14318kc , ra3aae dc receiver

I had made the linear (25w) using the IRF510 for pumping the radio waves into the ethers. At present only 20 meter antenna was known to work. The 40 meter dipole has the possible coax problem. I have long wire also. But I thought to test this linear on 20 meter due to constant traffic on that band.

I had the ra3aae receiver prototype receiver to test tx on the 40 meter but nothin on the 20. I also wanted to  modified original PA2OHH design for the INDIAN conditions. So made this receiver for the 14318kc cw/dsb tx using the 7159kc crystal.
Will house it in a neat sleek box so look like a walkey talkey.

Hope to monitor it for long range.
***************************************************************


building blo

RA3AAE, Poliakov sub-harmonics mixer. by VU3INJ, Indrajit sinh 04dec2014

Diode mixer for amateur :: At the first glance we thing that how the lowly doiode will help us ? But, fact is that they are easily available, very simple to make, gives a very good result, they have high dynamic ranges... can process small signal as strong signals.

In this particular detector, i have made atleast 3 prototypes on the three different frequencies. Now, it is safe to say that its a reproduceable design.

Block diagram:::

First stage is the BPF + RF amp, Detector, AF Preamp, AF Amp. Xtal VXO, ( power supply, antenna and speaker switching, casing etc Hardware).

List of components:::

Ckt Diagram of the first version as derived from the PA2OHH.

This latest Working Version. :::

Tips for building it on copper boards. :::

Problems and solutions.:::

I did not encounter the problems. As most of the problems were solved at the first prototype. Be symmetrical and dont hesitate to use liberal adhesive to solder the copper pads on the copper boards. You will need crocodile clips to hold the components and pads togather. Use wood for giving support during cutting. Please cut the copper carefully so that its straight & clear. Carefull during toroid making so wire does not get shorted.

From this where ?

Its a serious toy. Can impress with childrens. As a gift to new local swl for listeing your signals or as a single frequency local net receiver. field-fone...　

This receiver is  housed in the metal box but i think you should place it in a plastic box. works okey in monitoring my own tx signal i.e 14316.04kc beep beep beep.........

　

 14318kc receiver



QRT-november2014

For some time I was not able to post into the blog due to some minor technical problems of the cookies and something else but hope will be able to post here some more experiments done during this times.

During that time I had created a facebook page to upload my images here is the link https://www.facebook.com/pages/vu3injblogspotin/752990588098632
I have seen that when you upload the images to facebook its very faster than blogger and the software at the websites makes your images light so it becomes easy to upload on this blog.

If hand drawn image please use black pen to sketch JPEG formet is ok.

I am maintaining this blog as well as the facebook page.

ON AIR 14315KC,  will be installing the single frequency set-up....

CW

CQ CQ CQ DE VU3INJ
CQ CQ CQ DE VU3INJ VU3INJ VU3INJ AR

VU3INJ DE***** **** **** KN
TNX **** UR RST 599   5 N N  KN

PLS QRS  QRZ  DE VU3INJ.

VU3INJ UR RST 557 KN
**** DE VU3INJ CU AGN TNX.

CQ CQ CQ DE VU3INJ

Mixer TA7358

I have used the FM FRONT END ic ta7358ap (LA1162 etc) in the mixer for arriving at the 7059kc in 40 meter band. During testing the old tech school VWN tx I needed one stable frequency as 7.159 MHz xtal was not available and at that time 7100-7200kc band was also not available. so this was on hand and it worked.

***
As of the 7dec2014 I have got the crystal due to a generous help from the Delhi ham friend. Hope to put the 40 meter VWN TX on this 7159kc

y2kissrx

Around the year 2000 when it was written as Y2K and we had to fix the bug of dates , I made one homebrew receiver. It is still giving me loud signals. you can download the pdf files at the Indian Homebrewers facebook group.
thanks,
de vu3inj
***************************************
it is being written up and uploaded as pdf file in indian homebrewer group in the facebook.
y2kissrx1.pdf contains brief details and essential components,
y2kissrx2.pdf about testing and dbm making.
y2kissrx3.pdf about completing it (IF making, IF Osc, RF osc, AF, IF, RF Amp stages etc (work still in progress)

 

ETCHING A PCB (old tech)

I have started etching the pcb on the old style, with oil paint and brush using the free hand drawing small non critical pcb.
it worked out good . will soon publish the foto graphs of the process. its an 80 meter oscillator and buffer.
***
Etching the PCB

From my last visits to metro I bought glass epoxy pcb 1foot size, prize rs.175/- .

I needed something to etch. I was very busy. Now, when I am not working for govt, I have to put more quality hours for family ,works etc and its little odd  for me. So, I started  with a small simple thing first carved out 1.5 inch by 2.5 inch piece from big board by small hacksaw.

