The critical thing you need is baluns at both ends of each pair.
There are baluns for purchase that are intended for data on
CAT5, but I suspect they aren't very effective on 160m, but
you could buy one and test it. Otherwise, you can make your
own with the usual binocular ferrites. The RS485 is already
differential, so it may be OK as is, although it might help
to put common mode chokes at the ends. The four pairs each
have a different number of twists per unit length. This
well known technique goes back 100 years to telephone trunk
cables. It keeps them from coupling to each other. I think
you will have a high probability of success if you play your
cards right.
73
Rick N6RK
On 2/9/2025 7:42 AM, Gary NA6O via TowerTalk wrote:
Very nice work Bela. One question for you. I have never measured crosstalk in
CAT5E cable so I was wondering if the RS485 couples into the receive signals at
all. From the data that I have seen, isolation should be very good in the HF
bands, at least 60 dB. Good thing you have a LNA for each signal.
73,
Gary NA6O
From: Vojtech Ritzko <om8aw@yahoo.com <mailto:om8aw@yahoo.com>>
Subject: [TowerTalk] CAT5E based RX SWITCH for remote RX ANT
distribution
HI ALL
Our QTH at OM0M ?islimited in space and there is not room for extended phased
beverage systems.
I am trying my best to build system with RDF well over 14dBon limited space QTH.
(Kill the side lobs and your RX will love you too.)
W1FV-9 circle for 4 directions as well as linear 4el inlinesystem for USA were
built in field day styleprior the CQ 160.
Well done, but how to connect the hamshack with RX HUB?
Single RG6 and CAT5E FTP ?cable were directly ?buried ?undersurrounding road?
in past.
Initial design - RG6 for RF and CAT5E for relay control isnot sufficient nova
day.
No cable duct = no way to extend anything.
The only chance is to use the unoccupied 100 Ohms pairs inCAT5E to carry RF too.
CQ WW 160 was the best chance to test RX systems in toughcontest conditions.
Technicaldetails on enclosed google disk file:
PDF :
https://drive.google.com/file/d/1gTtywxB_sgZYRfgy42YB9wCTE9RqV3Cr/view?usp=sharing
Eznec for 9CC:
https://drive.google.com/file/d/1idf6JsQ32UrEQNs_7yc3hrrMWKT77DQH/view?usp=sharing
Eznec for 4el:
https://drive.google.com/file/d/19E_VXwYVG1HiDWNU9yybygsKPt0yjeKY/view?usp=sharing
VY73 DX
BelaOM8AW
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