W4NJA Field Day Computer Networking 2014 - … · 05/04/2014 · Document: W4NJA Field Day Computer...

Document: W4NJA Field Day Computer Networking 2014 | Version: 20140405 1

W4NJA Field Day

Computer Networking

2014

Document: W4NJA Field Day Computer Networking 2014 Version: April 5, 2014 Author: Paul Smith – ND4X


For the last few years the Paducah Amateur Radio Association (PARA) has had

excellent HF radio equipment, computers, and most importantly club members

showing up to operate the radios and assist in any way they can.

The one issue we have been facing however is a reliable wireless network, to link

the logging computers (N1MM software) together in a 100% reliable manner.

Because we have been operating from within a DES communications bus, an RV

and a public pavilion, all spread out over a local park, we were taking normal

wireless cards past the limits of their normal ranges.

So this year, for the 2014 Field Day event, PARA decided to tackle this hurdle, with

an improved wireless network plan. The RV has always been in the center of the

operating area, so we decided to place an external omni‐directional vertical

antenna there, and use high gain directional antennas at the other two locations,

pointing back to the RV and the omni‐directional antenna.

Ed, AB4IQ built the omni‐directional antenna for the RV. The beam antennas are

commercial units manufactured by MFJ and are model MFJ‐1800. The Model

MFJ‐1800 is a 2.4GHz Wi‐Fi antenna made for 802.11b and 802.11g wireless

networks, providing 15 DBi gain with 16 elements.

Now that we came up with an antenna solution, the next step was to figure out

how to connect the logging personal computers to them, in order to achieve that

100% reliable network we were striving for. The standard USB style wireless

cards would not work, because they had no means to connect to the “N” style

connector found on the antenna.

We then decided to purchase three of the commonly available Linksys (Cisco)

Wireless‐G broadband routers, Model WRT54GL, Version 1.1. These units

operate on the 802.11b/g wireless standard at 54Mpbs.


This would give us the flexibility we would need in 2014 and for several years and

events to come. The dual antennas on the back can be unscrewed from the base

unit. By utilizing this feature, we could leave one of the standard antennas

connected for local wireless connectivity in the immediate operating area if the

need should arise, while removing the second antenna and connecting it to the

beam or omni‐directional antennas for wide area support, through a coax jumper.

The second feature that we saw as am important feature was the ability to

connect up to four personal computers to each of the routers through the four

integrated 10/100 Mbps Ethernet ports. The third import feature of these units is

that they are DD‐WRT compatible. By upgrading the standard “out‐of‐the‐box”

unit and firmware to DD‐WRT, we could control the network to an extent not

possible before. For more information on DD‐WRT, see the benefit summary and

configuration procedure later in this article. By building on this platform, it now

becomes easy to expand our operation from the three current stations, to any

number we wish in the future, by adding an additional antenna and router with

the upgraded firmware.

The site we use for Field Day is heavily wooded, making wireless networking in

the 5 GHz frequency range extremely difficult. Because of this we choose to use

the 2.4 GHz range, which is native in the Linksys router. Also, since the N1MM

logging program used at field day passes all data between the logging computers

in plain text, we decided to lower the transmission rate from 54 Mpbs to 11

Mpbs. Faster is not always better in extreme environments, 11 provides more

than enough throughput, and by locking all routers at 11 Mpbs, there was no

interruptions caused by trying to auto‐negotiate for a faster link.


The logging personal computers are to have statically assigned IP addresses in the

192.168.1.70 through 192.168.1.99 range.

A WAN link to the internet is possible by using an Ethernet modem connected to

the Internet Port on the central router.

After you configure the firmware upgrade to DD‐WRT and then set all the

configuration parameters, you still have one very important job to do before

testing. Label Everything. This cannot be said enough. If you use the routers


once a year at field day, you will forget some of the settings and setup from year

to year. This especially helps others who are assisting with setup. Trying to

remember which cable goes where, or which box is which in the middle of a

thunderstorm is not a fun way to begin setup. Here is how we labeled our

routers.

