best antenna

[abcd567]

No need to cut the whip.
Unscrew the whip and use a thin copper wire like one of 6 wires from a scrap network cable, or a thin steel tie wire like the one in first two photos below.

Optimized Whip Steel Tie Wire.jpg




Optimized Whip Steel Tie Wire-Dimensions.jpg


Dimensions of Optimized Whip.png




Use one of the many wires in a Scrap network cable





category_5e_ethernet.jpg

[Lufthansa]

20220403_180505.jpg


Does anyone have an idea how I can shorten this antenna for 1090 MHz? Bought this antenna through Amazon a few years ago for some bucks, but it has performed / performs TERRIBLY....

I don't know how to count the coils in the total length of the antenna (λ/4=6.88 cm or λ/2=13.75 cm). I've already read/searched a bit about coiled antennas/whips here in the forum, but didn't found a solution.

I am grateful for any suggestion!

[Bill@2020]

hello gentleman...
i would like to show you my results of my development because of antennas. Years ago I started this development because of the unreliable ADS-B data during flying sharp u-turns, curves.
The ads-b signal is generally vertical polarized. During flying curves the antenna is not vertical. Rod antennas and all other antennas on the market have all a vertical polarization.
To avoid that problem I developed a new antenna which is very tiny, has a perfect pattern, can be used as sector antenna and no more filter is needed.
attached I have a video which I made 2 days before ...the result was perfect and follows all simulated parameter ....

Have fun

Bill2002

Sorry I have made comments in german....but you will understand :-/

[bg6snj]

Same wire data as above, simulated in software MMANA-GAL, gives Gain = 7.35 dBi, & very high SWR = 133 !!!!!!

Which software to trust????

Wire dia = 3mm
Gap between stub wires =6 mm (center-to-center distance between stub wires = 1.5 mm + 6 mm + 1.5 mm = 9 mm)
Optimum cable tap position = 45 mm from open end (or 69 mm -45 mm = 24 mm from shorted end)


[ATTACH=CONFIG]4509[/ATTACH]. [ATTACH=CONFIG]4510[/ATTACH] . [ATTACH=CONFIG]4511[/ATTACH]

I used 3.5mm diameter copper wire with 6mm spacing, built the Franklin antenna according to your size, and tested it with a 50ohm feeder. The resonance point is 1080MHz, and the SWR is as high as 3 at 1090.

Can you tell me where there might be a problem?

[abcd567]

Do I need a filter?
Here is my data capture record
Screenshot 2021-09-17 195508.png

Yes you do need a filter. Heavy mobile phone signal present in GSM850 band.

Optional: You may conduct this scan also. It covers full band of DVB-T (24 Mhz to 1800 Mhz)

In thread "Do I Need a Filter":
OPTION-4:
DVB-T plugged into Windows Computer - Using GUI Spektrum.exe

[raptor22]

Did you cut the top of the antenna down and put it on a can?

I can't make that decision from this side of the world. All those commercial ones are far too expensive in our local value.
But a DIY from wire to test may be a cheaper investment to try. Many use home-made and have good range.

Do I need a filter?
Here is my data capture record
Screenshot 2021-09-17 195508.png

[abcd567]

raptor22:

Please brows these two threads:


3 EASY ANTENNAS FOR BEGINNERS


QUICK SPIDER - No Soldering, No Connector



.

[Oblivian]

Did you cut the top of the antenna down and put it on a can?

I can't make that decision from this side of the world. All those commercial ones are far too expensive in our local value.
But a DIY from wire to test may be a cheaper investment to try. Many use home-made and have good range.

[raptor22]

Known as MMCX or mini-sma

https://en.wikipedia.org/wiki/MMCX_connector

The antenna looks like it might be normal or RP-SMA (reverse pin)

It would need a MMCX-SMA short length. Or some good coax and use a MMCX 'pigtail' between. Just remember each connector adds a little loss.

Should I buy this antenna or DIY a new one myself?
this is my theoretical range but I get only 32NM using the antenna which came with the dongle.
WhatsApp Image 2021-09-16 at 11.56.11 AM.jpeg

[Oblivian]

Known as MMCX or mini-sma

https://en.wikipedia.org/wiki/MMCX_connector

The antenna looks like it might be normal or RP-SMA (reverse pin)

It would need a MMCX-SMA short length. Or some good coax and use a MMCX 'pigtail' between. Just remember each connector adds a little loss.

[raptor22]

I am using this rtl-sdr dongle with Homeassitant. FR24 is installed in docker. Which port is this and which antenna I can use with it? How can I use the following antenna https://www.daraz.pk//products/i2274...L&urlFlag=trueb04d57081307991260a68871841afc95.jpg58e00ad19b6245c536f2d5bb1dbd46d5.jpg

[buenti]

My approach to building an antenna with a sma connector and copper wire:

sma.pngthreaded.jpg
bottem.jpg
solder.jpgfranklin_spider.jpg

[abcd567]

Mag Mount Antenna’s Whip Replaced By V-Stub Wire Collinear

Comparison of "V-Stub Wire Collinear Whip" with "52mm Optimized Whip"


V_stub_wire_collinear_vs_52mm_whip-c.jpg


Thin (0.5 mm dia) Steel Tie Wire used to make collinear whip with V-stub.
Thin wire can easily be wrapped over threaded stud of magnetic base.

Steel Tie Wire.jpg


MEASURED PARAMETERS: V-Stub Collinear Whip


SWR.jpg


R_X_Z_SWR.jpg


AIRCRAFTS SEEN & MESSAES RECEIVED (per sec)

aircraft-messages.png


.

[abcd567]

Do you suggest to keep the plastic bottom of these antennas or to remove it before putting it on a metal surface?

No need to remove plastic adhesive covering of the base. I have once removed the black plastic adhesive circle from base, but it did not give any improvement. Even with plastic in place, there is enough capacitive coupling between base metal and the food can.

[Mephisto]

2. If you keep the magnetic base, and place it on a large metallic can, you get a good ground plane, and dont need to add radials. This is exactly what I have done. The Butter Cookies lid is providing a good ground plane, no need of radials.

Do you suggest to keep the plastic bottom of these antennas or to remove it before putting it on a metal surface?