Programmable CW keyer with arduino

CW is a great fun, but operators are lazy... So am I. Bands are so quiet many times, while stations are there, but listening only instead of calling seek you. Propagation is made by stations this time. You never know if the other side can hear you until one of you calls CQ. 
I often work at my desk, where my transceiver is. Leaving the radio on does not disturb me in the work. Automatic keyer can call CQ instead of me I only need to touch the paddles when hearing a coming back station. 

The heart of the gadget is an arduino board, with an Atmel chip. It is so so tiny.
There is no big room inside, only few features, and 9 memories fit in. Memories are located in the non violate part of the memory, so one does not have to be afraid of wearing it out. 

The original project can be found here: https://blog.radioartisan.com/arduino-cw-keyer/

K3NG Jim is a genius! The whole project is amazingly sophisticated and well documented. After reading the page you will have no questions.

My friend HA7MAC Gabor helped me out with some questions and also helped me out with a tiny arduino board. It infected me in a second:)

The board needs only few capacitors, resistors, a led, a piezzo buzzer, and a project box with buttons and connectors.

If you need immediate success, just go ahead and jump on into it!

I will make a smaller, battery powered version as well specially for qrp portable operation. There s touch paddle option available in the software, therefore sensitive paddle is not needed to be carried out to the wood. Only two screws or other metal surfaces needed for it.




Programming and using the keyer is easy and straight-forward. 



I think no more words needed... let's grab the key!

The best CW paddles ever...

CW is a great fun. I've been playing with it since my childhood. It was a secret language to talk to friends that time, later it became a wonderful way of listening the world, some years later a perfect tool to keep in touch with friends from all over the world.
Beautiful it is, I am too lazy for straight key, therefore I use paddle.
Recently I gave my iambic paddle to one of my best friend, who is learning the code nowdays, so I had to buy a new one. Again I called the best man for a key. He is a Hungarian HAM, HA8KN Janos. It is the fourth key I have from him. Iam fully satisfied again. Far the best... 
I can transmit with 40WPM or even more using this key with no error. So so fast... It is hard to find stations being able to receive this speed.

Amazing quality, reliable and fast shipping. 

THANK YOU JANOS!

Lego helps to hold the cable...

My son is a heavy LEGO-fanatic. He has two characters he does not like to play with. I decided to recycle them in the perfect way. Now they are slaves and holding my usb cables on the side of a shelf. 

Pictures tell everything, nothing more to say:)

One more antenna tuner

Recently I made an antenna tuner (can be found below) for HF QRP portable operation. I am pretty satisfied with it. It is solid like a rock, not too big and does the job it needs to do. Good as it was I felt I need to build a new one with some more features. 
I built a switchable 1 to 4 and 1 to 9 broadband transformer to the end of the "L" network. It is a MUST! After testing several tuners with high impedance random antennas I decided to use transformers after the tuning circuit. Sometimes you can double or triple your signal. In QRP field operation the it means you can just jump above the noise floor. 
In dark environment the led was so easy to use. Making difference between transformed and straight mode signal with the led is complicated. I simply could not remember exact light strength after tuning, while needle tells the truth so accurately. Hence I built in a small led and a lithium battery. The switch of the meter gives power to the led in one position. 
Experiences are so nice with the new monster. Yes a monster, because it does not look good, but it really does it's job as I expected. 

I had a sick idea and tuned my 1.5m long telescopic whip indoor on 80m band. SWR was 1:1. I touched the whip when testing with 0.25W. I felt the RF burning my skin. It was impressive. Of course I don't plan to use my short whip on 80, but it was clearly visible the power entered the tuner was not lost finally.

After the first tuner I received mails saying "please send a schematic".
Well, here it is. Sorry for the ugly sketch, I don't have any sort of cad software to draw fancy schematics, paint is so "paintful" for me:)

Important! There is a 5 pF capacitor between the antenna and the tuning aid circuit (diodes) I was tired when sketching. 

Coils are mainly on toroid cores, except the fist three ones. DPDT switches are used, so coils are isolated when not used. The transformer is a standard 1:4 and 1:9 broadband one. I used a ferrite toroid core I tested before. It shows no significant loss from 3.5 to 30MHz. Variable cap is an old plastic one. I used the the two caps serial to reduce the stray capacitance. The meter is also from an old CB radio, while germanium diodes are ABT 60 yrs. old Hungarian "Tungstram" models. 

