Delta Loop vs End Fed Half Wave on 20m

Recently I came across a post by a German OM DL3TU who was quite pleased with the results of a delta loop on 20m.

I have a delta loop for 40m but rarely use it as it is quite big. For 20m a delta loop becomes very manageable. 

As my best DX antenna - the portable hexbeam - is not always an option from a time, effort or space perspective, I am always curious if there is another design that could beat my default go to option: the vertical end fed half wave antenna.

So I read through the notes of DL4AAE (who designed the antenna DL3TU wrote about) and built the same antenna. The nice thing about the version he designed is that it has an impedance of around 50 ohm. The design I used for 40m has 75 ohm and therefore needs some matching solution (like a quarter wave piece of rg59).

The new delta loop

Two antennas in the field

One of the beacons

This afternoon I went out to test the effectiveness of the antenna as compared to the 20m EFHW vertical. As always I did this by running two identical WSPR beacons for a while. I didn't have a lot of time before sundown so the dataset was put together over 30 minutes in which both beacons transmitted 9 times.

After examining the WSPR signal reports I found an interesting outcome.

Blue points are the averaged differences between the signal reports of the same spotter for the Delta Loop over the EFHW. The spotters are plotted by their distance from me.

The plot shows that in EU to about 3000km the delta loop beats the EFHW at most spotters, although four spotters only heard the EFHW (orange cross) and the EFHW got more reports in total. So it would probably be hard to tell the difference between the two within EU during a field activity.

Outside of EU the story is a different one. There were three DX stations picking up the WSPR signals. W7, VE6 (6000km) and VK5 (15000km). The VE6 copied both beacons a couple of times but the EFHW was clearly stronger (by average 8dB). The W7 only copied the EFHW but only barely and once - so we will skip that one. The VK5 copied the EFHW 4 times without picking up the delta loop beacon. 

The delta loop deserves a bit more testing but at first sight I would choose the EFHW for both its performance and practicality.

I did a thing today

So.. today I did a thing.

Today I went out portable - nothing new here - on my bicycle - OK that is slightly out of the ordinary - to activate PAFF-0085 in CW only - eh?

This was the first time I was out using CW copying by ears only. Up till now I have used CW on a few occasions but only in complete computer-mode. Then it is just another digital mode and very boring.

Inspired by the challenge Jakob OZ7AEI's set himself somewhere in August last year - to be able to use CW in WWFF activations in 2022, I decided the time had come to really force myself to learn CW to the level I could use it without any skimmers.

Four years ago I tried to learn CW over the summer holiday - while I was in OZ. It was too hot to do anything else than sit in the shadow and move as little as possible. So three weeks with plenty of time to practice. 

Going into that summer I had tried to learn CW with a game on my phone that learned you characters in a "visual way" - by tapping short and long. I found out that was not useful at higher speeds (you keep on counting dots and dashes). However, by the end of that summer I could copy individual characters up to 24 wpm. So some recognition of the sound of complete characters was there.

However I still didn't acquire the skill to copy several characters after each other. I needed too much processing time per character. So there was no real practical use for the level I was at. Then after the holidays life happened and I left the whole idea for four years. Up till Jakob's challenge.

From October 2021 onwards I focused on learning to copy series of characters. RufzXP was a good tool helping me forward. When I got to the level I could copy series of characters quite accurately at 15wpm, I moved to MorseRunner. That application has a more game-like feel to it than RufzXP so I felt it was more motivating to use. It allows you to make things more complex - and more live-like - using variables like qsb, qrn and qrm. Practicing pileups I found quite challenging but I could slowly increase the activity level (increasing the chance and size of pileups). 

In MorseRunner I am now at a level I can do 80 Q/h running at 25wpm and an activity level of 6 (with regular pileups of 4-7 callers). I thought this would be good enough to do some real life testing.

So today I went out to a nearby reserve - PAFF-0085 Rosendael - by bike. I took my FT-857d, a LiPo, a laptop, the end fed impedance transformer and a couple of wires. I used my catapult to get the wires up in a tree.

My keying still needs a lot of practice but thanks to PE5TT I now own a tiny WinKeyer. That works marvelously together with N1MM. That combination has the same look and feel as MorseRunner.

I decided to call at 17 wpm. Starting on 17m I logged 11 QSOs in 30 minutes. It was nice and slow - a good way to start. Then I went over to 20m and logged 10 QSOs in 10 minutes. A bit more activity but after these 10 QSOs it was quiet for a long time. So I decided to try 30m. In just under an hour I logged 27 QSOs. Then it was time to go back home.

