Category Archives: Articles

Antennas, Articles, Guest Posts, News, QRP

Dale uses WSPR to test counterpoise orientation

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The CHA MPAS Lite

Many thanks to Dale (N3HXZ) who shares the following guest post:

Does your antenna counterpoise orientation matter?

by Dale (N3HXZ)

I am an avid SOTA and POTA activator and love field operation. I use a portable vertical whip antenna with a single counterpoise for my antenna system and have always wondered if orienting my counterpoise would provide some signal strength gain in a particular direction.  I decided to run a series of tests using WSPR to gather field data, and use statistics to answer the question:

Does one counterpoise orientation favor another in terms of average signal strength?

WSPR is a great tool for antenna testing. You can study various antenna configurations by making some WSPR transmissions and then checking the data on the WSPRnet database to see how well the signal was received at various stations located all over the world. You have to be careful in interpreting WSPR data though as receiving stations have different antenna and radio configurations, and the band propagation can vary rapidly at times. So how do you take advantage of all the data you receive from stations and draw some meaningful conclusions? I have found that using proven statistical theory in analyzing the transmitted signal strength received from individual stations can provide you results that you can confidently trust.

So what statistical algorithm is helpful?

For antenna signal strength comparison between two configurations, you can use an independent two-sample t-test with a one-tailed t-test evaluation. It sounds like a mouth-full, but it is quite simple. For our purposes, the t-test compares the average signal strength at a given receiving station from two different antenna configurations. The one-tailed test validates or invalidates the hypothesis that one antenna configuration produces an average signal strength greater or less than the other antenna configuration.

The testing requires that you run WSPR long enough to gather multiple reports at a single receiving station for both antenna configurations. Using the signal strength reports, you compute the average signal strength and the standard deviation of the signal strength over the sampled data points. Excel can easily provide that data.  With this information and the number of sample points for each antenna configuration (they can be different), you then run a calculation by hand or in Excel to compute the ‘t’ value.

This ‘t’ value is then compared to a critical value for the number of sampling points from a ‘Students t table”. If the ‘t’ value is less than the critical value you can confidently conclude that the hypothesis is false and therefore conclude that there is no significant difference in the mean value of the signal strengths between the two.  If the ‘t’ value is greater than the critical value you can accept the hypotheses that one antenna configuration produces a greater or less average signal strength than the other configuration. Continue reading Dale uses WSPR to test counterpoise orientation →

Accessories, Articles, Field Radio Kits, Field Reports, Grab And Go, Morse Code, News, Portable, POTA, QRP

Testing my new Headrest QRP POTA Field Kit!

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I love field radio kits.

If you’ve read my “Anatomy of a Field Kit” series, you’ve likely gathered that field kits are a bit of an obsession. [Yeah, understatement alert!]

My field kits roughly fall into two main categories: modular and fully self-contained. My modular kits are ones where components like the battery, antenna, throw line, key, and radio are in separate pouches and can easily be combined to make a complete station before I leave for an activation.

My fully self-contained kits are ones that quite literally have everything needed to perform a park or summit activation in one pouch or box. A good example that I’ve documented here is my MTR-3B field kit.

For more on this, again, check out my “Anatomy of a Field Kit” series.

Vehicle kit

If you’re a devoted park and/or summit activator, I think it’s important to keep a dedicated kit kit in your car at all times. Why?

  • It’s ready to grab for impromptu activations
  • It’s handy in case of road-side emergencies in remote areas
  • It’s always  accessible to demonstrate amateur radio to those who are curious
  • It’s always always there for those times when you hadn’t planned to play radio, but the opportunity presents itself

I always have a full radio kit in my Subaru and over the years, I’ve changed and adapted it. For the most part, though, it’s been located in the trunk/boot and lives with anything and everything else I keep back there. Sometimes, it’s in the way when we need to fill that trunk space with family items for a trip or when we’re hauling things around town. Other times, it’s floating/sliding around freely in the back.

On long family trips, I’ve been known to store radios under the floor, but it’s a true hassle to remove them because I have to remove anything in the trunk before lifting the floor.

Contraband I hid in the car during our two month Canada trip last year.

I’ve always wanted a way to store my kit in the car in a dedicated space. In the past, I’ve tried to make a kit that could fit under the driver’s seat–thinking that might be ideal–but there’s very little clearance under it and it’s difficult to remove.