Few words about the meter light... There is a bright led fed by a lithium battery. It will be enough for the next decade I think. To have a really nice dimmed light around the meter all you need is some sand paper to polish the surface of the led a bit. It will become matte white with no such a magnifying glass effect at the tip of it. I use to change old meter lights in CB radios exactly the same way with very nice result. 

Some pics from inside:

You can see the old plastic capacitor in the middle. The RF choke on the left was there just for test reasons. You can see the small coils on the left and the high inductance on the right.

Finally here is the front end.

Not too nice, but works amazingly good. I am not going to stick labels to the switches. Everything is so easy and straight-forward. The line of switches on the top is the inductance. Switches on the middle belongs to the capacitor. The right side is the output. The first switch on the right column is to select between straight output and the transformer. The next is 1-4 or 1-9. It is a three position DPDT switch, so the output is not connected to the transformer when it is in mid. position. Below that  the meter switch and the big knob on it's left is the variable cap. The one on the left below the 36uH switch has no function. The knob on the left is the pot of the meter sense.

The UHF connectors at the two ends makes the tuner able to be used even mounted to a PL magmount with whip inserted right to the top of it using the output connector. Also it can be connected directly to the radio with a 90 deg. coupler and used with the whip. The banana plug on the right is the gnd. It is ideal for connecting counterpoises. (recommended)

The circuit is not a new thing, it is more like "inventing hot water". One can find several ideas like this. It does not have source, it is so so evident, even I wasn't born with this idea in my head...

A good old active filter...

Nowdays everything is digital. I hear old mates talking on 40 meters complaining of the voice of their brand new HF radios. Digital … as they say... never sounds as good as those old rigs with tubes inside.

I have been using an FT-450AT for a while. Why FT-450? When I moved to Hungary it was the cheapest piece from a trusted seller. It has everything I need, specially narrow CW filters. Almost a decade ago I had an IC-7200 I really loved. FT-450 is very similar in it's category. Of course just similar, but not as good. Okay, I am not complaining, it does it's job, and for a casual ham like me it is more than enough. It is not a contest “king of the field rig”, but if one is able to understand it's features this radio can be a good friend.

This post is not about FT-450, there is something else. 

Few weeks ago I had a deal with a local ham. Finally I received an old DAIWA AF606K filter. Originally I wanted an external speaker, but I was curious, and it has a big speaker inside, so why not to give it a try?

It is built like a tank. Reminds me pretty much the good old 80's. Basically it is an active filter for SSB and CW mode. There is a PLL function is, but I would not use that in real life.

It has four knobs on the front. Notch, PLL lock frequency, band pass for CW and mode. Input is low impedance, so speaker can be connected straight. When turned off, it behaves like a speaker, turning it on the filter starts working.

I have almost broken it at the first time. Pwr supply connector is reversed... inside is negative and outside is positive. Ghrrr... I changed it so quickly therefore it fits to my domestic standard. After trying it I noticed a strong feedback noise in SSB. I checked the whole station, and found everything fine. The weakest chain was the filter. Also the speaker had terrible voice, while using my headphone it was perfect.

After several minutes I found the problem. Few ferrite filters inside, and proper ground connection between the front panel and the PCB made it OK.

Result is amazing. I really like listening CW QSO parties, and also taking part... The filter saved me dozens of pain killers. I turn on narrow CW filter on the 450, and turn on the filter, play with the notch, and no noise, no static, just the pure signal. No matters how weak the signal is, it makes it easy to copy, easy do dig out from the noise and above all CW reception has become relaxing.

If you find one on a hamfest, or even ebay, do not hesitate to buy!

I will make a short video clip later to show what it does... and picture as well of course.

Another transformer...

Size matters. Funny as it is, in QRP world the smaller the better;) 
I've given my QRP transformer to one of my friend, therefore the time has come to build a new one. 
I don't want to carry patch cables, coax connectors and so on, an UHF male connector is the perfect idea to connect straight to the tuner or the radio. 

