The Ironman

I really like my FT817. It is built like a tank, the only weak point is the front of the radio with sensitive VFO and function knobs. This part of the device cries for some protection.
I always work from the field hence I need to unpack the radio, set it up whenever I want to work from and pack it back at the end several times. I am very careful with my gear, but it is so easy to drop a gadget in the dark in the middle of the wood.

A decade ago I had an Icom 7200. I loved it so much. It had its handles on the front. When I took it to my trips the handles saved the front panel sometimes. I needed those handles for my FT817.
After seraching long hours, I found some versions of theese side rails with unreasonable prices from overseas.
Finally I found Timo OE5EUY who makes Rigiron rails.
I was lucky to catch him on facebook and order a pair of theese beautiful laser cut side rails.

No more words needed...

If you want one for your FT817, you can find him on FB https://www.facebook.com/rigirauta/

Is noise blanker of FT817 any good?

I have been asked about NB in Ft817. Many HAM friends said it is crap.
I spent some time making QRP QSOs sitting in my car. It was cold outside hence I turned the engine. Noise appeared of course. It can not be filtered out, so I tried NB from the menu.

Voila, it works. See how...

XT 60 on ft817

I like XT 60 connectors. They are rock solid, work up to 60A and impossible to pair the wrong way. 

I always cut the original power cords in the middle and insert a pair of XT60. That is the standard connector in my system for 12V.

I found it on thingiverse https://www.thingiverse.com/thing:3551608 .

A good friend of mine Gabor HA7AST printed it out.

I used some hot melt glue inside... (it was too hot, so I had to put the whole stuff into the deep fridge for a while.
The result is something I really like.
I do not have to struggle with the original connector, I can use my standard XT60 plug.

Z-817 mod

I live in a suburban area, where no antennas allowed. I need to go stealth, just under the radar.
I mainly work from the park, or hilltops, but sometimes it is good to make few contacts from home too.
Small vertical can help a lot, but on the lower bands it is not so effective.
I recently got a Z-817 from LDG. I had it before and liked it so much. It is an L match tuner, works up to 600ohms. In fact it is only effective up to 300ohm. Of course it works in the range of high impedance, but only with compromises.

My mod helps it to be a bit better.

I installed a 1-4 and 1-9 un-un into the box. They are selectable with the two switches on the back board.

The difference can be several dB on the field meter.

I also changed the GND connector, because I use banana plugs.
There is an RCA connector for remote and a switch to prevent it to drain the batteries in the backpack.

The transformer is a standard one with 42 material core.

An easy battery idea

Battery is an evergreen topic in QRP world. It should be cheap, light-weight and high capacity...

FT817 eats av. 1A/h. (SSB or CW mode) Hence 6Ah battery gives you 6A fun.
It is more than enough for a long walk.

I made a 6Ah 3s Li-Ion Battery pack using 6x18650 cells. Soldering is a bit tricky, but not a rocket science.
Isolation is done using hot-melt glue and some tape.

You can see the balancer connector and my standard PWR supply connector (XT60).

For more than a day one can build a bigger pack using 18650 cells.
I still use the internal NIMH battery of the radio. I keep it charged. In case of FMing with 0.5W it still gives one-two hours. It is also handy when I need to hunt for noise sources.

6x18650 ->6Ah 3S battery pack for Ft817 and others...

Go green

Sun is for free. I like renewable energy even if I have a chance to carry extra batteries with me. It simply makes me feel good :).

I found this tiny solar panel walking around the market few years ago. It gives just a bit more than 5V, hence it is perfect to charge 5V USB powered devices.

I charge my UV3R using this.

UHF/VHF handy for hiking

I love hiking. Playing with ham radio on a top of a hill, far from noise sources is a great fun.
It is always a good question what to take with you... The answer is: The smaller the better.
As I often say: "size and price" counts.

The smallest and cheapest FM rig is an old UV3R from China.

I prefer the older one. It gives 2Wtts only, while other rigs do 4-5W. What is the difference? Nothing. between 4 and 1W there is only one "S" value on your meter.

To make it way better, I do not use the original antenna. I have a small, more flexible rubber duck and a full size telescopic whip. Both are connected to the radio via a BNC-SMA adapter.

It is also easy to connect external antennas to the rig, such as coax colinear or small yagi.

The other big dear is the external PWR supply connector. For some reason that is missing from the radios nowdays. Most radios can be charged using a so called "stand in charger" which I do not want to take with me... This small creature needs 5V, so an everyday USB powerbank or my small solar panel can charge it quickly. NP6 batteries are cheap on the market, one can pack few spare batteries as well.

The rig is probably not the best, but sensitive enough, voice quality is perfect and the size is ideal.
And at the same time it is cheap. Very cheap! In case of a driving rain on your hiking day you do not have to worry if it gets a bit wet :).

