Tram 1199 Antenna

[pkrawetz]

I have a Tram 1199 thru the glass antenna but I want to remove the glass connector/cable and mount it directly to a BNC right angle connector. Does anyone have a lead on a tnc/bnc 90 degree angle adapter? I've done some searching but can't find one. Also maybe TNC is not the right name for the threaded part of the antenna.

Thanks in advance.

 

[W9WSS]

Did you try Tower Electronics? Run by Scott KB9AMM and Jill KB9PZF.

www.pl-259.com

 

[pkrawetz]

Did you try Tower Electronics? Run by Scott KB9AMM and Jill KB9PZF.

www.pl-259.com

That is the end of the antenna that goes to the connector box. I want the adapter to find the end of the antenna itself which connects to the swivel on top of the connector box.

 

[pkrawetz]

Here is the part of the antenna I need a connector to go to the back of the scanner (BNC).

 

[mmckenna]

Not sure if the whip diameter is the same, but this will do what you want:

Larsen BNCQ VHF 136-512 MHz Tunable Antenna w/ BNC Connector

Larsen BNCQ Field Tunable HT Antennas - Manufacturer: Radiall Larsen; Model #: BNCQ; Frequency Range: 136-512 MHz; Length: 23"; Construction: Chrome Whip;

theantennafarm.com

You can remove the 1/4 wave whip and see if your whip will fit in. Just bend the whip 90º.

 

[pkrawetz]

Not sure if the whip diameter is the same, but this will do what you want:

Larsen BNCQ VHF 136-512 MHz Tunable Antenna w/ BNC Connector

Larsen BNCQ Field Tunable HT Antennas - Manufacturer: Radiall Larsen; Model #: BNCQ; Frequency Range: 136-512 MHz; Length: 23"; Construction: Chrome Whip;

theantennafarm.com

You can remove the 1/4 wave whip and see if your whip will fit in. Just bend the whip 90º.

Now that is an interesting solution! I might try that. The frequency range doesn't include gHz but I'm guessing that is based on the length of the antenna not the connector.

 

[mmckenna]

Now that is an interesting solution! I might try that. The frequency range doesn't include gHz but I'm guessing that is based on the length of the antenna not the connector.

Correct. That's just a generic length 1/4 wave whip. You'd cut it to your frequency if you were going to use that whip.

Glass mount antennas are usually designed to be 1/2 wave since the glass mount does not provide a ground plane. The base should have some sort of impedance matching in it to bring it down to 50Ω. Removing the base is going to remove that matching.

It'll probably still work fine for local scanner listening. Won't be a "perfect" antenna, but usually the stock scanner antennas aren't, either.


As for the Tram 1199, I have no idea what connector that is on there. Might be TNC, but might be SMA, mini-UHF, or something else. Either way, the coaxial cable is probably part of the counterpoise for the 1/2 wave whip.

 

[pkrawetz]

Correct. That's just a generic length 1/4 wave whip. You'd cut it to your frequency if you were going to use that whip.

Glass mount antennas are usually designed to be 1/2 wave since the glass mount does not provide a ground plane. The base should have some sort of impedance matching in it to bring it down to 50Ω. Removing the base is going to remove that matching.

It'll probably still work fine for local scanner listening. Won't be a "perfect" antenna, but usually the stock scanner antennas aren't, either.


As for the Tram 1199, I have no idea what connector that is on there. Might be TNC, but might be SMA, mini-UHF, or something else. Either way, the coaxial cable is probably part of the counterpoise for the 1/2 wave whip.

So the bottom of the antenna to the base of the connector is hollow (no center pin) and what connect the antenna to the base is a solid screw stud. Honestly I have nothing to loose trying your idea!

 

[mmckenna]

So the bottom of the antenna to the base of the connector is hollow (no center pin) and what connect the antenna to the base is a solid screw stud. Honestly I have nothing to loose trying your idea!

Right, if the size is right, you should be able to drop that new antenna whip right in and tighten down the set screw.

I had one of those Larsen antennas when I first got my ham ticket. I'd try it with the included whip first and see if it does what you need. A VHF 1/4 wave antenna will be 3/4 wave on UHF.