I've dropped it to the floor right after finishing it as the proof of the pudding... As I wanted it is military standard "IP howmuchever standard":). No damage, mechanically quality-tested.

Nothing more to write about it, all you need is in the pics. 


The transformer is the traditional trifilar one, 8 turns on a ferrite (god knows what type, it is from the local DIY shop, but I have tested with analyser and found it perfect from 3 to 30MHz), inside of the box is full hot glue. 
Hot glue is my favourite... it makes everything waterproof, shockproof ant so on. 
The only disadvantage is the "no way back" effect:) Once you have filled the box with this plastic stuff you will never take it apart again... 
No chance for mistakes. In the HF range it has no effect on the system.

Ground has a banana socket on the side, while 1:4 and 1:9  output has their dedicated connectors (two red gadgets on the right side)
Few words about the UHF male connector... 
There is a piece of PCB with a whole inside. The connector is soldered to the PCB. It is the easiest way...

Miniature tuner for end fed half wave antenna

I said good bye to my military backpack. I used it too hard, weight was to much for it, and quality was not good enough. In most cases I take many things with me up to the mountains. Small survival pack can grow so big quickly when a tuner, few more battery pack, or few extra meters of wire (and so on...) should be carried. 

I decided to put a lightweight and small setup together. The old Ft-817 can not be lighter, also LI-PO batteries are the lightest options, but my tuner is not the smallest no matter how good it is working. My favourite setup is a fishing pole and tuner combo antenna. I wanted to create something smaller than that. 

One of my friends Gabor HA7MAC told me about the idea of using a transformer with a cap at the coax side with half wave radiating element. Gabor is a top bloke and also fanatic QRPer. If he says something I will listen, because there is always something to learn... The original idea is from PD7MAA. The source of the circuit can be found here: http://pa-11019.blogspot.hu/2012/04/149-transformer-for-endfed-antennas-35.html 

I had some FT-243-like toroids and started the test on a rainy afternoon. 

Finally I decided to use a smaller core, but it is still well enough for QRP usage.

This is a recycle project, only used parts are in the box. The cap is changed to a vinyl variable one, and a small tuning aid with a led is also built in. You can find the description of it below. It is switchable of course not to eat too much from the QRP power.

 Size matters... as you can see it is really small. Smaller than a cigarette box.

Banana plugs are used as connectors for CP and the radiating element. 

The switch on the right side is to disconnect the tuning indicator from the line. 

I prefer using counterpoise even with a single wire antenna. It makes the system stable and easy to tune. There is a set of radial wires for my vertical setup with banana plugs at the wires' ends, therefore I didn't have to make CP wire kit for this project.

Using is easy. Just connect the half wave wire to the ant banana socket and twist the cap for best SWR on the radio, or the brightest light on led.  

As you can see, inside is not over-sophisticated. The white stuff on the core is plumber tape. Hot glue can help to keep things on their place. Germanium diodes are made in Hungary in the mid of 70's, variable cap is a cheap Chinese one from a small broadcast receiver.

The transformer is a bit tricky. PD7MAA describes every details of it. In nutshell, there are two times seven turn, plus two more with twisted wires at the feed. The end goes to GND, while the twisted to the input. 

One has to be careful not to touch the output of the transformer while transmitting! It can burn your finger even at QRP level. 

On air tests? I need some time to test, compare and I will share my experiences later. My plan is to compare half wave end fed, norcal-like doublet with speaker cable, norcal-like doublet with professional symmetric feedline, doublet with 1 to 4 transformer 5m vertical with my L-match tuner, with tuner+unun and one of my mate's ZM-2 tuner. The goal is to find the smallest and the most effective antenna for QRP prtable use.

I will use swr meter, analyser, and field strength meter with live on air tests of course. 

Are you curious? Come back later! :)

Update:

I have tested many antennas comparing tuners, transformers etc... 
This one works. It just does the job. What you need to take care is the proper length of the counterpoise, the antenna height and the sloping angle. Honestly a quarter wave length vertical, or random wire antenna of course with radials performs just as well as the half wave one, with difference hardly noticeable. An "L" match tuner is a bit bulkier of course, but practically it is easier to work with it when operating qrp portable.
The half wave antenna with this tiny tuning unit is very useful, when one has a favourite place with fairly the same conditions all the time, same height, angle and so on. In this case big tuners can't beat the mini half wave coupler. 
In case of a weekend house or camp house I would prefer building a big matching box with large coils made of silver coated wire to reduce losses.
Anyway, It was good experience and great fun playing with it. I am sure I will take it with me to places where high watchtowers or trees are surely waiting for me...

