Scroll to the bottom if you are only interested in the FD checklist! Is Field Day worth it? This year, more than any other, it seems this question was popping up on ham radio forums across the internet. Other versions seem to be what is the relevance of FD in the day and age of POTA and SOTA. Discussions (disagreements) on what modes should and should not be allowed. Or even what the entire purpose of FD is (emergency communications exercise? ham radio publicity event?) I probably missed it in years past, but this was the first of my five years of both Winter and ARRL Field Days that I noticed people saying they just did not feel like doing it, or alternatively they felt they were unwelcome when they showed up at a public FD site.

I got my chops as the Field Day Coordinator for the first amateur radio club I ever belonged to. I was assigned the role less than a couple months after I received my license. Although I no longer participate in that particular club, I will forever be grateful for all I learned during that time. I took the position extremely seriously, and went from never having turned on a ham transceiver, to understanding quite deeply the variety of systems necessary for a portable multi-op radio contest. I still remember having to inquire as to whether a “tri-bander” was a name brand for an antenna, or a type of antenna. In this case, the term was referring to a 10-15-20M multi-band beam antenna. I would like to think I had been a particularly good radio event coordinator, and went on to organize quite a few group radio events particularly through the COVID-19 pandemic.

Simultaneously, I developed a tremendous love for portable radio, and in particular the Summits-On-The-Air (SOTA) program. I am proud of the fact that I can set up an antenna in nearly any condition. AA1F’s POTA Lion Award effort demonstrated this quite nicely. And, I can do it usually fast and efficiently, especially with a 20M EFHW wire antenna.

So, back to the question. Is Field Day worth it? Given that SOTA and POTA, and other versions of portable radio operations, make a Field Day-like experience possible at almost any time, is Field Day still important and relevant to the amateur radio hobby? Yes. Yes it is. Field Day is worth it. It is important. And it remains relevant.

Our FD station is shown below. It does look like a messy jumble of wires and cables, but there is a reasonable amount of organization in that jumble. My station is in front with the Yaesu FT-991A. AA1F’s station (with an FT-891) is directly across from mine, in the back. And facing toward the window is the FT8 station (FT-857D). In compliance with FD rules, this transceiver is set-up to run FT8, but is not simultaneously capable of transmitting at the same time as another station, keeping us a two bravo classification. Why am I so confident of that? If you take a look carefully at the window, you will see two coax cables feeding through…we only set up two HF antennas! We need to physically move the antennas from one station to another in order to operate. In fact, we do think some sort of antenna switching system would be an improvement for next year. This was also the first year we used a communications headsets (Heil Sound Pro 7) with foot pedals. What a tremendous pleasure!!

Our basic information from the day is in the table below. We decided to keep our antenna system to a minimum given the impending threat of thunderstorms all weekend. This meant that we would set up one 80M off-center fed dipole at about 20-25 feet off the ground and mostly horizontal with its long axis in the east-to-west direction. And then we would set up another 80M OCFD in the north-to-south direction. The choice of the 80M OCF would be so that AA1F and I would each have access to an antenna capable of getting on all bands at the same time, with reasonable resonance, although we were using external tuners on all radios. The perpendicular placement of the antennas was to optimize our directionality of propagation, as well as to hopefully limit interference from one antenna to another. It was also because of the convenience of using our property’s natural tree lines as antenna supports.

Station ID & FD exchange	KX1Q 2B ENY
Operators	KM1NDY & AA1F
Transceivers	FT-991A, FT-891, FT-857D, FT-4X
Antennas	80M-OCFD (x 2), 2M Magmount
# of QSOs	362
# of hours operated	14:46
# of ARRL sections worked	68
Bands worked	2M, 10M, 15M, 20M, 40M, 80M
Modes worked	FT8, FT4, CW, USB, LSB, FM
States not worked	AK, HI, NE, MS, NM

Weather considerations made us leave out putting up any mast structures. Not only did it rain in sheets, there were numerous thunderstorms, and even a tornado watch. Using the trees for support at least made us feel as though we would be less likely to attract lightning bolts, at least compared to a nearly 40 foot metal military mast propped up in an open field. We ran 100 foot lengths of LMR-240 coaxial cable from each of the antenna baluns back toward our operating station. Unfortunately, we needed to add another 100 feet of coax (this time of RG8X) to one antenna and 50 feet of RG8X to the other. On the desire list for next year’s field day is a couple of more runs of LMR-240 so we are not mixing and matching coax.

