Hello everyone.
It got a bit stuck when I took it off. A small, probably too strong, pull and I had 2 parts in my hand as well as 2 small copper plates.
In my opinion, it looks like you have to remove the small coil piece and then insert the smaller part from below together with the two copper plates.
Does anyone know how I can open the lower part? I don’t want to go for it and then break something. I haven’t found any instructions in a hurry.
Thanks in advance.
73 Marcel DM3FAM
Hi Marcel, sorry I can’t help with the antenna, but I wanted to ask a bit of a off-topic question: I see that you have a SMA to BNC adapter to connect with your HT, I have the same one and last week I noticed that the black coating on the shielding is not conductive, would you be able to test it with a DMM?
Thanks and GL with the antenna,
Carlo
Sorry for hijacking the thread:
I have purchased such an adapter many years ago at Wimo. This was black anodized and conductive. In 2017 I ordered a second one at Wimo - but I received a black lacquered one. I measured resistance of the shiny black lacquer and of course it was perfectly insulating. I dropped Wimo an email asking about the nonsense of an insulating adapter. They were sorry and told me, they received insulating adapters from their suppliers by error. I got a refund and they said, they would follow up the problem. In June 2018 I again ordered the adapter and got an insulating with lacquer, again. Again I got a refund - seems this black adapters are now all with insulating lacquer.
As I do not care about the color but want I short adapter I put it into thinner to remove the lacquer. I ended up with an adapter with the uncoated brass shielding. Not optimal but better than insulating.
73 de Michael, DB7MM
No problem! Anything goes.
Carlo @IU1KGS. Just held a continuity tester to it. I have continuity everywhere on the surface/finish.
Maybe Michael @DB7MM mentioned the right starting point. Maybe your adapter is one of those.
73 Marcel DM3FAM
Anodizing forms an insulating oxide layer. It can be very thin, and so punctured by a test meter probe, but is not sutable for surfaces intended to make a connection.
Current will flow in the aluminium beneath the anodized layer of course, so no problem for protecting the outside of a connector…
Sorry for the incorrect term - not being an English native speaker I was not precise.
You are right: Anodizing forms insulating layers and is limited to aluminium - in fact it is the process of deliberately building a defined aluminium oxide layer.
The bulk material of the SMA-BNC-adapter seems to be brass as this is visible at worn parts of the adapter.
So anodized is the wrong word. Black finished or black oxidized could be better, despite this term is also limited to iron in the exact sense. Anyway: The old adapters have some surface treatment which is conductive even if not explicitely punctured with a probe tip, prone to build white residue when exposed to humidity and both thin and hard. Now the metallurgists can take over to name the process.
But the important fact @IU1KGS was asking: There are two variants of these adapters. An old one which has a conductive surface and a new one with an organic lacquer which is insulating. This lacquer can be dissolved in organic solvents (color thinner).
73 de Michael, DB7MM
Possibly. Or maybe the tube is a constant diameter and there is a swaging die used to swage off the top of the section. i.e. the top is compressed to shape once the next section and copper plates have been inserted during manufacture and this stops them coming out.
That could also be the case, but I would have to measure the diameter exactly. Thanks for the tip. I tried to loosen the lower part, but unfortunately it didn’t work. It seems to be pressed. At first I suspected that there was a thread and the BNC part was screwed on. This does not seem to be the case.
I could also glue the antenna in place, it just wouldn’t be as compact. Otherwise I will probably order a new one.
73 Marcel DM3FAM
Sorry, Marcel. I have never had much luck repairing telescopic whips. You’re right that the section that pulled out should go back in through the bottom, but that means taking both the coil and BNC connector off. Then you’ll have 3 broken spots instead of one!
The dimples on the copper pieces fit into the holes on the bottom of the section that pulled out. Try to flare the top corners of the copper pieces SLIGHTLY, then then put the pieces on place, and slide the assembly back in to the section it came out of.
Hopefully you can get it back in, then try to swage the larger section at the top to keep the smaller section from pulling out.
I’ve managed to get them back together, but they never last long once broken.
Good luck! Rick N8TGQ
Thanks Rick @N8TGQ for your advice.
I tried to solve the bottom part today anyway. Didn’t manage it. I was amazed at how firmly and well it all holds together. Now I have lots of scratches.
So I’m not going to do anything else. Fix the middle section, even if it doesn’t look nice. Function is important. Otherwise I’ll get a new one.
73 Marcel DM3FAM