In total I logged 48 QSOs in two hours. Most probably the smallest and slowest activity in all my years of doing WWFF, but I was a happy activator. Checking my log at home I think I only made one error - a non-existing call.

Thanks to all the chasers - especially those that QRS-d.

Mobile whip versus end fed half wave vertical

Those who have read previous reports of my portable activities know that I usually put in quite a bit of effort to set up a DX worthy station in the field - when possible using my hexbeam and a bit of power.

On the other end of the scale I still have a mobile antenna laying around from when I re-started the hobby in 2010. The antenna is known as D-Original DX-UHV and had some glaring reviews at the time. I did work across the pond to W with up to 7500km in phone and to PY and LU on psk31 (11.000km).

Quite quickly however I moved on to using end fed half wave wires for my portable activities, trying to cover more distance. 

Noticing that there are a number of castle (WCA) and nature reserve (WWFF) activators that use a mobile antenna, I was wondering how effective that antenna actually is. I have no doubt the end fed wire is superior to the mobile antenna, but how much better is it? Should I consider going back to using the mobile antenna?

So time to bring out the two WSPRLite beacons (two identical 200mW WSPR beacons that I can use simultaneously) again and head out to my test location north of Arnhem. My reference antenna is a half wave end fed set up vertically - or almost vertically in the case of the 40m version as the pole I use is 18m high. 

I started out with the 20m configuration of both antennas. The mobile antenna is in this configuration 147cm long. I chose to bring the feed point of the end fed wire about 2m off the ground as I have used this set up as a reference in other tests as well - and it is a set up that would only require a 12m pole so probably more relevant to the average activator.

For the second test of the 40m configurations, I fully extend the 18m pole and then sloped the last couple of meters of the end fed wire so that the feed point was about a meter of the ground. This is how I usually set the 40m end fed up in the field. On the mobile antenna I changed the element for 20m to the 40m version (the antenna is then 195cm long). The DX-UHV antenna can hold two different elements at the same time but for this test I decided to use one at the time.

As expected there is a clear winner on both bands - not surprisingly this is the vertical wire. The question I had was how much the two would differ. Here is a breakdown of the data I managed to collect in the time I had (1 hour on 20m and 1 hour on 40m), 

Results on 20m

On 20m in 1 hour:

• DX-UHV - 16 transmission - 56 spots - 11 spotters
• End fed half wave wire - 16 transmissions - 118 spots - 24 spotters

DX-UHV did reach NA	End fed wire copied by the same and more

Odx for the mobile antenna was 6000km to W2. Odx for the end fed wire was 8000km to W7. 

There were not a lot of stations that copied the signal from the mobile - less than half of the stations that copied the beacon on the end fed wire. There were 6 stations that copied both signals multiple times. Looking at the reports from these stations there is an average 9dB difference in the signal strength reported. 

Results on 40m

On 40m in 1 hour:

• DX-UHV - 15 transmissions - 119 spots - 27 spotters
• End fed half wave wire - 12 transmissions - 317 spots - 56 spotters

DX-UHV	End fed wire

Odx for the mobile antenna was 2200km to SV8 (1 spot -29dB). Odx for the end fed wire was 3100km to EA8 (7 spots). Looking at the reports of stations that copied both signals multiple times, there is an average 10dB difference in the signal strength reported. 

On 40m the difference is more pronounced looking at the amount of spots. With less transmission cycles of the beacon the end fed wire reaches more than twice the amount of stations. The reach is considerably longer with TF, TA, 5B4 and EA8 only copying the end fed wire.

Conclusions

So what have I learned.. well the outcome really matches my expectations. 

Looking at it from the practical side, the mobile antenna is easier to set up and does not take any more space than the car itself does at the activation location - can be a huge plus in some places. It also requires a lot less room in the car so it might open up a few more possibilities for /P operations.

 

The consequences however are that I will reach less stations and especially less DX. I have also found that controlling a crowded frequency is more difficult if your own signal is relatively weak. On the other hand... it might not be so crowded if no one hears you (hihi) 

The difference is considerable but not overly dramatic though, when conditions are good and signals are around S9 on the end fed wire, you would still put in a good S7 with the mobile antenna. So I will give it a try in an activation when conditions are favourable and simplicity is important for whatever reason. tbc. 

This post is one of a series of antenna comparisons I have done. The index to the other tests is here,

Enjoying better conditions as PG44FF

With Christmas approaching I had a bit of time available and I had already arranged a special call for the holiday season. Looking at the slowly awakening sun I was motivated to go out portable again on Dec 24. Normally I would go out somewhere in the afternoon and into the evening to get both some DX on the higher bands and lively conditions on the lower bands but Christmas Eve meant I had to be back home at 16h local time.

