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Construction

Category for all construction articles at NK7Z.NET

Using a SDR as a RFI site survey tool, Part I

Over the past several years it seems I have done nothing but hunt RFI sources. This process reminds me much of the old childs game called “Whac-A-Mole”. So the use of a SDR came to mind… This is how I set up an SDR site survey tool. Continue reading »

Categories: Cleanup, Construction, Digital, Info, Quantification, RFI Mitigation, SDR as Site Survey tool, Tools | 11 Comments

Adding an external keypad to the K3

The Genovation keypads have either forty eight or twenty four keys on them depending on which model you purchase. Each individual key can be programmed to send a single character, or a series of characters. Further, each key has a removable plastic cover so you can put a label under the plastic. All of this allows you to program a key, then label it, then use it to send a macro trigger to the P3. Like the P3, the Genovation also needs to be programmed in advance of use. Fortunately Genovation provides a rather nice piece of software with each keypad for just this task. Once a key is programmed, if you tap that key, the Genovation sends out the character(s) you pre-programmed into it via the USB port. This lends itself well to the function of sending macro triggers to the P3. Continue reading »

Categories: Elecraft K3, Info, K3: External Keypad, Reviews, Setups, Software information, Station | 32 Comments

Review of the 30 Meter MonoGAP

The first thing I did was to start WSPR off using the new antenna… All the usual suspects came in all a bit better than before! Next I decided to see what one watt could do using JT65 and PSK Reporter… The photo at the left shows what happened, I am transmitting from Oregon… Continue reading »

Categories: Antenna Reviews, Construction, GAP: MONOGAP 30, Info, Reviews | 12 Comments

NI4L’s 7 Band OCF Dipole

This review of NI4L’s 7 band OCF dipole was prompted by my needing a quick deploy multiband antenna for both field day, and for RVing. Having looked over his antenna I decided on the 7 band version, as that would cover most of my needs while in the field. Last year on Field Day I was able to use an OCF dipole, and enjoyed the quick bandswitching it allowed, so I thought I’d try and find a good OCF dipole and give one an extended try. After looking around the net I found NI4L’s site. Interestingly enough I found it while on eBay, not with Google. His site is very difficult to locate on Google for some reason so here is the link to NI4L’s web site. But if you buy an antenna from NI4L, do it on eBay, it is a few dollars cheaper at this time. In any case, what caught my eye was that he is using Flex-Weave cable for the antenna. Others are, but for some reason NI4L’s site made it more apparent. Another reason is that NI4L is also using an off the shelf W2AU Balun. I have had good luck with that balun so that was enough for me. The W2AU is an all stainless steel hardware balun as well, so it will not be corroding off the antenna anytime soon. The W2AU balun also is good for 2 KW PEP, or 1000 at 100% duty cycle. I would not run it more than 500 Watts, but that is because I am very conservative. I would have liked to have it be good to 2 KW at 100% duty cycle, but alas, it is not. I called and ordered the antenna. It arrived a few days later in the package you see on the left and above. Continue reading »

Categories: Antenna Reviews, Construction, Info, NI4L: 7 Band OCF, Reviews, Station | 10 Comments

I have RFI, now what– House Cleaning

I then brought up each circuit one at a time… Remember I had all the major appliances unplugged, so this test is looking for the various vampire devices that suck electricity all the time, pretty much anything with a wall wart on it. First I brought up the kitchen. That caused no issues, so I started turning on lights, and plugging things back in. The first source of RFI I found was a set of LED lights I got from Walmart. They are the ones that look like a 100W light, and put out about as much light as a 100 watt light. I heard nothing from them on 80, 40, 30, or 20. However on all bands above 20, they put out a horrific spray of RFI. Had I not checked all bands between testing I would have missed this. OK I noted this in my log book, and put a note there to change them out later. I turned them back off, and plugged in the refrigerator, I got a bit of RFI, so I added a few 31 mix ferrites to the power cord, and that RFI did not return. Next the Microwave got plugged back in, again, a small amount of RFI, and again a ferrite or two took care of this. There were no wall warts in the kitchen, so that pretty well took care of things for the kitchen. Continue reading »