Below is the rain coming down in sheets, with a blue pop-up tent protecting our generator. The generator, a relatively new one that we purchased to power our newest trailer (on the right), stayed on through the entire weekend and was turned off one time only for refueling. This is a 5000W Predator Super Quiet Inverter Generator from Harbor Freight. We have the 2000W version of this generator that we have used for years. I highly recommend this brand. Remember, our entire farm operation is off-grid, so we generate all power. That includes solar panels on the top of each trailer. We propped the genny on cinderblocks to avoid water pooling underneath it.

This year we were fortunate to have acquired most of what we needed for Field Day already. We did make a couple of new purchases from Ham Radio Outlet in NH in the week prior. This included one of the 100′ LMR-240 cables and the Radiowavz 80M OCFD antenna. And Marc and I did splurge for the Heil Sounds Pro 7 communication headsets with foot pedals that I already mentioned. And I am really glad we did! It made operating SSB a joy! I also purchased a gigabit ethernet switch, and networked all 3 of our computers with it. I described that all in this post, including a how-to on networking computers with N1MM+ logging software.

And since we are talking solar panels, we did manage to sneak in a battery charge between downpours during the event to get our 100 points alternative power bonus points. That solar set-up is a SunKingdom 60W folding panel (which unfortunately does not seem to be available anymore), a Renogy Voyager 20A charge controller capable of working with LiFePo batteries, and a 15Ah 12V Bioenno battery. This set up can produce 2.5A of current in full sun.

The SunKingdom solar panel uses a SAE connector. I use an SAE-to-bare wire jumper to attach the solar panel and its native power cord with an SAE connector to the charge controller. From the output of the charge controller, I then use a bare wire-to-SAE jumper, that I then add a Thunderbolt (Harbor Freight) SAE-to-barrel connector adapter to attach to the Bioenno battery. The exact Thunderbolt product is pictured below; this is NOT any sort of affiliate link and I do not make a single penny off of this website. I have included this (and the picture is linked to the right Harbor Freight product), because it is a way to locally source a barrel connector that fits the very popular ham radio Bioenno battery. The other jumpers, especially the SAE extension cable, are nice as well and can be modified to suit your solar connection purposes.

We used standard 30A power supplies running off of the generator to power our SSB/CW stations. The FT8 station however ran entirely off of battery power, including one of which was charged with solar power in the moments of sunlight that we had.

Below we start getting into the nitty gritty of our FD contacts. I made contacts on 5 bands with SSB and CW. AA1F on the other hand made SSB contacts on 20, 40, and 80, and he also made FT8 contacts on those as well as 15M. The FT8 contacts are the ones marked “KX1Q” in the graph below.

Overall, I am quite pleased with the general performance of our Field Day set-up. We made 362 QSOs and reached the entire continental United States.

This included 68 separate ARRL sections and 45 states. AA1F made 24% more contacts than I did, with 206 QSOs compared with my 156 contacts.

It is interesting too to see how AA1F and I “specialized”. Below is a breakdown of our various modes. I did manage exactly 1 FM contact on 146.52MHz with a local ham via a 2m/70cm magmount on my van. In general AA1F took the low HF bands, and I took the higher HF bands, although we both shared 40M quite a bit. Also, I operated CW, whereas AA1F chose FT4/FT8 as his digital mode. In fact, this is the first time AA1F really used these modes beyond looking over my shoulder while I tap away on WSJT-X, and he made over a 100 contacts! Fortunately, our digital modes radio, i.e., the now discontinued Yaesu FT-857D, still works, as it was burning up by the end of FD with the workload of a full duty cycle. In order to get the 857 to play with WSJT-X, we had to run it through the Tigertronics Signalink as an audio interface. Unlike the Yaesu FT-818ND, I unfortunately could not get the Digirig to work with the 857, and scrapped it for the Signalink.

Mode	AA1F/KX1Q	KM1NDY	TOTAL
FM		1	1
FT4	62		62
FT8	39		39
USB	25	39	64
LSB	80	3	83
CW		113	113
TOTAL	206	156	362

Below is a map of our QSOs by band. The most interesting to me part of this is the very distinct propagations regions each band creates. 15M reaches the west coast and Texas. 20M is predominantly midwest. 40M is northeast and mid-Atlantic, and 80M is similar with a slightly smaller diameter. This map and the mode map below it were made by uploading the Cabrillo file to this website.

