Looking for omni-directional antennas at 406MHz

[Joost]

Hello,

I am searching for the following antennas for 406MHz:

- dipole
- omni directionele Rigth Hand Circular Polarized Antenna
- omni directionele Left Hand Circular Polarized Antenna

anybody any idea where to best get this?

I am from Holland,

gr
Joost

 

[flatulent]

Re: Antenna 406MHz

The selection is dependent on several factors.

The circular polarization ones will reduce the effects of some forms of multipath.

The vertical dipole will cost less

 

[Joost]

Re: Antenna 406MHz

I agree with the fact that it depends on several factors...


But the thing is we need them all, we need 3 antenna's for a test system.

I know the RHCP and Dipole are easily for sale, but not the LHCP antenna.
So I would like to Know where to get such an antenna.

Best regards

Joost

 

[sergio mariotti]

Antenna 406MHz

Please, consider that 406 MHz is a frequency protected by international law.
It's reserved for passive use, radioastronomy.

 

[FANT]

Re: Antenna 406MHz

And also TETRA ( if little bit large till 406,8 ) and military purposes.

Mandi

 

[shogun]

Re: Antenna 406MHz

One of the main uses for 406MHz is for the Emergency Beacons, you should not be playing with this frequency for recreational use or even for data transfer. You run the risk of interfering with the COSPASS-SAR Satellites which are used to detect the presence of the 406MHz signal.

Normally you are also required to transmit the 406MHz signal and a locating signal at 121.5MHz.

I would seriously recommend that you choose another frequency for your work, whatever that maybe as transmitting on this frequency could interfer with the COSPASS-SAR Satellites which intern could put peoples lives at risk.

Shogun

 

[bsiswoyo]

Re: Antenna 406MHz

If you want to try build this antena.

This is geometry for 406MHZ of Yagi 12 element

NOTES Automatically produced by first
FREQUENCY 403.000000
MIN_FREQUENCY 400.000000
MAX_FREQUENCY 406.000000
STEP_FREQUENCY 0.100000
ELEMENTS 12
DRIVEN 1
PARASITIC 11
ANGULAR_STEP 180.000000
#DATA_DRIVEN x y length diameter voltage(r) voltage(i)
DATA_DRIVEN 0.14888 0.00000 0.34107 0.00630 1.00000 0.00000
#DATA_PARASITIC x y length diameter
DATA_PARASITIC
0.00000 0.00000 0.35802 0.00630 reflector
0.20471 0.00000 0.31927 0.00630 D1
0.33871 0.00000 0.31575 0.00630 D2
0.49876 0.00000 0.31155 0.00630 D3
0.68486 0.00000 0.30734 0.00630 D4
0.89330 0.00000 0.30453 0.00630 D5
1.11663 0.00000 0.30103 0.00630 D6
1.35112 0.00000 0.29894 0.00630 D7
1.59677 0.00000 0.29614 0.00630 D8
1.85360 0.00000 0.29474 0.00630 D9

The result of antenna performance is:

# Driven=1 parasitic=11 total-elements=12 design=403.000MHz
# Checked from 400.000MHz to 406.000MHz.
f(MHz) E(deg) H(deg) R jX VSWR Gain(dBi) FB(dB) SideLobes(dB)

