To: rsgb_lf_group@blacksheep.org Date: Mon, 23 May 2005 14:28:08 +0200 MIME-Version: 1.0 X-Priority: 1 X-MSMail-Priority: High X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-SPF-Result: relay.thorcom.net: 213.46.243.18 is neither permitted nor denied by domain of chello.nl Subject: LF: Fw: Re: Modification of the blower circuit and VFO drive for the ROPEX LF TRANSMITTER Content-Type: text/html; charset=windows-1252 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v4.00s) Content-transfer-encoding: 8bit

To Mal and the rest of the members of the LF group

Tnx for your warning about the protection of the finals Mal . In my case the 1010,s did not explode without proper drive but only made a lot of noise in the receiver while practically not taking any input current . But that propably will not be so in all cases . So just to be sure I will make a protection circuit which prevents the keying ( or uses the protection circuit ) of the transmitter . In my transmitter the 1010,s are originally fitted and as far as I can check all the late versions of the Ropex have them fitted . Because the firm who was selling the transmitters ( maybe also producing them ) went out of business recently a lot of these sets ( 25 ) were sold for very low prices ( less then 30 Euro,s ) . I hope to work the buyers with manual CW in the near future .

73 to all of you

William PAØWFO

----- Original Message -----

From: hamilton mal

To: rsgb_lf_group@blacksheep.org

Sent: Sunday, May 22, 2005 5:39 PM

Subject: LF: Re: Modification of the blower circuit and VFO drive for the ROPEX LF TRANSMITTER

William you forgot to say, the PA explodes without drive !!!!!!!!!!!!!! not just TAKES OFF

The pa fets in my model are IRF1010N, maybe they have already been changed before !!

A protective cct is necessary so that the the TX cannot come on except there is already drive. I have such a cct on my home built TX as a precautionary measure.

Ropex modification operators beware because if the switch got moved accidentally from the Xtal position and there was no drive via an ext VFO you will end up with a heap of ashes!!

Beware de MAL/G3KEV

You can prevent this by leaving the switch out and just connect the VFO to terminal 10 off the oscillator , more or less as in Dicks PAØSE transmitter ( described in the LF experimenters handbook ) with the slight disadvantage that you cannot use the VFO on the Xtal frequency .

73,William PAØWFO