Categories: Cleanup, Construction, I have RFI: Series, Info, RFI Mitigation, Setups, Station, Tools | 13 Comments

I have RFI, now what– Quantification

Over the past few years my RFI problem has been getting worse and worse. 40 Meters was unusable due to QRM last year, I am only now beginning to be able to use 40 meters again. Other hams in the area, (1/2 mile away), closer to the source of the RFI have lost the entire HF spectrum. See the movie above. Hit play, and all looks well until about 22:30 GMT, which is about 3:30 PM in my local time zone. As you can see, the RFI goes off scale at that time. The S Meter reading for that signal is around 10 db over S9. It is also affecting three other hams in the area. One poor fellow is so close to it that all ham bands are wiped out, 160 Meters through 10 meters are unusable during this time frame. There is another ham located about 1/4 mile from the source, he has just moved in, and was unaware why his use of 40 meters was precluded due to RFI. So there are folks who have it worse than me in this! Note this is an older recording, currently the start time for the RFI has changed to 01:36, or 7:36 PM local time. All in all there are 4 and possible 5 hams affected by what is a single source, over one or two square miles, all from a single source. We have the general area pinned down, and this summer, (2014), we are going to locate the house, and either contact the owner, or request FCC assistance. Continue reading »

Categories: Cleanup, Construction, I have RFI: Series, Info, Legal Actions, Quantification, RFI Mitigation, Setups, Software information, Station, Tools | 4 Comments

Review of West Mountain Radio’s RIGrunner

What this means is that the device has the Powerpole connectors pointing horizontally out of the side, as opposed to pointing up out of the device. I was going to mount my RIGrunner 4008H on the side of a vertical desk support, and I wanted the power cables pointing downwards, and not out towards the wall behind the desk, so the H model was the model of choice for me. As can be seen from the photo at the left, the H version did exactly what I needed. I wanted to move the desk as close to eh wall as possible. I also wanted a pigtail so I could add ferrite snap on cores for RFI suppression to each 12 VDC lead.. All of this just screamed downward pointing cables. Hence the choice of the H version, so I ordered it and it arrived a few days later. Continue reading »

Categories: Accessories reviews, Construction, Reviews, Station, WMR: RigRunner 4008H | 1 Comment

Rebuilding the Shack– from scratch

In 2014 I decided to upgrade the station, I became retired in 2013, and my use of the station was no longer weekends, and holidays. I could use it anytime I wanted, day or night. I decided I needed a better radio, and a bit more desk space. After a lot of looking, the Elecraft K3 popped up on my radar. The K3 provided me with a better radio, and a bit more desk space, exactly what I wanted. At the time of purchase for the K3, I decided it was about time to do a station rebuild, starting with the station grounding , and working my way to the Coax, and finally the control lines. Continue reading »

Categories: Cleanup, Construction, Info, Reviews, Shack Rebuild, Station | 33 Comments

Phased arrays for 40 and 30 Meters

As you can see, even though it would fit, the compromises would be too much for 40 Meters… The radials in the North/South direction would be compromised, to say nothing about being up againset a chain link fence on the south side, and an eight foot metal fence my neighbor to the North put up… So… Change of plans! Continue reading »

Categories: Antenna Reviews, Construction, Info, Reviews, Setups, Station | 2 Comments

Review of Xtal Set Society Ultra RX-2 Ultrasonic Listening Device

When an arc happens on a power pole, it, in some cases generates not only RF noise but noise in the ultrasonic spectrum as well. Again the ARRL has a very nice article on this subject here. So this kit is designed to listen for that ultrasonic noise, using a fairly sophisticated DSP audio receiver. In fact, this device has a lot of similarities to to a SDR radio, again, the ARRL has a short article on SDR here. Continue reading »

Categories: Accessories reviews, Cleanup, Construction, Direction Finding, Info, Reviews, RFI Mitigation, Tools | 24 Comments