400.000 38.7 42.6 33.08 -15.10 1.734 13.437 19.488 0.000
400.100 38.7 42.5 33.19 -14.96 1.726 13.447 19.493 0.000
400.200 38.6 42.5 33.29 -14.82 1.717 13.457 19.495 0.000
400.300 38.6 42.5 33.40 -14.68 1.709 13.467 19.495 0.000
400.400 38.6 42.4 33.51 -14.54 1.700 13.477 19.493 0.000
400.500 38.5 42.4 33.62 -14.41 1.692 13.487 19.489 0.000
400.600 38.5 42.4 33.74 -14.27 1.684 13.497 19.482 0.000
400.700 38.5 42.3 33.85 -14.14 1.675 13.507 19.474 0.000
400.800 38.5 42.3 33.96 -14.01 1.667 13.517 19.463 0.000
400.900 38.4 42.3 34.08 -13.88 1.659 13.526 19.451 0.000
401.000 38.4 42.2 34.20 -13.75 1.651 13.536 19.436 0.000
401.100 38.4 42.2 34.31 -13.62 1.643 13.546 19.420 0.000
401.200 38.3 42.1 34.43 -13.49 1.635 13.556 19.401 0.000
401.300 38.3 42.1 34.55 -13.36 1.627 13.565 19.381 0.000
401.400 38.3 42.1 34.67 -13.24 1.619 13.575 19.360 0.000
401.500 38.3 42.0 34.79 -13.11 1.611 13.584 19.336 0.000
401.600 38.2 42.0 34.92 -12.99 1.603 13.594 19.311 0.000
401.700 38.2 41.9 35.04 -12.87 1.596 13.603 19.285 0.000
401.800 38.2 41.9 35.16 -12.75 1.588 13.612 19.257 0.000
401.900 38.2 41.9 35.29 -12.63 1.580 13.622 19.227 0.000
402.000 38.1 41.8 35.42 -12.52 1.573 13.631 19.196 0.000
402.100 38.1 41.8 35.54 -12.40 1.565 13.640 19.164 0.000
402.200 38.1 41.8 35.67 -12.29 1.558 13.649 19.131 0.000
402.300 38.0 41.7 35.80 -12.18 1.551 13.659 19.096 0.000
402.400 38.0 41.7 35.93 -12.07 1.543 13.668 19.060 0.000
402.500 38.0 41.6 36.06 -11.96 1.536 13.677 19.024 0.000
402.600 38.0 41.6 36.19 -11.85 1.529 13.686 18.986 0.000
402.700 37.9 41.6 36.33 -11.75 1.522 13.695 18.947 0.000
402.800 37.9 41.5 36.46 -11.64 1.515 13.704 18.907 0.000
402.900 37.9 41.5 36.60 -11.54 1.508 13.713 18.867 0.000
403.000 37.9 41.5 36.73 -11.45 1.501 13.721 18.826 0.000
403.100 37.8 41.4 36.87 -11.35 1.494 13.730 18.784 0.000
403.200 37.8 41.4 37.00 -11.25 1.487 13.739 18.741 0.000
403.300 37.8 41.3 37.14 -11.16 1.481 13.748 18.698 0.000
403.400 37.7 41.3 37.28 -11.07 1.474 13.756 18.654 0.000
403.500 37.7 41.3 37.42 -10.98 1.468 13.765 18.610 0.000
403.600 37.7 41.2 37.56 -10.90 1.461 13.773 18.565 0.000
403.700 37.7 41.2 37.70 -10.82 1.455 13.782 18.520 0.000
403.800 37.6 41.2 37.84 -10.74 1.449 13.790 18.475 0.000
403.900 37.6 41.1 37.98 -10.66 1.443 13.799 18.429 0.000
404.000 37.6 41.1 38.12 -10.58 1.437 13.807 18.383 0.000
404.100 37.6 41.0 38.26 -10.51 1.431 13.815 18.336 0.000
404.200 37.5 41.0 38.40 -10.44 1.425 13.824 18.290 0.000
404.300 37.5 41.0 38.55 -10.37 1.419 13.832 18.243 0.000
404.400 37.5 40.9 38.69 -10.30 1.414 13.840 18.197 0.000
404.500 37.4 40.9 38.83 -10.24 1.408 13.848 18.150 0.000
404.600 37.4 40.9 38.98 -10.18 1.403 13.856 18.103 0.000
404.700 37.4 40.8 39.12 -10.12 1.397 13.864 18.056 0.000
404.800 37.4 40.8 39.26 -10.07 1.392 13.872 18.009 0.000
404.900 37.3 40.7 39.40 -10.02 1.387 13.880 17.963 0.000
405.000 37.3 40.7 39.55 -9.97 1.382 13.888 17.916 0.000
405.100 37.3 40.7 39.69 -9.93 1.377 13.896 17.870 0.000
405.200 37.2 40.6 39.83 -9.88 1.372 13.903 17.823 0.000
405.300 37.2 40.6 39.97 -9.84 1.368 13.911 17.777 0.000
405.400 37.2 40.6 40.12 -9.81 1.363 13.919 17.731 0.000
405.500 37.2 40.5 40.26 -9.77 1.359 13.926 17.685 0.000
405.600 37.1 40.5 40.40 -9.74 1.354 13.934 17.640 0.000
405.700 37.1 40.4 40.54 -9.72 1.350 13.941 17.595 0.000
405.800 37.1 40.4 40.67 -9.69 1.346 13.949 17.550 0.000
405.900 37.1 40.4 40.81 -9.67 1.342 13.956 17.505 0.000
406.000 37.0 40.3 40.95 -9.66 1.338 13.964 17.461 0.000


Please build this antenna by using alumunium 6.3 mm

Added after 4 minutes:

Note:

If you need this antenna PM me please. I can send to you this antenna

 

[Joost]

Re: Antenna 406MHz

Thx for the reactions so far.

