Wednesday, December 29, 2021

2021 highlights, 2022 goals

 Traditionally this is the last post of the year. Last year I wrote that I hoped not to be infected by covid. Unfortunately it caught us as family. The downside of it all is that I'm not in the mood to do something with my radio hobby. The few things I did during quarantine was cleaning the shack and repairing the main 230V switches. The safety ground issue is still something I'm not satisfied about and it keeps playing in my mind. I have to sort things out.

This year started with my participation in the True Blue DXers Club Ultra Marathon. Many HAMs thought that it was only for those that did only SSB and CW and no FT8. It is not the case, everyone can participate and it is not forbidden to do FT8 as well. But of course only SSB/CW (depending section) QSOs count! So far, I hoped for some more SSB QSOs. Unfortunately time didn't allow me to make as many as I did FT8 QSOs. It is simply a matter of how easy you can make a FT8 QSO and how difficult and time consuming it is to make a SSB QSO. Besides that, FT8 is much more suitable to work remote from the living room while doing other things at the same time. I made over 2000 SSB QSOs this year according to the TBDXC marathon score server.

Of course I continued with DXing, something I love to do most on HF radio. Especially the 60m and 6m had my interest this year. I worked 8 new 60m DXCC this year but heard (seen) at least 16 new DXCC. It frustrates me sometimes I didn't work everything. Sometimes I was just too late, or it was just a too busy pile-up. In the end I probabely get another chance another year. What can I tell, I worked 177 DXCC on 60m till now, I think that is not bad at all. The ES season took off really well in April and I did surprisingly well I think with 20 new band DXCC giving me a total of 103 DXCC on 6m. 4m DX was rather disappointing, I only worked 2 new ones. What can I say, I shouldn't complain I think. There is always a next season...

Personally I think my most important post this year was about the discovery of the WW2 paraset (spy radio) manual. After my first post about it in March  I got many replies and requests. The story and manual is published at the cryptomuseum and after some research it was decided to give the actual "paracette" an own page. The story was also published in our local amateurradio magazine "Hunsotron" and in the national VERON magazine "Electron". After all it is an unique document, the only one known in the world.

I did some antenna experimenting as well. Changing the magnetic loop with some additional features and did some modifications to my all band vertical. Unfortunately the 5 band quad is still an idea. Will I ever build it? I really like to tinker with antennas to improve the station. Although I have still a lot to learn. So many ideas and not enough time...

And now my goals for 2022. When I look back at my goals for this past year I actually did well. Except may be not building a 5 band quad. I had a lot of ideas for next year. One of these was a 2022 challenge idea. Unfortunately I had not foreseen what would happen this month. I'm sorry but at this moment I partly lost my interest in the radiohobby at this moment of time. I really can't think of any goals for next year. So I keep it simple, no goals.

However, my dear blog readers, time and life goes on. I wish you and yours all a prosperous 2022.

Friday, December 24, 2021

Merry Christmas


My idea was to write a lot more this month. But I still feel very tired probabely still from covid. Besides that I have no inspiration at the moment. And time is, like always, an issue.

Wish you loyal blog readers a merry christmas...

Sunday, December 19, 2021

Complexity of a HAM shack safety earth (ground)

  It has been a while. Unfortunately personal things happened. And we all got covid-19. So, we had some difficult times the last 2 weeks. Hope to pick up writing again anyway.

Due to being not able to get to my job I had some free time after I had some health issues due to the virus. I decided to do some work in the shack. Something I should have done months ago. time and didn't feel like I had to do it. Might be not to urgent although the problem I want to write about gave some serious safety issues.

For the last couple of months I had serious problems to get power into the shack. When switching on the mains the earth leakage circuit breaker would trip most of the times. Unfortunately replacing the switches wasn't that easy so the problem was getting worse in time. It was indeed that worse that at some moment I couldn't even switch power off because the contacts were simply welded together! Well, I finally had some time to take a closer look. As seen on the photo, the switch was not repairable. I didn't want to use the same switches as well because it is evident that they are not good for this task.

I did invest in some better switches. Of course they cost at least 5 times more as these simple switches. But hope they are a lot better. Previously I switched both L and N. Now I only switch the live wire.

