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Arduino VFO

Arduino VFO

Download Arduino VFO By using an Arduino uno R3 and an AD 9850 or AD9851 DDS module a very stable VFO can be created to add a VFO to any crystal locked radio or to replace the VFO in an older VFO controlled radio that suffers from drift or add an external VFO. Give new […]

The National Broadband Network surprise

Up until very recently our phone service was provided via an overhead cable from across the street supported on the far end by a power pole. This phone line also carried our broadband internet service. The two adjoining neighbors were also connected in the same manner. I have long suspected that the broadband services were […]

Measuring Complex Impedances using the H...

Measuring Complex Impedances using the HP8405A Vector Voltmeter

Measuring Complex Impedances using the HP8405A Vector Voltmeter and a Return Loss Bridge Measuring complex impedances above 1000Ω is usually not possible with the average Antenna analyser however using a return loss bridge and a Vector Voltmeter this becomes possible. With a return loss bridge the amplitude and phase reading of the Vector Voltmeter represent […]

L Network Impedance matching

The tools required for calculating the vales in an L Network come from the following equations that can be found in the ARRL Handbook. XS = QRs and Xp=Rp/Q Q=Xs/Rs and Q=Rp/Xp Rp=Rs(Q^2+1) Rs=Rp/〖(Q〗^2+1) Q=√(RP/Rs-1) The L network is based on a technique known as series to parallel transformations.

Is Reflected Power Lost Power?

Is Reflected Power Lost Power?

After reading a number of articles by the late Walter Maxwell W2DU ARRL technical adviser, I was prompted to carry out some of my own experiments with mismatched loads. I carried out a couple of similar experiments that Walter described in chapter 19A of his book “Reflections”. My experiments were not as comprehensive as those […]