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BITX  An easy to build 6 watts SSB 
transceiver for 14MHz 
 
BITX is an easily assembled transceiver for the beginner with very clean performance. 
Using ordinary electronic components and improvising where specific components like 
toroids are not available, It has a minimum number of coils to be wound. 
All alignment is noncritical and easily achieved even without sophisticated equipment. 
The entire instructions to assemble the rig are given here along with relevant theory.  
The Indian hams have often been handicapped by a lack of low cost equipment to get 
them on air. A monoband, bidirectional design using ordinary NPN transistors was 
developed to cater to this demand. The design can be adapted to any particular ham band 
by changing the RF section coils and capacitors and the VFO frequency.  
BITX evolved over one year from the excellent S7C receiver described in the new ARRL 
book �Experimental Methods in RF Design� (an ARRLpublication) into a bidirectional 
transceiver. Several hams across the globe contributed to its design. A series of emails 
were exchanged with OM Wes Hayward (W7ZOI) during the evolution of this design. 
His contributions have been invaluable. He urged me to strive for higher performance 
from the simple design. The resultant rig has sensitive receiver capable of strong signal 
handling, a stable and clean transmitter capable of enough power to make contacts across 
the World. 
All the parts used in BITX are ordinary electronic spares components. Instead of 
expensive and hardtoget toroids, we have used ordinary tap washers. Broadband 
transformers have used TV balun cores. The entire transceiver can be assembled in India 
for less than Rs.300. I have designed a single side PCB with large tracks that can be 
easily etched at home or by any PCB shop. They are also available from OM Paddy, 
(VU2PEP, pepindia@yahoo.com). 
For those who don't read long articles ... 
There are a couple of things you should know before you start assembling the circuit:  
●
The same amplifier block is used throughout. But the emiiter resistors vary in 
some of the places. Double check the values. If you swap values, the circuit 
won�t stop working. It will work terribly. That might be a little difficult to 
diagnose in the end. Check the emitter values and the resistors that go between the ●
●
●
●
●
●
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base and collector.  
The receiving IF amplifier between the filter and the product detector is coupled 
to the product detector using a 100pf (not 0.1uf).  
The crystal filter worked for me, I used crystals from the local market marked as 
KDS. These are the cheapest and they work with the capacitor values given in the 
filter. Your crystals might require a different set of capacitors. Try the values 
given here, if you find the bandwidth too narrow, decrease the capacitances, if 
you find it too open then increase the capacitances.  
The microphone is directly coupled to the amplifier as my headset microphone 
needs 5V bias. If your microphone works without bias, then insert a 1uf in series 
with the microphone.  
The pictures show my prototype on two boards. Don�t do that, split up the VFO 
into a separate box.  
The predriver is built onto the main board. The driver and the PA are on a 
separate board. Keep the same layout to keep the PA stable.  
There is a 50uf on the power line soldered near the BFO, don't forget it. It cleans 
up the audio noise which would otherwise get into the receiver.  
On the PCB, there are jumpers between T lines and R lines across the ladder 
filter. There is a jumper from the BFO supply to the VFO supply.   
Development Notes 
Almost all modes of radio communications share a natural principle that the receivers and 
transmitters operate using the same lineup of circuit blocks except that the signal 
direction is reversed. The CW direct conversion transceiver is the simplest illustration of 
this principle. A more complex example is the bidirectional SSB transceiver.  
Bidirectional SSB transceivers have been quite common in amateur literature. A 
transceiver was described in the ARRL SSB Handbook using bipolar transistors. 
W7UDM�s design of bidirectional amplifier (as the basis of bidirectional transceiver) is 
referred to by Hayward and DeMaw in their book Solid State Design. The bidirectional 
circuitry is often complex and not approachable by the experimenter with modest 
capability (like me). 
The broad band bidirectional amplifier 
My current interest in bidirectional transceivers arose after looking at an RC coupled 
bidirectional amplifier in the book Experimental Methods in RF Design (p. 6.61). An 
easily analyzed circuit that was simple and robust was required. It began its life as an ordinary broadband amplifier: 
 