Then bought small FECL3. Ferric cloride. The dealer did not give me big bottle but  a small bottle for 50/- even that was half empty. Due to rainy weather this fecl3 became semi liquide from the crystal powder. Ok.

I can not find the small size drill-beat , so will place the components as  SMD style without any hole. The pcb was traced as an island pads with lots of ground plance to sooth the rf. Oil paint for covering the copper to protect it from etching. Then  let it dry for over night. It did not look like straight line but just work of the picaso ( the artist). In the morning I could not find it dry so, used a simple  fan to throw air on it .PCB dried somewhat after 4 hours.

Then put PCB into the solution for etching and after one hour it started eating up the pcb. After rinsing I will see what it looks like. i used small glass bowl for etching container. You should never use metal. Use plastic or glass. It is possible that material may stain your workbench, so i put the bowl away from childrens in verandah. within 1 hours it started eating the copper and around 1 and half hour it was done.

As of 28 april 2015 . I have downloaded and installed the student version of the deeptrace.exe. the pcb design software. Its very good one. It has everything needed for designing the professional quality pcb.

On suggestion of friends I tried the H2O2= hydroge paroxide, HCL-hydrochloric acid. Pour about 100ml of h2o2 in the plastic bucket. Then gently pour the hcl. put  the pcb and within 10 minutes your pcb is etched out . Clean it with water and its good. Etching process if very faster , even with this.

Earlier I was using the fecl3 but that took lost time and was not good.

How to etc PCB

Just few hours back , in Mumbai we had a very warm eyeball qso with OM Cyril and OM Sudhir bhai shah and OM charudutt.

In the island of shops I was not able to find the copper board but VU2UPX led me to the visha electronics on the third floor off lamington market on main road and I had my second big copper clad board after a two decades. first time I bought big copper board from Ahmedabad. ok, glass epoxy cost me around175rs/-, normal phenolic is 75/-. size is 1 foot by 1 foot.

I had used first copper board for making the VU2ATN 20 meter transceiver with mc1496 double balanced mixer. zeroxed the ckt layout from EFY magazine. Then to make it transparent applied oil to the papers and let it dry. then with the help of pensil and carbon paper traced it on copper board. Now, ball pens ink was used to mark the traces by hand. when it solidified after some time and tracks were visually checked with EFY magazines original layout. I finally put the pcb on a small lunch box poured some water and then goes the ferric chloride may be two or three table spoon. then let it eat the extra copper and atlast finally after an hour the copper board was taken out. seen that everything was done properly. satisfied, washed with water. then with the help of soap and kerosene it was cleaned. finally I got my firs etched pcb.

This is a very old tech. So, I feel at liberty to ask my junior hams but very seasoned in this etching pcb to help me out with latest techniques and here comes the reply from my friend JAYDEEP BANERGEE (VU3JOJ )I have seen he has made very good pcb better then professional quality.

with his permission , I reproduce his reply. Let it be verbatim. I hope it will be helpful to my friends. Foe any queries and question please call him up directly. He will be willing to help you out. He is available on gmail and facebook. thank 3joj.

HOW TO ETCH A PCB

For a professional look of your pcb I suggest you to follow what I learnt at my university of life.

1. first clean the surface of the clad board with soft scotchbrite. Do not press hard. You do it to remove the weather coating of the copper board.
2. Then clean the copper piece with soft cloth or tissue paper by pressing hard. The cloth/paper will become black. Then moisten another clean cloth with (no tissue paper) Acetone (if not available use spirit) and clean again until no black spot come on the cloth.
3. Before preparing the clad board (step 1& 2) you have to print the negative on a thin photo paper by tuning the laser printer in darkest mode. You also have to turn off the page scaling buttons of printer properties. Use photo paper because toner is not glued to this paper. If it is printed on a normal paper the image will be permanent and unfit for transfer on copper.
4. Now follow step 1 & 2. and place the negative on the copper clad board. Fix it with paper cellotape at corners to prevent displacement while ironing.
5. Now heat your iron to its full capacity. Place the copper board under a layer of a thick cloth ( I use my worn out denim). Remember the surface must be smooth for ironing.
6. Now the main secret. Do not iron initially on the paper side. Put it in up side down position under the thick cloth. Press iron hard for 30 seconds. Now reverse it ( put the paper side top). Iron light for a minute. Stop for 30 seconds and then again iron for a minute.
7. Now keep the board on the thick cloth and iron directly with light strokes until you see the pcb tracks.
8. Left it for cooling. Do not dip in water. Try to peel off the paper gently. Now the whole toner is transferred to the copper. The paper is absolutely blank.
9. Using a magnifying glass examine the tracks and if you find any paper residue wipe out with a soft brush. If you find any track missing or broken then paint with Erase X Pen ( permanent marker will not work)
10. Now dip the board in FECL3 copper side top position. Always cradle the container lightly until unwanted copper wiped away.
11. Clean the board with plenty of water. Do not drain the fecl3 solution. Keep it in a glass container with big mouth. For next etching just add little fecl3 and it will work. It is also illegal to drain fecl3 in foreign countries. There is scientific procedure to dispose it off.
12. Now wipe the board with VIM dish washer and scotchbrite until it is shining. Then dry it with a cloth and again wipe with acetone or spirit. Then spray ACRYLCOTE on it and leave to dry. Then spray the same on the reverse side olso.
13. Drill holes. See my homebrew drill on facebook wall.

