[time-nuts] Chinese made eBay antenna breakdown.

Bob kb8tq kb8tq at n1k.org
Fri Feb 23 10:43:00 EST 2018


HI

> On Feb 22, 2018, at 8:46 PM, John Green <wpxs472 at gmail.com> wrote:
> 
> I didn't mean to imply that all Chinese made products are garbage. But,
> some of them are. And, has been said, that is because people want to pay
> the absolute lowest prices for stuff. The company I recently retired from
> has a long history with Chinese competition. We had a product that had but
> one American competitor. We thought, foolishly, that being a low cost item
> with a modest annual sales volume, he wouldn't have to worry about foreign
> competition. We didn't take into account our main customer who would slit
> your throat over a tenth of a cent. It wasn't long before we began seeing
> competing products from China. At first, they either did what was cheapest
> without regard for RF concerns, or they copied us exactly. However, in
> recent years, I have seen Chinese products that show the result of some
> real engineering talent. In some cases, they are better than ours. These
> are parts that are molded in plastic, and the foreign competition certainly
> knows a lot more about molding than we do. Their parts are cosmetically
> superior to ours in almost every instance. Lately, I have suggested that we
> obtain some of these products and copy them. That is what it has come to.
> I noticed that the enable input is tied to the voltage input. I thought
> that it may have seen too high a voltage, but the specs say it should be
> able to take 20 volts.

Enable tied to Vin is pretty much “the way it’s done” with a lot of linear 
voltage regulators. I have never seen a failure traced back to an enable 
over-voltage. 

I *do* believe that the bypass caps could be the problem. I’ve seen it before.
Tired Old Bob grabs the reel of 0.047uf devices rather than the 0.47 parts
when he loads the pick and place …. It happens all over the world. 


> So, I don't really see any reason it should have
> failed. I will put a new 3.3 volt regulator in and see if I can get it to
> work. I want to do comparisons to other antennas. The rest of the circuitry
> looks OK to me.

You might try feeding it a regulated 3.3V and see if the beast works or not. 

Bob


> There is one SAW bandpass filter per band. Not like the Trimble, but should
> work fine for my purposes.
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