Jun 12, 2008

HB0- summer 2008 preparation; Packet Link Setup

Preparations for another summer trip to Liechtenstein (HB0) are runnning fine.

One of the things missing at our mountain top location on the "Sareiser Joch" in Malbun(www.sareis.li), is an internet connection. Disturbing how quickly you get used to that common luxury when it is not availably for a change. A Long, (very) long time ago we started with pen & paper log but got quickly spoiled by the DX option in N1MM logging program :)

In the past our group (HB0/PI4TUE) has always succesfully used a packet link, which provided dx cluster info and, entry to relevant convers chat channels. Unfortunately our packet-node mini laptop (toshiba Libretto) from Gert, PG5D died 2 yrs ago. We were desperately in need for a new setup.
Personally I very much dislike anything related to soft/hardware programming. But one great advantage in group dynamics is that there's always someone who does like this stuff and will go to the bottom to get such working.

What is needed for our local packet node setup?
  • Short 430 MHz Yagi Antenna
  • TRX with 9K6 capability (Kenwood TMD700)
  • Laptop with AX25 Packet Node on Debian Linux OS
  • Wifi Router/USB-Hub Philips

How to build your quick & dirty 430Mhz Short Yagi
Cannabalize an old UHF TV antenna and re-use its boom and mounting bracket.
Find some alumn pieces and cut them to the required lengths according a 9el design on DK7ZB's website. Next, cut some trespa pieces and 'pop' them together with the elements to the boom. Now use any water resistant(Class: IP65) wiring box from an electronics store for the dipole. The balun/impedeande transformer is made from 2 pieces 0.25 wavelength 75 Ohm coax.
All done in a saturdays afternoon. Can't be more simple than that, now can it?

The mast is a fibre type. At only 4mtrs height in the middle of a small village, it receives the packet provider PI1EHV on 430.925 at 22kms distance, loud enough for a probeabely solid AX25 connection.

Test setup
We're up and running! Nice to "hear" that vintage 9K6 noise data connection on the 70cm TRX again.
Compliments to Rens, PA3FGA who spent 3 weeks building & programming the whole setup including the antenna.

The dx-cluster runs on the above old laptop packet node on the left. From N1MM on the wirelless connected client laptop on the right, we can setup a packet link within seconds. Three different laptops have been tested simultaneously and work perfect.
I'm getting in that dx-pedition mood again :)

What is next?
  • Build a time server so all N1MM client laptops run the same system logging time
  • Rebuild the 5el 50Mhz DK7ZB yagi
  • Build a new 50MHZ long boom yagi ??
  • Rebuild and test the old K9AY
  • re-align the IC746 and do the IC151 mod
  • etc..etc..


Mark, PA5MW said...

I actually got it wrong on the text "The dx-cluster runs on the above old laptop packet node on the left".....
that laptop serves as an individual packet node only.

The dx-cluster is run from N1MM via 1 of the clients and distributed to the other clients automatically, avoiding unneccessary addiotnal packet link connections.

'73 Mark, PA5MW

pa3fga said...

small mistake in the drawing:
4xusb @ wlan router = 4x rj45