BITX V4 SMD Build

Finally, I have started work on the SMD Bitx which has been along time dream.

I plan to homebrew a dual band (or even maybe a fancy multi-band?!) transceiver with this board.

My plan is to log my progress  so that it may be of help (to me or to anyone else!) in the future.

You can follow the build at bitxv4smd.blogspot.com

73

New additions

Im in the process of adding more gear as usual to the shack.

An LC meter from VU3LTB Om Ashish was the most recent acquisition.

A Sweeperino is also in the works. I just finished putting together the Power detector section with the PHSNA AD8307 pcb.

While this awaits a suitable shield, Work on the Bitxv4 SMD has begun!

The lone villain, LM386, with his trouble maker sidekick, the "gain" capacitor soldered on :)

More soon,
73

Developments.. ?

I know I havent been keeping promises lately..

Its been more than a year since I promised updates, and there have been so many things I have been caught up with lately.

The shack now stands untouched for quite sometime due to my career. The antenna needs fixing too.

 Amidst all the QRL for the past few months, I got around to building the VUSDR ..! What a performer, at the given price (INR 8000)!!! I paired the 5 Watt 1-30 Mhz SDR with the infamous "Red-Box" PA-150 from VU3GEK. The Amp is a terrific steal at the price. My only concern was the lack of a proper BPF (under construction) for the linear.

I got around to playing with it too much without a cabinet that I now suspect there is a hairline short between those tiny little SMD components. I'm now looking out for hot air station to rework those solder joints.

I also manged to get my hands on the so-far-elusive si570s by organizing a group-buy.  I have some neat plans for them.

OK. I think I've written too much.  Here are some pictures,

The VUSDR, based on the AE9RB Peaberry

A Marine Engine room communication headset, purchased at MAHA MEET for a very reasonable bargain!

The MFJ tuner. I love the cross needle meter on this one!

More soon.

73

QRL QRL ..

I'm Sorry.

It has been a long, long time since I was QRV from my shack due to my post graduation and QRM from other things in life.

During all this, OM Shyam, 3UBR, kept nudging me to get my ticket renewed. After 6 months or so, of constant nagging, I gave in and sent off my papers to the WPC address and waited. A few weeks later, I received the renewal in my mail.

My plan was to build a receiver (My old junkbox and homebrew were gotten rid of when I was in the UK!)  and then work my way up to a transceiver. I started sourcing all the parts and got back on VHF to let my old friends know that I am back.

Amidst all this, I was looking for a HF transceiver to primarily fill my shack and operate portable(when time permits). After some looking around, I landed on a Yaesu FT-100D from a very friendly and well known local op and I've been thankful to him for that. The receiver with all its bells and whistles DSP is simply better sounding than any rigs I've made in the past*.

A quick Inverted Vee cut for 40M, some Old Co-Ax and a 30A Power supply was put together on a old table, and my first contact on HF-40M was with VU2PLL, OM Shan, from Erode, with a 5-9 sent and a 5-6 received on 20W. Not bad considering my Noisy location. A Few QSO's later, I had my very first DX qso with 4S7AVR, OM Noel from Colombo for a 5-5 received.

I'm in the process of starting to build a proper shack around my FT-100D. In a few following posts(I Promise, I will be regular this time) you will see a lot of related radio accessories before I go back to radios ( MINIMA, by Farhan looks like the next big project). I will also post updates on contests and other DXing info

A special thanks to VU2NKK(OM Krish), for reminding me to get back on my blog.

73

USB PIC Microcontroller Programmer on Sale!

Hello!

I've recently been looking around for a USB PIC programmer for Programming those Microcontrollers for Homebrew Projects. There are a few Programmer, but they are mostly Serial port devices, which are not at all compatible with Modern Motherboards and laptops. This is where USB programmers come into play.

There are currently 2 on offer for those who want to buy from India. One is from United electronics, based in Mangalore. It Costs around 1700 INR without shipping and Is based on the Blueroom elecronics's Junebug Programmer. The Programmer is a Self Powered Programmer, meaning, the USB port powers the programmer.

The Link to their webpage is http://united77.com/products.htm

The other is from eXtreme electronics, based in Jamshedpur. The Cost of this programmer is 999INR without shipping. My Guess is that the shipping charge would be close to 200 INR, so that makes this the cheapest USB PIC Programmer available in India. This Porgramer on the Other hand requires a 12VDC inout to program Microcontrollers.

