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Sorry, this time copied correctly. https://www.edn.com/cheap-and-easy-inductance-tester-uses-few-components/

https://www.edn.com/.../ *test*... *measurement* /.../ *Cheap-and-easy* - *inductance* - *tester* -uses-few-components Howard, n3fel

It's a good idea to wind and measure the inductance of the toriod before installation.? In my experience not all cores are alike especially the five for a dime variety found on Ebay.? Testing of

The 1n4001 seems to follow the? ?Cj = K/sqrt(V)? ?formula rather closely. From the graph of fig 4 on page 2 of the 1n4001 datasheet at https://www.diodes.com/assets/Datasheets/ds28002.pdf I read

Hi The phase noise numbers for the RFzero was recorded subject to a 50 ohms load, i.e. no additional 74xx buffer stage: 100 Hz -103 dBc/Hz 1 kHz -128 dBc/Hz 10 kHz -136 dBc/Hz 100 kHz -138 dBc/Hz 1

A minor error in my previous post where I said:? "assume our 10v power supply has 0.1v of pk-pk ripple on it" My subsequent calculations for the variation in capacitance assume noise on the power

I have built a lot of QRP radios over the years, both kits and from scratch.? Including the NC40A from the old group's project.? Have probably wound 100s of toroids in the process and have never

I think the curves on Diz's page are in the best format for varactor capacitance. We normally consider the voltage input linearly. If I'm graphing one, I automatically mark off the V (x) axis in

Chuck, It took me awhile to figure out how to make sense of it. Could be errors, but this is what I am currently thinking: Here's that equation again, a power of (1/2) means we take the square root:

Looking closer at the chart posted previously?from Diz's?diodes page http://kitsandparts.com/diodes.php SMD/SMT Varactor 1SV322.?would be a good choice. The V/C curve is about the same as the

Jerry,? That's a fun equation! The half-power Sqrt sez is not linear. I can't quite visualize** how the parallel capacitor calculation works out.? I may just have to get really curious and check out

yea..... we have another term here ...goes way back before BAOFENG showed up here...... Two decades ago we had a local radio club sub-group who gathered once a month for a fox hunt...direction finding

Hi Paul, Yes, you can measure your torroids. What I do is put the filter together on the PCB and sweep it using my PHSNA (poor ham's scaler network analyzer). Did my xtal filter too. See attached (I

I'm building a Norcal 40a and wondering if the toroids can be measured and verified prior to installation. I have an LC meter sitting here on the bench. Thanks. Paul VA3ZC

Gents, Absolutely great! Thanks for these suggestions and links! If this does not drag them out of Baofeng "Tech-hood" nothing will. -- William, k6whp -------------------- "Cheer up, things could get

This little noise generator would work fine: https://www.radiohobbyist.org/blog/?p=1884 -- Dale Hardin Elberta, AL

I second what Dale says, however (since measuring traps is the subject),? a simple noise generator along with a receiver can be employed to measure traps.? Example: < https://youtu.be/kuDkdrI4bBc (

Chuck, On page 16 of http://transport.ece.illinois.edu/ece340f12-lectures/ece340lecture27-junccap.pdf there's an equation for the capacitance of a reverse biased diode Cj =? ?A/2 *

Don't forget the "noise bridge".? Here is a simple one that can be built out of junk parts: https://www.radioexperimenter.us/rm-1996-05/antenna-noise-bridge-detector.html It is a very useful and

Gary,? What was the specified part? -- Chuck, W5USJ (ex K2OFN) Point, Rains Co, TX? EM22cv