Date: Wed, 26 Dec 2018 18:55:23 +0000
From: Chris Wilson <dead.fets@gmail.com>
Message-ID: <107957155.20181226185523@gmail.com>
To: Gaj Kumar <rsgb_lf_group@blacksheep.org>
In-Reply-To: <CANj9hPz8VeJM7XDEkX7YkYLq12fitkp07YQ7pu-_3ywmwXZEFw@mail.gmail.com>
References: <CF6820823EF84DF6BFF1C4EFAE7A675D@Clemens0811> <CANj9hPz8VeJM7XDEkX7YkYLq12fitkp07YQ7pu-_3ywmwXZEFw@mail.gmail.com>
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Subject: Re: LF: VU2BGS
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Hello Gaj,

Welcome to our small forum! You need to take a bit of care with
Chinese toroids, I have had some that when measured against branded
ones direct from the makers checked out well off specification. (I
have also had some that seemed fine, so it's a bit of a lottery. If
funds and hassle permit it's probably safest to buy from known vendors
of OE toroids. I run a QRP labs U3S without the PA section, and a
TS-590S as drivers. The 590S when "wide banded" by removal of a zero
Ohm resistor (or maybe it was a diode, I forget now but a very simple
mod) will give just under 1mW from the DRIVE socket on the back of
clean sine wave at 136 or 272 kHz.

I then use a simpler squarer powered from the ATU connector again on
the back of the 590 and a basic regulator to get square waves at twice
the desired TX frequency. Then I set the ADVANCED - X2 option in the
later versions of WSJT-X to give the correct output format. This then
directly drives a Class D LF amplifier based on the well tried W1VD
design and given 50V it will reliably give 1kW output. It will of
course run lower power on less volts, I have run it at 8V on occasions
for some QRP ;) You can build the same amp for MF, but my intermediate
licence here in the UK forbids me to TX on MF.

G0MRF has extremely well made and documented amp kits for about 400W
output on LF or MF should you wish a tried and tested complete kit of
bits.

The 590S when tested by David G0MRF on here, proved pretty good on LF
and MF receive too :) I am active on LF though and look forward to
watching and hearing of your activities. I also use a Red Pitay for RX
and it is a bit better than the 590 given a band pass filter and very
simple Ebay pre amp.

Very good luck, a happy Christmas and a healthy and prosperous New Year
to you and yours, it's very good to see you here :)

Wednesday, December 26, 2018, 4:14:10 PM, you wrote:


> Dear Clemens 
> Thanks for the kind suggestion I will look it up .
> does any one have some kind of Material and equivalent table .


> I find the post offices are charging  exorbitant duties , Yesterday i paid 57 % 


> while chinese goods come in easily with lower pricing !!
>  . I presume there would be some chinese companies making toroids .


> Thanks again 
> Best regards 
> Kumar


> On Wed, Dec 26, 2018 at 9:37 PM Clemens Paul <cpaul@gmx.net> wrote:

>        
>    
> Hi Kumar, 
>   
 >>only the ferrites are a big problems here ! 
>   
> You may have a look at  
> https://www.radio-store.co.uk/ 
>   
> They ship worldwidwe,sell also small quantities and have very competitive prices.
>   
> 73  
> Clemens  
> DL4RAJ   
>   
>   
>>-----Original Message-----  
>>From: owner-rsgb_lf_group@blacksheep.org   
>>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Gaj Kumar  
>>Sent: Wednesday, December 26, 2018 9:40 AM  
>>To: rsgb_lf_group@blacksheep.org  
>>Subject: Re: LF: VU2BGS 
>    


-- 
Best regards,
 Chris                            mailto:dead.fets@gmail.com