Tuning aid for QRP field gear

FT-817 is an ultimate QRP field radio. There are plenty of new field rigs, but the old 817 is still one of the best choice. Of course it has few minor bugs as all the other fellas have. Its internal SWR meter is one of them. It is more like an SWR indicator instead of SWR meter. The bulit in bridge is not so accurate, therefore it is not possible to tell the difference between SWR 1.1 and 1.8 simply watching bars on the screen. In both cases it says no bars at all...
The tuner I built last time has an internal tuning indicator. It is so easy. Two ge diodes, a cap, and a small meter. There is also a led for dark environment. Sensitivity can be set by twisting a 10k pot. This tuner works really good. I've tested it with a 5m long vertical and few CPs against a doublet with ZM-2 tuner. 
Mine was significantly better. The station was able to hear me loud and clear enough for reliable communication, while doublet and ZM-2 was weak, and signals were hard to copy. There were stations unable to copy the other setup, while giving fine reports to mine. 
While trying the doublet mounted next to my rig I noticed the needle was dancing on my tuner's meter. I tried the led indicator and I was able to see the light and observe the changes of the signals on that as well. I decided to build a stand alone field strength indicator for QRP field days. 
Here it is:

The circuit is easy. It looks exactly the same as the one you can find here https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRPO1C5HFqyEIOg818nPQvyP6Wsjo2fKdbagdgny89TvIJCAZHERdmFGFoI-_flwrRaVIkcYgMJuS_JsAdb0YuYkkrFyvFnqz29Yy3e_sEIz8evcPfxIrg0XbKKOzpxh3cniK1rRo639o/s1600/tuning+aid.GIF

 Thanks to PD7MAA!

There are two banana plugs for the antenna and GND cables. BNC for my small telescopic whip is mounted on the front. This way it stands on the desk if needed. The small patch cable with the croc at the end goes right to the gnd terminal of the FT-817. Sensitivity can be set just by twisting the pot on the middle. Few watts are enough to light the led up from few feet away from the antenna. 
After tuning the antenna to 'no bars' on the radio, just set the pot to low light on the led. Tune it until the led will give the brightest light.

Price is so low... every parts are recycled, except the plastic box. (aprox 30 cent:))

Update: 
My friends asked me to lend it to them for a test, therefore I made some stickers to the face of the box. Does not look professional, but helps to find out what is for what purpose on this over-complicated front end:)
Also I made a pic of the inside. As you can see it is not a sort of rocket science:)

QRP antenna tuner

I have sold my Z-817 tuner. I have been missing it since, but that time it seemed to be a good idea... Okay, let's forget the mistake and do something instead!

I needed a tuner. For all kind of wires, whips, dipoles, only for QRP portable use.
Mainly I use my FT-817. It has built in SWR indicator. Yes, it is only an indicator. When it says SWR is 1:1, indeed it will be somewhere between 1:1 and 1:8, or higher, therefore power indicator is needed.

I tried several cheap plastic switches for inductance, but they turned to be low quality with several Ohm resistance. The only way for an "L" network is a switched system. Basically it is the same as the LDG autotuner. Of course it is not auto. I use switches instead of relays. 

Coils start from 0.25uH up to 16uH, hence all together I have 32uH if needed. It seems to be enough in most cases. 
Cap is a plastic one from a pocket AM receiver. Unfortunately it does not start from 0!!! The small meter is from an old handheld CB. It was not working due to some mechanical sock, but after spending few minutes fixing it with a small screwdriver it came alive again.
Power indication is easy, just two old germanium diode via a 10pF capacitor, and a 10k trimmer pot. Input and output connectors are UHF ones, plus there is a gnd banana plug for counterpoise. 

