May 27, 2009

Es III; Building antenna's just for the fun of it

Seasonal holidays on Thursday and Friday.
Two days free from office stress.
Dry sunny weather.
Fresh Diemme coffee beans, grinder and Gaggia Espresso machine.
YL on a 5-day trip.
These are the perfect conditions for a few days out in the wild. Errr... the antenna backyard that is.

Step 1: collect aluminium

Collected all aluminum of the 7el 50Mhz long yagi which we succesfully used in HB0_2008. Taped it to my bicycle and of I go. What a nice way to start the day :-)

However, it turned out I missed the long middle boom-section. So after a nice espresso & cappuccino we collected the other antenna parts, including another 5el version, also home made. Us have plenty of (home made) antennas by now. It has paid off well. Both in the fun of building them, as well as using them.

My hybrid sports-bicycle has a pretty short wheelbase. And that is VERY scary with this pile of alu tied to it. As soon as you make a turn the alu is trying to keep going straight ahead and starts shaking its head and tail. The whole bike starts oscillating and that makes each road turn a struggle.
The second standard dutch city-bicycle (ages old model) did not suffer from this effect.

Step 2: build antenna

Empty transport boxes from last summers HB0 dx-pedition. Find baseplate, connection box, coax transformer and several brackets. Locate that carton of very special screws. Drink some more espresso & cappuccino.
Start building the element brackets again.

TiP: through the process we learn that it (would have been) is very important to proper indicate all parts involved, for future reference (yes, please?).

That ends day one. Time for some espresso & cappuccino.

Step 3: mount mast construction
Local rules and neighbourhood control prevent us from building a giant mast. But an antenna is an antenna and certainly beats no antenna. Next, Rens' garden has an almost free view to the west with very low noise. Opposite to my home situation, which makes this a valid remote rx site. Now let's start with some fresh espresso & cappuccino.

Stones are 10cm thick. A special mounting screw for professional use in machinery is being used.
Top bearing and G-1000 Yaesu rotor are added. Time for some lunch and more espresso & cappuccino. Not that you think we started already at "ooh-eight-hundrud". No way, it's holiday time ;)

Step 4: hoist up the antenna

At this relatively low height the antenna is easy hoisted up and mounted to the mast.
Both seriously sweating here under the direct sunlight. Now the 20m Ecoflex-15 (15mm dia) coaxial cable is attached and connected to an Elecraft K3 +pre-amp.
Let's catch some multi-hop-Es dx.
Fire up all equipment...... and .....
Band closed.
Time for some more espresso & cappuccino.

The 50MHz 7element, PA3FGA design @10mtr AGL, QTF caribic.

Step 5: fresh pork
Earlier this day we visited an 'old fashioned' butcher. One which cuts the meat in their back shop. Not any vague import meat from far-far away. No supermarket pre-sugared-thin-slices-crap.

Make fire.
Start with some lovely marinated spare ribs.
Next the real stuff.
Only meat today.
Certainly NO vegetables or salad-trash to upset your stomach.

Now, there's always room for a finishing espresso & cappuccino.

May 24, 2009

You get what you.......

Ok, what's wrong in this picture?

Issue #1
N-socket nicked, coming loose from its mounting plate.
Also some nickel plating chipped off on the right.
Result from rough handling? Wrong tools / overtightening the applied N-connector?

None of this all.
Its the Heavy Duty N-connector and Ecoflex-15 (15mm coax) which did this in just 2.5 weeks during our last fieldday setup in HB0 at 2020mtrs ASL. Despite the coax being taped to the boom, it put too much stress on the socket while being turned. Needs better fixation against self rotating,more slack around the rotating mast etc... next time.

Looking at this type of socket we need to invest in better quality stuff whenever it matters (doesn't that always?).
It became a habit of locating a good deal (read cheap) of connectors & sockets at every hamfest we visited. Nowadays we are more serious on buying large qty's of the good stuff together with other hams from:
UKW Berichte

So the nickel-crimped version is exchanged for a machined silver teflon version.

Issue #2
Spotted the rust color on the top edge of the socket on the 1st picture?
That's not from the socket, since these are made from chrome plated brass. It's the 4 mounting screws.
From the local DIY store, type galvanized. Equivalent to: lasts one weekend.

Now you might think "buying Stainless Steel ends this, right?".
Not really.
There are plenty of "SS" versions around and the ones with real durability are difficult to find. Your DIY store probabely only has the (again) cheap version available.....

I know; not every single screw needs to be 100 micron goldplated, navy-proof and such.
But think again when you come across the next auction of cheap stuff.

May 1, 2009


Trick 1a: monitor Es propagation on 27Mhz SSB
For 2009 I promised myself to pull some extra rabbits out of the hat.
Remember the old CB SSB contacts during the evenings in the 80's? We thought that making contact with South-France, Spain, Italy etc.. was the ultimate dx. What did we know about Es propagation back then when I was only 16? With 12W in SSB, 120 channels etc. (non-legal) and a simple half wave vertical on the roof, next to girls&cars life was exciting to the max!

So why not monitor some CB SSB frequencies to detect Es openings?

A quick jump in a pile of old gear and I dig out both a legal CB rig (22 channels, 0.5W and FM only) and a typical flea-market-worn-out-120channels SSB true DX-rig.
Within milliseconds after switching it on I receive colourful memories from the past; it's that analogue S-meter. This type S-meter was used in most CB rigs in those days and although it looks miserable small, it resembles my youth. I have stared for zillion hours at that tiny needle. Those were the happy days. Yes sure they are.

La Lafayette seems way off frequency, the SSB section is horribly mis-aligned, no TX, but who cares?
Ok, now where do we connect it to?

Trick 1b: a quick home made vertical for 27Mhz
That shouldn't be too difficult. Grab a short fishing rod and cut some wire.
The quarter wave vertical, using 1 radial, is quickly mounted to the side of the chapel roof. Some fiddling with the antenna analyser and we're done, right?
At first I get a resonance at 25.2MHz and it seems parked there, no matter what lengths I cut. It turns out to be the the aluminium strip at the roof front edge, which is very nearby and exactly in resonance at...... Anyway, moving the radial just 1m away from it and the resonance goes up more than 3 MHz. Now both lengths are too short! I feel like an idiot.
Anyway, half an hour later we have CB antenna capability in the building.

The Lafayette offers muffled LSB signals from Mediterranean countries, thus proving there is Es going on.
Can you remember the 'old calling frequencies'?

26.620 South Africa
27.450 France
27.555 General calling freq. but mainly Italy
27.765 Germany, Austria, Switzerland
27.805 Holland + Surinam

I think I better keep it parked at 'triple five'.
Let's see what this trick will offer me, besides some nostalgic feelings :)

Worked some more countries on 6m during Es: 9H1 and an IT9.


2009 Sporadic-E Season on 6m has started !
I witnessed some minor Es openings on two evenings in a row, but that was between Spain, Italy and SV.
Never expected it would happen up here in Holland that soon.
However, this afternoon we enjoyed a short but strong opening direction South Spain, Marocco and the Canary Islands.
I managed to work EA9IB. That is country #4 this year.

See ON4KST screenshot below with lots of humor in the text.