Enter the BROG Headrest Pouch Kit

Before I placed my initial order for the Blue Ridge Overland Gear (BROG) Gadget Bag, I checked out other items on their website. One that immediately caught my attention was their Headrest Kit.

It consists of a Velcro panel that fits around a vehicle headrest and a pouch (or pouches) attach to it.

BROG caters to Overlanders and vehicle storage/organization is huge in that community. The headrest kit makes a lot of sense: it’s using space that’s accessible, doesn’t interfere with any passengers, is off the floor, and is otherwise underutilized!

The big questions, of course:

  1. would the pouch offer enough space to store an entire radio kit,
  2. and would the kit weight too much for the Velcro back to hold it in place?

I asked for the Headrest Pouch Kit ($47.99) to be sent with my Gadget Bag order.

BTW: Big thanks to BROG for giving me flexibility with this order. Since I had no experience with their gear, I asked that they send me a list of items and allow me to evaluate them, then pay (full price) for what I decided to keep. 

Would it work?

I knew I’d need to store a very small transceiver in this dedicated pack. A few could potentially fit the bill–namely the:

  • Mountain Topper MTR-3B
  • Venus SW-3B
  • QCX-Mini
  • TEN-TEC R4020

I eliminated the QCX-Mini from this list because it’s mono band (mine is set for 20M) plus, I really love the field kit I already designed for it. Same for the MTR-3B–the kit I built for it is now time-tested and I love it as-is. The R4020, while quite compact, is the largest in this group of wee rigs. Continue reading Testing my new Headrest QRP POTA Field Kit! →

Accessories, Articles, Guest Posts, Portable, Reviews

Coax cables I used for SOTA/POTA – A horror story

32 Comments

by Thomas (DM1TBE)

I think every portable operator thinks about their coax cables and how to use more light and flexible types. During the last few activations, I have switched from my rigid Aircell 5 to the lightweight and flexible RG316. I have bought a couple of different lengths, mainly from Chinese online sellers at AliExpress.

However, I had some hard to define issues like the vague feeling that I am not getting out as good as I should, or a changing SWR during an activation. So I thought I should check my cables before looking at other parts of my equipment.

My professional and educational background does not have anything to do with electronics, and I don’t have the equipment to measure the cable loss directly. But my goal was to check if the cables were faulty, not to measure the exact attenuation.

I have an SWR and Power meter from DJ9PK as per image below. It can measure PEP and has, according to the seller, an accuracy of +/-4 percent.   You can find more details about it here in German or here in English (Google / auto translated).

My KX3 with a CW paddle served as signal source. As large differences are easier to spot than smaller, I switched to the 10-meter band as the HF band with the highest attenuation.

I then measured a short cable with a very low loss, a 1 m / 3.3 ft RG213, which should have an attenuation of less than 0.1dB (excluding plugs).

I simply checked how much power came out at the other end of the cable. That value I have used as reference. This cable (and all others) was plugged directly between the KX3 and the power meter, no ATU involved anywhere. The power meter was set to measure PEP. Continue reading Coax cables I used for SOTA/POTA – A horror story →

Articles, Field Reports, Guest Posts, QRP, SOTA

SOTA in the Czech Republic – When everything goes wrong

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by Thomas (DM1TBE)

As I have mentioned in my two previous posts, I have visited my family on the other side of Germany. On the way back, I wanted to make a “tiny detour” and activate a summit in the Czech Republic. I like all kinds of numbers and statistics, and that includes my SOTA stats. My goal is not being number one or be in the top region somewhere, but seeing it progressing and developing satisfies me. Until July last year, the upper right pie chart was only light blue, i.e. I had only activated summits in region DM, Germany – Low Mountains. So I use every chance to push the light blue back.

sotl.as

After some concessions, my family agreed and the way back increased from 6 hours and 583 km / 362 mi to 8:30 hours and 732 km / 455 mi.

Route on Google Maps

On the drive to visit my family, I noticed that I forgot my wallet, so I had neither an ID card nor my driving license. In many regions of the world, it would be probably very difficult to cross an international border two times without papers. However, many countries in Europe have signed the so-called Schengen-Treaty, which led to the creation of Europe’s Schengen Area.