Here is the Link to the eXtreme electronics E-shop : http://shop.extremeelectronics.co.in/product_info.php?cPath=21&products_id=78

Before Buying, make sure you read all the technical data presented on the website to make sure that the programmer supports the PIC microcontroller you are planning to use.

I'm planning to buy one/homebrew (based on time+cost+availability factor) soon. Ill post reviews later.

73's

Ragav

Hello!

Phew! It's been a hell of a hard time these days. I Managed find a job right after graduation and am now sitting from my office typing this in my outdated blog. Amatuer radio of all things has taken a backseat and motocycling is in! I managed to get my hands broken this year but I'm recovering now!

There have been some upgrades in the shack as well. A Kenwood TS450 is now a part of th shack along with a mismatched 7 Mhz Dipole which works Incredibly well on 21 Mhz! To supplement the TS 450, I have a 10 A Junk market Power supply. Both of these are courtesy of VU2ABS and VU2JA! Thank you guys! I've had my share of fun on SSB with a Homebrew 7 Mhz Rx and a Homebrew 7 Mhz TRX.

Since It been almost a year since I wielded a soldering Iron, I've decided to allocate time on my long lost, yet favourite hobby to keep my spirts high. I still ahvent boxed up my SDR nor is that BITX complete! Need to work on that soon! I'm planning to order a USB-PIC programmer (due to the cost and laziness factor involved!) from Extreme Electronics. That should give me some opening to PIC microcontrollers and a chance to study after a long time!

The Blog will be updated as and when I get time! I swear! Since Geocities has shut down I'm looking forward to move the blog to a better host and have my own personal website.

Look forward to more Homebrew electronics and antenna projects soon!

73's

Ragav

The SDR ... Its Alive !!

Hello!

After some QRL , I found some time to work on my SDR Receiver which i have mentioned about in my earlier posts. After adding a BC 547 RF Preamplifier, I connected it to my PC and fired up M0KGK's SDR decoder and voila .... I picked up this transmission from a "french" (Not sure) Station. It still needs tweaking and boxing up but alas, It fianally works.

The Preamp is powerful enough to bring in weak stations with just a 3 Mt wire thrown around the room!

A well deserved break , I should Say!!

73's

Ragav

Back after a long spell ....

Hello!!
Its been a long time since i updated this blog.

Almost a YEAR!!!!

College QRL had kept me from my shack and i decided to break the spell and attended a Software Defined Radio Workshop By VU3WJM, OM Rahul. Anna University, Chennai had done a great job of arranging a workshop to promote SDR's here.

Shyam, 3UBR and I got a kits of a simple SDRx for homebrewing. Since Shyam's Interest in the subject is simply too high, I took some tips from him which gave me a lot of things to think about before I could say "Yeah....I think I understand now..."

Once back in the shack after a brief dinner, I set my sights on the kit. I quickly put together the 5V regulator section and tested it. Next were the Jumpers on the board. After some struggling the jumpers were soldered on. Next were the Resistors, Followed by the non-electrolytics. Then came the IC sockets. The electrolytics and the Crystal were soldered only after the 2 transistors.

After a short break I returned to the shack with the pin layouts of the 3 IC's :

1. 74HC74
2. 74HC4053
3. NE5532

The Pin voltages were measured and were found to be well within the specs of the IC's. Next in line were the 2 transistors. No problems there. Frequency measured was at 28.325 Mhz.

Close enough!

Now to interface it with a good PC (My laptop lacks a Line IN).

I have M0KGK,Rocky and WinRad installed. Lets see :)

73's

Ragav

P.S.: I also got the New BITX v3 PCB from VU3SUA and WOW... look at it guys!! absolute fun to assemble! More on that later!!!

A Simple USB PIC Programmer !

Hello!

I was on the hunt for a USB PIC microcontroller programmer after losing interest in the GTP-USB-Lite.

After a night long search, I found the June Bug Programmer by Blueroom Electronics. The programmer Side is a PICKit 2 Version without the EEPROM's used for On the Go Programming.

The trick to getting this programmer to work is to use a 18F2550 programmed with a .Hex file provided by Microchip. Once this is done, you can calibarate and use the programmer. Oh yes! Once the Chip is programmed, you can update it's firmware by pressing a Push-button on-board.

This makes sure you can program the latest supported PIC micro controller.