The photo shows when I just removed the old switches. I use one switch to power on the computer and other appliances. The other switch is for the transformers feeding only the transceiver. The PSU in use is galvanically not connected to the mains of the house. It is separated by a 1:1 transformer. I really don't know if this helps to minimize interference for all kind of switching transformers on the mains net. But at least I like to believe so.

The new switches are installed now. I also renewed the cabling. I have to say it looks very nice but different from what I use to have installed. I did a search in my archive and found some post I made in 2013 about the electricity in my shack:

Another issue I had was with my safety earth system. Since I do power my transceiver through a "safety" transformer I don't use the house safety earth system. However, the computer does ( I thought it didn't). I also have a separate earth rod outside especially for the shack which is connected with a thick copper cable to the coax entrance patchpanel near the wall. It is not a RF ground but just for safety in case of static or worse a direct lightning hit into the tower. What happens is when I want to plug in the USB cable from the computer to the IC-7300 I get shocked! I measured why and there is at least 100V between my computer and my IC-7300. Clearly this is a earth potential problem, as long as the USB cable is connected there is no problem because everything has the same potential. I didn't have a simple solution for it since whatever I thought I should do it would give me a groundloop which I want to prevent. I didn't want to disconnect the house safety earth from the computer as well. The main problem in a HAMshack is probabely the outer screen of the coax, since that is also a conductor and connected to everything earthed from your transceiver. I actually used it as my "safety" earth and did not connect the starpoint of my counterpoise/RF earth to the earth rod because it would make a groundloop. But what if I disconnect the coaxcables from the entrance patch panel? In that case the earth connection would be gone. A dangerous situation in case of a malfunction. Yes, the USB cable would still ground my radio to the house "safety" earth. You see, but what if....the question kept playing in my head. Even reading my own article about the subject didn't give me the right "feel".

In the end I think for a good safety earth everything should have equal potential. You can only get that by bond all wires together and don't rely on the outer screen of your coax cables and yes it will give you groundloops. And yes, I know the separate groundrod should be connected to the house safety earth groundrod to prevent these kind of problems. But unfortunately this is impossible since I have no access to the house groundrod. I decided to minimize the groundloop effect by using a few #31 material ferrite clamps at least every meter and wind the earth wires through it. At the moment I have permanent earth wires to the wall socket of my computer and connected both house safety earth wire to my shack ground as well as the starpoint of my counterpoise. The PSU is grounded to the starpoint and again used ferrite to break groundloops. 

Finally the 100V difference between computer and TRX is gone now. I didn't notice any difference in receive or transmit yet. But didn't try all bands yet either. At least I feel a little safer now, though in a few years I could have a different view on this complicated matter.

Sorry if you find this blogpost a bit chaotic. It looks like the virus has blurred my mind. The whole installation of the switches and adding a few earth cables took me at least 2 days. Normally it would only took me a few hours. I had to think long before every step.

Update 21-12-2021: 

I'm more and more convinced I'm on the wrong "earth" path. Not only that but considering electrical installations differ in other countries it is quite dangerous to write about something like a safety earth. What works well in the Netherlands can be dangerous in the UK or the USA or any other country. I suggest to read MW1CFN's blogpost about some dangers of misunderstanding protective earth. At first I was thinking about deleting this post. However, I leave it as it is since I want to work to a safe solution for a safe earth. For now I warn everyone not to modify your home electricity wiring including the safety earth which is part of the whole installation. 

However, many HAMs use a separate groundrod for their shack. What to do with it? Read my post from 2013 why I wanted something like a separate ground in the first place:

But in time it only gave me questions. Is it really necessary to have something like a separate groundrod for your shack if a house safety ground is already there?

Wednesday, December 1, 2021

Grey world

 For the last few days we didn't see any sunshine much. It is getting colder, windy, it is getting darker every day. Rain, lots of rain. Winter is arriving. Lot's of people get depressed now. How many months till everything changes. 

But we can look back at a lovely summer...


