Re: [time-nuts] eBay GPS antenna test results.

2018-02-15 Thread Bob kb8tq
Hi As with any antenna mods, the issue isn’t so much doing them as proving that what you did had this or that effect. A lot of what you are paying for on the fancy antennas is the fact that indeed they went through some sort of validation process on top of the design process. An equally valid

Re: [time-nuts] eBay GPS antenna test results.

2018-02-15 Thread jimlux
On 2/15/18 6:04 AM, Bob kb8tq wrote: Hi There are a number of reasons to believe that these antennas are worse than the typical “telecom GPS” antenna for L1 only duty driving a TBolt. If you are going to do L1 / L2 work with something like a NetRS, then indeed you will need a dual band antenna.

Re: [time-nuts] eBay GPS antenna test results.

2018-02-15 Thread Bob kb8tq
Hi There are a number of reasons to believe that these antennas are worse than the typical “telecom GPS” antenna for L1 only duty driving a TBolt. If you are going to do L1 / L2 work with something like a NetRS, then indeed you will need a dual band antenna. These (the $99 ones) are the lowest

Re: [time-nuts] eBay GPS antenna test results.

2018-02-13 Thread Clay Autery
I would be extremely surprised if ebay does not rule in your favor. I've only had ONE case EVER opened against me, and it was CLEARLY not a valid case, but eBay still made me give the buyer his money back IN FULL to include shipping. eBay almost always picks the buyer over the seller. 73,

Re: [time-nuts] eBay GPS antenna test results.

2018-02-12 Thread Bob kb8tq
Hi Sitting here casually reading the data sheets for some of the modern Trimble survey receivers - they have gone to 7.2V (just below your 7.5V trigger point) as an antenna supply voltage. Who knows what that might imply relative to this antenna. Bob > On Feb 11, 2018, at 12:44 PM, John

[time-nuts] eBay GPS antenna test results.

2018-02-11 Thread John Green
They have issued a refund. The seller said that my antenna was defective. This is kind of a strange outfit. They are in Russia selling Chinese goods, shipped from China. Since I don't have to return it, I will disassemble it to see what went bad. I replied that if he could assure me that it would

Re: [time-nuts] eBay GPS antenna test results.

2018-02-11 Thread Bob kb8tq
Hi Well, good news / bad news I guess. The seller is at least responding to your input. They also did not come back with something about “there is no voltage spec”. It’s quite possible that they are the 5th person in a chain of sellers and a substitution got made (unknown to them) at seller 3.

[time-nuts] eBay GPS antenna test results.

2018-02-11 Thread John Green
I opened a "Not as listed" case and heard back from the seller. They said that the antenna is definitely 3.3 to 18 volts and have sold several that are in operation. They wanted to know specifically how I tested the antenna, why I thought it shorted, and if I actually ever hooked it to a GPS

Re: [time-nuts] eBay GPS antenna test results.

2018-02-10 Thread Bob kb8tq
Hi Ok, the antenna in the pictures on the listing *does* have labeling in English and it sure looks like it says 3.3 to 18V on the antenna. Certainly you have (and the rest of us may soon have) a case for “not as shown” in terms of what you got (and we get). Bob > On Feb 9, 2018, at 9:31 PM,

[time-nuts] eBay GPS antenna test results.

2018-02-09 Thread John Green
Bob wrote: Is it labeled 3.3 to 18V on the antenna? No, the writing on the antenna is all Chinese. The specs published on eBay state that it is. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] eBay GPS antenna test results.

2018-02-09 Thread Dana Whitlow
I would surmise that the antenna has (or rather had) a protection network to protect against voltage spikes or surges. Your description of events seems consistent with an triggered SCR crowbar circuit, and the 2nd attempt at the higher current limit shorted the SCR. Note that this may not have

Re: [time-nuts] eBay GPS antenna test results.

2018-02-09 Thread Dr. David Kirkby
On 9 February 2018 at 21:43, John Green wrote: > To those who doubted that the antenna was actually a 3.3 to 18 volt design, > it seems you were correct. Today, I hooked it up to a variable power supply > and slowly raised the DC voltage fed to the antenna. It began to pull >

Re: [time-nuts] eBay GPS antenna test results.

2018-02-09 Thread Bob kb8tq
Hi Is it labeled 3.3 to 18V on the antenna? Bob > On Feb 9, 2018, at 4:43 PM, John Green wrote: > > To those who doubted that the antenna was actually a 3.3 to 18 volt design, > it seems you were correct. Today, I hooked it up to a variable power supply > and slowly raised

Re: [time-nuts] eBay GPS antenna test results.

2018-02-09 Thread John Green
To those who doubted that the antenna was actually a 3.3 to 18 volt design, it seems you were correct. Today, I hooked it up to a variable power supply and slowly raised the DC voltage fed to the antenna. It began to pull current at about 2.9 volts and at 3.3 volts, took about 40 mA. I continued