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FIELD DAY PREPS: How To Set-Up And Synchronize N1MM+ Ham Radio Logging Software On Multiple Computers By Using An Ethernet Switch To Create An Offline Local Area Network (Step-By-Step Instructions)

By: KM1NDY
18 June 2024 at 06:35

For last year’s Field Day, I took a stab at networking a couple of computers together with an ethernet cable so that our N1MM+ logging software could be synced up. It was both surprisingly easy to do, but equally daunting due to the curious lack of reasonably digestible tutorials tackling the topic on the interwebs. So now that Field Day is again upon us, I felt that same sort of dread that comes from staring up at a steep learning curve. Because quite frankly, I could not remember at all how to create a N1MM+ computer network. I checked back at my blog page on the topic, and was dismayed at how little of the process I documented. So, I am here to rectify that.

Here is my use case. I want to have three computers with Windows 10 operating systems host logging software (N1MM Logger Plus) for a multiple station ARRL Field Day event. All of the computers need to be synchronized with each other in order to avoid such dreaded contesting faux pas as “dupes”, i.e., getting the same person twice. I also do not want to have to rely on an internet in order to maintain communication between these computers.

As far as hardware goes, I already was in possession of three (quite aged) computers. I splurged on three new 25′ ethernet (CAT 6) cables (one for each computer), and a Linksys 8-Port Gigabit Ethernet Switch. I set up the computers simply by plugging one end of an ethernet cable into its ethernet port, and the other end of the cable into the switch. Remember the gigabit switch does need power to operate!

Before I began networking the computers, I had updated all of the necessary software, including Windows and N1MM+. All of the computers need to have the exact same version of N1MM+, as well as exactly the same inputted contest information, before N1MM+ is able to synchronize between multiple stations.

Once the hardware was gathered and the software was up-to-date, I followed the step-by-step procedure documented below.

Step 1: Go to internet icon, click, and “Open Network & Internet Settings”.

Step 2: Select “Ethernet” on left, and then “Network and Sharing Center” on right.

Step 3: The “Unidentified Network” is set to “private” which is what I want it to be. For contrast, my wifi network is set to “Public” (see arrow on the left). Click on the “Ethernet” hyperlink.

Step 4: Click on “Properties” of the first box that pops up. Then click on “Internet Protocol Version 4 (TCP/IPv4)”.

Step 5: Click “Use the following IP address” and add in “192.168.1.200” for “IP address”. The “Subnet mask” should just show up as 255.255.255.0. While I am no expert by any means in networking computers, I do think you can choose the last three digits of your IP address from 1 to 255 254 [Correction sent to me by my favorite critic, AC1JR!] I picked “200” rather arbitrarily. Once you are done, click “ok”, “ok”, and “close” on the multiple windows.

Step 6: If you need to make your network private because it is showing as public (see Step 3 above), you need type “secpol.msc” into the search bar and press enter.

Step 7: In the pop-up window, click on the “Network List Manager Policies” under the “Security Settings” tab. Then click “Unidentified Networks”. In the next pop-up, choose “Private”. Hit “Apply” and then “Ok”. Your “Unidentified Network” settings should now say “Private”.

Step 8: Open the file manager and click on “Network”. Your computer’s name should be listed there. My computer is named “PC-1”.

Step 9: Now it is time to network your second computer. Go back through Steps 1-8, but this time on the new computer. Below shows all of the steps ordered numerically. Don’t forget to change the ethernet connection to “Private” as shown above. The only difference is that you want to assign this computer a different IP address than the first one. I chose 192.168.1.201.

Step 10: Check the “Network” tab in the file manager to make sure the second computer (in my case, “PC-2”) shows up.

Step 11: Repeat these steps as many times as you need to in order to connect all of your computers to the network. Just change the last digits of the newly assigned static IP address, as they all have to be something different. I have three computers that are now linked together.

Step 12: Once your computers are all networked, open N1MM. Under the “Window” menu, find and click “Network Status”.

Step 13: Make sure that the most recent version of N1MM is installed or else you will get an error message when attempting to connect to the other networked computers (in red below). You also need to make sure that everything else about N1MM is identical, in particular that the contest information for the log is the same.

Step 14: When all of the computers are identically set-up, with the same software versions and contest information, open up the “Network Status” window. A bubble will show that gives you an option to turn on “Networked Computer Mode”. Click it!

Step 15: If you see all of your computers listed with no red error messages, your networking efforts are a success! Make sure you have designated one of the computers as the “Master” by checking the appropriate box.

There you have it! N1MM Logger Plus synchronized across multiple stations for Field Day! I hope to catch you on the air!

Forever,

KM1NDY

Why we have "BW Limit" Switches on our Oscilloscopes

8 May 2024 at 13:18

Dean KK4DAS asked me why we have these switches on our 'scopes.  I didn't know.  Dean asked Alan Wolke W2AEW.  Alan knew: 

Alan Wolke wrote: 

Interesting background on the 20MHz vertical BW selection. This feature has existed on the vast majority of all oscilloscopes since the 50s or 60s (both analog & digital). When I explored the history of this, I spoke to some of the folks at VintageTek.org, and wound up having a chat with THE engineer that did it first!  Tt was John Addis, designer at Tektronix. 

At the time, Tektronix was located in Portland Oregon. While working on a wideband vertical preamp for a new scope (the 7A11 vertical plugin for the 7000 series scope), John Addis was plagued with interference from the local television broadcast station in the 50MHz band. So, he popped in a 20MHz low pass filter that he could switch in/out so that he could complete the work on the preamp. Since it was deemed useful, it was left in the design. 

 

And, since Tektronix added a switchable 20MHz low pass filter  in their scope, and Tek was the leader in oscilloscope technology, other manufacturers followed suit, and this feature has "stuck" as a staple in vertical setting controls. 

 

The main reasons you'd use this filter would be to improve the signal to noise ratio (SNR) for signals when their frequency content is below 20MHz.   You've probably noticed that, even without any signal connected, the thickness of the trace is thinner when you engage the 20MHz filter. 

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Alan sent a link to a Wiki page about the 7A11 that John Addis was designing.  Alan says this places the initial inclusion of the 20 MHz BW Limit filter to the mid 1960s: 


https://w140.com/tekwiki/wiki/7A11



Thanks Dean, thanks Alan!  

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