Sunday, November 28, 2021

#CQWW CW 2021 - no inspiration


green=40m, dark blue=20m, light blue=15m, yellow=10m

I really had no inspiration for this contest this year. It might be the highlight of the year for others but not for me this time. There was no Dutch record that I could go for and so I had no goal. I decided to make at least 50 QSO and search for DX only. When 10m and 15m closed I tried some DX on 20m. But I couldn't really get the contesting feel. I decided to stop early with 52 contacts in the log.

Sunday, November 21, 2021

Friese 11 steden contest 2021 review

 This is a dutch language contest, open for international traffic. But since the content is only interesting for the dutch I'll write it in dutch for archive purposes. Main target is working the 12 multipliers and as many stations as possible during this 3 hour contest.

Event: Friese 11 steden contest 2021
Section: Outside R14
Logger: N1MM+ 
Station: Icom IC-7300 100W
Antenna: Inverted-V apex 12m

Dit is een erg leuke contest zoals altijd. Het is natuurlijk gaaf om direct te horen waar iemand vandaan komt. Soms kom je ook rare plaatsnamen tegen waar je nog nooit eerder van gehoord hebt. Net als vorig jaar kwam ook "oude zeug" weer voorbij. Zoek dat maar eens op...

Ik ben dit jaar wat anders te werk gegaan. Eerst maar eens gelezen waarom ik vorig jaar maar 10 multipliers heb gewerkt. Ja, dat kwam omdat ik lui was. Ik ging eigenlijk niet op zoek maar alleen maar roepen. Dit jaar ben ik begonnen met 15 minuten roepen, daarna 15 minuten zoeken en daarna weer 15 minuten roepen etc. etc. dat werkte prima. Vandaar ook denk ik dat de 12 multipliers weer gewerkt zijn dit jaar. Alleen maar "runnen" is dus in deze contest zeker niet de strategie.

Voor mij waren het moeilijkst te werken PA3DTY uit Bolsward en PA6VB uit Stavoren. Vooral PA6VB was erg zwak en soms helemaal niet te ontvangen. Ik heb het idee dat de meeste stations hem helemaal niet gehoord hebben. In de video hoor je hoe zwak het signaal was, het is het laatste station van de video. En dan heb ik vergeleken met de meeste stations een erg lage ruis op 80m.

Wat erg leuk is in deze contest is dat het er eigenlijk niet toe doet wie wint. Althans die indruk heb ik. Men wisselt gewoon zoveel mogelijk info met elkaar uit waar de multipliers zitten en welke stations daar zitten. Winnen is leuk maar meedoen is veel leuker.

Nu nog even het log nakijken en alle punten optellen, daarna kan het weer naar de organisatie gestuurd en dan wachten op de uitslag...

En volgend jaar.....dan doen we gewoon weer mee!

Tuesday, November 16, 2021

Paraset instructions new insights

 If you came to this article from a different source or link and never did read my blog before I would like to point you to my previous article about this subject:

This article has also been published in a slightly different form and in Dutch in the local radioamateur magazine Hunsotron and in the Dutch VERON radioamateur magazine Electron.

It actually surprised me that I didn't write a follow up here on my blog so far. Since the guys from the Cryptomuseum here in the Netherlands wrote me some new insights about the document. They also published a high resolution scan and a reconstruction from the document in PDF format on their site.

I would like to write about the conclusions Paul and Marc from the Cryptomuseum made regarding my article and of course the valuable "Paracette" manual.

First of all I wrote in my previous story that the paper was "rice paper". But that seems not to be the case. It is a kind of very thin carbon copy paper they used to make multiple copies with a sheet of carbon paper between the sheets on a typewriter.( I remember my dad used this as well on his typewriter in the seventies of last century. )

The document is definitely a WW2 document written by an englishman. "TLK de JCB" should be "TLK de JCD" when you look at the letters closely. Unfortunetaly the letters are still a big mystery. The pencil written S.2441 probabely means the week that the set and or the manual was released. Like week 24 from 1941. A gamble is that the S means Sweden. Since this paraset with manual definitely came to the Netherlands from Sweden. The name "Paracette" was the nickname the french gave this radio. This radio was actually designed for use in France only. The idea to use this radio in other countries came at a later date when the SOE (Special Operations Executive, british secret service) got interested. The name Paraset probabely came from the original "Paracette" name.