In any bipolar transistor, the current flowing from the collector to emitter is a multiple of 
the current flowing from the base to the emitter. Thus, if there is a small change in the 
current flowing into the base, there is a bigger change in the current flowing into the 
collector. What follows is a highly simplified explanation of working of the above 
amplifier. 
In the above circuit, imagine that a small RF signal is applied through R
 to the base of 
in
Q1. Also imagine that the R
 voltage is swinging up. The transistor will accordingly 
f
amplify and increase collector current causing more current to flow through the R
 (220 
l
ohms) collector load. This will in turn drop the voltage at the collector. The drop in 
voltage across the collector will also result in a drop at the base (base voltage is a fraction 
of the collector voltage due to the way the base is biased). This circuit will finally find 
balance when the increase in base current flowing from R
 is balanced by the decrease in 
in
base current due to the voltage drop across R
. In effect the RF current entering from R
l
in  
flows out through the feedback resistance (R
). The impedance seen at the base is 
f
effectively very low and the signal source will see an approximate input impedance of 
R
. 
in
Thus, Vin/R
 = Vout/R
 (Eq.1) 
in
f
Another factor to consider is that that emitter is not at ground. At radio frequencies, it 
looks like there is a 10 ohms resistor between the emitter and the ground. Thus, when the 
base voltage swings, the emitter will follow it. The AC voltage variations across the R
e  
(10 ohms) will be more or less the same as that across the base. The current flowing into 
the emitter will mostly consist of collector current (and very little base current). Thus, if 
the emitter current almost equals collector current, 
Ie = Vin / R
 = Vout / R
 (Eq. 2) 
e
l
We can combine these two equations to arrive at: 
Vout / Vin = R
 / R
 = R
 / R
. (Eq. 3) 
f
in
l
e
This is an important equation. It means several things. Especially if you just consider this 
part: 
R
 / R
 = R
 / R
. (Eq 4) 
f
in
l
e
Let�s look at some interesting things:  
1.
The voltage gain, and the input and output impedances are all related to resistor values and do not depend upon individual transistor characteristics. We only 
assume that the transistor gain is sufficiently high throughout the frequencies of 
our interest. The precise value of the transistor characteristics will only limit the 
upper frequency of usable bandwidth of such an amplifier. This is a useful 
property and it means that we can substitute one transistor for another.  
2. The power gain is not a function of a particular transistor type. We use much 
lower gain than possible if the transistor was running flat out. But the gain is 
controlled at all frequencies for this amplifier. This means that this amplifier will 
be unconditionally stable (it wont exhibit unusual gain at difference frequencies).  
3. You can restate the eq 3 as R
 * R
 = R
 * R
 . That would mean that for a given 
f
e
l
in
fixed value of R
 and R
, the output impedance and input impedances are 
f
e
interdependent. Increasing one decreases the other and vice versa! For instance, in 
figure 1, R
 = 1000, R
 = 10, if we have R
 of 50 ohms, the output impedance will 
f
e
in
be (1000 * 10)/50 = 200 ohms. Conversely, if we have an R
 of 200 ohms, the 
in
output impedance will be 50 ohms! 
In order to make bidirectional amplifiers, we strap two such amplifiers together, back to 
back. By applying power to either of amplifiers, we can control the direction of 
amplification. This is the topology used in the signal chain of this transceiver. The diodes 
in the collectors prevent the switchedoff transistor�s collector resistor (220 ohms) from 
loading the input of the other transistor. A close look will reveal that the AC feedback 
resistance consists of two 2.2K resistors in parallel, bringing the effective feedback 
resistance to 1.1K. Thus, the above analysis holds true for all the three stages of 
bidirectional amplification. 
Diode mixers 
The diode mixers are inherently broadband and bidirectional in nature. This is good and 
bad. It is good because the design is noncritical and putting 8 turns or 20 turns on the 
mixer transformer will not make much of a difference to the performance except at the 
edges of the entire spectrum of operation. 
The badness is a little tougher to explain. Imagine that the output of a hypothetical mixer 
is being fed to the next stage that is not properly tuned to the output frequency. In such a 
case, the output of the mixer cannot be transferred to the next stage and it remains in the 
mixer. Ordinarily, if the mixer was a FET or a bipolar device, it usually just heats up the 
output coils. In case of diode ring mixers, you should remember that these devices are 
capable of taking input and outputs from any port (and these inputs and outputs can be 
from a large piece of HF spectrum), hence the mixer output at nonIF frequencies stays 
back in the mixer and mixes up once more creating a terrible mess in terms of generating 