The locations of our QSOs by mode is shown below. The red pins, denoted oddly as “Standard” by the software, are CW, and they correlate to the fact that I made a lot of the CW contacts on 15M and 20M. Likewise, the yellow data pins show that most of AA1F’s FT* contacts were made on either 40M or 80M.

And let’s just talk a little bit about my CW contacts. I am not a particularly good CW operator, although I try. I needed to use a decoder. The one that I think is the best is the android app Morse Expert. It uses the same technology as CW Skimmer. All I do is rest my cell phone near the speaker of the transceiver and let the app decode the CW simply via ambient audio. It works extremely well, particularly in the type of event where nearly everyone at least to me seems to be sending CW via a machine. Now for sending CW (which I am reasonably okay at — my deficit is definitely at hearing it), I used the voice memory channels of my 991A using the “text-to-CW” mode. I programmed in “KX1Q” in channel 1 and “2B ENY” in channel 2, and made channel 1 and 2 into the soft buttons at the bottom of the Yaesu display. I also programmed in “TU” and “AGN” in channels 3 and 4, just in case I needed them. Although, usually I would just send these with the paddle if I did. With this set-up, and some reasonable knowledge of CW, I found making morse code contacts was like shooting fish in a barrel. This was the first time I used this type of semi-automated operation, and it was delightful! I expect I will get to be more efficient at it by next year. Or who knows? Maybe, I’ll get better at code by then too!

And we did also try for an FM satellite contact with a nighttime pass of SO-50. Given that it was in the middle of a thunderstorm and we were standing underneath the awning of our trailer to avoid getting soaking wet (not to mention pointing a handheld yagi at lightning bolts, hey, we wanted that contact!), it is not particularly surprising we did not make the QSO. We did hear SO-50 though, so we considered it a kind of win. We used two Yaesu FT-4X HTs to try to make the contact. The shame though was that it was otherwise a perfect 80 degree pass over our open field…

The farm is open to the public, so we did set up an information table. Oddly (surprise surprise! Look at that rain!) we did not get any visitors, but we did claim our bonus points.

…And the grill was DEFINITELY not just for show! Here is AA1F showing off his delicious meat. Yup, cooking in the downpour like the seasoned farmer that he is!

Georgie, our Field Day guard dog, watched over everything with her one eye. Including the coax. Okay, really this is just a gratuitous picture of this gorgeous mutt.

And finally, here it is! Our entire ARRL Field Day 2024 checklist (of radio gear only, you need to make your own toiletries list!) Feel free to download and adapt it as you would like!

So, successes? We made over 100 more contacts this year than last year which we consider a win. We were on the air nearly at the start of Field Day (okay, 11 minutes late, but still that is great for us!) This was because we set up nearly everything Friday night (including our antennas in a thunderstorm and by headlamp thanks to bad traffic out of Boston). The early set up meant we were less fatigued by start time. We operated 6 bands and 6 modes. We had little to no interference between our stations, made possible by using band pass filters on both operating transceivers at all times. We were never at a lack of station possibilities for contacts, and more often than not if we could hear a station, we could work a station. The use of multi-banded 80M antennas seemed like a good choice overall. Our antenna locations made working the entire United States possible, with only 5 states not contacted. I learned a way to semi-automate CW contacts and AA1F made a bunch of WSJT-X contacts for the first time. All of our computer equipment was networked and worked. In all, we considered the entire operation a success…

But of course there are always things we can do better. Quite frankly, I would like to get more contacts. I suppose we will try for at least 500 next year. Would it be beneficial to get the antennas up higher than 20-25 feet? Should we use only LMR 240 instead of mixing and matching it with RG8X coax? Should we put up a single banded resonant 40M antenna? Or maybe focus on more resonant antennas in general? We only operated for about 14 of the 24 hours in total. We did get tired fairly early in the event ( I think I turned in before 2am on Saturday; AA1F made it a bit more) and we slept a bit later than we wanted to. How can the two of us manage more on-air time given the exhaustion inherent to being a two-person FD operation? And one that needs a significant amount of travel time to reach our FD location?

And of course, the things out of our control. The bad traffic on Friday that turned a 3 hour trip into a 5 hour trip, and left us setting up in the dark and rain. The weather…thunderstorms (and tornado watches!) all weekend. And when it wasn’t raining, it was 90 degrees with air so humid you could ring it out. We also suffered from being distracted a decent amount by Georgie, who as a shepherd teenager still requires a lot of minding.