vwn wire antenna

Wire antenna experiments



Little lamentations

I opened my logbook and saw that for the last month(april2014) i have been not doing any HF or the usual SWL ! A month of absense.... People were claiming lots of contacts within a day.CW,DX etc etc band was very wide open, this happens very rare.

In the social media i wrote following lines and become QRT to examine the faults with my vwn transmitter & antenna systems. I was in deep anguish, lost hope so much that i shunned my self from other projects. Reason not able to radiate effective power to even neighbouring hams 100km. Lots of things were at stack. It was my reputations, other new-hams hopes etc....

But, in actuality we have very few hams and desnsity is really very low. So, what works in europe and amerika don't work in VU.  we need more than 5 watt to communicate.

Antenna

Research going on...... saw lots of articles on the inter-nets. atlast came to the conclusion that for 40 meter i have to increase the power. May be my some power might be in harmonics also. Raise the power from 5 watt to somewhere about 50watt... as well as make some wire antenna, i.e LONG WIRE, MONOPOLE VERTICAL, END FED HALF WAVE.INV-L,

Please note that , Inverted-Vee, FULL DIPOLE dose not work as a first antenna. All the myth of loading the antenna was shattered. I dont have atu, gdo, antenna analizer etc.

The more i read the success story, one thing stood out, that they used some sort of tuning, be it a simple lamp, variable capacitor or atu. In the past sought indian hams with vwn transmitters, used the dipoles strung between the coconut tree. I never herad inverted Vee or long wire. For the first antenna anyother antenna is not recomeneded , instead Just strung the wire.... and tune it with ATU, AMU ETC. Fact is, no body hinted this to me. Its not their faults. Most of the hams have commercial gears and producing 100 watt powers. So, basically there are very few hams who works QRP/p. Piece be on them. They dont have first-hand experience of real homebrew qrp and its challanges.

My systems

My all systems are homebrew from the scratch. It does not have standard 50ohm input, output or anything standard at all. Standard comes from the quality of measuring instruments. which i lake (its a candid truth). That was the reason that i asked fellow hams, who have successfully brewed some transceiver to pass one of those working trx. Nobody understood it. Instead the formula of "teach a man how to fish instead of giving the fish was enacted". Well, what i can say on morale standards.... they are my friends and helped me without any gain.

So, person has to make everything on his own and when he makes it , he is so much harassed that he don't pass on the informations to others and same cycle of frustrations goes on with another fellow........ one day he buys some second hand tx,rx and enjoy the bliss of commercial gears. Even in the second hand saling- there are few cheats who dump their non-working junked sets on others.

Big Sorry

Please don't get offended due to my candid words ! I brewed the tx in last year, 2013.... and it is still in the self idling..... group effort is needed to put a person on air. I know lots of friend called on me, we fixed sked and they tried hard to help me. My sincere thanks goes to them. That your effort, constant words of sympathy and comments is keeping me on.

Field test

i compared the tx signal strength with inverted vee it did not go even 100meter. Then tried long wire fed at one end without any tuning. what a brave person i am to declare the results..... it radiates more than 100 meter with 599 report. i will test it for few km and then will make a tuner. 22swg, about 70 feet hung between two trees.

As of 7 may 2014 made a test receiver using the ra3aae detector. I am operating the 9volt pp3 batery. will ride a bike and go to few km listening it. if it gives me 599 signal in the city area within 10km then will tell you friends.

{As of 27Jan 2015 I know the main culprit is two fold. low power, unturned antenna. For first try brewing the linear of atleast 20watts. Second  antenna. Now I will try this antenna with 20watt linear}


Well thats it folks. when wheel starts working you will know yourself by tuning on 7059kc , 30seconds on off pulses , 5watts, cw carrier. if you hear me please call me on my mobile number and we will have a sked.

(27Jan2015   SKED:- May be using the R7 Dayton receiver and this vwn cw tx + 20watt linear you might hear me. will give you a call when ready....... )

Realizations

(19august2015 As I gifted my VWN tx to a ham friend and linear was made only for 20 meter. Busy with many things etc so did not test anything. But, meanwhile realized that  antenn is good, tx is good but I need the damn 20watt... so once again repair first VWN transmitter and do the test... or instead of re-making for all projects. Make a linear for 20/40 meter and test everything....
)