RCB Circuit in BBS 1000 & 10" Tornado coil

[Minelab50]

Does anyone know if the RCB circuit is in the Excalibur 1000 standard 10" coil? I know the Tornado 10" and the Excalibur II 10" coils have it. this circuit is used as a depth booster.

thanks,

good diggin........................................randy

 

[Critterhunter]

As far as I know all Minelab and most aftermarket coils have the RX gain circuit inside the coil. I have read that there were some aftermarket coils that didn't use it, and my guess is that maybe the first Kellyco Penetrator coils years ago from Detech didn't use them. I know the SEF coils have the circuit, as well as the S12 and I would assume WOT does. A coil lacking this pre-amp circuit would be a rather poor performer. All it does is take the RX signal and give it an initial boost so that it's strong enough to travel to the control box where the sensitvity control performs another boost in gain of the signal based on where you have that set. By boosting the signal some at the coil you are also doing this before noise is picked up traveling to the control box, so in effect you are amplifying the signal before it gets more "dirty" later on. That's why shortening the coil cable could improve performance as it should pick up less noise, not to mention less wire resistance means more power at the TX winding.

 

[Critterhunter]

As far as I know all Minelab Sovereign coils have the pre-amp. I also saw one salvaged from a S-12 in another forum, and my readings taken of the SEF coil pin outs show that they have them as well. I caught a small blurb on another site that said some early after market coils didn't have one. I would guess those might have been the early versions of the detech penetrator round coils because they were said to be poor performers and the WOT appears to have this circuit, which is the only other aftermarket coil being made early on as far as I know. There are guys on the Geotech forums that have built Sovereign coils and have duplicated this circuit, providing a schematic.