I have been using mine for almost ten!!! years. It is one of the most reliable chinese handy. (honestly I would not give more money for a Chinese radio ;) )

If you meet one of this radio on a ham fest, I recommend you to buy one and drop it into your hiking or surviving bag.

UV3R with BNC adapter and rubber duck antenna.
The red reflective sticker on the front helps to find the radio in the dark. It is bright red in the light of a flashlight. If you lose it you will find it easier. 

Easy to charge using a powerbank.

External PWR socket... a forgatten idea

Full size antenna with no loss.

...even tilted...

Short antenna for stupid situations...

I rent a flat in a small city. It is a big house with small heart, so goodwill is missing sometimes. People are engaged with meaningless things, hence I don't want to be a target with my hobby. All I can do is to use some hidden stuff.

First I tried using random wire. It was OK, my X5105 tuned it quickly with its atu. Now Xiegu is far away, and my uBITX and the FT817 does not have atu. What to do?

I tried my magloop. It is very effective. In the previous house where I lived before this one I made contacts from the room in SSB 5W. Here I have got buckleys... The building is full of steel. I live on the first floor, so I have three more above my head.
The balcony does not work, because it is also full of steel. I tried the magloop, and even the reverse beacon network was unable to copy my signals.
I did not want to buy an expensive atu... what to do?

My new toy seems to be helping me out. It is a D-original antenna. Not a mobile, because it is not waterproof and not strong enough to stand strong wind. It is some kind of pedestrain mobile whip.

D-original pedestrain mobile whip. It is tuned to 40m. You can see the counterpoise rolled up at the bottom.
It is stealth as much as it can. After making contacts it is easy to remove hence no curious eyes will see what I am doing on my balcony...

It works from 40 meters.

I tested it yesterday evening. In CW mode the first station was not a DX, around 500miles away from here. He gave me 549. I was happy... I had time just for a short test, so I quickly packed the stuff back to it's case when I realized that the radio was on 0.5W. Ups... it is not too bad... not 5W, it was 0.5W.

The antenna passed the test. Today I tested it again. SSB 5W 1000miles and 55 report. Actually I received the station with the same strength.

I am always hacking things. I have a 2.2m long telescopic whip. It is a treasure... I asked a good friend who has some turner experiences to make me a coupler, so I can use the telescopic whip insted of the original. This way it will be much longer (all together around 3m). I belive also more effective as well. At the same time it will be easier to carry. Just a 45cm long pack on the side of my backpack.

Idea two: I can connect a wire antenna to the end of the coil of the antenna to make it longer. This way If I use a 5m long fishing pole, I do not have to take a tuner with me. The coil makes the whole thing electrically longer, this way I am able to achive perfect SWR at the feed point of the antenna.
I can't wait having time to test it in field situations... maybe tomorrow.


PS:

I found a blogpost on the net. The guy said this antenna is crap. Of course... one has to know this is not a full size antenna, compared to a long wire it's results will be way far behind a long wire. At the same time it is working, if you know the rule.
The rule is:THERE IS NO ANTENNA WITHOUT GROUND OR COUNTERPOISE!
If you just hang a few meters of wire right from the base, you will increase its performance so much.
Don't use tuner for this. It can be tuned altering the length of the radiator or the coil. It must be 50Ohm at the feedpoint. Tuner between the 50ohm coax feed and the radio is one of the dumbest idea in the hystory of HAM radio. :)

Update:

It's been a while... I have been using this stick for months by now. I was able to make real DX-es such as USA from Hungary with my QRP setup. It was mounted exactly as you can see in the pic. Do not think only about CW, I worked a lot in SSB as well.
It is proven to be working fine:)

Ubitx vs FT817

There is a time when a factory built radio is too expensive for you. Or maybe for your wife... :) No panic, you do not have to give this great hobby up!

If you are not afraid of a soldering iron, you have a good chance of having a radio with no compromise. 

I do not waste your time, just go straight to www.hfsignals.com and see yourself. 

The result is a QRP rig with no compromise. It works as well as an FT817 (maybe it sounds better). it is an "allbander" (including 27MHz if you are a CB fun next to your HAM hobby).
It gives you 5-7W on every bands.

All you need is a good enclosure and a long weekend. 

The rig is fully hackable. If you visit https://ubitx.net/ you will find a hell of a lot of information.

Some guys made Icom-like rigs from the original mainboard using touchscreen and factory made enclosure.

What is the difference between uBITX and FT817?

If you receive 599 on your 817, the half of the report is deserved by Yaesu. 

If you receive 599 on your uBITX, the quarter of the report is deserved by Fahran and the ladies in India who soldered the smd parts to your mainboard. :)

Both of them are great fun!

Actually my uBITX is about friendship. I received the mainboard from my good friend Gabor HA7MAC when I had no chance of making QSO's with anything. I played with it a lot until one day I had a great backback radio. I enjoyed every minutes of it. Thanks again Gabor!

