1. Manuals
  2. Brands
  3. TelePost Manuals
  4. Measuring Instruments
  5. LP-100
  6. Manual

TelePost LP-100 Manual

Digital vector hf wattmeter
Hide thumbs Also See for LP-100:
Table of Contents

Advertisement

Quick Links

Download this manual
LP-100
Digital Vector
HF Wattmeter
Operating &
Assembly Manual
June, 2006
TelePost Incorporated
Rev. B2
1

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the LP-100 and is the answer not in the manual?

Questions and answers

Related Manuals for TelePost LP-100

Summary of Contents for TelePost LP-100

  • Page 1 LP-100 Digital Vector HF Wattmeter Operating & Assembly Manual June, 2006 TelePost Incorporated Rev. B2...
  • Page 2 E.I. du Pont de Nemours and Company. PICmicro® is a registered trademark of MicroChip Technology Inc. Material in this document copyrighted © 2006 TelePost Inc. All rights reserved. All firmware and software used in the LP- 100, LP-100 VCP and LP-100 Plot programs copyrighted © 2004-2006 TelePost Inc. All rights reserved. MicroCode...

  • Page 3: Table Of Contents

    Table of Contents Introduction ......................4 Parts List......................... 5 Assembly Instructions .................... 7 Initial Checkout ....................15 Calibration ......................17 Operation......................21 Circuit Description ....................24 Schematic ......................26 Software ....................... 28 Troubleshooting ....................30 Specifications and CAL Table ................32 Warranty ......................

  • Page 4: Introduction

    Introduction The LP-100 is designed as an accurate instrument for monitoring station performance. It provides a number of unique features not seen before in a ham radio wattmeter. The most obvious of these is the vector display. This display shows the complex impedance of the load in two ways. The top line of the display shows impedance in polar form…...

  • Page 5: Parts List

    Parts List Pre-installed SMT parts QTY Part No. Description C9,10,12,13 0.01uF 50V R4,18 Resistor 26.7 1% .25W R5, 12 Resistor 49.9 1% .5W R6,21 Resistor 56.2 1% .25W R9, 27 Resistor 56.2 1% .5W R10, 20 Resistor 422 1% .25W Resistor 174 1% .25W Resistor 120 1% .25W Resistor 32.6 1% .25W...
  • Page 6 Parts List cont’d QTY Part No. Description CEM-1212C Piezo transducer SW1, 2, 3 4mm tactile switch, rt. Angle & keycaps Toroid core FT37-61 LM7805 18F252 PIC TLC-271ACP MAX6225BEPA MAX232N LM34DZ MCP3304 Resonator 10 MHz Pwr Cable Enclosure Main Main Heatsink for 7805 IC Socket 8-pin...
  • Page 7 Assembly Overview Below is a parts layout of the main PCB. These markings match the silk-screening on the PCB, but are repeated here for clarity. You can also cross out the parts on this graphic as they are installed. Note that several components with markings on the board are not included in the final product, namely…...
  • Page 8 Digital Multimeter NOTE: The LP-100 is what I would call an intermediate level kit. If care is taken, you should have no difficulty building it. I would peg the assembly time at about 8 hours total, along with some reading through the manual in advance, and some time for calibration. Take your time, and double-check your work.
  • Page 9 Assembly cont’d Step-by-step assembly instructions for main board. Below is a picture of the assembled PCB. The SMT parts come pre-installed. It is recommended that you print this manual to allow for easy reference while building, and to allow you to check off the steps as you complete them.
  • Page 10 Assembly cont’d Install miscellaneous parts such as resonator, Piezo transducer, etc. NOTE: Remove the protective covering on the transducer before using. Also, the “+” lead goes to the side with the jumper, per the placement guide. Do not install chokes yet. Install connectors and switches.

  • Page 11: Initial Checkout

    Step 2. Power the board up again, and verify that you are seeing the “splash” screen with version and copyright information, followed by the main LP-100 screen. The screen should look like the screen on the photo at the top of the “Operation” section of this manual.
  • Page 12 Assembly cont’d Step-by-step assembly instructions for directional coupler. Refer to the drawing and pictures during assembly of the coupler. These pictures are courtesy of Stan, W5EWA. Construction of the coupler consists of only a few steps. The main components are the transmission line, toroidal transformers and the attenuator PCB. The most critical step is the winding of the transformers.
  • Page 13 Assembly cont’d Prepare the two pieces of coax as shown in the diagram. Make sure that the shield wires don’t short out to the center conductor on either end. RG-142 is double silver shielded. You may find it easier to remove the outer shield to keep the twisted shield connection more flexible and easier to work with.
  • Page 14 Assembly cont’d Before slipping the nylon bushings into the wound cores, take the two long pieces of Teflon® tape, peel the paper off of the adhesive side, and wrap each of the nylon bushings with the Teflon® tape. Then take the medium pieces, remove the paper, and stick them in the cores between the windings, with the thicker one against the core.
  • Page 15 Final Checkout and Assembly Before going through the CAL screens, it is necessary to verify that the remaining basic circuits are working. Power up the LP-100, and verify that the current draw is correct. 160 mA Connect the Current and Voltage ports of the controller and coupler together using the supplied 6’...
  • Page 16 Connections… Power: 12-16 VDC, center pin +. The lead with the white stripe on the supplied cable is + PTT: Loop the PTT between your amplifier and rig through the LP-100 using RCA connectors RS-232: Connects to computer. Current/Voltage: Connect to corresponding jacks on the coupler using supplied RG-174U cables.