This Is a Must Have for Any Hobbyist!!!

Since The PCB is not available on the internet, I decided to ask Theo, a Young Lad who seems to have the knack, even though he is not into RF Design and Construction (yet!).

Here is the PCB and the Component Layout in PDF format.

The Hardware is supported by MPLAB and the hex file can be found in the MPLAB installation directory.

More Updates soon!

73's
Ragav

Getting a VHF Rig!

Hey!



I am finally getting a VHF rig after much pushing around. The Rig ( A KYD TK-750A) is on its way from Bangalore! Here Is a Picture with all specs...covers the whole VHF spectrum!!!

Thanks to VU2POP (Prathap) ,VU3KCA (Keerthy) ,VU3TLR (Sujay) ,VU3UBR(Shyam), VU3HMU (Barath....Yes he is finally Licensed) !!!!

Drop a Call on 2 meters (Main repeater is on 145.175 600 Positive Shift)

73 !

Ragav

Broadcast SDR receiver !

Hello People!

I received these plans for a Broadcast Software Defined Radio Receiver from OM Sarma In Hyderabad. It Uses a LC tuned VFO to cover 3-16 Mhz. Although this can be used to tune to Amateur radio transmissions it will be difficult to fine tune into a signal....

Use One of the following sofwares to decode the signals:

• Rocky
• Win Rad
• M0KGK SDR
• SDRadio

Here are the files:

• Documentation
• Local Oscillator Schematics
• PCB Component Layout
• PCB design

Three Cheers for VU3WJM OM Rahul for the design!!!

Will be making this soon!

73's

Ragav

RX 20 and The Signal Gen Project

Hello!



Here are the schematics of the RF gen which is a PLL VCO . The original circuit was designed by KD1JV.

The RF gen proves to be a cheap source of signal for checking your homebrew Receiver.

Here is the documentation for the RX-20 circuit.

more up in next post!!!

73's

Ragav

Hamfest India - 2007

Hello!



I came home a couple of days back from Guntur after attending the much awaited HamFest India '07. I really appreciate VU3 RSB OM Sharath Babu for organizing this hamfest and for also personally seeing to it that all delegates were happy throughout the visit.

The photos can be seen over here

Had a Great Eyeball with VU2POP,VU3KCA,VU2RMU,VU3URJ,VU3HDK and a lot of other Hams....Best part is I got an eyeball with ex.VU2FAX OM Farhan!!

73

ragav

RX 20 - Initial Circuit

Hello :)

I had been QRL with college and did not find time to update this blog.

I quickly opened the BITX circuit diagram and made some quick changes (removing the TX RF/IF/AF amplifers) ....

Take a Look at the circuit here . It looks much simpler now doesnt it :)

There are several optional additions to the circuit such as a Automatic Gain Control, Digital Frequency Display and also a Active/Passive AF SSB respsone filter which will be added later on


More in the next installment :))

73's

RX 20 An Adaptation Of The BITX 20 :)

Hey people!

There has been a lot of buzz about the BITX transceiver over the internet. A friend of mine expressed his need to get a RX in his room as a bedside Receiver for monitoring DX and other traffic on the 14Mhz Band. Although propogation is bad on 20M we still decided to go hunting for the best Rx design with the usual criteria :

1. Should be a low cost design without compromising on performance.
2. Should be a easy to construct and troubleshoot design.
   
3. No hard to find / Exotic components.
4. Should be well documented as the Rx may be used for Research at a Undergraduate Level

We were still not satisfied after looking at almost all designs on the internet. After a Quick convincing session me and my friend decided to make a Rx based on a exsisting TRX design and we did not go anywhere else except The BITX site.

We decided to make a few modification though. The extra amplifiers needed for Tx are to be omitted and a Xtal Controlled LO with varactor tuning is to replace the LC VFO (We know that the tuning range will be limited but it is a sacrifice we are willing to make to avoid the Coil.)

Other Inclusions are a 3 Khz Active / Passive Audio Filter for SSB reception along with a AGC with a Override Switch. An S-Meter is also a fancy option which we might just add.

The only thing troubling us (lest we forget the College QRL) is the VXO. I was planning to get a standard 4.00Mhz Crystal available in the market for usage with the clock timer chips. The trouble is to pull the Frequency of the LO upto +/- 60 Khz using a super VXO design. I was thinking if these xtals would be able to do that.