PAFF-0167

Trying to find a PAFF nature reserve that I had not activated before and that looked like it would allow me to set up my hexbeam (so not in the middle of a forest) I found one at 1.5h driving distance. Even though this would mean I would spend more time travelling than on the air I settled for it.

Setting up in the mud	Hexbeam looking towards OC

The weather forecast showed overcast but dry conditions. This turned out to be a but too optimistic. It was raining when I arrived at the nature reserve. The area I had selected to set up my station had turned into a big muddy pool. Still I managed to set up the hexbeam without getting everything covered in mud.

It was around 10.30 UTC so contacting the far east and perhaps even OC was theoretically still possible. So I started out on 20m with the hex pointing northeast. Skip within EU was a bit unstable but strong most of the time. After about 20 QSOs ZL3LF came through the pileup with a signal peaking at S8. A very nice surprise indeed. I called for more DX but got no reply however 6 minutes later VK2ON made it through the EU chasers with an S9. It shows that the band was wide open in that direction. I called OC a couple of times but it seemed everyone else was enjoying Christmas Eve away from the radio.

222 QSOs spanning the globe

It was busy all the time. In 2h20m I logged 222 QSOs in phone with chasers from a whopping 43 DXCC, 8 different W states and 3 VE provinces. 

I tried the higher bands but 10 and 12 were dead and even 15m did not result in more than a handful of QSOs. It would probably have served me better later in the afternoon. However the skip in EU was quite wide running all the way from 150km (still within PA) up till the edges of EU. So there was no real need to go down to 40m - which would have required changing antennas.

Nice wide skip in EU on 20m (orange = 20m, turquoise = 15m)

All in all again a pleasant activity and worth the 4h travel and setup time. HNY to all!

Time flies: 10 years as WWFF activator

It is hard to believe but it is 10 years ago that I did my first WWFF PAFF activity on June 27, 2011. I had just upgraded my license after getting back into the hobby in 2010.

Actually sharing the experience of it is only the third post I wrote on this blog.

As I was just back on the radio after 15 years of inactivity, I took equipment with me whenever I could, working /P and /M regularly. That day in June I was in the north of the country for work, staying in a hotel. At the end of the afternoon I was able to get out of the office and head over to national park Lauwersmeer (PAFF-0014). It was only the second day that I was using my new PH0NO callsign. 

I had read about PAFF, probably on the blog of Hans PA3FYG or some other radio amateur website and was curious to see what it would bring to my /P operation.

In that period my FT897d was back to the dealer for repairs. So I only had an FT817nd that I bought as backup radio. With my whopping 5 watts, my end fed wire antennas and a rather thin Spieth 10m fiberglass pole (with extension rods to get the 20m wire off the ground) I was not expecting too much.

I was in for a surprise. It was the first time I had to deal with a pile-up. I logged more than 150 chasers and even one JA7 (mind you, SSB with 5W).

After this first experience I was sold. This started a hobby in a hobby doing many WWFF activities in various countries in Europe and VE, including memorable YNOMY team expeditions to LX, HB0 and GJ. 

Being enthusiastic about the program I was keen to help grow it both in PA and worldwide. I ended up coordinating PAFF and working as part of the WWFF team a couple of months later and up till the present day.

Impressions from 10 years WWFF

In all these years I met a lot of people. There are thousands of WWFF chasers but there is a hardcore group in the hundreds that have become familiar voices. I was also lucky to meet a couple of WWFF-ers in real life both in PA and abroad.

As a sort of commemoration I will be returning to PAFF-0014 on June 27. This year that is on a Sunday which is rather convenient. I will be using the last - so far unused - of the series of P*44FF calls that I have used before: PH44FF.

PAFF-0079 on the high bands

Acceptable weather for a change motivated me to go out to activate PAFF-0079. This reference had had some attention in the past (>500 QSOs) but most of it years ago. Expecting some Es conditions I brought my hexbeam and my 2-4-6m yagi.

Hexbeam and 2-4-6m yagi

It was rather busy in the area with people happy to be able to go out for a walk. It was difficult unfolding the hexbeam without getting in people's way. Ofcourse I got a lot of questions about this rotary clothesline..

The rotary clothesline

I started out on 6m but that band was not really alive. I only worked one EI station. So much for the effort to bring and setup the yagi.

