Building the Ultrasonic Antifouling Kit from Jaycar

**Norman_E** · 15-02-11, 18:19

Originally Posted by nigelmercier

Not sure this is a good idea, unless it is a trickle/float charger. Otherwise the batteries get a boost charge with no time to absorb it. Might be better to do it for a couple of hours once a week.

Its an old but good quality charger that switches to float mode. I have run it that way last winter, with no load on the batteries, without ill effects.

**photon** · 16-02-11, 16:57

I have followed this topic and am now in the process of building 2 of these kits. The component the mystifies me is the one that NormanE has placed in the PCB marked "link". I assume that this is a small resistor-like component, sand coloured and with one black band in a central position. The component is part of the kit and is the only bit not identified anywhere in the information that Jaycar sent. Can anyone confirm this?

Otherwise this kit seems easy to build even though the last kit I built was just after transistors were invented. The components are not always easily recognised, especially the two small zener diodes.

Regarding potting the transducer, the outer packet material for the urethane potting compound is a aluminium/polyethylene foil laminate and is an excellent substitute material for the cling-film mentioned in the instructions as it does not ruck. It has a paper label glued on the outside which could be used with PVA glue to adhere this material to a flat sheet of board with the packet inside face upwards. I can confirm that with a tiny smear of vaseline on the inside face material it released from the cured compound leaving a very smooth potted transducer.

**wizard** · 16-02-11, 17:50

[QUOTE=photon;2835992]I have followed this topic and am now in the process of building 2 of these kits. The component the mystifies me is the one that NormanE has placed in the PCB marked "link". I assume that this is a small resistor-like component, sand coloured and with one black band in a central position. The component is part of the kit and is the only bit not identified anywhere in the information that Jaycar sent. Can anyone confirm this?

I had the same problem when I was building and did in fact put the "resistor" to one side thinking it had been put in by mistake - but on checking it with a DVM it produced zero ohms and looking at the colour photo -there it was.

**Norman_E** · 16-02-11, 20:46

See the very first post on page 1 of this thread. In my case the 10 ohm resistors were coded brown, black, black gold, brown, meaning 100 divided by 10 = 10 ohms, with 1% tolerance.

I have not seen one that is coloured as you describe, but if it has very low resistance, and you have correctly identified and placed all the others, then it is the link resistor.

I had to use an illuminated magnifier to be certain that I had all mine correct.
EDIT: Look at it very carefully with the magnifier, the brown and gold stripes do not show up very well to the naked eye.

**photon** · 16-02-11, 23:19

Thanks. to both respondent The component must be the 10 ohm resistor but with a certain economy of ink! Both circuits finished now and in testing makes my AM radio whistle like a canary when the transducer comes near.

**Norman_E** · 17-02-11, 10:26

I never tried it with a radio, but that sounds correct. Both of my units produce a faint clicking sound when operating, but you have to be in a quiet place to hear it.

**wizard** · 17-02-11, 17:52

Originally Posted by photon

Thanks. to both respondent The component must be the 10 ohm resistor but with a certain economy of ink! Both circuits finished now and in testing makes my AM radio whistle like a canary when the transducer comes near.

Any particular frequency?

**Talbot** · 17-02-11, 18:46

Originally Posted by wizard

Any particular frequency?

More to the point - is this going to be a problem for an SSB?

**petehb** · 17-02-11, 20:04

Originally Posted by photon

I have followed this topic and am now in the process of building 2 of these kits. The component the mystifies me is the one that NormanE has placed in the PCB marked "link". I assume that this is a small resistor-like component, sand coloured and with one black band in a central position. The component is part of the kit and is the only bit not identified anywhere in the information that Jaycar sent. Can anyone confirm this?

Otherwise this kit seems easy to build even though the last kit I built was just after transistors were invented. The components are not always easily recognised, especially the two small zener diodes.

Regarding potting the transducer, the outer packet material for the urethane potting compound is a aluminium/polyethylene foil laminate and is an excellent substitute material for the cling-film mentioned in the instructions as it does not ruck. It has a paper label glued on the outside which could be used with PVA glue to adhere this material to a flat sheet of board with the packet inside face upwards. I can confirm that with a tiny smear of vaseline on the inside face material it released from the cured compound leaving a very smooth potted transducer.

Sorry not been able to do it earlier but here is a close up of the board with the link in place:

Should confirm what you have done. There is a reference to it in the componant list R1R1500 and it is shown in fig 2 page 38 of the accompanying blurb.