Walkie Talkie Antenna Question

[Handy Andy]

It's why I suggested the external antenna jack.

There is a circuit in the output - past that EXTERNAL antenna jack that loads - uses - matches - to the EXPECTED antenna it was designed for - so to place a BNC on it - you'd have to open up the unit and see if the BNC can work with the loading circuit still inside. You'd have to remove that loading coil/cap or combo - to obtain the same "ohmic" impedance the External Antenna Jack already provided. But, if it makes it convenient - once the old loading circuit is removed you should be ok to put in the BNC.

If you just put in the BNC and try to use it without removing the originals', there may be a performance hit against you due to the purpose of the loading circuit provided for the original antenna. You may lose out on a more efficient way if you just removed that socket and put in the BNC without looking at the loading/matching network the HT used. Doing it this way, you can possibly even damage the final the HT uses - because of the loading originally used is different to match a different antenna setup than what you're trying to do with the BNC.

 

[sunbulls]

I was aware of the additional loading in some of the fixed antenna talkies I modified, but never tried to bypass it with the BNC conversion. In any case I did so far I never felt any excessive heat off the final or excessive current draw, maybe I’m just lucky. My TRC-207 had a single conductor mount same as a fixed antenna. I used that same connection plus grounded the outside portion of the BNC to the chassis. Tapping off the RCA jack would be a sure thing, but I didn’t feel like fiddling with an extra piece of coax without testing the results with the simpler connection first. After tuning the final stage, at least on my TRC-207, I found no discernible difference between the RCA and the BNC. Both connections showed a ted under 3 watts RMS with nice audio. Testing was done with a 13.8v external power supply attached. Amperage draw was in normal range. For the sake of battery life, amperage was my main focus. I’ll think about that extra loading circuit in the future whenever I get around to changing another brand, but my TRC-207 is staying as is.

 

[Handy Andy]

Thanks Sunbulls. Just did not want to ruin a great idea by forgetting something....

 

[Niceguy71]

great thread guys ( I know it's 5 years old) I have a TRC 207 I bought new in 1990-92 it was only good for about 500 feet range.... but I always liked it. I just got into CB again and put the Amazon HYS 27Mhz 9-Inch to 51-inch Telescopic/Rod HT Antennas on 5 of my other handhelds... they now work from one mile to up to 5!!!! so I was hoping to do this with my TCR 207 but after reading the post I see I will not find an adapter for it... so that little handheld will get left behind to sit on the shelf for another 30 years.
I was able to get some adapters for my two Maxon handhelds and they seem to work pretty good...MX BNC Antenna adapter for Motorola Maxon ICOM Radios
seeing the Maxon antenna just screws on like the TCR207 I thought I could get one but I see the Maxon has two connection points unlike the single connection of the TRC 207.....
thanks again you guys stopped my hunting for a part that doesn't exist