Posts by DK3HU

Ja, danke für die vielen Kommentare.

Ich bin jetzt froh, daß ich irgendwas Resonantes bei 2,4 GHz habe! Vorher waren die Resonanzen ca. 80 MHz zu hoch. Das bekommt man vlt. noch durch Einbringung von dielektrischem Material hin. Ich finde dies aber nicht elegant. Hab mal gelernt, daß dielektrisches Material Verluste mit sich bringt.

Den Buckel kann ich leicht durch geringes Verbiegen auf die 2,4 GHz schieben.

Sollte ich nochmal einen Patch bauen, werde ich die oben gezeigten Abmessungen verwenden, die im Übrigen proportional zum Bauvorschlag geändert wurden.

...bis bald mal auf dem Satelliten...

OK Guys,

thanks for your support. I think the problem could be solved by increasing the dimensions. I made a sample during the weekend and took a reflection measurement. Here is the result:

The dimensions are here:

The back-plane is the same as earlier. I did not change the spacing so it is still 3mm.

A Little 'bending' is also required, but this can be done easily.

I am happy to having found a solution. I think it is reproduceable and i would be happy to hear from you with your results.

73, Herko, DK3HU

Oh yes,

thank you for the numerous comments.

Let me state:

0) Why do you apologize for writing in english ? - Brexit is not so far in the past

1) The hole for the connector can not be seen but it is 4mm in diameter. There is no dielectric material around the pin and this is the way Remco recommends.

2) The reflector is the 3rd attempt in hope to get a better result. No1 and No.2 has been round and had a diameter of 105 mm -> same problem f_res is too high.

3) The spacing between reflector and front-panel is exactly 3mm. I used two spacers especially manufactured for this purpose. By bending the distance of the edges, you obtain a variation of +- 10 MHz . Also the the right angle between the tube and the antenna is exactly 90 degrees.

4) The thickness of the material is 1 mm as recommended. But surely it is made of brass and can not be bent as desired.

So, my hope was that someone perhaps could correct the diameters by simulation. I am not able to calculate these parameters. As i stated earlier and i am not the only one who watched the deviation when building this antenna.

73, Herko

Hello,

here are the pictures. Possibly the soldering is not so sober, but i am sure this is not the main cause of my problems. Meanwhile i talked to other experienced OMs and they noticed the same problems with a too high resonance.

Thanks for your comments!

Regards Herko

Hi OMs,

thanks for your comments so far. I will send some pictures tomorrow. I use an SMA Jacket that is mounted by 2 screws, carefully aligned in length not to protude the reflector pane. I also did a lot of alignment, bending any possible edges and also soldering some drops of tin on different locations. As johannes stated, it is possible to put some things inside the resonant area, let it be dielectric or metal , but this is not the way i would prefer, because the circular characteristic is affected. On Remco's plots i see a clear resonance in the desired range, i get these characteristic RL, but this is abt. 80 MHz too high :-((

Best regards

Herko

Hi People,

i like to focus back on the main theme: 'SWR verbessern...'

I built 3 POTY-patches from the official assembly instruction and none of them (even with small variations) will match on 2400 MHz. I find a resonance about 80 MHz above the target - this results to 2480 MHz . My serious question: Are the original dimensions valid until now?

My dimensions from the original publication:

Thank you for a helpful comment.

73, Herko DK3HU