[NLRS] SWR infinite on 432.....rats!

[Dr. Gerald N. Johnson]

www./mouser.com shows about 74,000 74AC14 in stock in various packages 
and makers. 14 pin DIP package for through hole mounting is 47 cents 
from TI. Shipping will be at least $5.00

I quit adding the stocks when digi-key got to 50,000 on hand that they 
will sell as individual units. www.digikey.com

Jameco has a few on hand and several they can ship in two days. 
www.jameco.com


I'm sure that most electronics distributors have a good supply, but 
Mouser and Digi-key are more individual friendly than the majority of 
electronics distributors.

73, Jerry, K0CQ



On 9/7/2016 10:15 AM, Doug Reed wrote:
>
>
> Hi David.
>
> If you have little or no test equipment, then you have pretty much
> expressed your only option. Personally, I'd want to take the power
> meter up the tower with you so you can directly measure power at the
> far end of the coax. That will let you verify cable RF loss while you
> are doing all this.
>
> The other alternate is to make a good solid RF short with whatever
> connectors it takes, and screw that on the far end of the coax when
> you check return power from the transmitter end. Don't try to prove
> anything with the dummy load until after you've proved the coax and
> connections are good. You can of course do a DC ohms reading on the
> dummy load from the shack to prove it isn't shorted or partially open
> along the way.
>
> A better option might be to attach the dummy load to the coax in the
> shack before you climb the tower. Then use the DVM to measure the DC
> resistance back to the shack as you get to the different connecting
> points. You should see a few extra ohms on the far end of the coax,
> but if resistance is wildly higher or lower, you're starting to
> localize the problem. I wouldn't take an expensive DVM up the tower,
> one of the "free with coupon" cheap DVMs from Harbor Freight will be
> fine for this job and you can laugh if it takes the fast way down from
> the tower.....
>
> <https://www.youtube.com/watch?v=Il_eju4D_TM>
> The #37 video explains how to do a basic TDR measurement with a simple
> scope and square wave generator. Doing the TDR measurement with the
> fast square wave from W2AEW's #88 video will be more accurate but
> finding the 74AC14 to build it could be a problem. Anything that
> generates a waveform with a fast rise time would do the job. But I
> haven't tried this myself so I don't know what works in real life
> instead of theory.....
>
> Good luck!
> 73, Doug Reed, N0NAS.
> ______________________________________________________________
> NLRS mailing list
> Home: http://mailman.qth.net/mailman/listinfo/nlrs
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:NLRS at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>