31 May 2007

Magmount base apocalypse

D@mn d@mn d@mn!
After 15 years I bought a new magnetic base to use on my car. At the local shop (yeah, we still have a CB/HAM store!) I got a thing called BM-180-PL, 100% China Export.

The magnet is large but I have the feeling it is not so strong.

At the first usage the nut holding the SO-239 in place lost its thread and the center conductor from the RG58 cable detached (it was even a cold solder joint!) . Forensic analysis showed that the nut was made of aluminium. No wonder...

After my fix the rubber protection does not stay in place anymore.

Today I tried to detach my old "President Dallas" antenna from the base but... antenna and SO-239 were turing together!!!!!! D@mn d@mn d@mn!

28 May 2007

Boom to mast

I could finally work out a way to plug the 5 element on a fishing rod.

My mast will be a telescopic fiberglass fishing rod. I need a way to attach the boom that does not compress the rod structure: no screws and no holes!

So I sled the "4m telescopocket" fishing rod into a segment of 25mm PVC pipe: it stops somewhere at about 2.3m from rod bottom. Enough for a VHF yagi! So I found this way of attaching the PVC pipe to the boom:

I might also add a small 3mm screw in the intermediate holes to reinforce the whole assembly.

Please do not tighten nuts too much otherwise the PVC pipe bends inwards!

22 May 2007

Lab in the kitchen

You don't need a whole room to have a lab, the kitchen table can be very helpful for some night building sessions!

Don't forget to clean it up for next morning breakfast!

17 May 2007

How does a DRM converter looks like

This is what I built for an SWL for his R-75.

From left to right: IF cable (top), 12 kHz cable (bottom), converter, 9V clip, on-off switch.

08 May 2007

No HAMs allowed?

Apparently only "Citizen Band" CB cars were allowed at these gates!

Effect of CW narrow filter (500 Hz)

Listen how a narrow filter (500 Hz) turns CW from a fatiguing activity to a fun and relaxing mode!


The filter used is homebrew using manufacturer original parts, but it costs half of it.

07 May 2007

FT817 battery pack (external)

One lucky day at a supermarket I found "4x2600 mAh NiMH + wall charger" incorrectly priced at 9.90€. Two packs came home with me to become an alternative power source for my FT-817.

Off-the-shelf cells cannot be soldered, so I got hold of a 8xAA holder and added red/black female "banana" sockets. It also had a fuse, but the chna plastic holder broke the second time I opened it (for preliminary fuse inspection).

This pack holds at least 3 hours of VHF SSB contesting at 2.5W. I have not tested it 'till the end, but the voltage still read above 9.6V when I got back home.

It weights about 300 grams, whilst a Sealed-Lead-Acid 12v/3Ah weights about 1kg

Got and get them! 2500/2600 mAh AA cells are now even cheaper!