## Introduction

The BiQuad antenna is fairly easy to build and provides reliable gain and it has very forgiving design. You can make quite a big margin of error in the construction and still get 10-11dBi gain. Hence here is the Double BiQuad Antenna and BiQuad Antenna calculators for handmade antenna based on average data.
However I highly recommend to follow my instructions, which are based on computer antenna simulation software 4nec2, to maximize performance. Here is listed currently available instructions, simulated with computer software, for handmade 13-14dBi Double BiQuad external antenna.

Note: The dBi scale is logarithmic in base 10, where +3 dBi is a doubling in gain! An increase in gain of +1 dBi is equivalent to an increase of 26% and +2 dBi is equivalent to an increase of 60%. This means that the increase in +1dBi is a big deal.

## Double BiQuad Antenna Calculator

 Frequency MHz λ cm ED cm D cm EL cm Wire Length cm RL cm RH cm S cm LH cm Wire diam. mm Wire area. mm²

## BiQuad Antenna Calculator

 Frequency MHz λ cm ED cm D cm EL cm Wire Length cm RL cm RH cm S cm LH cm Wire diam. mm Wire area. mm²

## Parts Required

• N-Type (female) panel mount connector
• Reflector - Any metallic sheet like copper or Copper Plated Blank Circuit Board 1.6mm thickness
• Cable - read this guide before doing anything else: Guide to Antenna Cables & Connectors
(Very important to choose proper cable! the longer the cable length, the more signal loss you'll have through the cable. Long cable will defeat the purpose of the antenna. Read the guide for more info.)
• Copper wire for the element.
• Spacers in each end of the element to hold its position and spacing correct height between the radiator and the reflector. Spacers must be from any non-metallic material. Plastic will do alright.

 N-Type (female) connector

 Single Sided Copper Clad Board

## Building the antenna

I will not show you picture after the picture how to drill the hole in center of reflector. How to use ruler. How to do proper soldering. What kits to use and etc. There are plenty of tutorials for these steps: http://www.ziva-vatra.com/index.php?aid=16&id=SGFyZHdhcmU=, http://martybugs.net/wireless/biquad/ or http://martybugs.net/wireless/biquad/double.cgi
(Note: all calculations in links are for 2.4 GHz WiFi antenna. Use calculator calculated data and measurements for your antenna.)

(Note: Pictures below not to scale)

### Element bending

Before you start to bend the wire, make it straight as you can.
 Ensure each side of the element is as straight and symmetrical as possible. The element sides are rectangular and widths are correct, measured from wire center to wire center.  The more accurate you do the better as the analysis shows a huge impact in element dimensions.

﻿
 Mine wire bending technique in the crossing sections. Note: You must leave a ~1.5 mm gap between the element wires cross overs and solders.

### Guidance and recommendations

 N-connector in the center of reflector. Maintain correct reflector’s dimensions.

 Maintain correct spacing between the element and the reflector!

 You must leave approx. 1.5 mm gap between the element wires cross overs and soldered contacts. Use spacers in each end of the element to strengthen its position and spacing proper height between the radiator and the reflector. Spacers must be from any non-metallic material.

 Finished. Lying on the belly.

## Usage

 This antenna should get the best performance at horizontal polarization. Note: The antenna is horizontally polarized then reflector is held vertically.

Last updated on 14 Jul 2014

1. I have HUAWEI E5776 and I need external antenna for frequences
800, 900, 1800, 2100, 2600 MHz and maybe 2800MHz is good to have too. I do not know all mesurements
and I am not so good with math.

1. You can use the calculator above

2. 1800 2100 2300 MHz need to use if i make target frequency BiQuad like 2100 MHz its only catch 2100 right?Should i make individual BiQuad? so need to know how can i combine them? diplexer? or can i use single BiQuad receive all these

3. take a look at discone antenna
regards from poland

2. very nice project sir. i need one help can send me the detail theoritical calculation to find ED,D,Wire length etc

3. Isn't the connection flawed?

The outside braid(shield) of the coaxial is there is keep the centre core coppers energy from escaping out and preventing outside noise interference reaching the core. The braid must shield the core till it reaches the actual transmission part of the hardware . I don't understand why you soldered the end of the copper quad to the shield. Both core and shield are shorting at the quad.

