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The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: But what are you sending with the reduced power rig ? SSB ... Normal CW Opera all have low duty cycles and result in low heat build up But if you running at 100% key down sending qrss and the like , then , yes the rig will heat up , in the early days I always though wspr should of been named Icarus , with the number of thermal run a ways caused by 100% duty over 120 seconds ( not a problem at Hf where power levels are low, but down here at 1:400 efficiency's = a lot of heat) [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.12.242.59 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: f1284eec928b6c66f973fc41cf683e42 Subject: Re: LF: TRANSVERTERS Content-Type: multipart/alternative; boundary="----=_NextPart_000_009A_01CDBC50.A31AA390" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME autolearn=no version=2.63 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-aol-global-disposition: G x-aol-sid: 3039ac1d40cc50995e193510 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_009A_01CDBC50.A31AA390 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable But what are you sending with the reduced power rig ? SSB ... Normal CW Opera all have low duty cycles and = result in low heat build up But if you running at 100% key down sending qrss and the = like , then , yes the rig will heat up , in the early days I = always though wspr should of been named Icarus , with the = number of thermal run a ways caused by 100% duty over 120 seconds = ( not a problem at Hf where power levels are low, but down here = at 1:400 efficiency's =3D a lot of heat) The rig will have a class AB1 or similar PA with high = standing bias to reduce cross over distortion =3D splatter on ssb = , so standing dissipation will be high ..not much you can do ... = add a fan to cool the heat sink , but be careful of the thermal = gradients , out side cold , wont mean inside is also at the right = temp ..may still be very hot , if parasitic 'ambient' cooling = is part of the equation and the fan is only cooling the last = part of the heat path .. 73 -G.. From: mal hamilton=20 Sent: Tuesday, November 06, 2012 4:45 PM To: rsgb=20 Subject: LF: TRANSVERTERS RIG/TRANSVERTER HEAT I have noticed when running a Transceiver at low power for Transverter = or other use the Transceiver PA gets very HOT so it would appear that = this is an inefficient approach except the Transceiver has a dedicated = low power output. I was wondering what system was used to reduce this power. It would be = better to disable the PA and take the output from the driver stage. It is vy noticeable on an IC-706 de G3KEV ------=_NextPart_000_009A_01CDBC50.A31AA390 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
But what  are  you  sending  with the  = reduced=20 power   rig  ?
 
SSB  ...  Normal  CW    = Opera  =20 all  have   low   duty cycles   = and =20 result  in low  heat  build  up
 
But if  you  running  at   100% = key  =20 down  sending   qrss  and  the  like  =  ,=20 then  , yes the  rig  will  heat  up , in = the =20 early  days  I always though   wspr  should = of =20 been   named  Icarus    , with the =20 number  of thermal  run a ways  caused  = by   100%=20 duty over  120 seconds   ( not  a  problem at = Hf=20 where  power  levels  are  low, but  down = here =20 at   1:400  efficiency's  =3D a  lot of = heat)
 
The  rig  will  have a  class  AB1  = or =20 similar   PA  with  high  standing  bias = to =20 reduce  cross over  distortion  =3D splatter  on = ssb  ,=20 so  standing  dissipation  will  be  high ..not = much  you  can  do ...  add  a  fan = to  =20 cool the  heat sink , but  be  careful of the  = thermal =20 gradients  , out  side  cold , wont mean inside  is=20 also  at the  right  temp  ..may  still  = be=20 very  hot , if  parasitic  'ambient'  cooling  = is =20 part of the  equation  and the  fan is only  = cooling =20 the  last  part of the  heat  path ..
 
 73 -G..
 
 

From: mal hamilton
Sent: Tuesday, November 06, 2012 4:45 PM
To: rsgb
Subject: LF: TRANSVERTERS

   RIG/TRANSVERTER = HEAT
I have noticed when running a Transceiver at low = power for=20 Transverter or other use the Transceiver PA gets very HOT so it would = appear=20 that this is an inefficient approach except the Transceiver has a = dedicated low=20 power output.
I was wondering what system was used to reduce = this power.=20 It would be better to disable the PA and take the output from the driver = stage.
It is vy noticeable on an IC-706
 
de G3KEV
 
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