Central Router (There is only one router configured as the Central Router, any other attempt will not end well during

testing.)


Secondary Routers (Note the top has different WAN labels, and the bottom has the unique IP information for each

secondary device.)


Logging Personal Computer Configuration

Connected to Router W4NJA‐001 W4NJA‐002 W4NJA‐003

IP Address 192.168.1.70 192.168.1.71 192.168.1.72

PC name


DD‐WRT Benefits

DD‐WRT firmware lifts restrictions on a router by providing advanced capabilities that can improve your Internet experience. Here's a list of a few specific DD‐WRT benefits:

1. Adjustable antenna power to increase your wireless spectrum. 2. Stability of running a Linux based non‐proprietary firmware. 3. VPN (Virtual Private Network) pass‐through capabilities. 4. Advanced QoS (Quality of Service) controls for bandwidth allocation to your

various Network connections. 5. WDS wireless bridging /repeating protocol AKA the "Repeater Bridge"

mode, which allows you to easily expand your network using a second wireless router.

6. Cycle your router from the Administration settings. 7. Built‐in DNS (Domain Name System) caching ‐ speeds up your connection to

an array of sites. 8. Viewable performance graphs and statistics to watch your network

performance and measure your bandwidth levels. 9. Configure the router as a Wi‐Fi hotspot for your business or neighbors with

a verification page using the integrated Chillispot or NOCATSPLASH. 10. Radius Authentication for additional wireless security. 11. VLAN (Virtual Local Area Network) Support. 12. A functional DHCP (Dynamic Host Configuration Protocol) server. 13. Create unique SSIDs (service set identifiers) when using multiple routers. 14. NAT (Network Address Translation) support. 15. Frame Bursting Capabilities. 16. Software support for the SD‐Card hardware modification.


DD‐WRT Configuration Procedure

First the DD‐WRT software must be downloaded to your personal computer.

Version 24 was available for the Linksys routers at this time. You will need to

download both the mini and standard versions into two separate download sub‐

folders on your personal computer.

The download site is “http://www.dd‐wrt.com/dd‐wrtv2/down.php?path=

downloads%2Fv24‐sp1%2FConsumer%2F Linksys%2FWRT54GL_1.1/”.

Make sure the WRT54GL is connected to a UPS power supply.

Now, disconnect your personal computer from the outside internet and hook it

up to LAN Port 1 of the router you are going to upgrade. Do not go through a

network switch, doing so will cause the upgrade to fail and you will brick the

router.

Give your personal computer a static IP address of 192.168.1.73.

Now you have to do a hard reset on the WRT54G router. If you do not do it

exactly like this, you will turn your router into a brick for the trash man to pick up

next week. This is known as a “30 30 30 reset”. To do this:

1. Press the reset button with the unit powered on for at least 30 seconds –

do not release the reset button until you are completely done with the

third step.

2. Now, still holding in the reset button, unplug the router for at least 30

seconds, still holding in the rest button. Do not release the reset button

until you are completely done with the third step.

3. After 30 seconds, plug the router back in, still holding the reset button in.

Keep the reset button in for 30 seconds. Now after a total of 90 seconds

“30 30 30” has finally passed, you for release the reset button.

After you have completed the reset on the router, use your web browser and surf

to it using the IP address of 192.168.1.1. You will be prompted for a User Name

and Password. Leave the User Name blank and enter a password of “admin”.


Note the existing Firmware version in your router. It will be shown in the top

right corner. In this example, it is Firmware Version v4.30.14.

Now click on the “Administration” tab.

You will again be prompted for the User Name and Password. Use the same

information you entered earlier.

Now on the menu line under Administration, click on “Firmware Upgrade”.

Browse to the folder on your personal computer where you downloaded the DD‐

WRT firmware upgrades and select “dd‐wrt.v24_mini_generic.bin” file. You have

to upgrade to the mini version first, and then do another firmware upgrade to

install the DD‐WRT Standard version. You cannot go straight to the DD‐WRT

Standard version, your must upgrade to the Mini version first.