Camoka4, CC BY-SA 3.0, via Wikimedia Commons

The Schengen Area consists of 27 European countries with a population of over 400 million, who have abolished border checks. However, random inspections still happen. The worst case would be a control in the Czech Republic and the official requirement to go to the German embassy in Prague for new papers.
As expected, the border crossing was easy and it could easily been overseen.

If you missed that sign in the photo, you only note that the town names have changed to Czech, as Czech names are quite different. After the border crossing, the summit is just minutes away, and you can drive up to the very top – pretty convenient for a 10+3 points summit.

Derived from User:Rdc, Public domain, via Wikimedia Commons

The summit Klínovec (OK/KA-001), also known as Keilberg, is the highest mountain in the Ore Mountains, located on the border between the Czech Republic and Germany. With a peak reaching 1,244 me / 4,081 ft above sea level, Klínovec has been a popular destination for outdoor enthusiasts and tourists, and is the most important winter sports area in the region. The mountain has a rich history that includes mining activities for silver, lead, and tin in the dating back to 2500 BC, and it has evolved into a popular skiing and hiking destination in recent years, attracting visitors from both countries. According to reports, the peak has attracted people for hundreds of years, with the earliest observation tower erected in 1817. Continue reading SOTA in the Czech Republic – When everything goes wrong →

Articles, Field Reports, Hams, Morse Code, News, People, Portable, POTA, QRP, Skills, Videos

Join Brooks (KO4QCC) on his First CW POTA Activation–!

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Friday, March 24, 2023 was a very special day for Brooks (KO4QCC) and for K4SWL.

I’m so excited to share this with you.

You might recall that, last year, I met up with Brooks at Tuttle Educational State Forest as he performed his very first POTA activation in SSB. He did such an amazing job!

Since I first met Brooks, he’s always had a goal of learning CW and activating parks and summits using Morse Code.

I’ve been in touch with Brooks regularly over the past year and have followed him as he progressed on his CW journey.

Though, like me, he has an active family life, Brooks has found the time to practice CW both through lessons and actual on-the-air contacts. Fortunately, this is all possible because–again, like me–his wife and family are very supportive of his amateur radio adventures!

Early this year, we met on 80 meters and had a good one hour rag chew at about 12 words per minute. I could tell he was ready to do his first POTA activation in CW.

To give him a little real-world practice, we decided to hit the field on a day when I was performing an activation and he could log for me in real-time.

I could tell by how well he was logging as I worked stations at 18WPM  that he was ready to perform his first activation, so we made it a goal to do so within the next couple weeks.

Fast-forward to 8:30 AM on March 24 when Brooks and I met at the Folk Art Center on the Blue Ridge Parkway. Coincidentally, this is the same location where I performed my first CW activation!

We deployed his MFJ-1984MP 40 meter EFHW (End-Fed Half Wave) and connected it to his Xiegu X5105 transceiver in very short order. Brooks also chose his lucky CW Morse paddle for this activation.

But before hopping into the field report, let’s back up just a bit…

First CW Activation: Getting there…

Brooks very kindly wanted to share a bit about his CW journey in this field report. He writes:

From the moment I knew of its existence, becoming a POTA activator using CW has been at the top of my “radio bucket list.”

It seemed like the ultimate challenge and I knew I would never be satisfied until I was able to confidently activate parks using CW. There is also a bit of mystique to CW that other modes lack, making it inherently more interesting to me. In this article, I am going to share the path I took to learn CW and how it culminated in a very successful CW activation.

Continue reading Join Brooks (KO4QCC) on his First CW POTA Activation–! →

Articles, Field Reports, Guest Posts, POTA, QRP

Another POTA activation close to the “Bridge of Spies”

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by Thomas (DM1TBE)

Intro

The day after my activation of Park Babelsberg, I wanted to activate a second new POTA park. The new Park Sacrow is a picturesque park located on the River Havel in Potsdam, about which I have written a brief summary in the  QRPer activation report for Park Babelsberg.

One of the prominent landmarks in the Park Sacrow is the Heilandskirche, also known as the Church of the Redeemer.

This neo-Romanesque church, completed in 1844, is a striking sight with its red brick façade, white stone accents, and tall tower. The Heilandskirche is overlooking the Havel River and offers panoramic views of the surrounding park and river.

