Wednesday, January 16, 2019

SLA batery charging

SLA battery charging.

I have few batery lying in the shelf. Not charged. Its sealed lead acid battery. that means its sealed. its miniversion of car vehicle batery. Generally 4 vollts are standard. So i have 500 ma - small batery, 1 amp and 2 amp batery. All just not charged , deep discharged.The previous usage experience is that i have to regularly charge it. But, could not find the commercial charger circuit.

There is very strange theories as we have used this batery system 100 years.Ohh baghdad battery ? Anyway i will be makinhg a simple charger circuit and one is fully charged then will constantly tripple charge it.
For amazement look at the battery which might have used for GOLD-electoplating the Egyptian idols and possible to light up lamps.
baghdad batery

baghdad batery


Have a look at the baghdad battery.





















And i opened my SLA batery.

Need to get the distilled water and a syringe to fill it up. You have to reverse connect it. Then fast charge it. Trickle charge it. And use it and recharge it.

2. Cover opened
1.SLA batery

3. Bottle opened
I have to buy the distilled water or use the rain water. yes, i have plenty of rain water. i collect it during rainy season and keep it in bottle for a year long use to worhip my gods idols.  Water tastes good.
Today is 19/August/2019.
I saw a vedeo where a person was rejuvenated the big SLA battery with  rain water and a professional charger. Used syringes. Topped water. About two injections it needed.
Anyways. I do not have charger , so I did use my bench power source and gave 12v directly to this battery. It measured 0.2 volt a very bad condition. But I knew it needed water . It was charging and suddenly I hear a pop up sound . I looked but There was nothing . Transformer was hot ! Battery was hot. Then after some time measured the battery voltage . It was 2.2 volts. then show that seal was open and water was bubbling! Ok due to gas pressure it opened. Then , found it removed other rubber cap. Let it charge. It’s heat intensive process so use fan ! Once it’s workinb is tested will let you know. 

Sunday, January 13, 2019

Silent key

every radio station when closing down calls for last message anyone waiting any last message. Station vu3inj calls for this.  From now on everything should be taken as  SK.
Life is beautifully ful 

Sunday, January 6, 2019

7159kc trx qsk

I had a rough time understanding and choosing a proper qsk for my TX and receivers. If you see my early post you will see that I used different modules to make Transmitter and Receiver

In this transceiver i tried to implement TX and RX chain in a single BOX. My results are very satisfactory. So, lets hear the success story of QSK.

By the way For this TRX Next step is to make a cw band xtal VXO of 7000kc (This xtals were given by my friend Arya ) , and 7159kc DSB TX.  Need of VXO is apparent. A single stage af filter is also good. But let me first put it on air with just 10 foot high about 50 feet long wire. It works. Years of homebrewing has told me to make a solid brew. Put your modules firmly , in  a box, shield them. use decoupling , use plenty of space. Make modules and make it in small steps. Test it and see that it works.
Filter 40 meter

Qsk

Filter


Yes wheel is reinvented and revised.
I have put the few fotographs here and will write more about it.

1. You need a Relay DPDT (8 pin relay) , a must to change over the Antenna and Generate control Vcc  ie. RxV, TxV.

2. Transistors can be used to switch few modules. (will describe later on). For SSB single relay will work but for CW you need more control mechanism. Or use a relay and manually switch TX RX on off, clumsy.

3. You also need Diode 1N4148 switching for protecting the front end of RF Amplifiers. I implimented the M0DGQ as given in the SPRAT magazine. picture given below. Here if there is no control voltage switch protects our front end. This switching always introduces some signal loss . but ok with good dipole external antennas.

4. You should use "10k+LED" for indication of Vcc, On-Off,TX,RX, etc. This indication helps in quick visual  fault finding or working of the stage. It helps a lot during the development stage. If current consumption is an issue then later on remove it.

5.I will be listing all the switches usage. Relay, Diode, NE555, 1N4148, BC548,1N4007.




QSK

TRansceiver

VK3YE 

It has RF amp, Ground switch 
and Control voltage

Another QSK


VK#YE VXO