Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

<time-nuts@febo.com> > Sent: Thursday, August 11, 2016 1:20 PM > Subject: Re: [time-nuts] Safely getting the electrical length of a connected > antenna feedline > > I used the PPS from a Thunderbolt (fast rise lime, low rep frequency, was > handy) and a digital storage

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

precise time and >frequency measurement <time-nuts@febo.com> > Sent: Thursday, August 11, 2016 1:20 PM >Subject: Re: [time-nuts] Safely getting the electrical length of a >connected antenna feedline > >I used the PPS from a Thunderbolt (fast rise lime, low rep frequency,

Re: [time-nuts] Safely getting the electrical length of a connected, antenna feedline

"The biggest variable will be the velocity factor." If you determine the length electrically, you will already have the electricallength. If you need the physical length, then multiply electrical length times the inverse of the velocity factor. -- Joe Leikhim Leikhim and Associates

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

ali...@gmail.com> To: Bob Albert <bob91...@yahoo.com>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Thursday, August 11, 2016 1:20 PM Subject: Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline I

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

I used the PPS from a Thunderbolt (fast rise lime, low rep frequency, was handy) and a digital storage scope and a couple of resistors to make a reflectometer based on this experiment: www.ko4bb.com/getsimple/index.php?I'd=coax-cable-impedance-matching You can very clearly see a 50 ohm/75 ohm

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

You left out the obvious time-nut solution: Calibrate and characterize an ensemble of HP5071A's to correct absolute time at NIST. Transport the ensemble (correcting, if necessary, for general relativisitic effects) to your house. Set the cable delay in your GPS receiver to zero. The delta between

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Thanks David.  I have ordered some from ebay, very cheap. 5pcs SO/SOP/SOIC/SSOP/TSSOP/MSOP14 to DIP 14 Adapter PCB Board Converter MA |   | |   | |   |   |   |   |   | | 5pcs SO/SOP/SOIC/SSOP/TSSOP/MSOP14 to DIP 14 Ad...US $1.32 New other (see details) in Business & Industrial, Electrical &

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

These are a little larger than what I was thinking of but were mentioned the other day in funwithtu...@yahoogroups.com and are probable more suitable for most projects anyway: http://qrpme.com/?p=product=MEP On Tue, 9 Aug 2016 16:10:38 + (UTC), you wrote: >Yes, a board with the required

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Hi: Another option is so Google for a "Breakout board" for the IC you're looking to work with. People like Spark Fun, Seed studio, make these. It's a board that holds the chip and the needed accessory parts, but needs something else like an Arduino. -- Have Fun, Brooke Clarke

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

On Tue, Aug 9, 2016 at 9:10 AM, Bob Albert via time-nuts wrote: > > Yes, a board with the required footprint would be the way to go. Where does > one find that? You can have small PCBs made for $3 each. There are places here in the US that will do PCBs for $3/square inch

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Yes, a board with the required footprint would be the way to go.  Where does one find that? On Tuesday, August 9, 2016 12:00 AM, David wrote: Richard mentioned the SMD to leaded adapters which work well. Another way which is more suitable for Manhattan or dead

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

From: Dr. David Kirkby (Kirkby Microwave Ltd) I thought i might be possible to do this with a VNA, and a test antenna located a known distance apart. So I asked in the Keysight forum on 8th Feb 2015 [] Dave ___ Folks, Yes, I've used the DG8SAQ Vector

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

If you have *the* active antenna, it is pretty easy to make a little quadrapole circularly polarized antenna out of a couple of pieces of 141 semi-riged coax, and to transmit signal into the active GPS antenna, and measure the signal coming out of the active GPS antenna. If you don't have the

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

I doubt it's worth mentioning that a random SMD footprint cut from a larger board and some of the currently available eBay SMD adapter boards may have plated through holes which could short if used to prototype on copper clad board so it's worth paying a little attention to insulating the

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Richard mentioned the SMD to leaded adapters which work well. Another way which is more suitable for Manhattan or dead bug type construction is to glue or solder down just tiny printed circuit board which has the SMD footprint and then solder directly to the leads or extensions to the pads. This

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

] Safely getting the electrical length of a connected antenna feedline Your comments on layout made me think again of how to implement these projects.  How do you use a 14 pin SMD IC?  I could try to connect it with flying leads but I'd like something better.  Is there some kind of socket for these devices

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

You could get a low cost GPS unit and compare the PPS from it to the PPS from your setup with the long cable. Modern GPS receivers are sensitive enough to work with a poor antenna (indoors) and don't cost much. -- These are my opinions. I hate spam.

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Gate drivers are pretty zippy when you leave out the capacitive load of a power fet's gate. They are also available in 8 pin dip. On Monday, 8 August 2016, Bob Albert via time-nuts wrote: > Your comments on layout made me think again of how to implement these > projects.

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

of precise time and frequency measurement Subject: Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline Your comments on layout made me think again of how to implement these projects. How do you use a 14 pin SMD IC? I could try to connect it with flying leads bu

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Your comments on layout made me think again of how to implement these projects.  How do you use a 14 pin SMD IC?  I could try to connect it with flying leads but I'd like something better.  Is there some kind of socket for these devices?  Or a generic board to receive such things? Bob On

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

I actually tested various 74120 dual 4-input NAND drivers which produce the sync output on my B function generator to find ones which would provide the fastest and cleanest pulse. AS (advanced schottky) and FAST (fast advanced schottky TTL) were the best for me. Modern inexpensive discrete logic

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

First, the nulls are sharper than the peaks.  What you do is measure the frequency of adjacent nulls and calculate what frequency makes both of those a half wave or multiple thereof.  Then you know the number of half waves to the mismatch.  It's the distance from the tee to the remote end. It

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

t" <b...@evoria.net> To: "Discussion of Precise Time and Frequency Measurement" <time-nuts@febo.com> Sent: Monday, August 08, 2016 2:18 PM Subject: [time-nuts] Safely getting the electrical length of a connected antenna feedline Earlier this year, with some help,

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

<bob91...@yahoo.com> To: Bob Stewart <b...@evoria.net>; Discussion of Precise Time and Frequency Measurement <time-nuts@febo.com>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Monday, August 8, 2016 2:18 PM Subject: Re: [time-nuts] Safel

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

voria.net>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Monday, August 8, 2016 3:14 PM Subject: Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline Hi An even more significant question: Is it worth doing? More or

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Hi An even more significant question: Is it worth doing? More or less: Do you know the delay numbers for your antenna? Do you know the delay numbers for your GPS module? How close can you *guess* the length of the cable? Knowing absolutely nothing at all about your setup, I’ll guess the

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

I host a group called something like HF Antennas.  There I posted a link to an article on how to measure coaxial cable.  The easiest way is with a spectrum analyzer and a tracking generator. You connect the generator to the analyzer through a Tee that goes to the unknown coax.  You will see a

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

b...@evoria.net said: > Earlier this year, with some help, I pulled the dish off of an old DishTV > antenna on the roof and put a 5V bullet antenna on the mast.  I also pulled > a new cable through by attaching it to the old one.  The problem is that I > was not able to measure the new cable. 

[time-nuts] Safely getting the electrical length of a connected antenna feedline

Earlier this year, with some help, I pulled the dish off of an old DishTV antenna on the roof and put a 5V bullet antenna on the mast.  I also pulled a new cable through by attaching it to the old one.  The problem is that I was not able to measure the new cable.  So, the question is, without