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View Full Version : Can two radios share the same antenna?



AtLarge
04-14-2019, 09:33 PM
I have a Bearcat 980 and a 29 LX. Can I put a tee on the A-99 and connect both radios? I was thinking of scanning USB or LSB on the 980 and the AM channels on the 29. If I go to transmit I can just turn off one or the other and not do any damage to either. :300 (17):

T-I-N-Y34
04-15-2019, 11:56 AM
The short answer...NO. You'll burn up a radio.

JesseJamesDallas
04-15-2019, 03:41 PM
You can have two radios hooked to one antenna using a coax switch, I have a RCI 2980 and a Cobra 2000 GTL, plus each radio has it's own amp hooked up in line to my dual polarity beam... I use two switches to switch between the two set-up's so I don't have to unhook coax's whenever I decide to use one radio or the other... Plus I can also switch between horizontal and vertical using the switches.
https://i.imgur.com/cYGTMPI.jpg?1

Now in my case, I can only have one set-up turned on at a time since one switch, switches between the two radios (switch on the left) If I have both radios turned ON, and try to talk on the radio that I have the switch set for, then it will cause a God-awful squeal to come from the radio not switched inline...so only one radio can be on at a time...

Not real sure if you could use something like a "T"connector to have two radios hooked to one antenna, then just turn off one radio before talking on the other without causing damage to the one that's off or not...(never tried it) I wouldn't think it would hurt anything since were not talking about electrical current that powers the radio, just the signal going out...The coax jacks on the back of the radio doesn't know if the signal is coming or going...

Only one way to find out for sure! :pop3:

https://images-na.ssl-images-amazon.com/images/I/415g1UZ%2BnlL.jpg

AtLarge
04-15-2019, 09:44 PM
Thanks Guys. I had thought about the switch boxes too but, the T would be cheaper. ;-) I'm on a budget here ya know. :-)

wookie
05-14-2019, 06:53 PM
hI IF YOU CAN BUILD IT THERE IS A CIRCUIT THAT USES A RELAY AND AN rf SWITCH THAT ALLOW YOU TO LISTEN ON 2 RADIOS AND KEY UP 1 AND THE OTHER WILL BE SWITCHED OUT OF THE ANTENNA PATH AND WHEN UNKEYED WILL RETURN TO LETTING BOTH RECEIVE ONCE AGAIN HOPE THIS HELPS.

AtLarge
05-15-2019, 06:43 PM
It does wookie. I have the ability and equipment. Just would need to see a schematic. Can you point me to that?

AtLarge
05-18-2019, 09:16 PM
Excellent Wookie and thank you. I will start giving this some serious research and thought. :thumbsup:

AtLarge
05-31-2019, 07:37 PM
Most everything is pretty much standard and available. That BT47 however, is going to be a tough nut to crack. The only originals I see are in the UK and shipping alone is $40. There is probably an alternate out there but, I am going to pass on the build for now. I went ahead and used a T triple female connector and two Heathkit switchboxes loaned to me from radio chum. I needed 4 jumpers and it's not real pretty but, it works fine and I can run scan on both radios simultaneously without any apparent problems so far. Just need to resist grabbing a mic before throwing the appropriate switch. SWR didn't budge either which is a nice perk too.

wookie
06-01-2019, 12:32 PM
why give up so easily these are general purpose relays and here is the part number GEI LS5-12-2ch they are 12 volts and 2 amps dpdt available in lots of sites and vendors both in the USA and all other countries i have some for sale if you would prefer as i have been asked to produce these once again for the company truckers that use 2 CB's on 1 pair of dual trucker antenna's 23702371 let me know and i am sure we can work something out. i hope this helps as i said before i had been producing these since back in the 1980s.

wookie
06-01-2019, 12:33 PM
her is the schematic again it got deleted please bear in mind that this circuit was designed fo CB and under 10 watts but the relays can be upgraded to suit the power needs you have the rest of it is straight forward i did design a bunch of other mods for those interested in mod-in older CB's as there appears to be a reurection of interest in them as they are easily converted and or modified let me know if you have any questions ill try answer them as best i can 73's to all 2372

technicianuk
06-17-2019, 04:37 AM
Awesome does it work... anyone building one? Sweet

Sent from my SM-G903F using Tapatalk

mjd420nova
06-21-2019, 10:47 PM
Switch boxes are really prone to failure if using extra power. Each connector and switch in line will increase the SWR and decrease the transmitted power. Better to use a patch panel with solid connections.

wookie
06-24-2019, 02:16 PM
hi yes it does work really well and has been around for many years since the early 1980s and if you want more power to pass through then you only need to upgrade the relays.
as for building them i am redoing the PCB artwork just to update it the i will begin selling them

wookie
06-24-2019, 02:19 PM
mechanical switches are unreliable but these are electronic ones with RF sensing and relays which have been well tried and proven for reliability and as for power the only thing that needs changing is the relay for extra power ratings

AtLarge
06-24-2019, 06:32 PM
Definitely keep us posted Wookie. I'd be interested when you have PCB's available.

wookie
06-30-2019, 11:57 AM
OK i will keep you all posted and bear in mind that initially they will be for a maximum of 10 WATTS but you will be able to change out the relays if you need more power and then if there is a need for more powerful ones i will make those available too thanks wooki.

nosaj
06-30-2019, 01:43 PM
OK i will keep you all posted and bear in mind that initially they will be for a maximum of 10 WATTS but you will be able to change out the relays if you need more power and then if there is a need for more powerful ones i will make those available too thanks wooki.
Foley huh, right next door in Pace, FL.

nosaj

BlueRunner
07-21-2019, 04:53 PM
Look up and study on the "Wilkinson Divider / Combiner". It is used industrially to combine multiple amps. Might be something interesting.

nosaj
07-21-2019, 05:01 PM
Basically the wire they use for big rigs to run colinear antennas on each of the mirrors,no?
i would think you'd still need the relay to prevent the transmitted RF from winding up in the other radio.
nosaj