Last weekend Paul (PE1BXL) from the cryptomuseum wrote me about more insights they got after reading certain things in the manual. Especially these sentences: 

… making sure that the correct receiving coil is in place.

… check all external connections and components such as coils, …

So far we all thought that this document was written for use with the common Paraset Mk VII. The paraset that was used most and is copied a lot after the war. But the Mk VII hasn't got any external coils! And so, Paul believes  that the manual is written for the original Paraset the Mk V.  

Actually the paraset Mk VII you see on many pictures on the internet and also in my previous blogpost about this subject might not be called paraset at all. This is probabely all a misunderstanding due to a book called "Sectret Warfare" from 1972. The information used at that time by the writer Pierre Lorain was not complete and limited. The Mk V was the first spyradio that was dropped above France. This radio was designed by the SIS (Secret Intellegence Service also known as MI6). The Mk V has been used in 1941 and 1942, the Mk VII came in service at the end of 1942. The parasets that came via the Swedish route in 1941 can't be a Mk VII because they didn't exsist yet. The "Paracette" manual is exactly right for use with the Mk V. Conclusion is that the OD and Dirk Rustema used a original Paraset Mk V.

Unfortunately, as far as Paul knows, only one original Paraset Mk V survived the war. The nice thing is that also only one original Paraset manual survived and is in my posession. Wouldn't it be nice to get them together at an wartime radio exposition?

Due to this last insights Paul decided to change the Cryptomuseum site. You can still find the story and copies from the original manual but now at a special Paraset Mk V page.

Find the difference between Paraset spy radios here:

Find all about the original Paracette spy radio here:

Sunday, November 14, 2021

PA-beker contest 2021

This is a dutch language contest, not open for international traffic. Since the content is only interesting for the dutch I'll write it in dutch for archive purposes.

Event: PA-beker contest section: SSB 2021
Section: high power
Logger: N1MM+ 
Station: Icom IC-7300 100W
Antenna: Inverted-V apex 12m

Dit jaar weer geen experimenten. Eigenlijk doe ik gewoon mee voor de lol want een beker of een prijs hoef ik niet. Het gaat mij meer om het meedoen. Voor deze contest is het heel eenvoudig: de 40m MUF moet gewoon boven de 7,1 MHz liggen voor 100-400km. Zo niet dan maakt vermogen of een speciale antenne niet veel uit.


Dat is eigenlijk hetzelfde gebleven als in 2020, met als uitzondering het werken van novice stations op 40m. Novice stations mogen nu ook met 100W en tot 7,2 MHz werken. Beginnen met een vrije frequentie zoeken op een rustig deel van de 80m band. Dat is dus meestal in het gedeelte tussen 3,600 en 3,650 MHz. Dit jaar had ik geluk en kon ik net boven 3,700 MHz een plekje vinden. Dan gewoon een uur CQ roepen (runnen) daarna de band afzoeken of er nog stations zijn die ik niet gewerkt heb (ben ik vergeten, volgend jaar beter op letten, eventueel opschrijven). De MUF goed in de gaten houden en dan rond 11 uur lokale tijd een rondje 40m doen.  Als er dan stations gehoord worden bij voorkeur zelf weer gaan roepen en dan maar hopen dat er wat stations reageren. Rond 12 uur lokale tijd beslissen om op 40 te blijven of om weer terug te gaan naar 80, dat is de moeilijkste keuze en kan beslissend zijn voor de eindscore. 

MUF aan het eind van de contest...
De contest

Net als vorig jaar begon ik niet precies om 10 uur maar wat later. Dat maakt op zich niet zoveel uit denk ik. Ik ben eerst maar eens op zoek gegaan naar een rustige plek ondertussen een paar stations gewerkt. Daarna een uur zitten roepen met best redelijk aanbod. Rond 11 uur zag ik de MUF snel stijgen tot 7,2 MHz. Ik dacht eerst even een rondje 40m te gaan doen en dan weer terug te keren naar 80m voor de ontbrekende stations/multies. Ik had alleen zoveel aanbod op 40m dat ik pas rond 12:15 even op 80m ben gaan kijken voor ontbrekende stations. Maar hoorde er eigenlijk geen stations. Heb nog wel 5 minuten geroepen maar geen enkele verbinding kunnen maken, weer snel terug naar 40m. De condities op 40m waren zo goed dat ik dit jaar meer QSO's maakte op 40m als op 80m. Dat is in de voorgaande jaren nog nooit gebeurd.


