It has been a few weeks since I posted on my RFI issues. I was able to have email conversations with Jeff, W4DD on my problem. He gave me some advice and sent me his RFI Mapper program, and with my Yaesu FT-857 in the car and a GPS device and a laptop, I was able to take S-Meter data around my neighborhood. It indicated an area that I should investigate further, which I did.
I used my Yaesu FT-5DR set to 137.950 Mhz AM. With the 137 Mhz Yagi I built, I found two poles in my neighborhood which appeared to be the culprits, poles #354 and #352. #354 seemed worse of the two.
Since I had already contacted my utility, I hoped this info would be helpful to them to resolve the problem. In the meantime, while I waited for them to call me, I decided to try and build an Ultrasonic Power Line Noise Detector. MFJ did have a version of this, but it was no longer available. So I referred to the April 2006 article in QST by Jim Hanson, W1TRC. Unfortunately, Jim is a SK. But there was some additional info online and FAR Circuits still had a PC board available. So I went about ordering the parts required. Mouser part numbers were included at the time of the article, but many have changed due to ROHS and other factors.
The most expensive item was the 18 inch parabolic dish from Edmund Scientific. With tax and shipping, it came to around $117. Most other parts were still available, except for a JFET mixer MPF102. It may have still been available from other sources, but I found a substitute at Mouser. The 40Khz Ultrasonics transducer was also not kept in stock at Mouser anymore, so I checked eBay. I found 2 used receiver and 2 transmitter transducers for $12. Other supplies like PVC pipe, I had on hand or went to Lowes.
Once most things were at hand, I started on the PCB. What should have been a simple build turned into a major pain. The board did not seem to take solder well. Maybe I should have been aware of this and some prep should have been undertaken. I don’t know. My guess these PCBs were made in 2006 and have been sitting around since then, They are clearly not top quality, but then again they were only $10 including shipping. But I did my best trying to get all the solder joints looking OK.
Thanks goes to my friend Gary, N2HPL, who provided me with some insulation displacement connectors and a fancy tool to make the connections. It saved me a bunch of time and having to make another Mouser order.
I also put my 3-D printer to good use, making an enclosure for it. I have heard that some have had issues when not using a metal case, but I thought I would try this method first.
Unfortunately, when it was complete and I began to test it out, it did not work. I did find one definite mistake that I made, which when fixed did not solve the problems. In all, I spent several days chasing down a number of problems. In many areas, I had to jumper a wire on to the PCB to get a good connection. I was very frustrating, and I continually had to repair wires that went to potentiometers and other connectors due to constant connecting and disconnecting which broke the stranded wires. A few components were also replaced along the way (they probably did not need to be replaced, but was running out of ideas).
Several times after I found an issue, I was sure that it would fix my problem. Most of the time, it didn’t. But I kept at it and eventually got it to work. My electronic magnifier got a major workout, as well as my soldering station.
What did I learn? Well one thing I didn’t really learn, because I already knew, is that my impatience often causes me trouble. Just more evidence to add to the list. I am not sure what else I would have done differently. I had no idea that the PCBs designed for this project might be problematic. During this whole process, I pondered just going to one of the PCB design sites and creating a new one based on the schematic with some tweaks. I have spoken to friends who have done this and it can be quite cheap to have some professionally made (in China). Luckily I didn’t have to resort to that.
While this project was ongoing, my RFI stopped. It had been present for over 3 weeks steady. I have never heard back from the utility. Maybe they fixed it without contacting me? I doubt it. My guess is that it is intermittent, which is often the case.
When it does come back, I’ll be ready with my Ultrasonic Detector. Hopefully my ultrasonic detector won’t be intermittent.
