1420 LNA_Filter

[Job Geheniau]

Hi all,

Hopefully the dish will survive the friday storm, but saturday I hope to connect my new lna_bandpassfilter combination for my 1.8 meter JRT.

The new bandpassfilter is 0.32db center band +/- en 20db reflected minimal with 50 MHz bandwidth

Here some pictures.

Job

[Hamish Barker]

That filter response curve is a thing of beauty! Is it a 4 pole or 3 pole interdigital design?

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[fasleitung3]

Excellent filter, Job!

It would be interesting to know what design has been used.

I should mention, that there is a design for cavity filters by Matjaz Vidmar described at http://lea.hamradio.si/~s53mv/cavity/cavity.html.

What I like about this particular design is that a filter for Hydrogen (and other frequencies) can be made from standard aluminum parts so there is no need for a milling machine. We have built several variants of this type of filter with excellent results.

Best regards,

Wolfgang

[Sajjad Mahdizadeh]

Very nice results

May I ask how difficult it is to tune the filter? And can you explain a bit about the tuning process?

Best luck

Sajjad

Wolfgang Herrmann در تاریخ پنجشنبه ۱۷ فوریهٔ ۲۰۲۲ ساعت ۸:۵۹:۴۲ (UTC+1) نوشت: