What is this CB device please?

[NoPizzaTonite]

Would someone be kind enough to tell me what this device is?

I assumed maybe a filter - it did a nice job of filtering some noise when the device was *unplugged*
But when I plugged it in and used it in OFF or ON position - it didn't filter anything that I could discern
so... now I'm puzzled

 

[midnight special]

is the so239 marked in or out(tx antenna)? it does favor looking like a preamp,,, when plugged in did recieved signals get louder

 

[NoPizzaTonite]

is the so239 marked in or out(tx antenna)? it does favor looking like a preamp,,, when plugged in did recieved signals get louder

so239s are marked Ant and Trans
I didn't notice the RX signal getting louder, but I wasn't paying that close attention either. I will check more closely a little later today. You are prob on the right track though. I hadn't really considered that since this came with a Texas Star amp which already has a pre-amp built in, but they may just have been used on different radios.

 

[GlocknSpiel]

You're correct in your assumptions. It's an inline bandpass filter to prevent TVI at the source. It's obsolete today, as modern TVs can do the job to begin with. When that was made, that wasn't the case, and even some radios weren't that good at filtering-out harmonics. That is where your box came into play. Good for parts, I guess.
I tried to dig up some data online about it, but drew a blank. However, being raised in dad's TV/radio service shop, I've seen my share of those....... Ones LIKE it anyhow.

 

[TM86]

I think Midnight Special is right and it's most likely a receive preamp. The relay would be to switch the RF path away from the small amplifier transistor so you didn't blow it up when you transmit.

TVI filters usually didn't have a power supply as they didn't need active components in them. Not saying there couldn't be one or more out there that does, since CBer's have always loved having our things that light up, but it would be unusual to say the least.

 

[sunbulls]

It's definitely a receive pre-amp with poor build quality. At least those two coils are tunable. Unlike the broadband single transistor types typically found in most CB amps that also boost the unwanted frequencies.

 

[NoPizzaTonite]

I just love love love the discussion little things like this generate. Nice to see such an active forum. I've lurked here for a couple of years or so now learning from these types of interactions all you experienced folks have!

So - I can attest this is most likely a pre-amp. Turning it on brought in some weaker signals. Give the points to Midnight with support to TM86 and Sunbulls (though Glock - you and I had similar thoughts). I suppose this unit might not be so bad for someone not having pre-amp capability. I got a bit of human "noise" when I turned it on. I should have paid attention to that when I was fiddling with it. Learning experience for me

Thank you all for being so nice with your time in helping me out with this!

-Alex

 

[midnight special]

and a warning,, dont use on the antenna side of your linear amp,,, have between radio and amp,, older preamps were not meant for high power,, so as a rule nothing higher than 10 watts,,, i have a dosy preamp and i let a fellow borrow it and i told him the warning and he still put in line wrong fried the transistors right up,,

 

[NoPizzaTonite]

and a warning,, dont use on the antenna side of your linear amp,,, have between radio and amp,, older preamps were not meant for high power,, so as a rule nothing higher than 10 watts,,, i have a dosy preamp and i let a fellow borrow it and i told him the warning and he still put in line wrong fried the transistors right up,,

Ouch! Though I have no plans to use it since my amps already have pre-amps, this is very sound advice, and that is the way I hooked it up when I tested it (kinda made logical sense haha).