1. The lengthening are 90 degrees out of polarization from the signal received. A Site Masters SA2500EX would be necessary, or use 2nec4.exe antenna modeling software instead. I would target on transmission line. In commercial application Lmr-600 minimum Lmr-1200 at best. Recommended of Lmr-400

4. is it possible to have RH (or any other variables) as a constant figure? my resource is limited to a long and narrow (16.5cm wide) sheet metal. also, i am not able to find calculatior for the version without the lips - is it (lips) a critical part of this antenna measurement? thank you for inspiring me to build my own antenna!

1. Hey Charlie, the only constant figure here is calculated to Frequency. You could use 4nec2 software to make Frequency and RH as constants and look for other variables for best results, but it doesn't worth a fuss. Save your time and do antenna with what ever you got, you will still gain a lot of it even with a huge inaccuracies. as i said before, this antenna type is very forgivable. so no LIPS are not critical part of it. Hope this helps, good luck !

5. the calculator produce wire diameter 4.99mm that would be quite hard to find. can i use copper tubing instead? or maybe 7strands of wire?

1. You probably doing one for very low freq, not sure if biquad is best option for 500mhz but you can try the thickest wire you got, should work.

6. Hi. I had build 2100mHz and 2600mHz double biquad antenna (without lips) using your guide for 3G & 4G respectively. tested it in countryside, WORKS GREAT!!!
I was wondering if you can prepare a calculator for calculating this antenna without lips. I find it easier to build an antenna without the lips. THANKS!!

1. Hey Raymond, i am pretty sure same measurements will work well for both type biquads.

7. Thanks I've built a few of these Bi-Quad antennas now from the calculator on this website.
Every single one of them give me good performance! I usually get about 100m range from a WIFI dongle to the router.
I think with 2 of these antennas pointing to each other I'm sure 200m is achievable

8. Hi, I wanna know for the lips effect, its said to avoid rear lobe radiation, and on the figures provided its seem for the HORIZONTAL PLANE (Vertical pol.) position, what if i want to fix the antenna as a HORIZONTAL POLARIZATION (Vertical Plane)? should i bend the RL to make lips? how length? same as LH? and what we do on LH?

9. This comment has been removed by a blog administrator.

10. Does anybody know the so called "LTE800-Dual-Quad-Antenna"? This kind of antenna looks similar to a BiQuad but works like a Quad-Antenna only and allows MIMO and it is polarized H+V. You can see it here:

http://www.brennpunkt-srl.de/LTE-Antennen.html (scroll down)

The two halfs of the antenna are connected in the middle like a "U". Its covered in the shown picture. I´m very much interested in how to calculate such an antenna bcoz that´s an easy way to use it as a feed-point of a satellite dish.

If you can help please mail to: sybille.koch[at]gmx.at

Thank you!

11. I've managed to build a double biquad for 2.4 GHz however I didn't have any 1.3/1.5 wire at home and I've used a 0.85 mm wire. Is it a problem? The power of my alfa network card should be around 0.6 watts.

Thanks for the support, the calculator is a great tool! =)

12. Dear Mr Sharinga, Your blog is awesome! Could you please design a multi frequency antenna? because 34/4g signals will change as soon as we start moving from one point to another point. somewhere we have 3g coverage and somewhere 4g coverage. beside each 3g or 4g network may be individually on different frequencies in each location. so we need a multi frequency antenna for a router to work everywhere, not only one location and one network. I'm Looking forward to hearing from you. Sincerely

13. where you get the calculation? what is your refrenction?

1. "the Double BiQuad Antenna and BiQuad Antenna calculators for handmade antenna based on average data ... which are based on computer antenna simulation software 4nec2"

14. I need for 1800mhz antenna wire diameter is 1.74 can I use 1.5 or 2mm cos I cant find 1.74

1. Just go for 1.5 as it is easier to work with then 2mm.

15. HI.
What do you think of replacing the copper wire with a PCB board that has the biquad double antenna printed?
something like in the following link:
http://patraswireless.net/d8c.jpg

What would be the dimensions of the copper path equivalent to that of the 1.5mm copper wire?

All the Best!