whistles, weird signals and distorting the original signal by stamping all over it.  
A simple LC band pass filter that immediately follows the diode ring mixer will do a 
good job only at the frequencies it is tuned to. At other frequencies, it will offer reactive 
impedance that can cause the above mentioned problems. It is requirement that the diode 
mixer�s inputs and outputs see the required 50 ohms termination at all the frequencies. 
In other words, they require proper broadband termination. Using broadband amplifiers 
is a good and modest way of ensuring that. A diplexer and a hybrid coupling network is a better way, but it would be too complex for this design. 
Circuit Description 
Although simple, every effort was made to coax as much performance as was possible 
given the limitations of keeping the circuit simple and affordable.  
The Receiver 
The RF frontend uses a triple bandpass filter for strong image and IF rejection. The 
three poles of filtering are quite adequate and the outofband response of the receiver is 
only limited by external shielding and stray pickups.  
An RF amplifier follows the RF band pass filter (Q1) biased for modest current. More 
current would have required a costlier transistor. There is 8mAs through the RF amplifier 
and the postmix amplifiers to keep the signal handling capacity of the circuit above 
average. The Postmix amplifier (Q2) does the job of keeping the crystal filter as well as 
the diode mixer properly terminated. The crispness of the receiver is more due to this 
stage than anything else. An improper postmix amplifier easily degrades the crystal 
filter�s shape and introduces spurious signals and whistles from the diode mixer. Note 
that the mixer is singly balanced to null out the VFO component and not the RF port and 
in the absence of proper preselection, 10MHz signals can easily break into the IF strip. 
The VFO is fed via a broadband amplifier into the singly balanced mixer. We used the 
simplest VFO possible with a twoknob tuning mechanism. It works really well and for 
those (like me) used to quick tuning, it offers best of both worlds, slow tuning through the 
varactor and fast tuning through the capacitor without any slow motion drive. Getting a 
slow motion drive is an increasingly difficult problem and this is an �electrical� 
substitute for slow motion drives. 
A word about the VFO: depending upon component availability, skills and preferences, 
everybody has a favourite VFO circuit. Feel free to use what you have. Just keep the 
output of the collector of Q7 to less than 1.5 volts (it will appear clipped on the 
oscilloscope trace, that is okay). For 20 Meters operation, you will need a VFO that 
covers 4 to 4.4MHz. The given VFO has low noise though it does drift a little, but I have 
had no problems with ordinary QSOs. After 10 minutes of warm up, the drift is not 
noticeable, even on PSK31 QSOs. 
A Hartley oscillator using a FET like BFW10 or U310 would work much better. You can 
substitute this VFO with any other design that you might want to use. If you are using the 
PCB layout, then skip the VFO on board if you want to use a different VFO and build it 
externally in a separate box. 
The simple IF amplifier has a fixed gain. Earlier it was noted that IF amp was 
contributing noise at audio frequencies. It was later traced to noise from the power supply 
and placing a 50uf on the transceiver power line has cured it. The IF amplifier has a 
100pf output coupling to provide rolloff at audio frequencies.  
The BFO is a plain RC coupled crystal oscillator with an emitter follower. The emitter 
follower has been biased to 6V to prevent limiting. 
The detector also doubles up as the modulator during transmit mode; hence it is properly terminated with an attenuator pad. It has no impact on the overall noise figure as there is 
enough gain before the detector. The audio preamplifier is a single stage audio amplifier. 
The 220pf capacitor across the base and collector provides for low frequency response. 
The receiver does not have an AGC. This is not a major shortcoming. Manual gain 
control allows you to control the noise floor of the receiver and I personally find it very 
useful when searching for weak signals or turning it down to enjoy the local ragchew. 
Transmitter 
The microphone amplifier is DC coupled to the microphone. This was done to steal some 
DC bias that is required when using a Personal Computer type of headset. If your 
microphone does not require any bias, then insert a 1uF in series with the microphone. 
The microphone amplifier is a simple single stage audio amplifier. It does not have any 
band pass shaping components as the SSB filter ahead will take care of it all. One 0.001uf 
at the microphone input and another at the modulator output provide bypass for any stray 
RF pickup. 
The two diode balanced modulator uses resistive as well as reactive balancing. A fixed 
10pf on one side of the modulator is balanced precisely by a variable 22pf on the other 
side. A 100 ohms mini preset allows for resistive carrier balance. The attenuator pad at 