I went over to the hexbeam starting on 15m as that band sounded quite active.. and it was. I logged more than 70 contacts on that band. Most of those were in the UK - there seemed to be a nice cloud over the North Sea. I was also greeted by Len VE9MY and Linda VE9GLF (P2P) and 5 US stations including the usual suspects Tom KG8P and Robert KD1CT.

After about 1.5h I went down to 17m again logging mostly UK stations and VE5. 17m was not too busy so after 30 minutes I went down one more time to 20m. 20m was in an okay state. It was never very busy but I did log almost 150 contacts in 2h. At the start I had the beam pointing towards NA - logging KA8H and W1OW - but I noticed spots to the east so I turned the beam. That probably helped me log 3 JA stations.

A cloudy but dry day out in PAFF-0079

I had skipped the 10m band earlier thinking the Es was not strong enough but I still saw spots on that band (past 20h local time) so I decided to go back up hoping for an opening to SA. With the beam in that direction I logged PU and some 20 more contacts in EU - mostly from south DL to I. 

It was getting late but there was one band to my immediate disposal I had not visited yet: 12m. The first response came from Max IK1GPG, who I just spoke to on 10m. In these last few minutes I logged a few more EU stations and FY to my surprise. 

It was so much fun on the higher bands that I never came around to breaking down the hex and going for the low bands. Normally I make most of my QSOs on those bands. However with a bit more time spent than usual (5h) I still managed to log 286 QSOs from 45 DXCC with 12 P2P.

Building a new lithium battery

For years I have been using lithium batteries to power my radio equipment when portable, both LiPo and LiFePO4.

If you want to know more about these different types read this post I wrote a few years ago.

I started out buying batteries from HobbyKing in China. Then I decided to build a few myself with pouch cells I bought from AliExpress. 

Recently I lost two LiPo pouch cells when I abused a battery - forgetting to attach the under voltage alarm. Another LiPo cell of a different pack turned out dead without a clear cause. I ordered a new cell but they are quite expensive. Losing three of those cells in a short period of time I suspect I might have to replace more in the future. So I started looking for other solutions with cheaper building blocks: smaller cells.

LiPo cell after abuse

Looking at smaller cells I first stumbled upon the 18650. A popular Li-Ion battery and quite small but you need a lot of them to get a useful capacity as they are around 2Ah a piece. However I found more practical LiFePO4 cells with a 7Ah capacity: 32700. I bought a set of those with strips of nickel attached to the ends for soldering as I do not have a spot welder (yet).

The voltage of four of these LiFePO4 cells is too low for my amp - that is why I opted for LiPo up till now - but as the amp is designed to handle up to 18V a battery of 5 cells would do the job. So I decided to go for a 5s3p design (5 cells in series and 3 in parallel).

Building a 5s3p battery

I bought a BMS as well with the idea that it will protect the battery from under voltage. And it allows me to charge the battery even with a simple (non balancing) charger. I was hoping that a BMS is more effective in balancing than the chargers I have - that take quite some time to balance an unbalanced pack.

Completed battery with BMS

Testing the battery my first lesson was that you cannot charge a battery that has a BMS with a smart charger. The BMS starts kicking in when the first cell approaches its maximum. The charger notices the increasing resistance and shuts down with an error ("connection break"). 

Charging through the BMS with a smart charger 

Time for Plan B I used a 12V source and a step up converter to 18V to act as a "dumb" charger. Meanwhile I checked the charging current and the voltage of the individual cells to see what was happening. 

This time the charger patiently waited for the BMS to allow for a current to run. The BMS would drain the cells for a bit and then allow a charge current until one of the cells hit around 3.5V and then the cycle repeated. However it did not seem to be able to bring the cells closer together. After an hour there was still a spread of 0.2V between the cells. 

After letting the pack sit for a while I found out that the BMS aims to keep the cells at around 3.4V (on my V-meter). So during charging - aiming for 3.6V - a cell might go higher but the BMS will continue to discharge it until it is back at 3.4V again.

I will have to see if this noticeably impacts the capacity of this battery pack. When I have some more time on my hands I will run some tests and see how it behaves under the stress of powering a 400w amp.

Update May 2021:

After using the battery pack for a while I decided to remove the BMS. In my situation - having balancing chargers - the BMS only adds complexity.

The second thing I noticed is that the pack was struggling delivering the high amperage the ALS-500m pulls. Testing the pack at home with a dummy load I saw the nickel tabs I used to solder the main + and - wires to became hot, red hot even. 

So I decided to solder wires to the first and last set of (three) parallel batteries to spread the current. Testing that thoroughly I found it to work perfectly. All cells now discharge evenly, even under high load.

Shrink wrapped end result (with built-in Voltmeter)