Antenna switch | Kits | Commercially available?
Hi All,
I've been looking high and low to see if there are any commercially or kit form Antenna switches - i.e multiple antenna -> KiwiSDR.
I see many use some off the shelf products such as USB controlled relay boards or connect up GPIO pins to switch the antenna feeds.
All these are feasible, however given that I am a) not overly keen on connecting directly to GPIO pins on my precious Kiwi, and b) generally time short to build from various off the shelf parts - I have "seen" one or two complete units or kits in boxes with SMA / BNC connectors and controlled via USB however I'm struggling to find these again.
AIA if this is a repeat post and my googlefoo has failed me.
Comments
All the currently supported switches, including Ethernet-based switches, are listed here: https://github.com/jks-prv/KiwiSDR/tree/master/pkgs/ant_switch
There is not a proper pointer to that in the base documentation, so I will fix that. Thanks.
Ah great thank you!
If using a relay board, I assume you simply strip the coax and connect to the appropriate terminals?
Or building a breakout box with the relevant connectors on it would be more suitable?
It would appear Snaptekk devices are no longer being made.
I was about a day away from ordering an MS-S5 from LZ2RR on eBay when the listing was abruptly pulled (with units still showing in stock). I've been watching eBay for about a month since, I have email notifications set.
So I'm back to the drawing table to design a switch controlled by the GPIO pins.
There's always KMTronic. No coax connectors though. Just Phoenix contacts.
I use an RF switch board with HMC849 (important because it goes down to DC) in conjunction with a relay module with ESP8266 (then flashed with the Tasmota firmware).
This is certainly not the ideal combination, but works well enough for me with 2 antennas.
Regards, Steffen
yeah - my aim is to try any make it look less hacky as few cables as possible (which is not really in the spirit of this hobby)
thanks for that. I suspect this is the path I may go down.......... maybe a gap in the market here? :-)
I received an HMC253 (DC-2.5 GHz) board today for $8. I also have an ESP8266 for $2. These are the cheapest materials from which you can assemble an antenna switch controlled via USB.
Well. But do you have a sw/fw for esp? I found this link .. https://github.com/F4BIT/Switch-RX-Antenna-V1
I have an ESP running an attenuator right now. I wrote the program for ESP myself. Everything has been working fine for almost a year. It will not be difficult to rewrite the software for managing this switch. And I don't understand why to use a board with a relay. GPIO ESP will be enough.
I post firmware to control PE4302 attenuator via ESP8266 on GitHub now.
https://github.com/studentkra/PE4302_attenuator
@studentkra
I use a home made ESP32 / DIN mounted, socketed, medium power 4PDT mechanical relay antenna switch. The ESP32 is co-located inside with the Kiwi, while the relays are mounted in an outside weather proof junction box. My old "Armstrong" antenna switch swapped jumpers in that box. The relays replacing the patch cords.
I have looked at the datasheet for the HMC253 and have two questions. The datasheet indicates this device need to be treated with full ESD Protection. Do you have any input with regard to this device holding up to the "EMP" forces found in HF antenna systems?
My second question relates to input isolation. My "Armstrong Antenna Switch" provided a 6 inch (15cm) airgap between disconnected antennas. Pretty good isolation, but I never measured it. The relays provide a 1/8" (2mm) airgap. That won't slow down a direct lightning hit to the antenna, but stops other lesser energies. That gap plus the other leakage paths in the wiring provide about 40db isolation on lower frequencies, but above 10 Mhz there is little isolation. (My V1 implementation of the relays needs a big layout redesign) What are you seeing using the HMC253?
The HMC253 could give a neater more professional switch layout in my patch box. I am considering using it in place of designing a V2 relay implementation. Your feedback would be gratefully appreciated.
Mike N8OOU
@n8oou
Hello, Mike! I have never used the HMC253 before. I have also not studied the documentation for this product in detail. I have a need to switch two antennas to one RSP1A receiver. I used a switch on a relay, but at frequencies above 1500 MHz I got a lot of attenuation. The HMC253 board is a cheap product and of course has disadvantages. I should study the documentation in more detail. As for the input protection, it is necessary to do it for each antenna input separately. On the other hand, if you don't mind spending $8 on a new HMC253 board (or just replacing the chip), then it will be enough to install protection only on the receiver input.
I stumbled across this today
its mostly for hams however it should work fine for the kiwi.
there is a a pic microcontroller on it with an optional USB port for connecting to your PC so I don’t see any reason for it not to work with the Kiwi, perhaps some code required.
ill reach out to the gentleman who makes them and see what he says
Oh he makes a 4 pole version too
Wow! Only 249 dollars. Good price!
Hahaha, yeah that’s the catch, however it is overkill but it has a lot of features. Maybe one day I’ll get a Ham licence and it will come in handy
My project of HMC253 and ESP8266 antenna switch on Github.
Not tested yet ))
Well this arrived today
Looks like my long weekend will be soldering this kit! :-)