Experiments In Nothing

Wow!  It has been a long time since I posted to the blog.  I am still experimenting with various topics in Amateur Radio.  Just have not tak...

Using the HP 8753B Vector Network Analyzer I took a look at what my Classic 33 Yagi and 3-band fan dipole looks like from the shack. The Cl...

I have not done much in the ham shack for a while. Have many project to do but it seems like the time is spent in other areas. That is lif...

I was working on a project for the radio club and needed a couple of filters. One for 571 Mhz and the other for 735 Mhz. Previously I made...

This is a follow up of the cable problem of the previous post. From the photograph you can see there is minimal copper braid but an inne...

I picked up a box of 3-foot and 6-foot BNC cables. The cables are marked as RG58. Overall construction of the cables look good as they hav...

I am having ABS issues on my van. The ABS brake system kicks in at very low speeds on dry pavement. There is a service bulletin about rust...

Test complted on the batteries in the UPS.  There are four PowerSonic PS-1272 7.2Ah batteries in the UPS.  Three of the pass as shown in t...

I have a 1400 watt rack mounted UPS that powers my computers. The computers and UPS are in a rack. Yesterday I discovered all my computers r...

I picked up an HP 5372A Frequency and Time Interval Analyzer. This box take time interval measurements: time interval, continuous time inter...

All this crap about man being the cause of global warming never ceases. In the political arena man is to blame and everyone totally discount...

An easy way to generate harmonics is to drive an amplifier into compression. MMIC amps are easy to use and the 1 DB compression point is li...

I assembled the two transponder oscillators yesterday. One is for 82 MHz and the other for 114.2 mHz. They are based on the initial design...

I etched the new boards over the weekend. The frequency of the 738 and 571 filters came out spot on. The pesky "step" is still t...

One final mucking with Ansoft dimensions on the interdigital filter. I started by changing the microstrip impedance to 82 ohms (40 mils on ...

I found the source of the 100 MHz frequency error in the earlier post. Ansoft converts the theoretical filter design into a physical layout...

After messing around with this interdigital filter I never could get a nice smooth response. At best there is “step” in the response as the...

Start length = 61mm   Pass band frequency per length of each microstrip: 61mm = 630 MHz 60mm = 642.5 MHz 59mm = 657 MHz 57mm =...

I have made the modifications to the 738 filter PC board layout.  I shortened the strips to bring the center frequency to 738 MHz. The ori...

I was playing around with Ansoft this morning and the 738 filter. First I adjusted the dielectric constant to see if I could account for t...