Double-biquad antenna with lips construction, which one is correct dimensions?

[Veronica71]

I want to build an antenna for 2100mhz lte. I am following these instructions: Double BiQuad sector antenna for IMT 2100 MHz / 3G / HSUPA / HSDPA / HSPA+ / LTE
But when i use the calculator, dimensions is a bit different: BiQuad Antenna Calculator

First one from Double BiQuad sector antenna for IMT 2100 MHz / 3G / HSUPA / HSDPA / HSPA+ / LTE



And calculated one is like so:



RH value is 15mm for first one and it is 15.7mm for calculated one. Other dimensions is a bit different too. What should i do? If i build the antenna with a little incorrect dimensions what would happen? It does not work at all or it will work but gain is not too much?

I am a newbie for constructing antennas, please help me. Actually i made a cantenna and biquad for wifi before but they didn't perform as i expected.(cantenna was better than biquad) But this one is important. I bought a cell phone repeater to use in village and i will attach the antenna to it when i build it.

Thanks for reply for now

(Sorry about grammar mistakes that I made, I am not native English speaker)

 

[K4EET]

Hi @Veronica71 and a belated Welcome to Radio Reference.

i believe this is where you found the calculator:

https://3.bp.blogspot.com/-kdYLRVJrRoo/U8FeCu4j4kI/AAAAAAAAAYE/pW4863UG1As/s1600/dbcalculator2.png

Have you tried other online calculators to see how they might compare with results? Quite possibly, errors due to rounding and precision point accuracy in the calculations might be a factor in the deltas.

Since the antenna will be used for both transmit and receive, dimensioning and layout will be fairly critical in that frequency band.

 

[Veronica71]

Hi @Veronica71 and a belated Welcome to Radio Reference.

i believe this is where you found the calculator:

https://3.bp.blogspot.com/-kdYLRVJrRoo/U8FeCu4j4kI/AAAAAAAAAYE/pW4863UG1As/s1600/dbcalculator2.png

Have you tried other online calculators to see how they might compare with results? Quite possibly, errors due to rounding and precision point accuracy in the calculations might be a factor in the deltas.

Since the antenna will be used for both transmit and receive, dimensioning and layout will be fairly critical in that frequency band.

Thank you very much. I already tried online calculators with the same design. Maybe I missed some points. I am doing research about this topic for a while. Actually the best way to find correct dimensions is making a lot of antennas and testing them. But I don't have too much stuff and money to do that.

 

[K4EET]

Thank you very much.
<snip>

You are certainly welcome, my friend.

<snip>
Actually the best way to find correct dimensions is making a lot of antennas and testing them. But I don't have too much stuff and money to do that.

You don’t say if you are in the States or abroad, but if abroad, your English is very good. Also, you mentioned that you are doing research 🧐 on 2.1 GHz Double BiQuad antennas. May I ask if this is for school or industry? Your post and resulting thread might be better served in a different sub-forum like this one:

Build Your Own Antenna

Discuss topics for building your own antenna.

forums.radioreference.com

Anyway, with respect to needing parts like wire to build models, think outside the box for low amperage used car alternators in junkyards. The windings can be unwound to get a supply of wire. Those alternators might be free depending on the disposition of the discarded car or available for next to nothing if you ask for burned out / inoperable alternators. Just a thought…

I’ve been in your shoes before where I used to reclaim inoperable VHF FM pagers for research on turning them into weather alert receivers for poor people in tornado-prone areas of the United States. We had practically a zero budget to repair and modify them and had to be very creative in finding what we needed.

My best to you on your research endeavors.

Cheers! Dave K4EET

 

[Veronica71]

You are certainly welcome, my friend.