Doelen stellen in deze contest is moeilijk. Het geheel hangt af van de condities op 40m. En die zijn moeilijk te voorspellen. Doelen had ik eigenlijk niet. Mijn doel was gewoon plezier hebben en zoveel mogelijk bekenden te werken. Achteraf heb ik het misschien nog niet eens zo gek gedaan. Immers doordat de novice amateurs nu meer ruimte en vermogen hebben op 40m is de kans dat je veel stations/multies kan werken op 40m ineens veel hoger geworden. Dat ik dus dit jaar meer stations op 40m gewerkt heb is dan misschien ook logisch.


Ik ben er zelf ook al eens mee de fout in gegaan. De organisatie van de contest kijkt streng naar de regels. Met name de gebruikte frequenties. Toch zag ik via het DXcluster diverse stations gemeld tussen 7,100-7,130 MHz, een verboden gebied volgens de regels. Helaas voor deze stations maar alle verbindingen in dit frequentie gebeid zijn ongeldig.

Saturday, November 13, 2021

SEGA Mega Play restoration - power supply


  Decided to remove the motherboard to clean and inspect. Insert the new battery on it with emergency repair. So far I don't see any malfunctions. 

Besides that I could test the powersupply and hopefully the high voltage TV monitor screens without damaging the motherboard eventually.

  I managed to power the powersupply through the variac. Slowly increased the voltage on it. So far everything went well. Checked all the voltages and they seem to be correct on all outputs. Can't figure out what the big transformer output is. Also I don't know what it is for exactly? Following wires is almost impossible, it is just one big spagetthi. I noticed safety switches at all the doors, this might be a trigger for supplying voltage to te rest of the equipment.

  Anyway, I decided to measure light fitting voltages first. Fittings are there, bulbs are gone! Assuming these could be 12V car lights but could not measure any DCV on it. Could be ACV of course. Then I touched the frame when measuring one of the poles by accident. Everything went dark....

I stopped for today....will have another a try tommorow.

Thursday, November 11, 2021

SEGA Mega Play restoration

Not about HAMradio this time. I really wish to spend all my available free time to build HAMradio stuff but real live is of course not like that. We have other things to do as well, not less interesting though.

 This SEGA Mega Play arcade system was brought by a friend and ex colleague almost 10 years ago. If I could take a look at it if time allows, no pressure. So, there it still stands in my garage after a decade I think it is time to have a look at it.

This system is from 1993. No SMD parts, lots of microswitches, high voltage TV screens that kind of stuff. All locks are broken like someone was desperate to find money. Yes, this old gear plays on vintage dutch guilders. And while inspecting and trying to clean some parts I found, as a surprise, 2 dutch guilders...

However my big concern is connecting power to this object since it hasn't been powered for over a decade. And I really don't know when it has been powered before I got it here. So I have to take extreme care before I switch this machine on.

Made some interior photos to show.

This is the motherboard. It seems it is used in more types of SEGA arcade machines. First thing I noticed was a very rusty CR2032 battery. Of course I broke the plastic fitting bracket when I tried to remove it, but that is repairable. Tried to remove the dust from the components with a brush but it seems to be pretty sticky. Compressed air didn't do the trick either. Any hints on how to clean this printboard? I already checked for faulty caps but so far they all look pretty decent.

By the way, looking for information on these motherboards I saw them sold with just one game in pristine condition for at least $2500 on eBay. Wow!

All switches are the same micro format, even in the joysticks. Luckely these are easy to get if some will malfunction. I noticed on that was partly broken but could fix it with a ty-rap.

Push buttons could only be pushed once, they just were that sticky. This kind of arcade machines could be found in lunchrooms and cafetarias/grillrooms. No wonder they are sticky. After cleaning them all is ok now.

Reading some tips & hints about restoring old electronic transistorized equipment I found some usable tips for my project.