16. 1800 2100 2300 MHz need to use if i make target frequency BiQuad like 2100 MHz its only catch 2100 right?Should i make individual BiQuad? so need to know how can i combine them? diplexer? or can i use single BiQuad receive all these

17. This comment has been removed by the author.

1. Removed for spelling error.

18. Using your calculator and instructions I built a biquad for 1900 mhz broadband internet service through a local carrier. I mounted the biquad on a 24 db parabolic reflector which was designed for 2.4 ghz. I mounted the biquad at the feed point by modifying the original feedpoint hardware. My signal strength went from -75dbm to -57dbm, a very nice gain. Thanks for having this on the web.

Bob in Kansas

1. Nice idea, can you share some pictures from your antenna?

19. I just built two of these for a Ubiquiti Rocket M5 to allow me to connect to a mesh network spanning my city and it is now -70 dbm on a noise floor of -90. Better than ever before! My Ubiquiti Nanobeam M5 gets -65 so this is about as good as it can get. Here is a picture! https://i.imgur.com/hygOLPB.png

20. Should reflector be connected to the coaxial cable shield or not?

1. I'm asking because I often see how people who make a biquad antenna do not connect the reflector to the shield of coaxial cable, does it affect on something?

21. This comment has been removed by the author.

22. This comment has been removed by the author.

23. This comment has been removed by the author.

24. how to apply for uhf tv transmitter, work at 855Mhz, which I ask how to get a small VSWR?
thanks

25. HI All.

I would like to build the double Bi quad antenna for 2000 MHz, but i've one trouble. My Huawei B593 is coming with two external antenna connectors.

May i prepare two antennas and then install one vertical and the second one Horizontal?

Could it works?

Thanks for your comments and greetings from Italy.

Maurizio

26. Sorry the correct frequency is 2600..

27. If i wanted to build a receiver antenna for an FM radio, 88 MHz to 108 MHz, should I take the difference between the upper and lower frequencies, plug that into the calculator, and use those dimensions for building it? Would this design be appropriate for such an application?

1. This style antenna is (IMO) not a good choice for your proposed application. The low frequencies would result in a VERY large, floppy and unstable BiQuad. Look at a tuned Grey-Hoverman model instead.

28. hello,can the grounding touch the reflector? Thanks.

1. Don't Ground it. That will loss signal some percentage.

29. What are the consequences if you use 6mm² wire for 2450Mhz? I bought the wrong wire :p

30. This comment has been removed by the author.

31. This comment has been removed by the author.

32. Should I first bend the wire for crossing section, and then measure the wire for angle, or vice versa?
I mean bending the wire for crossing section will make it nearly 1mm longer.

33. HI, a question...... i have 2 bands available in my house 800MHz and 1800MHz. It's possible to build a "multi frequency" biquad? or i need to choose only 1 frequency......
If i make an antenna with both wires (for 800 and 1800) soldered on the same n-type connector, it will works?
thank You.
Marco

34. Would appreciate if there were more details regarding the soldering of the wire to the n-connector. It seems to be at the top of the critical list, but almost no details and the photos are not descriptive.
Looks like the centre of the folded wire is soldered to the centre pin of the N-connector, but the two ends?
Big mystery and appears like a lotte solder spread around.
I appreciate a LOT of the info here... but the soldering is not clear exactly what is soldered to what and why it looks like a mess (no offence intended!)

Thank you.

35. i have double biquad like design basedd on infinite knot
would somebody be willing to test the performance?
Thank You

36. i have double biquad like design basedd on infinite knot
would somebody be willing to test the performance?
3ds , stl or dwg files at
https://www.thingiverse.com/thing:4252862
Thank You

37. Can we directly connect cable to antenna without using N-Type (female) panel mount connector?

Thank you
Sharath

1. I connected straightly cable. That's works without issues.

38. I found a really neat video showing a technique for getting wire really straight. It gives a much better result than my best efforts at feeling for kinks and nudging it straight! Takes a few tries to get the technique right but it's very effective...

1. The easiest way to make any wire perfectly straight is so very simple. Tie one end of your wire to something solid, a handrail, or anything else that is strong then chuck the other end in a drill, pull the wire tight with the drill and pull the trigger pulling tightly, your wire will spin/twist into a perfectly straight piece, don't over spin, the more you spin the stiffer and more brittle the wire will become. You can make soft copper wire extremely rigid. Just try this, there is no better way!

39. Frequency means required frequency level or currently available frequency ?

40. We stumbled over here different page and thought I should check things out. I like what I see so now i'm following you. Look forward to going over your web page for a second time.