You don’t say if you are in the States or abroad, but if abroad, your English is very good. Also, you mentioned that you are doing research 🧐 on 2.1 GHz Double BiQuad antennas. May I ask if this is for school or industry? Your post and resulting thread might be better served in a different sub-forum like this one:

Build Your Own Antenna

Discuss topics for building your own antenna.

forums.radioreference.com

Anyway, with respect to needing parts like wire to build models, think outside the box for low amperage used car alternators in junkyards. The windings can be unwound to get a supply of wire. Those alternators might be free depending on the disposition of the discarded car or available for next to nothing if you ask for burned out / inoperable alternators. Just a thought…

I’ve been in your shoes before where I used to reclaim inoperable VHF FM pagers for research on turning them into weather alert receivers for poor people in tornado-prone areas of the United States. We had practically a zero budget to repair and modify them and had to be very creative in finding what we needed.

My best to you on your research endeavors.

Cheers! Dave K4EET

Thank you very much Mr. K4EET I am not in states and I was not talking about wires, connectors or the other cheaper stuff. I can afford them thankfully. But I was talking about spectrum analyzers like Mr. Mcneil using in this video for instance:

Thank you very much for your effort to help me and your goodwill btw. Network analyzers show the real-world results in detail. If i could afford a network analyzer i would buy it because unfortunately I am a perfectionist. I want everything to be perfect. But they are very expensive.

If we come to school project or industry part, let me explain. I think I picked the wrong word to explain myself at the beginning. When I say "research" i was talking about digging the internet for finding true info about antenna making. I mean it is not scientific research and it is not for school project(I will attach the antenna to my cell phone booster). I know there is a lot of information in the web. But most of them are unreliable. So I decided to get help from some experienced people in the radio communication world. Because experience is more valuable than knowledge.

I prefer to build something by myself rather than buy it. It makes me happy to fix something or build something. I could easily buy a decent antenna made for 2.1ghz but I want to build it by myself. It gives me more satisfaction.

And thank you for giving me the correct sub-forum link. Actually I looked up for that sub-forum but i was not able to find it because i am not familier with this forum. I think I should open a thread in that sub-forum like you said.

Best regards

 

[K4EET]

<snip>
And thank you for giving me the correct sub-forum link. Actually I looked up for that sub-forum but i was not able to find it because i am not familier with this forum. I think I should open a thread in that sub-forum like you said.

Best regards

Click the “Report” button and ask that this be moved to that forum.

 

[K4EET]

@Veronica71, I applaud 👏 you for your attention to detail. If you are not already one, you would make a great research engineer. And if you are self-taught in antenna theory, simply wow! I guess you know antenna modeling software can be had for free, and NanoVNAs based on computer dongles that are essentially TV tuners can be had for USD $25 to $250 depending on capabilities and features. Here is a really nice Vector Network Analyzers that can be built as a project.

Well, I don’t want to tell you a lot of what you may already know. But please know that I am really impressed with your drive to build things for yourself and understand how they work at the same time. Awesome! My best to you!

Dave K4EET

 

[Veronica71]

@Veronica71, I applaud 👏 you for your attention to detail. If you are not already one, you would make a great research engineer. And if you are self-taught in antenna theory, simply wow! I guess you know antenna modeling software can be had for free, and NanoVNAs based on computer dongles that are essentially TV tuners can be had for USD $25 to $250 depending on capabilities and features. Here is a really nice Vector Network Analyzers that can be built as a project.

Well, I don’t want to tell you a lot of what you may already know. But please know that I am really impressed with your drive to build things for yourself and understand how they work at the same time. Awesome! My best to you!

Dave K4EET

It is nice to hear this from you, thank you very much I will take a look at DIY Network Analyzers. You are giving good tips, I really appreciated that. And I don't want to overestimate myself. (I hope I used the correct word) Actually I am not that knowledgeable. But curiosity and hard work help me to move forward. And thankfully there are people like you to share their experience and knowledge with other people. I am glad they are and I am glad you are It is really nice to get help overseas. The Internet is the best invention of the last century. Btw I reported the thread to move to the correct sub-forum. Thanks

Best regards, Eyup from Turkey.