During the time of the Berlin Wall, the Heilandskirche in Sacrow was located near the border between East and West Germany. The church was in the “No Man’s Land”, i.e. behind all East German border barricades – see photo from 1972 below with the Berlin Wall –  preventing anyone from visiting.

Ulamm, CC BY 3.0, via Wikimedia Commons

After the years of decay, when the bad condition became too obvious from the West Berlin side, citizens of West Berlin tried to stop the further decay. After long negotiations between church authorities and the government of East Germany, the exterior of the church building was restored in 1984/85. Today, the church looks as beautiful inside as it looks outside.

With the border between East and West at the middle of the river, the whole area was a kind of border protection zone, only available to locals or those with a special permit.

The park is close to the Glienicker Bridge, also known as the “Bridge of Spies” from Steven Spielberg’s blockbuster, on the opposite of my position the day before.

Arne Krueger, CC BY-SA 2.0, via Wikimedia Commons

As mentioned in my previous report, I have grown up less than a mile away from this famous bridge, in Potsdam, i.e. Soviet controlled part of Germany.

In my opinion, Steven Spielberg told the wrong story. There is another, more interesting story related to this bridge. It is the story of the Military liaison missions. A few British, US and French army members were allowed to roam freely in the Soviet controlled part of Germany and, vice versa, a few Soviets in West-Germany. These members of the military liaison missions had immunity from all German authorities. Since East Germany was frontline to the western world, the Soviet army had their most advanced technology there and the mission members’ task was it to spy, for example with this US Military Liaison Mission vehicle – note the license plate.

US Army

The uniformed, but unarmed mission members drove military-green cars with a special license plates – here a British mission car on display in a museum. For me as a child, those cars looked like from another planet.

Von allen watkin from London, UK – flickr, CC BY-SA 2.0, via Wiki Commons

The Glienicker Bridge border crossing wasn’t open for public, but only for those mission members and diplomats. The French and British mission houses were close to this bridge in the Soviet controlled part, the one for the US was some miles away.

French Mission House today:

British Mission House today:

Just imagine these two buildings with a huge British and French flag on top, in proximity to Soviet military installations behind the Iron Curtain.

It did not always go as smoothly as it could. The image below shows the Soviets handing over the corpse of Major Arthur D. Nicholson to the US authorities on the Glienicker Bridge. Nicholson was shot down in 1985 by a Soviet sentry at a Soviet army base in East Germany.

Alliiertenmuseum /Allied Museum Berlin / USMLM

In 1984, Philippe Mariotti, a member of the French Mission Militaire Francaise de Liaison died after the East German Secret Service has set up a trap and rammed Mariotti’s car with an army truck.

The British BBC aired an interesting documentary about the British mission The British Commanders’-in-Chief Mission to the Soviet Forces in Germany (BRIXMIS)  called “The Brixmis story”.  If you find the topic interesting, there is a lot of stuff on YouTube when searching for Brixmis or USMLM.

The activation

The weather was significant better than the day before, with sun shining and warm spring temperatures. I also had more time available. Continue reading Another POTA activation close to the “Bridge of Spies” →

Articles, Field Reports, Guest Posts, POTA, QRP

Park Babelsberg – POTA ATNO on a UNESCO World Cultural Heritage site

10 Comments

by Thomas (DM1TBE)

Intro

The holidays seasons like Christmas or Easter provide an opportunity to return to the family. So I drove across Germany to Potsdam, where I have grown up, during the extended Easter weekend.

Potsdam is a historic city located in the state of Brandenburg, Germany, next to the capital Berlin. It has a rich history dating back to medieval times, when it was founded as a settlement on the banks of the Havel River. In the 18th century, Potsdam became the residence of the Prussian royal family and was transformed into a center of arts, architecture, and culture. The famous Sanssouci Palace, built by Frederick the Great, is one of the many palaces and gardens that reflect the city’s royal heritage.

piotr iłowiecki from POLAND, CC BY-SA 2.0, via Wikimedia Commons

Close to the Sanssouci Palace, the Neue Palais, a grand palace, is located. It is a magnificent example of Baroque architecture, with its grand façade, opulent interiors, and beautiful gardens, and it was used as a guest residence for the Prussian royal family. Later William II, German Emperor and King of Prussia, made it to its main seat.

