to your gain settings and the ALC level of your rig. I hear signals every now and again that are totally whacked out, and most of the time it turns out to be an over driven transmitter from the sound card audio.

I snapped this pic a couple nights ago while operating on 40m PSK31. When the station in Cuba would transmit (his primary signal is on the left in the waterfall), an image would appear abt 700hz up the band (seen on the right in the waterfall). His signal sounded horrible, folks were trying to get him to try turning his gain down, but I don't think he understood what was going on. I'm not picking on him by any means, but you do see a lot of this on the air. I suspect his digital interface was over driving the bejesus out of his transmitter...


Saturday, December 24, 2016

Vintage Ham Radio stuff, Hallicrafters, Schlitz...

This isn't much of a blog post, but I wanted to put these things out there for those of you who also love old ham radio related stuff like me. A good friend, Joe (who owns Dit & Dash), found this old unused 1964 Hallicrafters Log Book and sent it to me. Having had my license since 1974, I remember the paper logs and the requirement to log everything, including tune up and test transmissions. I took a few pics of it, it really brings back fond memories.

Next, here's an old 1952 Schlitz beer advertisement, featuring a rendering of a typical 1950's hamshack. This pretty cool, I'm gonna try to turn this into a poster for my hamshack Studio B with my vintage gear.

Thanks to Joe over at Dit & Dash. Here's his Facebook link if you do Facebook:  https://www.facebook.com/DIT-and-DASH-Radios-Antennas-Accessories-285175181595643


Friday, December 23, 2016

Computers with Legacy Com Ports, & RTTY Interface

I was stranded an d unable to use my RTTY interface on HF, after a near lightning strike blew the 9-pin serial port on my hamshack computer. Thanks to Matt Harris KD4PBS, he had a spare plug-in card for my computer's PCI slot, to add on outboard serial ports! This provided the 9-pin legacy serial port I needed to get my RTTY hardware back working. Once I found the drivers for it, my old box was back up on RTTY.

For those of you who work digital modes, this is something to think about when you build or buy a computer... While you can use soundcard software to work most digital modes (including RTTY), it typically doesn't allow for hard-keying the FSK port of your rig for true RTTY, and often doesn't allow for hard keying your rig for CW. This means you're unable to use your narrow RTTY or CW filters (since you're usually in USB mod for all digital modes). The receiver can easily get overloaded and the waterfall gets washed out by strong stations on nearby frequencies.

There are almost no USB-to serial port dongles that support the 5-bit stream or reprogramming to 45.5 baud for this, so a USB converter is almost out of the question.

Most HF rigs have a terminal in the aux port on the back of rig for FSK control. Even my old Yaesu FT-901's have dedicated FSK and sharp receive filters for this. The majority of the digital mode interfaces that provide an output for FSK keying require a legacy serial or parallel port on the computer for this, and the majority of computers (esp laptops) have only USB ports and such, no physical 9-pin or 25-pin legacy ports. By controlling my RTTY shift through the FSK port, instead of using RTTY TX audio on USB like in DM780, I can use dedicated programs like MMTTY (love it!!) and work RTTY even in crowed contest band conditions. You might want to buy a computer that at least has an expansion port to allow for a serial port card with legacy ports for this.

Anyway, thanks again to Matthew Harris KD4PBS for the card to get my RTTY station back on the air!

Here's a pic from inside the computer, below the new add-on legacy com port card. This gave me a new com 1 & com 2 port, and disabled the old on-board port that was blown.

Another pic of the board, from inside the PC...

A pic from outside of the PC, showing the new com ports just below the ethernet card. I'm using com 2 for my RTTY interface.