I have been using it for almost two years. I am happy with it. 

HF antenna in a pocket

I belive in common sense. Antennas for HF needs to be as long as they can be. Okay, but what if you have no room in your bag, no chance to erect antennas on the top of your house or even on your balcony?

Many years ago I bought a small "miracle shit" antenna in UK. The performance was shocking.
There is a nice place near Manchester called Peel Tower Hill. Climbing up there with a short stick and an FT817 gifted me hundreds of contacts.

The antenna is easy as a piece of nail. Just a coil with taps, a PL or BNC connector on one end, while a telescopic whip on the other. Few meters of random counterpoise is needed to make it better.
All the stations I heard on 40 and 20m came back to me even using QRP power.

Later I gave it to my friend Gabor HA7MAC to walk with it. Few months ago he gave it back saying "you need it more...". My uBITX was happy with the antenna. A real backpack setup...

The anenna... source: moonraker.eu

It does need any kind of support...

Bands are selectable using banana plug and a piece of cable.

In the backpack...

The good old beast is back

After saying good bye to my X5105 I wanted to buy some smaller, but multifunctional QRP rig I can take with me to my caminos. I was surprised about the prices the very next day. Buying a small trail rig costs as much as a used Ft817. Ghrrr... It does not make sense.
I had no chance to build radios in the flat I live, hence I had to pay for something from the market.
It is karma, or luck, who cares... a local guy appeared on a ham swap page with a 817. Price was perfect and decision was quickly made.

The parcel arrived and made me very happy. That radio was literally unused. As the owner said it was tried once. It was bloody true!

It is my 7th Ft817 in the last twenty years. Now it stays. I decided not to sell it in the future.

I quiclky put my grab and go pack together.

My grab and go pack... Ft 817, SDR stick, telescopic HF whip, cables, earplug and some tools.

It is a great fun to have a good old beast again. I made several contacts from the park nearby.
Some wire and a fishing pole was enough for many EU countries even in SSB.

Of course I will keep my good old uBITX transceiver, as it still works pretty fine. For long walks FT817 will come with me...

Long time gone...

I did not have to write in the last years. Many things happened. I moved to a different city, while I was engaged with working instead of focusing on my hobby.

I jumped on into uBITX project. My friend Gabor (HA7MAC) ordered a kit from India. He build his own, and passed the mainboard to me.
We payed a lot with the PA stage. Finally new fets solved the problem. Now there are two RD06HHF1s in the box. Solid 5W comes out on every band from the final stage.
The signal is pure, SSB modulation is crystal clear.
The AF amp died after two weeks. Finally a chinese TDA chip based amp was installed straight to the board.
I made a temporary enclosure from PCB, but later I changed it to a brick like alu-box. I like it so much... Antenna connector is on the front panel, while the back is blank. It can stand on the back as a true manpack radio.

Experiences are pleasent. It does it's job. I made many QRP contacts with it, mainly using a very short SPX-100 telescopic whip.
The menu system of the radio is very practical, the whole rig is so easy to use. Mainly I use straight key, or my arduino elkey with it's memories, but there is a built in elkey too.

Here are some images...

Back again...

Ham radio bobby has not been the first priority in my life for a while. Life brought changes, and there were more important things to concentrate to.
The new thrill came when a good friend Gabor told story about ubitx.
Ubitx is a small and relatively cheep ready built qrp trx kit fro m India. It is simple, but on the other hand it does everything a portable qrp trx needs to do.
HF up to 30MHz, aprox 5W average (10 W-up to 10MBz and 2 up to 30MHz), ssb and cw modes (digit of-course) on a 16cmx16cm board. The perfect rig to get back on ham track.
Gabor decided to built a customized one for himself, but before starting he ordered a kit for test purposes. It works, and after some modification it became smarter tban one may think.
He started documenting it, so the history of my tiny transceiver starts somewhere here: www.ha7mac.com. 
The rig shows several features. There is built in keyer with programmable memories, which is very useful for cw fans like me, there is if shift, and cat port with the commands of the good old ft817. 
As Gabor have tested and checked everything on it, he is going to start to build his own one. The original kit is going to be finished by lucky me.
There are few things to be finished. The pa stage, which needs to have new transistors to have the power output equal on all bands, an additional home-made xtal cw filter, and the enclosure which will be as small and thin as possible.
I will use the little rig mainly outdoor, it needs to be small, rugged, and ergonomic.
The antenna tuner I will use is already under construction, I wil, post about it later on. Mainly I will use small and short antennas, or magloops with it from tops of hills behind the middle of nowhere.
These the plans, let's see how the turns to reality...

If you are interested, you will find further information on http://www.hfsignals.com/index.php/ubitx/ page.
There is akso a fb group you will find easily.

To be continued...

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!