Thinking Of Installing A Discone For My SDR Receivers

[jonwienke]

Prime shipping FTW.

 

[Merovingian]

I don't have Prime, that will be another $100 but I'll look into it tomorrow.

Prime shipping FTW.

 

[Merovingian]

I went up on my roof today to see what is going on with my VHF discone.

Guess what happened. . .

I un-clamped the antenna from the mast I put up, as I was lifting it up off of the top of the mast the coax cable fell out of the bottom of the little pipe that came with the discone.

I figured the cable pulled out of the connector and I would have to have it fixed. So I go down to the ground and look at the coax and see the connector and everything fell out of the bottom of the antenna, as if it was never screwed in. I know I screwed it in the other night before I wrapped it in tape. I know I turned the connector until it wouldn't turn anymore before I wrapped the tape around it. I don't know what happened. . . Somehow either it got cross threaded when it started and was only hanging by a fraction of a thread or I tightened it all the way and while I was wrapping it and attaching the little pipe, then carrying it outside with the coax, the coax somehow turned itself around and around until it came unscrewed.

Either way it is fixed now and it seems to be working good.

Here is the entire FM radio spectrum just for fun.

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I uploaded a big picture but the server shrinks it to a postage stamp.

 

[prcguy]

If the tape was stretched when applied it wants to return to its original size and will take things with it so always wrap the tape in the same direction that the connector tightens. I've seen tape that was stretched tight around a connector the other way start to unscrew the connector as the tape attached to the fixed connector works against the tape on the cable side connector. If you wrap in the direction of tightening the connector the tape will always put a tightening force on the connector.

I went up on my roof today to see what is going on with my VHF discone.

Guess what happened. . .

I un-clamped the antenna from the mast I put up, as I was lifting it up off of the top of the mast the coax cable fell out of the bottom of the little pipe that came with the discone.

I figured the cable pulled out of the connector and I would have to have it fixed. So I go down to the ground and look at the coax and see the connector and everything fell out of the bottom of the antenna, as if it was never screwed in. I know I screwed it in the other night before I wrapped it in tape. I know I turned the connector until it wouldn't turn anymore before I wrapped the tape around it. I don't know what happened. . . Somehow either it got cross threaded when it started and was only hanging by a fraction of a thread or I tightened it all the way and while I was wrapping it and attaching the little pipe, then carrying it outside with the coax, the coax somehow turned itself around and around until it came unscrewed.

Either way it is fixed now and it seems to be working good.

Here is the entire FM radio spectrum just for fun.

.
.
.
I uploaded a big picture but the server shrinks it to a postage stamp.

 

[Merovingian]

Hummm. . . I never would have guessed that. That could be what happened. Even with the Scotch 33+ wrapped over the Scotch 77?

I put a little stretch in the scotch 77 but not hardly any in the scotch 33+ that went over it. I would think the 33+ would stop the 77 from moving.

At least I know the cable is good. I'll have to keep an eye on them for a while to make sure none of them do that.

Thanks for the info.

If the tape was stretched when applied it wants to return to its original size and will take things with it so always wrap the tape in the same direction that the connector tightens. I've seen tape that was stretched tight around a connector the other way start to unscrew the connector as the tape attached to the fixed connector works against the tape on the cable side connector. If you wrap in the direction of tightening the connector the tape will always put a tightening force on the connector.

 

[prcguy]

If you wrapped both types of tape in the direction that unscrews the connector then both tapes will be working against you. The most I have seen a connector unscrew is about 1/4 turn because there is only so much contracting the tape can do. You may have unknowingly unscrewed the connector most of the way while wrapping the tape around it then a final small contraction of the tape did it in.

Hummm. . . I never would have guessed that. That could be what happened. Even with the Scotch 33+ wrapped over the Scotch 77?

I put a little stretch in the scotch 77 but not hardly any in the scotch 33+ that went over it. I would think the 33+ would stop the 77 from moving.

At least I know the cable is good. I'll have to keep an eye on them for a while to make sure none of them do that.

Thanks for the info.

 

[Merovingian]

I'm not sure what happened. When I wrapped the tape I had the discone sideways in my lap wrapping the tapearound the connector specifically so I wouldn't need to rotate the discone as I wrapped it. It is very strange. . .

MY other guess is that I somehow unscrewed the connector as I was coiling the cable up to carry the whole thing outside. Maybe the tape contracting left the connector hanging by a thread "pun intended" then it just fell out when I took the antenna down.

If you wrapped both types of tape in the direction that unscrews the connector then both tapes will be working against you. The most I have seen a connector unscrew is about 1/4 turn because there is only so much contracting the tape can do. You may have unknowingly unscrewed the connector most of the way while wrapping the tape around it then a final small contraction of the tape did it in.