To help everybody who's afraid I am gonna use the 406 frequency for recreational use... dont be.

We are building something for COSPAS/SARSAT, so I do not mis use the band.

I am just searching for nice of the shelf antenna's, but I am not sure which manufactor can deliver the antenna's at this frequency.

I got some more specified details:

SAR/TUS antenna
Transmit antenna specification
Linear (LP):

The following antenna characteristics are defined for elevation angles greater than 5° and less than 60°:

- Pattern : hemispherical

- Polarization : linear

- Gain : between -3 dBi and 4 dBi over 90% of the above region

- Gain variation (azimuth) : less than 3 dB

- Antenna VSWR : not greater than 1.5:1

The antenna characteristics should be measured in a configuration as close as possible to its operational condition.



RHCP and LHCP:

The RHCP/LHCP transmit antenna shall have the following characteristics:

Gain > 0 dBi for 0 - 60 degrees elevation
Gain > -4 dBi for 60 – 90 degrees elevation
Axial ratio <5 dB for 0 – 80 degrees elevation


Antenna Operating Conditions
The STB transmit antennas shall be able to function externally (with no protection against sun or rain) and to withstand input power up to 17 dBW.


Regards

Joost van Heijenoort

 

[bsiswoyo]

Re: Antenna 406MHz

Hi Joost !.

Please let me know.

Are you use one antenna for TX and one antenna for RX OR use only one antenna for TX/RX ?

Thx

Added after 7 minutes:

Note:

Please let me know about antenna type that you need.
Like Yagi, Log Periodic, Corner, Helical etc..

 

[Joost]

Re: Antenna 406MHz

All antenna's will be used as TX, it is a system that only transmits.

gr
Joost

 

[bsiswoyo]

Re: Antenna 406MHz

I try to build and test the Corner or LPDA antena. Because it width elevation and azimut, my be 120 degre.

 

[freqzt]

Re: Antenna 406MHz

Does anyone have the antenna design with the specifications like mention by Joost above? I need this antenna for my radiosonde research. The center frequency is 403 MHz. The bandwidth is around 6 MHz.

Please help me!!!

 

[Azulykit]

Re: Antenna 406MHz

Antennas generally meeting your requirements are readily available from commercial sources (easily three dozen sources and probably many more).

The dipole is easy.

You might consider one of the following CP types as well:

quadrifilar helix
conical helix
biconic with polarizing grid
Lindenblad (an old favorite)
Axial mode helix

The sense of the polarization is easily reversed so that should not be a problem.

I found examples that probably would work at:

Tecom Industries : w#w.tecom-ind.com

Seavey Antennas : w#w.seaveyantenna.com

European Antennas : w#w.european-antennas.co.uk


There are plenty of other sources if you want more alternates.

 

[freqzt]

Re: Antenna 406MHz

Hi Azulykit,

There are many antenna design in commercial market. But right now I want to develop the antenna by my self. So I can reduce the cost production of my radiosonde.

Do You know where is the right place should I go to get the example of antenna design? I have design the antenna in my laboratory but the gain is very low because the material loss is very high.

Any suggestion?

 

[freqzt]

Re: Antenna 406MHz

Does anyone have an idea to design a 406 MHz microstrip antenna? Please give me suggestion.

 

[Lupin]

Re: Antenna 406MHz

Hi, at this frequency I wouldn't recommend a patch antenna.. it would be quite cumbersome.. let's say about half a meter.. something less can be achieved but you pay it in therms of weight increase.. well.. it depends also on the application you need... for a commercial user? For a facility?

B.R.
Lupin

 

[ferdows]

Re: Antenna 406MHz

hi joost and other
1- if u want circular polarization (axial ratio <5 ) u should applied antenna with circular shape like spiral and i think helix has circular polarization at this frequency
2- u said linear polarization and in another part u said u want axial ratio <5 it look like that i said i want a circle with 4 side so PLS define clearly u aim
3- for omni application yagi and LPDA are not good but helix and discone and biconical are omnidirectional pattern