Ensure that you are connected to a UPS. If you should lose power to either the

personal computer, or the Linksys, during this process, you now have a nice new

fancy brick.

Click on “Upgrade” at the bottom of the screen.

The upgrade may take five minutes or more. Do not interrupt the process,

whatever you do. You will see a progress bar in the middle of the screen showing

percent completed. Read the next step below before clicking on any buttons.

Again, failure to do this will brick your router.

After the upgrade appears complete you will get the following message. Do not

immediately click on “Continue”. There are still processes going on in the

background. Just let it set at this screen for a full five minutes before doing

anything or clicking “Continue”. This is very important.


Now after at least five minutes have passed, process “Continue”. This will reset

and reboot the Linksys WRT54GL router.

You will now be prompted for a user name and password after the router rest.

Because we upgraded the firmware to DD‐WRT, the login information is now

different. The User Name is “root” and the Password is “admin”.

If all is successful, you will see the following screen.

As you can see when you compare this to the screen shown above, several things

have changed. Linksys in the top left has been changed to dd‐wrt.com. If you see

this, you can uncross your fingers and toes; you did not brick your router during

the upgrade. A close examination of the two screens shows several additional

features and changes.


You are now half way through the upgrade process. You have completed

installing the Mini version. Now you will install the Standard version.

The next steps will be much like installing the Mini version of DD‐WRT.

Click on the Administration Tab.

Click on “Firmware Upgrade”.

The dropdown for “After flashing, rest to” should be set to “Reset to Default

settings”.

Browse to the folder on your personal computer where you downloaded the DD‐

WRT firmware upgrades and select “dd‐wrt.v24_std_generic.bin” file.

Click on “Upgrade” at the bottom of the screen.

The upgrade may take 300 seconds or more. There is a countdown timer in the

middle of the screen showing how much time is left for the upgrade. Do not

interrupt the process, whatever you do. Read the next step below before clicking

on any buttons. Again, failure to do this will brick your router.

You will now see a message saying “Upgrade Successful” and the unit will reboot.

During the reboot you will lose your web interface page.

After the reboot is complete, surf to 192.168.1.1 again using your web browser.

You will see the following screen.


Key in a password you can remember. For our example we will use “paraw4nja”.

The User Name will remain “root” (this is a Linux based box). Remember your

password, without it you are dead in the water.

You will now be forced to click on the “Change Password” button.

There are so many new features; it is hard to begin explaining them all. One of

the interesting ones is the ability increase the standard transmit power of the

WRT54GL from the out‐of‐the‐box 70 mW setting all the way up to 251 mW.

While this does not sound like much of an increase, it makes a huge different in

range. One note on increasing the power setting however, with increased power

comes increased heat – so be careful in an environment that is not air‐

conditioned, like Field Day.

Now you are ready to configure the Linksys WRT54GL router. Only the changes

mentioned need to be made. If you make a change to one router, you need to do

it to all to keep them consistent.

Router Name W4NJA‐001 W4NJA‐002 W4NJA‐003Local User root root root

Local Password paraw4nja paraw4nja paraw4nja

Local IP Address 192.168.1.20 192.168.1.21 192.168.1.22

DHCP Address Range 192.168.1.200 ‐ 205 192.168.1.210 ‐ 215 192.168.1.220 ‐ 225

GUI Port 8080 8080 8080

Security Mode WPA2 Personal WPA2 Personal WPA2 Personal

WPA Algorithms TKIP+AES TKIP+AES TKIP+AES

WPA Shared Key PARAW4NJApara PARAW4NJApara PARAW4NJApara


Central Router Configuration – W4NJA‐001


Secondary Router Configuration – W4NJA‐002, Etc.

W4NJA Field Day Computer Networking 2014 - … · 05/04/2014 · Document: W4NJA Field Day Computer...

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