  • Page 17: Calibration

    You can download MCLoader on the Update page, as well as the latest firmware hex file. There is a summary of update changes listed along with the files. This is a simple process, and offers a great way to keep your LP-100 current...
  • Page 18 Before adjusting either of these parameters, it is necessary to provide an accurate means of measuring power that is independent of the LP-100. The simplest approach to this is to borrow a high quality meter like a Bird or Alpha to use as a reference, and connect it between the LP-100 and dummy load with a UHF male-male adapter.
  • Page 19 Calibration Cont’d If you don’t have access to these methods, you can send your completed LP-100 back to me for calibration if you are willing to pay for return shipping costs. The first step in power calibration is to set the Master Trim value. This should be done on 1.8 or 3.5 MHz. Make sure the Fine Trim setting for this band is 1.000, then transmit at a known power level and adjust the Master Trim settings for the correct power reading.
  • Page 20 Calibration Cont’d Final details If everything has checked out to this point, you can complete the assembly of the controller by adjusting the LEDs on the front panel to line up with the holes, and snap the switch caps in place on the switches. You can now install the cover on the controller.

  • Page 21: Operation

    Operation of the LP-100 is straightforward, and designed to require a minimum of input once set up and calibrated. There are only three buttons which are used in combination to access all the menus on the LP-100. There are four main modes for the LP-100, which are accessed by momentarily pressing the “Mode”...
  • Page 22 Peak SWR will show values a little higher than steady-state at times due to the wide dynamic range of the LP-100. As power drops to below 100 mW during speech, the SWR detector can sometimes grab a higher peak because of the lower accuracy at extreme low power levels.
  • Page 23 A simple way to provide reasonably accurate antenna Z on the LP-100 display would be to use a feedline which is a multiple of ½ wavelength in electrical length. There would still be some residual error due to feedline loss, but it would give a better representation of feedpoint Z.

  • Page 24: Circuit Description

    The LP-100 is unique in it’s design in several regards. Refer to the following block diagram during this discussion. First, instead of using a coupler that produces forward and reflected power signals, the LP-100 uses a pair of transformers that sample current in the transmission line and voltage across the load.
  • Page 25 Circuit Description cont’d Finally, the PIC provides a standard RS-232 serial interface for remote control and monitoring of the LP-100. Functions of the LP-100 can be controlled from a Windows® “Virtual Control Panel” program, either locally or over a network connection, including the internet.

  • Page 26: Schematic

    Schematic Page 1...
  • Page 27 Schematic Page 2 Coupler Schematic...
  • Page 28 Below are some problems that have been reported and solutions. If you still have a problem, I am always available by email at larry@telepostinc.com and the newly formed LP-100 Yahoo Group is available at http://groups.yahoo.com/group/LP-100/ For excessive current, always check for solder bridges and proper orientation of ICs first. If a step calls for more than one IC to be added and current is excessive, remove the ICs and re-install one-by-one until you narrow the source of the high current.
  • Page 29 Troubleshooting cont’d...

  • Page 30: Software

    TRX-Manager for display inside TRX-Manager, either locally or over the internet. The other, LP-100 VCP Master, allows the LP- 100 to use TRX-Manager’s remote telnet facility to make a remote connection between the LP-100 and the VCP. In addition to the LP- 100 VCP, you can communicate with the LP-100 with a terminal program or your own software using the following commands…...
  • Page 31 The “Splash” screen will now indicate the new version. LP-100 Plot I am putting the finishing touches on the LP-100 Plot program. I will upload the files to my Downloads page as soon as I finish it up. For more information, visit my website.
  • Page 32 Gain Zero 6m Trim Gain Slope Trim Phase Zero Trim Phase Slope Trim Lo/Hi Power Trim Reference Log the initial CAL constants for your LP-100 in this table. If you ever make changes, you can log additional constants in the spaces provided.

  • Page 33: Warranty

    If failure occurs within the warranty period, return the LP-100 to TelePost Inc. at your shipping expense. The device will be repaired or replaced, at our option, without charge, and returned to you at our shipping expense. Repaired or replaced items are warranted for the remainder of the original warranty period.
  • Page 34 Appendix A...

Table of Contents