the output was found necessary to properly terminate the diode modulator and keep the 
carrier leakage around the IF amplifier to a minimum. While this may seem excessive, it 
produces a clean DSB with carrier nearly 50db down with careful adjustments on the 
oscilloscope. 
Rest of the transmission circuitry is exactly the same as the receiver. There is an extra 
stage of amplification (Q14) to boost the very low level 14MHz SSB signal from output 
of the microphone tip to driver input level.  
The output amplifier boosts the SSB signal to 300mV level, enough to directly drive a 
driver stage. 
The Power Chain 
A simple power chain consisting of a lowcost medium power NPN transistor (2N2218) 
driving an IRF510 for 6 watts of power at 14MHz. The output of IRF510 uses a tap 
washer as an output transformer. The output transformer has 40 turns of bifilar winding; 
these can lead to enough stray capacitance to affect proper performance as a transformer. 
The halfwave filter that follows the transformer absorbs these capacitances as a part of 
the matching network. 
I used this power chain because it works for me and delivers 6 watts on 14MHz. I don�t 
use more power because I neither require more nor do I have a power supply that can 
source more. If you need more power, there are a number of things that you can do, you 
can simply increase the supply voltage on the IRF510 up to 30 volts and extract nearly 15 
watts of power from the same configuration. At 30 volts, the drain output will be at 30 
ohms impedance and the pinetwork will have to be designed to directly match the drain 
to a 50 ohms antenna load. Alternatively, you could try two IRF510s in pushpull. These 
are variations that you can play with. A word of warning though, The RF energy at these 
levels can give you a serious RF burn. RF burns can be more painful than fire or steam burns. QRP is not only fun, it is also safe. 
Construction 
I would highly recommend that you construct it over a plain copper clad board by 
soldering the grounded end of the components to the copper and the other ends of 
components to each other. Look at the pictures to see how it has been done. If you don�t 
know about this method of assembling RF circuitry, then you should read about it, there 
are quite a few write ups on the Internet about this method of RF experimentation. It does 
not require any PCB, it is quite robust and very stable. 
Assembling the PCB 
For those who feel intimidated by this �ugly� method, I have designed a PCB. The PCB 
layout (component side) is provided with this article. It is a single sided PCB with wide 
tracks that can be easily made in the home lab. I am making a run of these PCBs but 
shipping them abroad (outside India) maybe a problem. Drop a mail to me if you are 
planning to make some PCBs, I can put your contact information on the website. There 
are no copyrights over either the PCB, the circuit or even this article, feel free to copy 
and distribute.  
The PCB is laid out in a long line.It is 81/2 inch long and 21/2 inch wide. The circuit 
board is big for the circuit that goes onto it. This was done so that the board is 
noncritical and it works well. All the bidirectional amplifiers are similarly laid out. 
When you get your PCBs, inspect them thoroughly, preferable in the Sun. Check for 
small cracks in the tracks. Check for tracks that might be touching each other or touching 
the ground plane. The PCB layout was done to minimize this, but check it anyway. 
Especially check for the tracks that run diagonally to the base of each transistor in the 
bidirectional circuitry. These are laid out very closely and they are candidates for 
shorting. 
Almost all assembly instructions ask you to solder the transistors in the end. I would 
highly recommend that you solder the transistors and the diodes first. You are most alert 
when you start a project and if you place the transistors correctly, the rest of the circuit 
can be soldered around it. Be very careful about the orientation of each transistor. The 
microphone amplifier transistor (Q10) faces in a direction opposite to the rest of the 
transistors and the transistor pairs in bidirectional amplifiers face each other. The diodes 
have a ring to indicate which way their �arrow� is pointing. 
After the transistors are soldered, finish the BFO. If you are assembling this for 14MHz 
and above, the BFO will need a coil in series with the crystal (USB mode), if you are 
need LSB operation, you will need a trimmer instead (see the schematic). Apply power to 
the BFO and you should be able to hear it on your Short wave broadcast radio around 31 
meter band. It will sound like a silent radio station. It should be quite strong. Switching 
the BFO power supply on and off will help you identify your BFO signal on the radio. If 
you have an RF probe, or an oscilloscope, you should be able to see the oscillations. 
Expect RF of 2 volts or more. 
Next, assemble the VFO. Winding 150 turns of the VFO coil is one of the most tedious 