41. is this antenna 50ohms?

42. would this still work @ 13-14dbi, when the elements are circular (circumference = 1 full wavelength), such that the double biquad will look like audi's car badge.

43. this is great site.. i've made some quad antenna based from this calculator. from biquad,double,six,eight,omni,dual pol. they're works well.. thank you for sharing this

44. As I remember, more than 30 years ago, people use biquad antennas for receiving TV broadcasting (analog) for far away stations. There are 2 widespread models: one small, for the channels in the range of 40-50 and one big, that receive channels 6-12 also. The last have 2 biquad of different sizes. Unfortunately, there was no internet and I cannot find any info about construction plans for such antennas. I had the small one and it have an amplifier, with BIAS T, and we used to receive TV stations from neighbour countries, at more than 100Km away. I would like to made a broadband one, for 300-1000MHz, in a log-periodic style.

45. For lower the wind profile the reflector was not compact but it was made from thick bands of aluminum. The space between bands is equal with the width of the bands. Some people use perforated sheet or a fence stock with the same results.

46. Hi. Why wire length is much more than 8*ED (or 16*ED)?
Also I'm afraid about "S". as I know S should be about Wave_Length/8

1. Biquad antennas actually is an array.
So consider ED length to reference for your "dipole" length.
The distance of active element from reflector (S), interferes on capacitance of antenna. To 50Ω impedance this distance works well.
I've tested it with 2.4Ghz. I don't know about high or low frequencies.

2. Also you need to bend the ends to connect it to the reflector and cut off the excess.
Yes biquad element is conected to the gnd.

47. This details are very important ⭐️⭐️⭐️⭐️⭐️.

48. my dialog router show red light and no internet .so this antenna suitable for me

49. my dialog router show red light and no internet .so this antenna suitable for me
pleas sendme your phone number.
my phone 0770123250

50. My router does not have external antenna port. just putting the router on the cable will work atleast. Thks

1. Try to check inside, there could be internal antennas connected by UFL pigtail connector.

51. Wonderfull blog, congratulations.
can i use this antenna as a transmitter after a repeater?
thanks for attention.

52. If I were to use a steel wire instead of copper. Would it have any difference to the calculation?

1. Yes big difference...

53. Can I use SMA connector for its small size and light weight?

54. I can't understand about wire. calculator said Wire length 149cm, wire area 7.9mm². How to fix it?

1. For 850MHz it is correct calculation. There are existing wires 7,5mm^2 and you can use them. However, it may be difficult to bend them correctly, perhaps you will need to heat it a little.
Other option is to use some different shape of antenna, or rework old TV antenna (this may be problematic in some countries, check it first).

55. Hello from Europe.
In my area is general problem with ANY connection. I was able to get -101dBm in the good conditions, sometimes even worse. Resulted into very poor connection stability. I'm using TP-Link Archer MR200. This one has two antennas connected by SMA. First of all, most of the routers (including mine) are having something that is called RP-SMA, that is reversed pin, therefore it creates issues when want to simply buy SMA cable with commercial antenna. Thanks, FCC.
First of all, I was thinking to disassembly any tiny antenna from old wifi, that contains connector and few cm of cables. However, you can try by yourself, that there is probably filter included in that kind of antenna, so works only focan tv antennas act for 4Gr 2,4GHz and blocking LTE signal. At least in my case, signal was worse with wifi antenna than without any (with naked SMA pin only).
Luckily, inside the MR200 are small pigtails (UFL) connectors, that can be obtained fcan tv antennas act for 4Grom old laptop, including the cable. Bending wire (2,5mm^2 = 1,74mm dia) for the 1800MHz, as my router claimed the Band3 is used. Then I've take an old PC case top part that was very closely fitted the prescribed dimensions of reflector. Drilled hole thru and fitted dual bi-quad shaped wire. On the ends, I've just squirted a small pile of silicon, sink ends of shaped wire into it and let it dry while keeping it 1,5cm above reflector by piece of wood. When solid, I've removed the wood and carefully solder the coax cable with pigtail on one end.
After one antenna (out of two, that can be handled to my router), signal improved to -93dBm and stability is much better. Now. Guessing the second antenna will push it even further. If possible, try to find out, where exactly is located your BTS station, so you can position your antena in the right angle to it (this can gain another 3dBm).
Thanks for this idea and wish you all the best!