Experiments In Nothing

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...

I etched the board for the microstrip band pass filter.  The desired center frequency is 738 MHz.  The problem with designing such a filte...

It appears the high harmonic output is generated by the last MMIC amp.  Not sure why unless it is sensitive to the impedance seen by the i...

I have been working on a few oscillators for a radio project.  The test oscillator is crystal controlled on a carrier frequency of 104.727...

My domain controller started to blue screen today. This is an old box so my first thought was the old hard drive was failing. At time it act...

What a pain for something that should be simple. I have a lab of six systems. About half I can't get WUS to run. I found the following s...

Well, I sure have not used the blog much have I? Just get busy doing other things and first you know a year has gone by. Judging by the nu...

Still wet from drizzle and no noise. That suprises me because I would think the nightguard noise would be coming from the electric eye. I w...

Tonight it is raining. No noise from the nightguard.

The local TV station ran a news story last Friday about the FCC approving BPL. Everyone thinks BPL is so great but the general public does ...

The noise is back from the NightGuard light. The noise does not appear to extend down into HF. It stops around 28 MHz. Can't tell the up...

This morning the noise was gone after sunrise. I did not have the receiver on prior to sunrise so I don't know exactly when it went away...