Complete step-by-step manual of creation Quadrifilar Antenna to receive 137 MGHz signal from NOAA weather satellites.

1. Necessary components and equipment :

• sewage pipe (length – 1.5 m, diameter 50 mm)
• straight copper pipe (skinharded, length – 1420 mm, diameter 15 mm)
• soft copper pipe (bunch, length – 3120 mm, diameter 15 mm
• copper angle (90*, 10 pcs)
• pipe closer for sewage pipe 1 pc.
• blowpipe to solder copper pipe ( I use the blowpipe and propane bomb)

Expenses for components - 20$, all the components are available on any hardware market or store.

2. Cut the pipes as on the picture below, four short pipes we make from straight skinharded pipes, another four, relative longer, from soft pipes.

3. Buffing end of pipes

4. Make a blanch of buffed end of pipes and angles

5. Four long pipes (two – 804 mm and two-752 mm), which we made from soft pipe, need to bow. It is allowed to use the car’s wheel as on the picture below. Diameter is not critical, below I explain why.

6. Finally we got the set of components as on the picture below :

Then, take two short direct pipes (343 mm) and two short curved pipe (752mm), four 90* angles and assemble it to the loop as on the picture below, using the blowpipe. Please note that spiral of small loop must be counter clockwise, if look from the top. The same need to do with long set of pipes and angles. Spiral of loop must be the same as the small loop. So, if you not made a muddle of pipes, you will have two loops as on the picture below.

7. Next goal – to make the straight pipes on the loops parallel and placed on the certain distance from each other. On the way to that – use your legs as on the picture below. Distance between pipes for small loop – 507 mm, for big – 542 mm. Make a strong control of the distance between straight pipes, use both of the end of pipes. Remember – they must be parallel.

8. Place the loop to have a spiral against clockwise, as on the picture below. In the middle of the pipe make a 22mm cut as on the picture below.

9. Assemble loops between each other with angles, as on the picture below. Small loop marked by “M”, big one by “Б”.

First stage is finished, now we are going to make the last part.

BALUN

Components:
- syringe
- Copper wire without cover, diameter 1.25 mm, about 50 sm

Make six holes in the syringe, then make three coil with two turns each. Solder according the electrical scheme or just see pictures below.

Continue assembling antenna.

11. Make two discs (material - glass fibre laminate) diameter a bit less then diameter of the sewage pipe and drill holes according picture below.

12. Insert the balun’s connections in the holes of the discs, then insert two screw bolts (see picture below). Now we have assembled balun.

13. Cleanup and blanch the angles.

14. Insert assembled balun as shown on the picture below and temporary fix it by screw bolts.

15. Solder the balun and remove redundant pieces of balun’s connectors

16. Screw out the temporary fix and make second disc as shown on the picture below.

17. Cut up the sewage pipe as shown on the picture below. Cut up the pipe’s cup too.

18. Make four holes on the sewage pipe. The holes MUST be in line with cuts on the top of the pipe. The distances between cuts on the top and holes – 50 for small loop and 542 for the big one. IT IS VERY IMPORTANT that the distances were very accurate, note that holes and cuts MUST be in line. Note also that pair of holes MUST be placed on the sewage pipe at the angle 90* !

19. Disassemble antenna on the end against balun.

20. Insert straight pipes in the holes, to have a cross.

21. Pass the cable trough savage pipe and solder it to balun’s connectors. Central wire of cable PK-50 solder to the connector N1, sleeving to connector N2.

22. Make the final assembling of antenna. Don’t forget coil the pipes by wet rags to avoid the savage pipe melt, when you will solder the pipes. The assembling is light procedure. You will have difficulties only in case, if you make something wrong on stage 18. In this case it will be impossible to assemble antenna, because holes and cuts will be not in line.

23. After you finish assembling, cover the savage pipe by cap and reap by capron loop. Put waterproof compound to chinks. Inside the savage pipe put the sealing foam. After that the savage pipe become very hard

24. Remove from antenna flux and oxides, process the savage pipe with fine abrasive cloth. Color the device by nitrocellulose enamel.

Result looks like devices on the picture below. Left to right – my first and second antennes.

Antenna after coloring.

Good luck!