It works fine, a bit better than the good LDG... Okay, it is bot as easy to tune, but after the third try one can start thinking in binary mode:)

Here are the pictures. There is no schematic. Internet is full of these "L" network schematics, so just call google image search with the keyword "switched L network" and the help is on the way:)

(price is aprox. 13dollars... or below)

Kinder unun

There are few things you can not buy in USA. One of these is Kinder-egg. I don't really think it causes more fatal accident than reckless gun handling... anyway, in Australia or Europe it is easy to buy the dangerous Kinder-egg. 

One day one of my best friend started to think about building a portable end-fed QRP antenna for portable setup.

He found this link: http://pa-11019.blogspot.hu/2012/04/149-transformer-for-endfed-antennas-35.html

Easy to build, works fine and so cheap. Okay, but where to find a perfect enclosure? Here we go! Kinder!

If you live outside USA, don't hesitate to give it a try!

Give a little help to your tuner

Telescopic fibre glass fishing poles are very popular among QRPers. All we need is a piece of wire, a tuner and a telescopic rod to be on the air. The weakest chain in the system is the tuner. Unfortunately it can be lossy enough to "eat" our small power. Impedance of random wire antennas are not predictable. Nobody can tell how they will behave on a top of the hill. If the impedance is too high the L-match tuner will dissipate the RF power as heat. Transformers are more efficient, but not tunable. Using both together is very useful. 

How do I know if I need a transformer?

First we need a field strength meter. You can find a working one below in this blog.

Connect the un-un transformer to the output of your tuner, than tune the antenna with and without the un-un. Check the field strength to see what version provides better signal. The difference is clearly visible. 

I made transformers with 1:4 and 1:9 ratio with a small switch to select the suitable range. Sometimes the difference can be even more than 12dB. Using only 1-2W it is serious difference.

The QRP version with switch on the side.
(frequently in use)

The QRO version for up to 300W.
(collecting dust on the self):)

Why QRP?

Why QRP?

The gold question "why QRP" can be found everywhere on the net. Though one may think it is obvious, I often meet HAMs with no idea at all about the bitter-sweet relation between "S" value and output power. 
"I'm getting sick and tired of struggling with with my QRP Ft-817... it is nothing else but royal pain to make even a local QSO even from a hilltop with it..." I heard. What to say for this? Let's count!

I am not going to explain how decibel works. In nutshell the most important thing is dB is not linear. What does it mean in real life? Double power does not mean double signal strength. 

The whole station in a bag

For example:

If 100W produces "S9", 25W will give "S8", 6W will give "S7" on the other side.

Okay, but what if there is strong man made noise on the receiver side?

There are several ways to get rid of man made QRM.




Narrow band antenna

High Q antenna is one of the best way to get rid of broadband noise. High level signals from other bands such as broadcast stations can be eliminated due to narrow bandwidth of the antenna. One of the best well known high Q aerial is magnetic loop. It can be used as receive only antenna as well, being switched on only when receiving. Controlling is easy using a small relay-antenna switch triggered by the transceiver.




Pre-selector

High Q tunable filters are easy to build. The best solution is to transform the signal down to a very low impedance with for example a 9:1 transformer, and after an LC filter it can be transformed back to 50 Ohm. Bandwidth is reasonable narrow, while the circuit can be used as trap to notch out broadcast signals.




Phasing noise canceller

NoiseKiller by HA5IW Simi (military painted later)

Timewave ANC-4, or Noisekiller by HA5IW Simi etc... Basically there are few mixers in the box with phase shifting circuit and a small amplifier. A noise antenna is needed to catch the unwanted signal. The phase shifting turns the signal up side down (180 deg) against the same signal coming from the main antenna, while the amplifier sets the same amplitude, therefore the disturbing stuff will simply disappear, or will be reduced to a very weak birdie.
It is very effective, and does not take to long to learn to use.
I realized that the system works better connecting a bandpass filter to the noise input as well. This way strong signals from other bands will not come into the system from the noise antenna.




Filtering local devices

Ferrite filter on the incoming
cable of the broadband router
It really does it's job...

In most cases noise comes from the grid, or from local sources, such as plasma TV, computer, led driver and so on... Finding them is not so difficult, adding some filters or in worst cases changing them to noiseless ones can help. Try to avoid low quality power adaptors and use proper grounding in your shack to get rid of the anoying noise.