jobs while assembling this rig. It has to be done, so just dig in and do it. You don�t have to attach the 365 pf tuning capacitor yet. Check the oscillations on a receiver or a 
frequency counter. You may have to decrease the number of turns. Without the 365 pf, 
the 22pf trimmer should be able to set the VFO to 4.3MHz or so. If the VFO is oscillating 
at a lower frequency, then remove some turns from the coil. If the VFO is at a higher 
frequency, add 22pf in across the 22pf trimmer (if you are using the PCB, solder in from 
the foil side). You will require a wire jumper to carry power supply between the VFO and 
the BFO. They are the only stages that remain switched on during both transmit and 
receive. 
Assemble the audio preamplifier and the audio power amplifier and attach the volume 
control. When power is applied to the audio stages, touching a finger to the base of Q4 
should produce static in the speaker to move even the most diehard trash metal rockers. 
Next, assemble all the three bidirectional stages! This involves lot of soldering. But all 
the six stages are exactly the same. Finish one stage at a time. The capacitors are 
symmetrically laid out and all of them are 0.1uF with one exception (100pf at the output 
of Q3). Remember that the emitter bias resistors are 100 ohms, 220 ohms or 470 ohms. If 
you mix up the values, the rig will still work but it will under perform in the presence of 
strong signals and the transmission will be splattered. There are jumpers for T and R line 
across the crystal filter. Solder them up and power on the R line and then the T line 
alternatively. The emitters of bidirectional stages should show 2 volts approximately and 
the collectors should show around 8 volts and the switchedoff transistor should show 
zero voltage on all the three leads. 
For the moment of truth, solder the three coils, trimmers and capacitors of the RF filter, 
attach an antenna and switch it on! Check that the stages are working starting from audio 
end. If you touch the volume control�s control pin, you should hear AC hum and static. 
If you touch the base of Q4, there should be a pretty loud static. Take a lead from your 
VOM and touch Q3, you should get very loud static, probably mixed with local AM 
broadcast. Touch the base of Q2 with the test lead and you should get lesser static as the 
filter allows only 3 KHz of 10MHz through.  
Finally, connect the antenna properly at the input of the RF bandpass filter and peak up 
the three trimmers for maximum atmospheric noise. Attach the 365 pf and start tuning 
around the band, peak the RF frontend on a strong signal and then tune in a weaker 
signal and peak for maximum clarity (not maximum sound). 
An important note:
 Be sure that you have connected a proper 50 ohms antenna load. 
The RF filter performs correctly only at 50 ohms. If you use a long wire to do the initial 
testing, you will have to touch up the trimmers again for the proper antenna.  
Take a break, spend the evening listening to your new homebrew. If the CW signals tune 
to dead beat and rise on the other side again, your BFO has to move its frequency. For 
USB, add more turns to the coil to the BFO coil, for LSB, tweak the trimmer. You should 
have a perfect single signal reception. If you tune past the deadbeat of a CW signal, the 
signal should drop out completely. 
Assembling the microphone amplifier (Q10) and the output amplifier (Q14) will 
complete the exciter portion of the transceiver. To put the transceiver in transmit mode, ground the R line and apply 12V on the T line. Attach the output of Q14 to an 
oscilloscope but don�t attach the microphone yet. Null the carrier with the 100 ohms 
preset and the 22pf trimmer. Each affects the other so you might have to go back and 
forth between the two controls. 
Now plugin the microphone and speak into it. You should be able to see clean SSB of 
between 200 and 300 mV on the scope at the output of Q14. Instead of the oscilloscope 
you can use another 14MHz receiver to test your transmission quality. Switch off the 
AGC of the other receiver while setting the carrier null. A soft whistle (if you can 
manage) into the microphone is should result in a full carrier at the output. 
Next, assemble the power chain. At this point, you will need a suitable chassis to house 
your project. Any metal box will do. If you don�t have any, you can solder pieces of 
copper clad together (like I did) and make a U shaped chassis. Keeping the VFO in open 
air makes it drift a bit. A closed box is really very useful. 
A big cookie (or chocolate) box of tin is really ideal. With a hand drill, you can easily 
make holes to fit the two PCBs inside it. Tin is easily soldered on. Use the biggest knob 
you can find for the main tuning. The plastic broadcast capacitors usually have a very 
short stub that cannot take a big knob. It takes on a small plastic drum that is held onto 
the capacitor spindle with a retaining screw. Clip on the drum onto the tuning capacitor, 
tighten the retaining screw well and with epoxy glue, stick a big knob over the drum. This 
will make your main tuning mechanism. 
