Jul 6, 2008

HB0-summer 2008 preparation; 50MHz 7el PA3FGA design

Design 50MHz long-yagi by PA3FGA

From 7th july onwards PC5A, PA3FGA and PA5MW will be QRV from HB0 (www.sareis.li).
We have decided to use 2 different 50Mhz yagi's in order to maximize our performance; one 5el/5mtr boomlength DK7ZB design and a 7el/9mtr boomlength PA3FGA design.

Rens PA3FGA designed this long yagi, starting from a basic 7el/28Ohm DK7ZB version. He optimized the pattern, using a boom length of max 9mtr for reasons of transportation restrictions (max.3 mtr). The F/R specs have been optimized at only minor gain loss. See radiation plot.

Building the antenna

During these last 3 weeks Rens has been busy building this 'portable' 7el/9mtr(30 ft) boomlength long yagi. The whole package should be easy transportable on a car roof. However; Rens is not the kind of guy to produce just any 'temporary light- weight easy-to-go' construction. This meant balancing the various criteria, stretching all mechanical possibilities.

The single elements are mounted with help of customized 'perspex' plates which clamp on the boom.

Matching to the '28 Ohm' radiator is done via a 2x 1/4 wave 75 Ohm coax in parallel, according original DK7ZB design. Boxes are type IP66 and 100% waterproof.

The completed 30ft/9m antenna just fits in the backyard garden:

This is us, positioning the 28/50Ohm transformer section on the boom (PA3FGA, PA5MW).

Any practise results yet?
That is a defenitely no. We have no time left and just count on our luck ( and perhaps Murphy?).
There are still other things left to do before our departure tomorrow.

Meanwhile, while packing my stuff I managed to work from my shack:

6m today:

earlier this week:

Jul 2, 2008

HB0-summer 2008 preparation; IC746 alignment

My holidays have finally started; spend time in the shack, do the garden and visit a barber.

Time to do the Icom 746 alignment

Goal: check/optimize receiver adjustments.
Some 5 years ago this rig has been upgraded with INRAD SSB and CW filters and the RX gain setting was changed.
The master LO is dead on 60Mhz, showing 8Hz offset. The Philips PM6615 frequency counter (incl txco) was calibrated >5yrs ago. It is within 10Hz from the Marconi 2955 which was calibrated when I bought it in Germany in......ooh well!

What settings were re-aligned?

LPL VCO Lock voltage; level at 1.84V instead of 2.0V
- RX peak L241
- Receiver total gain; setting from '38' back to '32' (about 30deg. on the potm)

All other adjustments proved within specs.
The software menu adjustment procedure was skipped; s-meter settings and stuff do not make QSO's.
Hooked up the 746, just in time to work TO5E (st Barthelemy dx-pedition), COOL!
Pity my logging software(DXBase 2006) is so difficult to upgrade with new countries; already 3 not recognized: E7 Hercegovina, 4O3 Montenegro and the TO5.

Time to collect stuff from my garden-house:

From left to right:
- 5el +boom parts 6m DK7ZB home made yagi
- 10m fibreglass DJ6NI pole for K9AY setup
- 10m Alu mast (70mm bottom, 35mm top)
- Comet GP3 2m/70cm packet antenna
- Rotor cable
- 'Tool' to find clear HF frequency, manage pile-up etc. :)

Good propagation today on 6m!

This morning, while eating my cereals, I worked Man JL8GFB on 50095.5 He was in and out the noise but very LOUD. I touched him on a few occasions but due to QSB he copied my callsign only partly. With some patience I wkd him during his peak some 20 minutes later. Check out his breathtaking setup at:

6m band is exploding today; zillions of signals calling asia and many other directions. Just wkd CN & CT3 which brings the country total at 46 for 2008.