Subject:Hold Function for Radio Shack Frequency Counter (Did It!)

From:galen@picea.CFNR.ColoState.EDU (Galen Watts)





How to add a hold function to the Radio Shack RF Frequency Counter:



Ground TP17.  In the schematic, TP17 is pin one of U3, connected to

+5V thru a 47k resistor.  On the circuit board, TP17 is on the display

side, just right of the lower-right corner of the IC.  Grounds are about

1/4 inch below and to the right, the three non-tinned points in the large

area of metal.



I grounded TP17 directly and the display stopped.  After lifting the ground,

the counter resumed counting at the beginning of a sampling cycle.



Personally, I would ground TP17 thru a 1k resistor.  I haven't performed

the mod to my RS counter, since the pads are VERY small and my fine-tip

iron is at work.  I will try the 1k Hold mod on Monday and give a report

(unless somebody beats me to it).



An amplifier mod to increase the sensitivity is in the works, reports to follow.



Happy Trails to You,

Galen, KF0YJ





Newsgroups:sci.electronics,rec.radio.amateur.misc,rec.radio.scanner,rec.radio.amateur.equipment,rec.radio.amateur.homebrew

From:galen@picea.CFNR.ColoState.EDU (Galen Watts)

Subject:RS FREQ COUNTER HOLD MOD!!!!!!!!!

Sender:news@yuma.ACNS.ColoState.EDU (News Account)

Message-ID:

Date:Mon, 15 Nov 1993 19:15:32 GMT

Nntp-Posting-Host:storm.cfnr.colostate.edu

Organization:College of Natural Resources, Colo. State Univ.

Lines:18





How to add a hold function to the Radio Shack RF Frequency Counter:



Ground TP 17.  In the schematic, TP17 is pin one of U3, connected to

+5V thru a 47k resistor.  On the circuit board, TP17 is on the display

side, just right of the lower-right corner of the IC.  Grounds are about

1/4 inch below and to the right, the three non-tinned points in the large

area of metal.  TP17 is the tinned pad next to a SM resistor marked '473'

for 47k.



I rigged a momentary switch to ground TP17 thru a 1k resistor (you never

can tell) and it works just fine!  I drilled a small hole to mount the switch

just above the plastic depression so I could push the button with my right

thumb.  A small toggle switch would fit.



I'll be trying the other TP's to see what wonderful things RS didn't put

on the front.



Galen, KF0YJ

Amsterdam



View Our Stats










CLICK FOR A FREE DOMAIN NAMES HTTP://WWW.YOURNAME.TK FOR YOUR OWN WEBSITE




IF YOU CLICK HERE AND YOU CAN VOTE FOR OUR FREE WEBSITES IN THE TOP 100 LIST




WANT A TOP RANKING ? USE THE ULTIMATE SOFTWARE SUITE FOR WEB SITE PROMOTION




FreeWebSubmissions Submit Your Site To The Web's Top 50 Search Engines For Free




THE ALEXA BANNER, THIS BANNER GIVES THE DALLY STATISTICS OF THIS FREE WEB SITE



The World of Free Packet Radio Software Amsterdam

---

The World Of Free Packet Radio Software Amsterdam The Netherlands