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. 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.
There is one SAW bandpass filter per band. Not like the Trimble, but should
work fine for my purposes.
HI
On Feb 22, 2018, at 8:46 PM, John Green wpxs472@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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