I call BS on this product!

[rwgast]

https://www.tindie.com/products/hbouzas/wifi-wireless-ham-radio-coax-antenna-switch/

I want to mount an sdr and mini computer with gigabit ethernet on a 60 foot tower. I have been looking at ways of using one reciver for multiple types of antennas for a long time and all ive come to is DiPlexing of very FAST coax/RF relays which cost more than an antenna or credit card sized PC!!

Would this switch lines in in the HF range, I cant tell if the traces are a 50 ohm transmission line but I dont think so, and how about impermanence of relays?

I emailed these guys haven't heard back if someone educated on her can explain what this is usefull for I may consider it but I doubt it will work in the VHF/UHF/MICROWAVE range which is where i play mostly. Id like to switch one huge long wire antenna on for shortwave/HF reception and the moon raker already on the tower, would this even work for that kind of stuff??

were talking RX only no TX..... But I emailed the guy asking if those were traces were even a 50 ohm or 75 ohm impeadence transmission line and how the impeadence of the relays effect reception... no reply

 

[ko6jw_2]

Not being familiar with this product, I can't help a lot. However, it would be extremely rare to find any product for ham radio that would not be 50 ohm. The fact that it uses UHF connectors would be a clue that it is not intended for UHF or microwave use.

 

[mikewazowski]

Their documentation says it only does up to 150MHz so I'm not sure how you can call BS?

 

[902]

I wouldn't call it 100% BS, although I think it's overstated.

That doesn't look like a finished product. There needs to be jumpers going from the pads under the Antenna 1, etc. to the center part of the SO-239 connector. That, and from the transceiver connector to wherever that goes.

I don't doubt this will work for QRP HF work (I wouldn't use it at 100W, let alone 250W as it advertises), and I'm pretty confident it could work fine for that, but I think there would be a bunch of problems, like melting, fused relay contacts, arcing, and stuff like that.

It's not impossible to make something that works for VHF and UHF scanner frequencies, but I would use PIN diodes rather than relays. Heck, I'd have rather used PIN diodes for HF, too. You could get into some pretty rapid switching with them, and you wouldn't have to worry about the cycling of relays and problems with moderate amounts of RF flowing through the contacts.

At least someone tried pretty hard with this. I like the app thing, although it would suck to have someone from anywhere go in and change antennas on me in mid-use (as if I wouldn't do that to my kids with the house wifi thermostats and apping my way in from 2,000 miles away to turn the air conditioner off on them...). Going back to the drawing board for a few things, I think they could have a pretty neat product.

 

[Voyager]

I find it odd that its advertised as "wireless", but needs power connected. At that point, what's another couple wires for switching?

And yes, it definitely needs connections between the relays and the antenna ports.

Then there is the RF interference potential...

 

[rwgast]

hmmm i did not see the 100mhz limit on the page... It looks like a cool product I would buy, the guy never got back to me though and I couldnt help but wonder?

What is a pin diode? I have been told that transistors/fets/relays wont work at VHF and up and you have to invest in special RF/Coxial relays looking on ebay those are alot. I have a I want an array of 10 different recving antennas from 0-2ghz including a discone, I have broadband LNA that will cover that whole spectrum too, I just dont know how to switch antennea easily when the radio and comuter is up on a 60ft tower?

 

[rwgast]

When you buy a digital TV antenna they have a loop and dipole, how do those antennas connect togather with out causing all kinds of problems, is just becuase there tuned for way different bands

 

[mmckenna]

Not sure what your ultimate plan is for this, but it looks interesting.

For reception only, it would probably work fine. Sure, UHF connectors are less than ideal at higher frequencies, but they don't create a brick wall that no RF can pass through. Same with the relays and traces, it'll pass RF. Maybe not ideal in the GHz ranges, but I suspect it would work just fine.

I'd be curious about having a WiFi antenna on the same circuit board as the antenna traces. Seems like you could either end up with some WiFi on your RF, or some RF on your WiFi if you were transmitting.

There are a lot of solutions out there that will do what you want. True RF relays are available, but are not necessarily cheap. There are many remote RF switches that will do what you want. You'll just need to haul some power/switching up to the top of your 60 foot tower. Something you'll need to do for your Ethernet connection anyways. Just pull a second piece of Cat6 cable up there at the same time.

 

[rwgast]

Well I want to cover 0-1.8ghz as good as possible using a few special antennas tuned to ADS-B, ISM Frequencys, NOAA, The tower already has a moon raker.... not sure if thats just a CB thing? But I want some discones for genral coverage and a long wire or something, im also interested in listening to far away shortwave. I plan to use a beagle bone or something with a highly modified SDR dongle (this thing has almost all new part faright everywhere and is in a Faraday cage each module, TCXO, LNA, and Remote Analog Filter pre selector are in there own cages surrounded by a big cage to house them all. Basicaly copper clad boxes in one big copper box. Then I will run the ethernet to the ground in the house and log in remotly from another house. The point is to get quality reception all over the band. The antenna selector is where things become hazy.... I will look in to RF switches and just add compontents to make the computer contol them, but I dont think ive ever seen a switch with a lot of inputs that works in UHF

 

[mmckenna]

Yeah, this would be mostly a hobbyist thing. Professional high end receivers usually have at least a few different antenna inputs that can be selected.
I've got an AOR AR2300 at one of my high sites at work that I use for remote monitoring of our systems. It has two antenna inputs. I can select those remotely from my computer and it covers 40KHz to up above 3GHz.

There are a number of remote antenna switches for the amateur radio market that should work up into the low GHz range. N connectors, etc. If you are keeping your feed lines short by putting the radio at the top of the tower, then you should do pretty good. A few millimeters of circuit board trace isn't going to mess things up.

And yes, a Moonraker is a CB antenna. Likely it would work pretty well for VHF Low band and some higher end shortwave stuff.

 

[Flatliner]

I find it odd that its advertised as "wireless", but needs power connected. At that point, what's another couple wires for switching?

And yes, it definitely needs connections between the relays and the antenna ports.

Then there is the RF interference potential...

If this was externally located, this looks like an ideal solar power project, me thinks!

 

[Flatliner]

hmmm i did not see the 100mhz limit on the page... It looks like a cool product I would buy, the guy never got back to me though and I couldnt help but wonder?

What is a pin diode? I have been told that transistors/fets/relays wont work at VHF and up and you have to invest in special RF/Coxial relays looking on ebay those are alot. I have a I want an array of 10 different recving antennas from 0-2ghz including a discone, I have broadband LNA that will cover that whole spectrum too, I just dont know how to switch antennea easily when the radio and comuter is up on a 60ft tower?

Pin diodes can help with speed and frequency, but they can also produce unwanted artefacts.