Modify ST2 Antenna for Airband

[kf5bti]

Has anyone tried to modify a ST2 Antenna to improve Airband reception? I don't have any VHF Lo activity that I care to listen to and was considering shortening the elements on my ST2 to improve the VHF Hi reception. Currently I have a dedicated air band ground plane antenna that clearly works better than the ST2 but that requires switching coax between the 2 depending on what I am listening to.

 

[rbm]

Has anyone tried to modify a ST2 Antenna to improve Airband reception? I don't have any VHF Lo activity that I care to listen to and was considering shortening the elements on my ST2 to improve the VHF Hi reception. Currently I have a dedicated air band ground plane antenna that clearly works better than the ST2 but that requires switching coax between the 2 depending on what I am listening to.

Somewhere, back in history, I made a post here on RR where I experimented with cutting the elements on an ST2 antenna.

If I can find that post, I'll add it here.

For years I've noticed that all of my ST2 antennas show some 'variable' sensitivity, on various frequency bands, at various times.

I wasn't happy with the way they performed on the Civilian air band or the MilSat frequencies.

They'll never be the equal of a dedicated antenna for those bands, but I WAS able to improved the performance of them.

I've never been a fan of the 'slide together' mechanical connections they use for the elements of that antenna.

So, about 3 years ago, I modified two of my ST2 antennas. ( I have FIVE of them in use. )

I used small, #2 and #4 stainless sheet metal screws that I found on ebay. (1/4" and 3/8" long)
(PAN HEAD SCREWS #4 LENGTH 3/8 BOX 100 18-8 STAINLESS)

I drilled a small pilot hole for each screw.

It took around 30 minutes to do each antenna. Not including the time it took to take it down and put it back up.
Every single 'slide together connection' was drilled and screwed in place.
Then for good measure, I covered the head of each screw with silicone sealer. (not really needed)

Those two ST2 antennas have consistently outperformed the other three since then.

I really should do the other three antennas, but I haven't found the time to get up on the roof to take them down and do it.

Rich

By the way, if you've ever used a volt or ohm meter to make a measurement, you know why I don't trust any electrical connection that is not firmly, and permanently, attached.

Edit:

Well, I found my old post ............... but ............... it won't help you much.
The air band (128.150 MHz ATIS at the local airport) remained about the same until I shortened the elements to 19" and then it dropped off.

http://forums.radioreference.com/sc...support-st2-antenna-question.html#post2011854
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[rbm]

I forgot that I took a few photos of my changes to the ST2.

This one will give you the idea.

Every element is solidly connected via the stainless screws, circled in red in this photo.
There are screws on the back of the elements where you can't seem them all.

That includes the smaller 'wings' and the 800 MHz elements as well.

Rich



And then there's this one.
I'm not proud of posting an out of focus photo, but it's all I have that shows how I put the screw into the fold out wings.



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[Mtnrider]

There not being made anymore.....sadly....careful experimenting..

 

[737mech]

For better airband first try the fm trap inline with your scanner. Cheap ones at radioshack or expensive ones from parelectronics. There are many posts of how adding the trap improved airband.

 

[kf5bti]

Thanks for the responses, I think I am going to leave the ST2 alone for now and just continue to use a dedicated antenna for the airband. I already have the RS fm trap in place which made no noticeable difference in my case.

 

[Dreamflight767]

Thanks for the responses, I think I am going to leave the ST2 alone for now and just continue to use a dedicated antenna for the airband. I already have the RS fm trap in place which made no noticeable difference in my case.

How do you use a dedicated antenna for the airband and the ST on the same scanner?

 

[kf5bti]

How do you use a dedicated antenna for the airband and the ST on the same scanner?

I only use 1 at a time. 2 separate coax that I simply swap at the radio.