698-3800 Mhz Yagi

[yeam 7]

On 1/18/2021 at 4:11 AM, clanon said:

i build a model...check it ou...(didn't like the resonances...small S11)

yagi.cst

Hi Clanon, the cst file had some problem. Anyone can provide me the cast file?

[yeam 7]

9 hours ago, clanon said:

you're RIGHT ...i was tweaking and fiddling with it...trying to get the  S11 right....(closer to the measurements...)

i think that the cylinder thing helps widen the band...and NOT sure about the port distance (dipole gap)

dont forget the IMPEDANCE MATCH with 125ohms quarter wave...

I think the impedance match cable are half-wave length without shielding (not sure how many ohm, but I suppose is 125 ohm)

 

[yeam 7]

5 hours ago, clanon said:

i think i'm close...2.3ghz is not showing REMEMBER to use a 300 ohms port

yagi.cst

Why 300 ohm is used? the cable is 50 ohm, and I am using 50ohm tested it out

[clanon 246]

50 ohms to 300 ohms (ALLFOLDED DIPOLES)

quarter wave transformer 123 ohms (125)

 

[clanon 246]

11 hours ago, yeam said:

Hi Clanon, the cst file had some problem. Anyone can provide me the cast file?

is a 2020 file you can't open it with an older version

[yeam 7]

10 hours ago, clanon said:

50 ohms to 300 ohms (ALLFOLDED DIPOLES)

quarter wave transformer 123 ohms (125)

 

I see, but the 125ohm cable is half-wave length. May be you can simulate the result in 125 ohm? 

10 hours ago, clanon said:

17 minutes ago, clanon said:

is a 2020 file you can't open it with an older version

Any ways to open 2020 file in 2017 version? 

[clanon 246]

3 hours ago, yeam said:

I see, but the 125ohm cable is half-wave length. May be you can simulate the result in 125 ohm? 

i could save on the other formats  drawing only...

TRY to IMPORT from 3d

Yagi 3 formats.rar

dont't forget if you don't adapt to 50  ohms USE 300 Ohms port... (or build the adaptor of 125 ohms) not easy...

Edited January 19, 2021 by clanon

[Admin 2545]

Clanon, your antenna is not positioned at the zero point of origin...!!!!

 

[clanon 246]

5 hours ago, Admin said:

Clanon, your antenna is not positioned at the zero point of origin...!!!!

 

 

...SO....? you can make ANY point your point of origin ...translating the WCS...

 

CHOOSE any point and make it! Point zero

 

Edited January 20, 2021 by clanon

[Admin 2545]

,,,such a thing is not common in design...!!!

[clanon 246]

9 hours ago, Admin said:

,,,such a thing is not common in design...!!!

Where is the ZERO point in SPACE (REAL AIR or Vacuum)...?

[jbckdsav 7]

So did you simulate it in CST yet? Thanks.

Edited March 1, 2021 by jbckdsav

[devton 27]

the right name for "698-3800 Mhz Yagi" is "Log-periodic antenna"  =)

[Admin 2545]

HERE IS ONLY YAGI, NOT LOG-PER...!!!

[jbckdsav 7]

So how wideband is this antenna?

[jbckdsav 7]

[jbckdsav 7]

New test with short cable. Seems less than 2.5 VWSR.

[yeam 7]

1 hour ago, jbckdsav said:

New test with short cable. Seems less than 2.5 VWSR.

This results from seller right? Don't misleads by the seller. 

On 1/19/2021 at 9:38 AM, clanon said:

50 ohms to 300 ohms (ALLFOLDED DIPOLES)

quarter wave transformer 123 ohms (125)

 

I see, but the 125ohm cable is half-wave length. May be you can simulate the result in 125 ohm? 

On 1/19/2021 at 9:38 AM, clanon said:

On 1/19/2021 at 7:25 PM, clanon said:

 

[jbckdsav 7]

Thats what they gave me.

Edited March 2, 2021 by jbckdsav

[yeam 7]

The results they shown are also bad. Swr 2.1 at 1.7Ghz...

Please take your time to read my previous results and clanon simulation results...

[Admin 2545]

Product Description

Frequency Range：690-960/1710-3800 MHz

V.S.W.R:≦1.5

Gain：12/16 dBi

Cable Length：1,2,3Meter etc.

Polarization：Vertical

Cable Type:RG174 or others

[clanon 246]

Is THIS right...? 

(the values for swr...)?

[clanon 246]

7 hours ago, jbckdsav said:

So how wideband is this antenna?

It's wideband by several PEAKS of resonance...if your frecuency of interest doesn't FALL inside one of those you're  out of luck...

So it's NOT continuos WIDEBAND like other designs...

[jbckdsav 7]

No, 2 is 2.5 i think.

[clanon 246]

3 minutes ago, jbckdsav said:

No, 2 is 2.5 i think.

my bad! it cant never be under 1:1

Edited March 2, 2021 by clanon