First of all I should connect the power supply through a variac (variable mains transformer). I find a reasonable prized one on the internet

This system contains a main transformer which I think feeds some auxillairy equipment like lights etc. and a multivoltage powersupply unit that probabely powers the motherboard. More photos from that in another post.

My biggest concern is not the transformer and the multivoltage unit but the 2 high voltage TV screens. I inspected and tried to clean the electronics behind the smallest screen tube. But so far didn't find a way to access the big screen electronics yet.

My idea is to continue cleaning the motherboard. Disconnect all connections from the powersupply. Disconnect the screens from the mains feed by pulling the fuses. Adding mains voltage slowly to the powersupply and measure all outputs first when reaching 230V in. Then connect the TV screens one by one adding again voltage slowly with the variac till 230V. If those are working I'll connect the motherboard.

Since I have no experience restoring this kind old equipment all tips are welcome. Please let me know in the comments below. I especially would like to know how to safely clean the motherboard without damaging the components. I guess placing the thing in the dishwasher is not a good idea ;-).

Thursday, November 4, 2021

#CQWW DX SSB Contest 2021 review


Event: CQWW DX SSB contest 2021

Section: SO Low Assisted 10M

Logger: N1MM+ 
Station: Icom IC-7300 @100W
Antenna 1: 10m LFA @14m
Antenna 2: Multiband vertical @16m
Antenna 3: 2x20m inverted-V doublet

Wow, what a great CQWW SSB contest it was. I really concentrated my efforts to 10M this time. The amount of QSOs on 80m is from running in the evening since 10M was open late and closed early. But when 10M was open it was really open.

Yellow: QSOs made on 10M

Can't remember I had such long runs to the USA ever before. Thanks to some DXcluster spots of course. But also heard from several stations I had an excellent signal. Stations kept coming for at least an hour with a rate of about 75/h it was not like a 80m run (120/h) but very nice for 10m.

I worked some nice DX on other bands as well. But my main focus was 10m. In previous years I made a list per band from interesting DX worked, this year I will only take the 10m band.

Most interesting DX worked: CB8E (Chile), PZ5RA (Surinam), V26B (Antigua&Barbuda), VP9I (Bermuda), HC5VF (Ecuador), OX7A (Greenland), HD8R (Galapagos Isl.), V3A (Belize), 7P8RU (Lesotho), PJ4K (Bonaire), PJ2T (Curacao), V51JP (Namibia), 7Q6M (Malawi), 5Z4VJ (Kenya), VK6N (Australia), BA7LOK (China), HS5NMF (Thailand), VU2DED (India), ZS9Z (RSA), PY0F (Fernando de Noronha), NP2X (US Virgin Isl.), FG5GP (Guadeloupe), D4F (Cape Verde), FR4KR (Reunion Isl.), YF9PBZ (Indonesia), FY5KE (French Guyana), HL2WA (South Korea), JA6MWW (Japan), 9G5FI (Ghana), VR2T (Hong Kong), UN4L (Kazachstan)

Worked much more DXCC but personally above are the most interesting from my point of view.

But the most memorable contact during the contest was actually made by accident. I was tuning in near 29MHz and noticed I could hear some FM signals from the USA. Then I heard AE7KI Gerry from Tennessee calling on 29.600MHz FM with a 57 signal. I just gave him a shout and we made a short QSO. This was my first FM QSO with the USA ever. You can imagine how signals from the US came in here.

Hopefully the 10M propagation will be just as good during the ARRL 10M contest in December...

Friday, October 29, 2021

#CQWW SSB contest this weekend

 Just as a reminder for the largest SSB contest of the year with about 35000 participants around the world. If you search for really nice DX contacts made with your own voice your chance is this weekend!

The 10m band is open lately and if propagation holds on I could try to submit a single (10M) band effort. Or I can try to beat last years score...