All that said, I am really happy with 2024’s ARRL Field Day. Despite what I see online, the airwaves were hopping and it was clear A LOT of hams were enjoying the event! It made me giggle a bit to think of the number of electromagnetic signals flying around the general public’s head, of which they had no clue. Don’t get me wrong, I know it is the same for cell phones, etc, but usually a giant international event would have some sort of footprint. Runners blocking streets as they raced along. Or traffic on the way to a particularly popular concert. But hams can take over the world in the quietest and least intrusive of ways, unless you know how to listen for it.

My radio friends in Beantown seemed to all have nice club Field Days as well based on the reports I have been seeing and getting. I am happy for them! I realize though, at this point in my trajectory through this hobby that I am not particularly interested in partaking in Field Day as a club event. Maybe this will change? Through the years I have done quite a bit to promote Amateur Radio. Heck, this website, although it is really for my own entertainment, does see quite a bit of traffic at least based on my standards and I would like to think it has a positive effect. And I am really glad for the club Field Days I have both organized and been a part of.

I am getting more protective though of my time. And particularly the time I get to spend on what has become one of the most important aspects of my life. Over these last five plus years, radio has burrowed its way into becoming a core component of my existence. I mean it with that intensity. When I started this journey, communication, as in the ability for one party to convey information to another, seemed to be the backdrop of this radio journey for me. In essence, it was a social experience. The ability to communicate was inherently social, and I took to radio in that manner: join a club, help provide radio experiences for others, provide a public service — a social service — in doing so. But as the wonder of the science of radio, the art of radio, and most importantly–radio for the sake of radio–seeps in, the social aspects have been fading away in some aspects. Don’t get me wrong! I love all of the real friends I have made in this hobby, and hanging out with them is not what I am talking about. Enjoying the company of other hams (which I do!) is also not what I am talking about. More so, an event like Field Day, the Super Bowl of our hobby, is something I want to do as a largely asocial experience these days, instead relishing in the marvels of RF and my own ability to tap into it. Maybe it simply comes down to the fact that I do not want to share. There are many ways in which I can share radio, and many ways that I do, but for the time being, I do not think Field Day is not going to be one of them.

And why Field Day? No other radio contest (non-contest?) has a wider range of amateur radio operator skills and stations available to pluck contacts out of. Overall, the event is not extremely competitive nor is it made out of the finest radio stations. It means you can make a lot of contacts with other stations that are also cobbled together…just like yours! It means that you can significantly improve from one year to the next, learn your equipment better, perfect your station set-up, and harden your skills. You are largely not competing with amplified multi- mult- contest stations blasting 1500 watts with giant directional antennas. In Field Day, you actually stand a chance. If used appropriately, ARRL Field Day can be a great way to become increasingly more proficient in the hobby, year over year. And it is an experience I want to grasp with both arms and not let go of for anyone.

Is Field Day still relevant? You better believe it is!

KM1NDY

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

With ARRL Field Day around the corner, it is the time of year where amateur radio operators far and wide wonder if they are going to be stuck having their QSOs wiped out every time their neighbor keys up the microphone. Interference between stations in a multi-transmitter field day operation can be the norm if you didn’t think to use band pass filters.

So out my stash of little gray metal boxes came, and I began checking their VSWRs for a down-‘n’-dirty pre-Field Day check-a-roo…

I don’t love the VSWR trace of this 6M filter, but it will probably suffice for Field Day, where I plan on setting up a 6M 4-element beam, and operating largely on FT8 to try to intercept the “Alpha” stations that are trying to rack up the “Free VHF station” points. That, and when else do I get to put up my 6M yagi???? FT8 is operated on 50.313 MHz which should have a VSWR under 1.2.

These Array Solutions elliptic filters have a beautiful looking VSWR. I really wish I had spent my ham bucks acquiring a full set of these. Apparently Array Solutions is not making them anymore, but a company called Hamation is? Oh, and for anyone not familiar with the RigExpert Antenna Analyzer (1-port VNA), the blue portion of the display indicates the ham band with frequency along the horizontal access and VSWR on the vertical access. Keep in mind that the VSWR we want is as close to 1 as possible!

Now 12M is a WARC band of course, meaning you cannot use it for contesting. In general, it is second only to 60M as my least used band. But, boy, that band pass filter looks great!

I expect 15M to be hopping on Field Day. I am glad this filter looks good.