I use a simple double pole triple throw switch for Transmit/Receive switchover. If you 
prefer PTT operation, you can easily substitute the switch for a relay. Be sure to solder a 
reverse biased diode across the relay coil to prevent reverse voltage from entering into the 
transceiver power line. 
Use shielded cable for all the connections between the power amplifier and the main 
board. 
Tuneup and Operation 
Set the VFO to correctly cover 4.0 to 4.4MHz. If you can, take your rig over to a ham 
friend�s shack, you can monitor your VFO on his rig at the edge of 80 meters band at 
4.0MHz. Set the trimmer so that you can hear the VFO when the friend�s receiver is 
tuned to 4.0MHz and your tuning capacitor is fully closed (as much as it will go 
anticlockwise). After this, connect the antenna and peak the RF coils for maximum noise 
in the speaker. If you can tune it to a weak signal, then peak the RF coils for best 
reception. 
You might find that although you are able to tune in CW stations, you are unable to hear 
the SSB stations properly. This indicates that your BFO is not properly set. We will take 
that up next. 
On amateur bands above 10MHz, SSB is transmitted on upper sideband and on bands 
below 10 MHz, it is transmitted on lower sideband. To tune a upper sideband signal, 
your BFO has to be at the lower edge of the crystal passband. You will require either the 
inductor (for USB) or the capacitor (for LSB) in series with the BFO crystal. If your BFO 
is set to proper frequency then the signals will tune in and as you continue tuning across the signal, they will drop in pitch and disappear. If the signals appear muffled, then the 
BFO is set in the crystal filter�s center, add more turns to the coil (USB), or tweak the 
trimmer (LSB). If the signals appear shrill and you are unable to zerobeat them, then the 
BFO is too far away from the filter�s frequency  Decrease the coil�s turns (for USB) or 
tweak the trimmer (LSB). 
The transmitter tuneup essentially involves setting the carrier null. It is best to tune up 
the transmitter on a dummy load. I use 8 220 ohms, 2 watts resistors in parallel as my 
dummy load. It is worth the few bucks to have a proper dummy load. Attach the dummy 
load on the transmitter, and attach an RF probe to the dummy load (or an oscilloscope). 
As you speak, you should get 20 volts or more peak voltage on the dummy load when 
you whistle or just go �haaaaallow�. On another receiver in the same room, connect a 
short piece of wire as an antenna and monitor your own signal. You will probably be able 
to hear your own carrier as well. Null it by tweaking the 100 ohms preset and the 22pf 
balance trimmer. They both interact, so you might have to go back and forth between the 
two controls. 
A word of caution, the diode mixers are prone to generating odd harmonics. The third 
harmonic of 4 MHz is at 12MHz. So, if you simply peak the coils for maximum output 
on transmit, you might wrongly peak the RF frontend to 12 MHz (I did that). The RF 
bandpass filter is best tuned in receive mode over a weak signal at 14.150MHz or so and 
left at that. 
Conclusion 
There might be a kit (components and the PCB in a bag) soon. I personally don�t have 
the time to put kits together. If somebody is interested in doing so, just go ahead and do 
it. The design is free, you don�t need to ask my or anybody else�s permission. If you 
can drop me a line, I will list you as a kit supplier on my site. 
This is also the first time I have put out a PCB design for my rig. The purpose is to 
address the need among Indian hams in particular for an SSB rig that is easily and 
cheaply built. My original aim was to keep the price under Rs. 1000. The current design 
brings the cost to well under Rs.300 (less than 7 dollars). Contact OM Paddy (VU2PEP) 
for the PCBs. His email is pepindia12345@yahoo.com (I have added �12345� to 
confuse programs that automatically gather email addresses from my site, there is just 
�pepindia� before the at sign). 
 
Pictures  
The top view of the transceiver 
The big board has the entire exciter. The smaller board on the right is the linear 
 
 
The IF and audio section 
The present was soldered onto a small piece of veroboard (copper side) and the 
veroboard was in turn soldered onto the ground plane with small pieces of wire. 
  
The RF frontend  
shows only two coils in the RF filter, the third was added later. The upper coil is the 
VFO. The mixer transformer is seen on the lower right part of the picture. 
 
 
The Power chain  
The IRF510�s heat sink is soldered onto the ground plane. Use a mica washer to isolate 
the IRF510 from the heat sink. 
 
The PCB layouts 
The main board is 8.5 inches by 3 inches. The power amplifier board is 4 inches by 2.5 
inches. 
Download the PCBs here 
Note: The PCBs are in GIF format. They are also in word doc format so that they print at 
correct size. 
If you are getting the PCBs made somewhere, be sure to tell them the exact dimensions 




==Ref==

===Kits===

* https://amateurradiokits-in.3dcartstores.com/Case-Bitx-Version-3_p_30.html

of both the boards.