Thursday, October 28, 2021

UHF connectors mounting K3LR style extra tips

I got the idea about this post after seeing a well known youtuber struggling soldering connectors to his coax. Ending in a short inside one of the connectors a few videos later. And yes, I hate those so called "new" "watertight" style UHF (PL259). At a certain moment you have to slide a kind of metal head into the outer screen of the coax. It looks easy when a pro does it. Like in this video from M&P. But it isn't easy and faults are easily made when you're not experienced. Although I have to tell that I really like the design of M&P evolution UHF connector, I'm shure this is a high quality connector that will last for many years. Especially the heat stress on the coax can be avoided with this type of connector, and a big pro is that the connector can easily be salvaged if needed. 

However, I still have a bag full old salvaged UHF connectors and even new "old style" ones. In the past.....well 10 years ago I installed them like this:

Resulting in a few issues with the connection of the screen to the connector especially when it ages.

Then a few years ago I read about the K3LR (famous contester from the USA) style UHF connector install. I have to say, I really like this style and adopt it since a few years. Best description how to install K3LR style can be found in this document:

Basically the outer screen is not soldered through the soldering holes but at the backside of the connector. However, in practice, of course things will work out different. So, I got a few tips.

First of all file and clean the backside of the connector for easier soldering

Second tin the backside of the connector. Don't apply too much.

Personally I prefer to solder the outer screen only to the backside and don't fold it over the connector. This is a choice of course. I think it is easier to slide a heat shrink tube over it this way.

Nice and tidy result. And if needed the connector can easily be salvaged.

Sunday, October 24, 2021

5 band quad HF antenna design, building and ideas (part 1)

 Recently I spoke a few stations from around the world on 10m which were reasonable strong. All those stations were transmitting with 2 or 3 element (multiband) quad antennas. And for shure these stations were way stronger then any other on the band at that moment. If you ask antenna experts they all say there is no difference between a quad and yagi radiation pattern and f/b ratio in the end. With other words, you can do the same thing with a yagi as a quad. But I'm not really a HAM that does rely on theoretics, I want to see what something does in the real world. Being this something is an antenna or anything else.

This post is primarely for myself to write down some ideas (and receive some ideas in the comments if you as reader has them). It is no secret I want to build a 5 band HF quad antenna for quite a while. But it brings some technical design challenges and takes time. In my last musing about antennas earlier this year I wrote about the only user of the particulair DK7ZB quad design I know; G0VXE Dave definitely tuned the reflectors on his antenna and that seems to be the biggest challenge. However, the f/b ratio will be about 10-15dB which is not to be compared with 25-30dB a yagi will have. I expect in practice it will show about 1-1,5 S-point in comparisation between front and back. However, it seems side rejection will be excellent.

This post is about design ideas I found on the internet. Ideas that are simple but can be forgotten just as simple.

My idea is to make my 2,85m boom from the green militairy glasfiber poles I used for my 80m horizontal loop in the past. To mount the glasfiber telescopic tubing on the boom I found this idea made from alu corner profile, I made one prototype:

Since I use cheap glasfiber fishing rods for the prototype antenna I use alu tubing to reinforce the first 50cm of the rods since I think this is the part of the rod with most of the stress.

Made two prototypes. I will wrap the rods with black tape against UV and weather influences. The rods are quite strong. To test I grabbed them at the thin top and hold it horizontally in the air. 

The full weight is now at the weakest part. It does bend but doesn't break. I feel confident the rods are holding everything in the air at high windloads. The rods are 4,1m long.

Above the alu tubes I use to reinforce the rods. They are wrapped with tape to better fit in the rods. I also ordered a spool of 2mm alu wire. I really thought about insulated copper wire but there is a big disavantage, the weight is substancial higher. Also I would have to recalculate the design published on the DK7ZB website

To get an idea of the size I put some rods in angle configuration to simulate one side of the quad.

It is the idea to mount the quad in the mast the square way and not in diamant shape like G0VXE did. The advantage is that the sides are a lot shorter. Approx. 2,75m. Making total width of the antenna 5,5m which is managable in my garden.

Not to forget the details. I learned this from another antenna experimenter on youtube. It is definitely the best way to prevent the telescopic rods to get loose and slide into each other. This can happen when force is applied by mounting the wires. Count on big forces in a storm. I don't know how these rods will behave when temperature will be freezing in winter?

I found this idea to mount the wires on the poles. The tube used seems to be UV resistant airbrake hose.