Another WARC band, i.e. Field Day no-go… But a good looking filter!

Now 20M. Let’s just say I am not at all happy with this filter. Granted, it has probably been heavily abused over its several years now with me. Dunestar has gone out of business since August of 2023. Their original owner became a silent key right around the time that I purchased this set. I decided to try out Morgan Systems Surestop bandpass filters for 20M and 40M for this year’s Field Day. You’ll notice the 40M filter looks reasonable, but when actually under use, the VSWR seen at the transceiver is often high. And we can’t be without a highly functional 20M and 40M stations when it comes to Field Day operations. We will see how the Surestop filters behave…

The 30M filter looks superb! Of course, there is no operating 30M on Field Day.

The 40M filter looks a bit janky. Technically, it should function okay. But like I mentioned, this filter often creates a high SWR at the transceiver. I have a replacement here for it now.

Ugghh. The 80M filter is downright scary looking. I probably should have replaced it when I had a chance.

The top band filter isn’t great. What else can I say? I am not sure I ever even used this filter on 160M. I do think I will slowly start replacing my filters with one of the other manufacturers with time. Although I am grateful to have been able to get a set of Dunestar filters, especially since they provided a boatload of good multi-operator experiences over the years, the older and wiser me wishes I had put my money elsewhere.

Here are the “guts” of one of the Array Solutions 3rd order elliptic filters. Note the interesting use of a hot glue like substance to hold the windings in place, the beefy size of the enameled wire, and the use of ceramic capacitors. Silver-Mica capacitors are often recommended for use in band pass filters

…and a representative schematic from this excellent LC Filter Design calculator by Marki Microwave…

Now we can contrast the design and construction of the Array Solutions band pass filter with the 2nd order Dunestar bandpass filter (below). This design consists of two airwound coils and capacitors mirroring and shielded from each other on the input and output side.

Every time I get around to thinking about, testing, and opening up my band pass filters, I can’t help but think: It would be so much better to make these myself. For some reason, this does not seem to be an area that has been overly tackled by hams. In fact, there is really only one prevailing design by Lew Gordon K4VX, a 3rd order Butterworth filter, that is well-described and seems easy-ish to reproduce by the average everyday ham (i.e., one that does not design RF products for a living). The W3NQN band pass filter design article is a much more complex document to follow.

I have dabbled in making band pass filters before, but have found myself hindered by the testing process. I since learned to use the “low Z” setting of my oscilloscope. So, once I again, I found myself constructing an ugly little device, this time a low-power 160M version of K4VX’s Butterworth filter. The schematic, construction, and component values are all documented in the article. This is nothing more than a capacitor (~4000 pF) and inductor (~2.2 µH) connected in parallel on the left hand side as well as a capacitor (~4000 pF) and inductor (~2.2 µH) connected in parallel on the right hand side, with another capacitor (~400 pF) and inductor (22 µH) in series in the middle connecting the two sides. I just soldered everything together and attached it across VHF connectors.

And although the Marki Microwave design tool proposes different capacitor and inductor values for its version of the 160M 3rd order Butterworth band pass filter, you can still get an idea of what the schematic, and scatter plot parameters (insertion loss and return loss) of the filter should look like.

The first test I performed with the band pass filter was pass a sine wave through it from below the 160M band (which spans from 1.8 MHz to 2 MHz). I started with 500 kHz and passed the signal into my oscilloscope, making sure to turn on the low impedance (50 ohm) setting.

I did indeed have a fairly weak signal.

When I increased the signal generator frequency so that the waveform outputted was within the pass band of the filter (1.8 MHz), the oscilloscope showed a much larger voltage. Keep in mind that it is Channel 2 (“CH2”, the bottom box!), that you want to be looking at on the signal generator if you are following along with the pictures.

There is no change to the oscilloscope settings between the 1.8 MHz input (below) and the 500 kHz input (earlier). Clearly the voltage recovered at the 1.8 MHz setting is much larger.

Now to take a look at the NanoVNA results. The filter was simply placed between port 0 and port 1 of the NanoVNA. The vertical gray bar represents the frequency range of the 160M ham band. The filter I constructed did not use components of the exact values recommended in the K4VX article, thus the reason the filter performs at a lower frequency than expected.

