N4BKT's blog
Toroids Made Easy
If you ever wanted an easy way to calculate Inductance or turns on a toroid it doesn't get much simpler than the Toroid Core Calculator by Wilfried, DL5SWB.
Solving for AL
One handy feature is the ability to characterize the AL value and therefore permeabiltiy to help identify unknown cores; to do so it is necessary to get a measurement of inductance using the unknown core. To have fair accuracy, wind at least 10 turns on a toroid core and measure the inductance. when the values are plugged in the program displays results in nH/N².
Calculating Permeability µi
Using the AL-value from the first result and the physical dimensions of the core you may discover the initial permeability (only valid for very low field strength). The magnetic characteristics effective length and effective area are computed from the physical dimensions.
Permeability depends upon temperature, frequency and magnetic flux. As a material parameter it may be used to discover an unknown core material.
Why not give it a try? Thanks for making this helpful program Wilfried!
When ordering ferrite cores, bear in mind the same cores can have different names depending on supplier- even from the same manufacturer. I found the catalog of RFMicrowave.it listing the Amidon BN-43-1502 with their alias of FB-43-1502. Ordering a FB43-1502 will get the correct part if you order an Amidon FB-43-1502 from RFMicrowave, but if you order direct from Amidon you must use their number of BN-43-1502 or you will get an entirely different part.
Below is a screen shot of the RFMicrowave catalog showing the BN-43-1502 listed as FB-43-1502.
Always check the dimensions before ordering. Amidon's FB-43-1502 matches the dimensions listed on their web site. Had I double checked, I would have the correct part in my hands now. I'm not complaining here. I have posted this in the hope that it may help someone avoid the error I just made. I'm not new to ordering and specifying parts- but I am not sure how the metal cores naming convention continues publishing with such inconsistent naming conventions.
I have now read several articles on Software Defined Radios written by my fellow Amateurs referring to QSD/QSE without defining the acronyms. Here QSD/QSE are defined: QSD in the context of SDR means Quadrature Sampling Detector and QSE means Quadrature Sampling Exciter; hence they are seen referred to as QSD/QSE. It would be nice if authors would define/describe acronyms when first used in their articles to avoid ambiguity (QSD means "is my keying defective" as well). Chances are you will find this post while trying to figure out what an author means- hope this helps you.
This is really cool guys- a HF transceiver simulator which runs on your computer. It simulates HF propagation to your QTH and you can use it to get experience working an HF station while making real QSOs without worrying about a note from an OO (Official Observer). A topic at our last ham meeting was how to practice CW on HF. Some of the people wanted to try CW on VHF- well, here is a great way to do your code practice whether you have an antenna and rig or not. If you're reading this post, you probably have all you need to try out the HF Transceiver Simulator HamSphere 2.0. If you like it, don't forget to donate to the creator so he can keep the network going!
I don't care if it's "real radio" or not- it is a great way for novice operators to cut their teeth so when they want to get on the air at Field Day or a SET (Simulated Emergency Test) they'll be good to go- and not limited in experience on the air. It also should be loads of fun for anyone who travels or just is limited in rig and antenna capability.
Note: There also exists a similar program from QSONET.com which only runs under Windows making it less able to run cross platform. QSONET requires a valid ham license making it's use (and utility for prospective new hams) more limited. Most limiting of all is the requirement to subscribe to a service to use the program. This does have the advantage of offering some incentive to QSONET to continue operating the network. The Hamsphere package is free to use, works anywhere you have a Java runtime (works on Linux/Mac/Windows), needs no license (come guys it's a virtual radio- you don't need a pilot's license to use Microsoft Flight Simulator). Hamsphere is not requiring payment for it's use- making it more suitable for training usage for all.
Hi Guys,
I just picked up a MFJ-8043 Curtis Keyer- it is labeled MFJ-401 but the difference seems to be the case is smaller. The first 8043 keyer from MFJ had the weight and pitch controls on the panel and ran on C cells. Mine has the controls internal and uses a 9V battery or wall wart.
I scanned the page for my own use and thought others may need it one day- I'm sure they're out there as they were popular. This is a very early MFJ product and not built well mechanically. But since my OM (KC4KM) bought it, I'm sure it was cheap :-) Just kidding OM. I can't complain as it was a gift- and it now works after a minor repair to the power jack. I'm running it on battery for portable use.
As MFJ does not list the item, here is a PDF of the MFJ-8043 and MFJ-401 (original) manual for download. Don't sell it or include it on a CD for sale please- and please do not post it on BAMA.
73
Bill
N4BKT
I was amazed today when I looked at the Reggie transceiver. Reggie is a one-transistor, 80m, QRP transceiver designed for the minimalist. It's a "dual-action" QRP radio; not only does it transmit a small signal, but the receiver converts every signal on the band into QRP. Pretty cool. Read the QRP transceiver article
Hi Guys, I created a group called ditdahdit for people interested in learning morse code. I have a forum post in the group for software to learn morse code - please don't learn the hard way. The hard way is to start slow and increase your speed gradually- whis is VERY hard to do- that is how I learned Morse the first time. Save yourself the hassles of reaching a plateau that seems impossible to overcome by learning Morse at the best speed for you. For most of us, that is much closer to 20-25 WPM (really). The programs I have used to relearn morse are using the Koch method- not to be confused with the Farnsworth method which reduces the gap between the letters as you become more proficient. Koch starts off just learning two letters at full speed and adds an additional letter once you reach 90% proficiency until you have mastered them all. How hard can it be to learn ONE letter? Not hard at all. You too can be a know code ham.
The ARRL is really excited about the rapid adoption of the "Logbook Of The World" or LOTW. They have a nice presentation on the LOTW but unless you shell out the bucks for PowerPoint, you cannot view it. I converted the ARRL presentation to html and flash. Have a look at the Logbook of the World Flash Presentation
Hi Guys,
This is the wildest demo of virtual reality radio I've ever seen- crazy Finns up in Lapland have a 25 Acre club station with a *huge* antenna farm and a complete Virtual Reality control. Main reason is to recruit younger people into the hobby. What do you think?