Steffenheilfort, CC BY-SA 3.0, via Wikimedia Commons

Potsdam was also a significant location during World War II. During the last days of the war, the 12th German Army tried to break through the Soviet blockade around Berlin, which caused fierce fighting close to the city.

Less than a month before Germany’s final surrender, 1700 tones of bombs were dropped causing destruction of a large part of the city center. Still a lot of dangerous stuff from those times is found during construction works until today.

The city also served as the site of the Potsdam Conference in 1945, where leaders of the Allied powers met to discuss the future of post-war Europe – here with Winston Churchill, Harry S. Truman and Josef Stalin during July 1945.

U.S. National Archives and Records Administration

Before I started the trip, I checked which ham radio programs offer outdoor activations in the region. The whole area is more or less flat, so not SOTA summit within a radius of a one-hour drive. Also, no POTA park existed, so I thought suggesting two would be good, for me and POTA :).

One new park later accepted by POTA was the Babelsberg Park with its Babelsberg Palace. The palace was the summer residence of Prince William, later German Emperor William I and King of Prussia, and his wife.

Raimond Spekking & Superbass, CC BY-SA 4.0, via Wikimedia Commons

The park and the palace is on the UNESCO World Heritage list.

From the park, you have a good view to the Glienicke Bridge, probably better known from Steven Spielberg’s movie “Bridge of Spies”.

The Bridge of Spies connects Berlin (formerly West-Berlin part) with Potsdam, (formerly East Germany), hence formerly the Soviet and Western (US, UK & France) controlled parts of Germany. The bridge was used as an exchange for spies between Western and Eastern powers. Probably most prominent was the CIA pilot Gary Powers, who was shot down over the Soviet Union with a U-2 spy plane in 1960.  Below is an image of the beginning of another spy exchange in 1986.

CC0, Alliiertenmuseum / US Army

I grew up during those times less than a mile away from that bridge, in Potsdam, i.e. in the Soviet controlled part of Germany, and the area up to the bridge, where a lot of Soviet army installation were located, was my playground. Continue reading Park Babelsberg – POTA ATNO on a UNESCO World Cultural Heritage site →

Accessories, Antennas, Articles, Field Reports, Guest Posts, News, Portable, QRP, SOTA

Steve tests the Gabil 7350T antenna, Gabil GRA-ULT01 tripod, and BaMaKeY TP-III paddles

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Many thanks to Steve (MW0SAW) who shares the following field report:

Mini Field Report: Testing the Gabil 7350T and BaMaTech TP-III on a brisk SOTA activation!

by Steve (MW0SAW)

Went for an early walk/SOTA activation up Fan Fawr GW/SW-005 (734m) this morning (9/4/23). I think someone said it was supposed to be the hottest day of the year in the UK. It was about 5 deg celsius with a bitter wind chill of -2c on the summit! It’s very close to the highest peak in South Wales, Pen Y Fan (886m).

As I mentioned a couple of weeks ago in our emails, I wanted to test a new compact antenna I purchased recently, called the Gabil 7350T in the USA, and branded as the Sharman MD-3500 in the UK where I got mine. I also took the Gabil GRA-ULT01 MK2 tripod which I did purchase from the USA on Amazon.com.

The Gabil 7350T Compact Antenna and Gabil GRA-ULT01 MK2 tripod

Another first for the the activation was the Bamatech TP-III ultra compact paddle, Dinos were included 🙂

Starting my walk, the lovely view of the reservoir quickly disappeared and was the last view I would see ascending into the mist.

I took refuge in my Decathlon 1 man camping shelter, setting up the tripod and antenna close by.

The wind was howling and turning my back the antenna toppled over. This was quickly resolved with a tent peg on one of the tripod legs. Quick setting of the slider with the analyser got 1.2 SWR and so after a slurp of coffee, I started to call CQ on 20m CW. A nice stream of European qsos ensued with good reports (many 599), it was pleasing to hear with such a small antenna (about 8 ft). Just as the contacts were drying up, I was taken aback by a strong VK station! Always great feeling to get some dx like that but especially pleasing with this tiny antenna on its maiden voyage 🙂

I switched to 20m SSB for a few more QSOs but struggled with QRM on two frequencies. My allotted time was running low and my fingers were numb, so I packed up the HF and got the handie out to catch a few local VHF contacts.