Raising you voice against disturbing signal sources

Every countries have it's own authorities dealing with spectrum licensing. (OFCOM in UK, or ACMA in Australia) First of all locate the noise source. Knock on the door and ask. Offer help to eliminate the source. If the owner is not helpful, explain the situation. In case of emergency the noise is not only against a hobby, it is making the job ARES services very hard. Radio is a nice thing to waste ones free time, but also it is way of saving life and goods. 
Final solution is to call the authorities to find the noise and do their job to switch it off. 


A station can be copied only if the listening station really wants to hear!
Being able to hear is a great thing. DO WANT TO BE ABLE TO HEAR!
Get rid of local QRM and give a chance for QRP!

Baofeng UV5R battery eliminator

I use UV5R as base station radio. I did not want to kill my batteries with constant charging, changing the batteries and charging them every day simply does not make sense. Time has come to buy a battery eliminator. 
After the first try I noticed the heat coming from the back of the radio. I decided to open it to see what's going on inside.

It was shocking...

It is a hight-tec solution:)
A barefoot 7808, two caps and some hot glue. Real ham job by Baofeng.

There is a tiny piece of aluminium to get rid of the heat. 
7808 can give you 1.5A. It is not too efficient, minimum almost the half of the power running through it converts to heat... The radio can "eat" around an Amp. on transmit. 
Chinese engineers did not take it too serious... okay, it's so cheap...

I quickly changed this regulator to a switching one rated around 3A. Efficiency is around 98% which meets my requirements.

Here it is...

I also changed the power supply wire to a bit thicker one. 

The construction is not over sophisticated, hot glue holds the board as I needed. 

No heat, no noise, constant 8V. What else do I need?

Baofeng UV5R as base station radio

I am not too active on VHF-UHF bands, simply because here I have no local ham-mates to talk to. Repeaters nearby are reachable even with few watts, therefore I decided not to buy expensive base station transceiver for these bands. 

Chinese UV5R does the job, but in fact it is not too convenient. 

Charger cradle can be used to hold the radio, but it can be pulled out easily simply by holding the microphone. 

I wanted to make it a bit better... here comes the solution. 

It takes five minutes to create a stand like this. 

Only a jigsaw, some sandpaper and a hot-glue gun is needed. 

Cheap stealth dual band VHF-UHF attic dipole antenna

They can not see it, therefore it doesn't hurt. Ham radio is painful for neurotic people. Stupidity is like a religion. If one thinks it is harmful, you won't be able to change this software in his mind. It is hard to explain the difference between a 2W 1800MHz mobile phone right beside your brain and a UHF or VHF dipole with also 2W far from living beings up on the roof. Religion is a religion, needs to be respected until it does not hurt too much... 
I mainly use VHF and UHF for local communication within maximum 30 miles range, so I don't need serious antenna system. A dipole in the attic is more than perfect. 

What I needed for that project:
-copper rods
-plastic box
-pl259 connector
-ferrite choke
-some cable
-13 minutes

Tuning is easy, I needed to cut tiny pieces from the elements and check SWR on the meter. 
Later I added plus UHF elements to the VHF version to make it dual band. The VHF part is wider than the UHF, but both cover the whole band with reasonably good SWR.

Test shown the antenna is like an average vertical dipole. The test station was located in the crowded town about 15 miles away from me. He had his antenna on the roof among tall buildings. With my 0.5 W and the improvised dipole I produced 2-3 S signal on his radio on the VHF band. I was also able to reach a repeater standing on a hilltop 60 miles from here. Of course it really depends on the location, mainly the height of the station. Anyway, it is the best price-value ratio. I did not have to buy anything, just used some stuff from the junk.

Next time I will try the same with some telescopic whips to make it easier to tune. 

If you need a reasonably good aerial for VHF-UHF bands, it is one of the best choice.

Inside the plastic box. The shiny stuff in there is hot glue. 

The UHF version. There you can see a ferrite on the cable.

It behaves as an RF choke to prevent current on the cable.

You can also use a 4-5 turns coax cable coil instead.
Diameter is about one and a half inches. 

The VHF version. 

Later I added UHF elements to the original dipole. I has not changed the VHF performance.

No retuning was needed no the VHF band.

Finally here is the dualband version. You can see the UHF element growing from the main dipole. 

Looks so strange, but does the job...