Dr. Ulrich Rohde: Electrically Short Antennas

If it could be "done easily", tracking narrow-bandwidth front end selectivity would be used in all receivers, even cheap ones, and perhaps 80-90 % of my worries as a systems designer would be gone.

The problem is just that RF selectivity with even a few percent bandwidth represents a major undertaking if it is expected to be frequency agile.
This is why an R&S FK101 or Telefunken VS1800 cost "an arm and a leg".

As systems engineers, we need to see the whole picture, and identify the areas where improvements provide most "bang-for-buck".

I am not entirely convinced that concentrating on receiver performance only is the panacea for system performance issues. There is a balance point between the performance of the different components which make up a communications system.

73/
Karl-Arne
SM0AOM

 

And I guess that is why the heterodyne receiver was born. Moving the signal to the filter instead of the filter to the signal.
Just so I'm clear the "done easily" part is in the DSP and not analog.

73
Dale

 

DHL just dropped off my copy of "Communications Receivers" by Dr. Rohde "and friends". 676 pages of bed-time reading

 

For your 2m and 70cm bands unless you are talking mobile maybe a couple of repeater diplexers tuned wider and just use one side?
edit
I guess they a more band reject than band pass.

 

The duplexes are more carrier noise reject in the pass and, carrier notch at the Tx frequency and TX noise at suppression at offset of 5 MHz at UHF.

 

correct, the notches eliminate hopefully the TX side band noise in the RX channel. As there are so many pagers and other services on top of the tall Marco Island buildings I always add one single pass band cavity for the RX frequency.

 

For those of you who like to get an additional introduction of SDR technology problems and application and results please go over the attached presentation. I will make a much more technical 5 G related and SDR related presentation here availabl which I composed with members of the engineering staff of my company Rohde & Schwarz, Munich , Germany, once I solve the space upload problem here .

 

Why not put it up on your own web site and provide a link here.

73, Meindert - PAøMHS

 

That’s a good option, but if my website has a problem, which can happen, then the access is lost. If it’s here, everything is together.
I will come back on this issue. Thanks.

73 de Ulrich

 

Thanks to Fred LLoyd the very technical presentation is now found here :


https://s3.amazonaws.com/files.qrz.com/downloads/UlrichRohde.IEEE.2019.pdf

73 de Ulrich, N1UL

 

Kudos to Ulrich and R&S staff on producing this encyclopedic overview of 5G!

If you don't see something you relate to, then keep on reading. It's there.

73,
Chip W1YW

 

Thanks Dr. Rhode! Enjoyed your QRZ page and links as well.
73,
Hugh WA2LXB

 

m

 

Mr. Rohde
Thanks fro your very interesting, clear and well done document, about the antennas.
Greetings from Rome
73's de Giovanni Francia I0KQB

 

Thanks, ,73 de Ulrich, N1UL