So what can I summarise from this activation, well I can safely say I love the Gabil/Sharman antenna and Gabil tripod. They would make a really nice additional to a small go bag, they seemed to work almost as good as a full size 1/4 on 20m. Time was limited this trip and I was too cold to hang about to try more bands, but extremely pleased with the performance so far.

The Bamatech key is a pure work of art, beautifully made, sensitive and precise. Probably my best portable key to date in my collection.

Equipment:

(Note: Amazon links are QRPer.com  affiliate links.)

Thanks to all the chasers.
73
de MW0SAW/P

Accessories, Articles, How To, Kits, New Products, News, QRP

Assembling a K9DP BCI Filter Kit (Photos)

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If you own a Xiegu G106, X6100, or any other radio that is prone to overloading when in the presence of an AM broadcaster, you should consider building an in-line BCI filter!

As many of you know, I’ve been testing the Xiegu G106 over the past couple of months for a review that will be published in the May 2023 issue of The Spectrum Monitor magazine.

One criticism of the G106 is that its front-end overloads when there’s an AM broadcaster within a few miles of where you choose to operate. The Xiegu X6100 is identical in this regard.

One quick way to remedy this is to build or buy a BCI filter. We’ve mentioned in the past how you can homebrew them and I planned to do so. After checking my parts drawer, though, I realized I needed to buy a capacitor, toroids and at least one of the two BNC connectors needed if I wanted an in-line filter in a small project box.

I decided it would be much easier to simply buy a kit and, based on a tip from a reader here on QRPer.com, I purchased one from Dan (K9DP). Continue reading Assembling a K9DP BCI Filter Kit (Photos) →

Articles, Field Reports, Guest Posts, Portable, POTA, QRP

Quick test of a homemade 20-meter band antenna at a beautiful POTA location

15 Comments

by Thomas (DM1TBE)

Intro

You may, or may not, know the situation when you are invited for the birthday of your mother-in-law and the whole day is just a chain of meals. As the SOTA activation of the Wasserberg the day before was rather short, I needed to escape and do something outdoors. An antenna test at a nice POTA location would be perfect.

When I started with amateur radio, many fellow hams told me that a real ham must build its own stuff. This is not easy when you have 10 thumbs like me. However, from time to time I try smaller projects. When I am operating portable, I usually have a 10 m / 33 ft mast with me. I have a 30/15-meter- and 12/17-meter band antenna, both with coils and shorter than my mast, and a homemade 10-meter band antenna which I can raise vertically on my mast. A mast with one of these wire antennas can be used on most of the locations I have visited.

However, I was missing something for the 20-meter band. I have a 10 – 80-meter 5 band antenna that covers 20-meters, but raising it as a sloper with a length of app. 24 m / 79 ft is tricky sometimes.

Building

So, I thought it would be a good project for me. As a half-wave for 20-meters is exactly the length of my mast, and I did not want the feed point at or too close to the ground, I wanted to add a short coil. I had a finished 1:49 mini-impedance transformer from K6ARK available from a project I’ve never finished. So, I just needed a screw, a cable and a piece of a PVC electrical conduit.

I have cut the PVC electrical conduit in three parts, one for the coil, one for the upper-end to allow easier mounting at the mast, and one for a simple strain-relief. My wife was a bit nervous when I used her best knife for cutting it, not sure if she worried about me or her knife. The dimension of the coil is based on pure guess. Bringing the whole antenna then into resonance was easy – just cutting step by step. After completing, the antenna still looks a bit makeshift.

Testing

So, I used an opportunity between two meals to leave my mother-in-law’s birthday and drove to the next POTA park, which is the Kaltes Feld (DA-0410). However, this time I did not go to the SOTA southern activation zone for Kaltes Feld (DM/BW-659), but to the opposite direction, where I have not been before.

The weather was nice, and the way was without any ascent. Behind me, a bit higher, was the SOTA summit Kaltes Feld and on the right the SOTA summit Bernhardus (DM/BW-848).

On Google Maps, I have seen that there is a viewpoint with a wooden bench and table. It was not too hard to find, and the place will probably become one of my favorites. Continue reading Quick test of a homemade 20-meter band antenna at a beautiful POTA location →