Re: Re: LF: RE:G4HUP aerial current meter

["dhchurch@lineone.net" <dhchurch@lineone.net>]

Having just put this meter into use, I must point out that the dc output from the BAT42 diodes is about 15V for the 1A range so I would have thought actually potting this down after rectification with 10A would promptly see off the diodes which, I think, are rated at 30piV.

Hugh, M0DSZ

---

dhchurch@lineone.net

 

From: DK7FC

Date: 2017-08-05 10:46

To: rsgb_lf_group

Subject: Re: LF: RE:G4HUP aerial current meter

Hi Ian,

 

When the range of a current tranformer should be increased from 1A to

10A, the best way is to increase the number of turns of the secondary

winding by a factor 10. This transforms the current down by a factor 10

(not up) in the secondary winding...

I*N has the same value on both sides (ideally/theoretically).

 

73, Stefan

 

Am 05.08.2017 11:35, schrieb i.frith@ntlworld.com:

> Hello Allan

>

> I assume the 10A mod is a matter of increasing the series R with the

> meter to around 800k?

>

> I suppose a 3way switch and extra trim pot could be added to preserve

> the 1A range too.

>

> Thanks for the note re-shipping Monday.

>

> Look forward to getting the Kit.

>

> 73

>

> Ian G4GIR

>

> -----Original Message----- From: Alan Melia

> Sent: Friday, August 4, 2017 9:36 PM

> To: rsgb_lf_group@yahoogroups.co.uk ; rsgb_lf_group@blacksheep.org

> Subject: LF: RE:G4HUP aerial current meter

>

> It has just occured to me that the 1A range may not be high enough for

> some

> of the LF QRO merchants. There is a simple mod which will extend the

> range

> up to 10A though you should be aware the ferrite core has not been

> tested at

> this level of RF. These cores are used on mains leads carrying up to

> 13A so

> I think they will be OK.

>

> Thank you to those showing interest, there are a few kits still

> available.

>

> Alan

> G3NYK

>

>