The first step in this project would be is to complete the LO along with a Buffer and feed the signal to a frequency counter to see how far these xtals could be pulled.

Rest in the next Installment :)

73's

Other Homebrew Projects ...Plans for the Future ?

Hello,

These are the plans I had in mind for the Semester holidays :

1. Homebrew
2. Travel
3. Homebrew
4. Homebrew
5. Homebrew

As you can see from my planner I have decided to spend some serious(??) time for homebrewing.

Here are a couple of projects I saw and was quite Fascinated\Interested\Curious About....

1. A Double Conversion RX for 7 Mhz with a S-meter Option

2. A Portable 7 Mhz Superheterodyne Receiver

3. A L and C Adapter for a Mulitmeter

More to come ....

73's

Test Equipment :)

Hello :))

Its been a long time ... My College QRL and Other things have been pushing me to the limits.

Today I had a Eyeball with 3UBR and we were Discussing the prospects of the FCL-X meter we are currently working On....

I also came across this Interesting Homebrew Project .... A Single IC based RF signal Generator.
The Link for the project is here .

An exteremely useful and a versatile tool :) ... Looks Compact too :)

Oh well I guess its time to go back to the homebrew bench ....

73's

Homebrew PCB's :-}

This is my favourite and most used method of making PCB's...The Toner Transfer Method.

I dont have a digital camera now. I will post the pictures as soon as possible. Here is How I do it:

• Make the PCB CAD file using EAGLECAD. (I use the student version).I usually add text such as my call to make sure that the design in inverted.
  
• After making sure the board is inverted I print the whole thing on a PHOTO GLOSSY PAPER. Other types dont work!!! It costs around Rs. 10/Sheet here in Chennai.
• After geting the print onto the glossy paper, Cut a Blank Copper clad PCB material Board. One Sq.Mt of this costs Rs. 100/- and give you a lot of PCB's(depending on the size of your design.)
• To cut the board use a metal ruler and a good quality Pen knife(US:X-acto Knife). Score a couple of times with the pen knife on both sides of the board and you can very easily break the whole thing with a snap.
• Use a dish scrubber(I use a Scotch-Brite vessel scrubber) and scrub the whole PCB material you just cut.
• Wear Proctection over your Face as the copper dust is potentially unsafe.Once you Have cleaned the whole thing just make sure you dont touch the board directly(to avoid the nasty finger oils). Use Gloves Or something :))
• Place the PCB material on a waste newspaper and place the PCB on it.Place the design on top of the PCB and secure it if needed.
• Switch on your Clothes Iron and set it at Max. Temperature.
• Iron for 5 to 6 minutes until the paper turns brown.
• Soak the pcb without removing the paper in a dish of water.slowly peel of the paper.
• If the toner is not transfered well use 2 to 3 coats from a permanent maker(AKA OHP maker/US: Sharpie).
• Use Your Favourite Etchant to etch the board. Although I use Ferric Chloride now, I am planning to switch to acidic cupric chloride . This seems to be easily available and environment friendly :)

As a standard disclaimer Act Responsible Now. I will not take balme if you go wrong somewhere.
Knifes,Etchants,copper dust etc. are dangerous. Take Adequate Protection.

Have Fun,

73's

Homebrew Planner....

Hello!

Here is a list of projects I hope to get up and running in my Homebrew bench up and soon ...

• Variable 1 Amp 1.2 - 12 v power supply ( LM 317 Based )
• PIC programmer ( RCD programmer )
• 30 Mhz Offsetable Frequency counter( Py2RLM's Design )
• 40 Meter DC-40 Standalone Receiver ( VU2FAX's Design )
• BITX 20 And the RM-96 Transceivers (Scroll down below)
• Multiband Dipole 20 and 40 meter Ones ( Hamuniverse )
• LC meter (PY2CSU's Design)

Tempting to See on other's pages....My hands are already twitching to get started :))

73's

Software Defined Radio :)

I had tried to post messages before on the blog but strangely my browser just did not allow me to upload my posts and would keep showing errors and now that I have upgraded to Firefox I can go ahead and Blog without any other problems.

I recently saw a couple of Software Defined Radio Rx which are quite simple to construct on YU1LM 's Homebrewing Site. I was quite Impressed with what can be done with very little components.

The circuit of Interest to me is the DR2C . I am planning to homebrew this Nifty Little receiver to 14 Mhz (20 meters).

Rest later :)

73's