DIY Red Heat Lightning 4 coil, help needed

[RH-Lightning]

Hi,

I'm trying to keep a Red Heat Lightning 4 alive, the original 8.5DD coil is faulty, it faults on mechanical impact and slight pressure.

Original coil is 4 pin

Original coil cable:


Pin1-Pin2 (red-black, Rx?) = 28.2 Ohm
Pin3-Pin4 (white-green, Tx) = 30.6 Ohm

I've found induction data for concentric 9'' coil on this forum:
1-2(Rx?)=5.6mH; 3-4(Tx?)=5.4mH

Drain wire is soldered to Pin4 at the control box at attached to ferrite screen in the coil.

It looks like Rx and Tx are wound with the same wire, 0.4mm it seems.

What could you say about this coil? Tx Rx small resistance difference is ok?
Concentric and DD induction data is always the same? Can I use that data for reference?

Is it possible to tell which one is Rx and Tx?

I will try to make a OO coil (a la Nexus) with the same winding diameter.

FOMA's method seems ok to me
http://www.geotech1.com/forums/showt...or-Very-simply

Although this method describes how to measure using a generator for the case when you only have a coil, without the control box. I would use a frequency measurement from detector itself, not from the generator. Is this achievable by reading from the pins?

Please help to extend the life of this rare beast.

[RH-Lightning]

Measured resonance frequencies, measured from control box:
Tx = 13,412 kHz
Rx = 12,484 kHz - measured by connecting Rx to Tx pins.

Something is wrong with my calculations:


I've measured resistance of 28.2 Ohm, why is the calculated resistance so low? To get the needed 28Ohm I need a >200cm diameter.

[homefire]

Looks like you managed to get it apart quite well. The issue could be as simple as your shield connection in the housing. Have you investigated that and seen what's going on ?

[RH-Lightning]

thanks for a reply.
shield connection seems ok in the coil and at the control box. Graphite screen was also ok and connected to cable shield.
my guess is that original coil is not mechanically stable and the problem got worse over time.

I'd like to wind a coil myself, mostly for the sake of experiment and also to make the detector more stable.

[ivconic]

Coil with lower inductance is TX coil.
Easy to trace connection on pcb and see which one is which.
Any older Tesoro coil should suit there too.
Coils like at Golden Sabre, Silver Sabre etc.
Here on forum you have so many examples and primers how to diy such coil.
Look up for it at "TGSL" threads.
Red Heat is nothing but customized Tesoro.

[RH-Lightning]

Thanks ivconic.

Early Red Heats are indeed iterations of Tesoros. This is a 4th detector in this line, probably just updated, I don't know.
Control box is glued together, I will not open it now. I will open it when it dies

I'll make a small coil first, OO with 10cm D for one winding. to test the skills.
What does it mean 'faster' coil? I understood that if Tx is wound with thinner wire, coil is called 'faster'. I've tried to search it on forum without success.

[Qiaozhi]

What does it mean 'faster' coil? I understood that if Tx is wound with thinner wire, coil is called 'faster'. I've tried to search it on forum without success.

That only applies to PI detectors. The RH detectors are all VLF.

[kt315]

first of all you need to exchange cable on new one. without that you can not run ahead and all thread is senseless chatter. also right away
add the fitting.

[kt315]

guys, i took this pic from PDF with schematics. can anyone tell about this coil?

[ivconic]

guys, i took this pic from PDF with schematics. can anyone tell about this coil? [ATTACH]38862[/ATTACH]

Arado?

[homefire]

All I see is a Typical TR Balanced/Null type coil set up. Without any other values it could be set up for a number of frequencies.

[RH-Lightning]

hi,

Sorry for upping an old thread.
I have once again got the old Redheat out of a closet..

I don't know why I did not check it first time, but all 4 pins are shorted.. any two pairs..
same thing with shield wire unsoldered in the connector.

This means that resistance measurements cannot be trusted. What about frequency?

I will start with a TGSL type coil and see how it goes.

Any ideas/help are appreciated.

[waltr]

Measured with a DVM?
Maybe due to it cannot measure that low of resistance. What does the meter measure when connecting leads together?
Or, the cable or connections inside the coil housing are shorted.

[kt315]

This means that resistance measurements cannot be trusted. What about frequency?
---

we need (mean) INDUCTIVITY measurement, NOT Ohms - that we call 'L', in milli-Henry or micro-Henry (unit). also resonance frequency, if there is possibly.

[sinclairuser]

to be fair KT suggested changing the coilwire up the thread, i would do this, and while the cable is unsolder-ed i would take measurements direct from coil, you can check the wire too while its not connected.