Regardless, you can see below that the shape of the S11 (return loss) and S21 (insertion loss) parameters are very similar to that predicted by the Marki calculator. My filter is below:

And, again, the S11 and S21 parameters as predicted by the Marki calculator:

Well, there you have it. Band pass filter season! Field Day is almost here, and we are going to go with what we have. However, my mind has been spinning around the idea of constructing my own band pass filters so that I can more easily fix and replace the rather fragile devices as needed. And although this was a tiny little experiment, I think it shows that these band pass filter designs are indeed reproducible with accuracy. Will a KM1NDY band pass filter design show up here in the near future?! The Magic 8 Ball says “Reply Hazy. Try Again Later”!

Catchya on the flippity flip!

KM1NDY

And boy-oh-boy did we make a lot of noise! Running three generators, a cement mixer, and a tractor equipped with a scary-looking auger, we managed to dig…a hole!

Congrats AA1F, on not only digging three feet into the ground, but on fixing your auger after it snapped a shear bolt when it wedged itself under a cow-sized rock.

It may not be radio, but darn it…just go ahead and look at that cement mixer…What more do you need? Besides a chainsaw and chipper of course.

Really yours, I mean it.

KM1NDY

So much for playing radio this weekend. In the last half hour my 200mW Zachtek WSPR transmitter, cycling from 80M to 10M every 15 minutes or so, managed to be heard in 2 places… Both in Boston and presumably by ground wave.

By comparison, here is a half hour block from a good propagation day:

Simply amazing! Enjoy the Aurora!

KM1NDY

Doing a little hammy ham ham research during the solar eclipse at the Ole Farm-O-La…Welcome to the first Technical Bulletin of the KM1NDY – Secret Amateur Radio Journal.

Every now and then I decide it’s time to homebrew a receiver. You may remember my attempt back here. Or even way back here. They never work. So this even more complicated, 3 transistor, 2 diodes, and audio amplifier IC definitely did not work. Again. Well sort of. Technically it is actually a receiver. Just not what I was hoping for.

See the electrolytic capacitor I am pointing out down below? And the resistor that is in series with it? If I touch either with my fingertip, while the circuit is live, radio stations play through the loudspeaker. These components form a loop from pin 8 to pin 1 of the LM386; these pins are the “gain” pins of this low voltage audio amplifier chip.

This is a lot like what happens back in my last receiver build attempt, except for this one, I needed to touch the potentiometer in order to pick up stations. I’ll repost the video from that build below so you know what I mean. Essentially I could remove the entire rest of the circuit and as long as I powered up the LM386 and touched the top of the potentiometer, I could hear a station through the loudspeaker.

I am not through debugging this current circuit or I would go into more detail about it. In fact, in preparing this blog, I can see I left one end of a capacitor floating. The cap in the arrow below should be sitting between pin 3 and pin 4 of the IC. Pin 3 is correct, but then you can tell instead of hitting the ground rail of the chip at pin 4, the other end of the capacitor is just freely hanging out in its own row in the breadboard. To be fixed! And if I make any headway, I’ll write up a more complete description of the circuit.

One of my most successful and useful builds is in action down below. This is the KM1NDY Voltage Converter that I designed out from scratch that uses 78xx series of linear voltage regulators in TO-220 packaging. The voltages are interchangeable, and for this receiver attempt I used a 5-volt 7805 chip. The power source is a 12 volt LiFePo battery. This system includes a replaceable fuse as well, as an attempt to minimize any potentially dangerous currents from reaching me when I accidentally short something out. This little device is actually quite handy! If I make another one, I’ll need to put a switch on it though.

Ok, now close your eyes if you are going to be squeamish, but it is probably too late. I just wanted to show the bloodshed that this ham radio hobby causes me. This cute little pattern of blood bubbles is what occurs when you send the pins of an IC socket deep into your finger. Don’t fret! I am okay!

So, yet another failure. But there is still some debugging left to do, so I won’t write off the entire project just yet. And there are some important mental successes. The first is that I can now start to see the various stages of a receiver circuit. They are making much more sense to me now. And I can see how you can work on each stage as a separate entity. I am already concerned that my antenna and tuning capacitor are not working properly. Or that there is not enough amplification at the RF amplifier stage. I have figured out inadvertently that the components of the audio amplifier stage work. I needed to substitute diodes, so am I not demodulating the AM properly? And I am understanding bit by bit how and what to probe, and with what instrument, to see what is working, and what is not.

Though not so secretly, I can’t wait for the day when I post a receiver build and it is actually a success. But I have always known that failure is not trying and failing. Failure is not trying at all.

That’s that.

KM1NDY