[SEDXC] 6 meter amplifiers

[Joe Subich, W4TV]

Some notes about these amplifiers: 

These are "drawers" in the overall transmitter and 
   will require some mechanical work <G> to use them 
   on a stand alone basis.  Here is a picture of the 
   Harris transmitter: www.k8dav.com/ntsclarge.gif 
   You can see the 54 slots for driver and final 
   amplifiers modules in the three cabinets.  As I 
   recall, the drawers are about 24" wide x 36" deep. 

TV amplifiers are rated for "peak of sync" power (or 
   PEP).  The peak sync occurs for very short durations 
   and the amplifiers generally run with 1 to 2 dB of 
   compression at that power level (the exciter/modulator 
   "stretches" the sync pulse to compensate).  I would 
   not count on more than 600 W PEP from the 1 KW units 
   in sideband service because of linearity issues but 
   they wood probably handle 1 KW in CW with sufficient 
   drive.  The gain of these modules is relatively low, 
   I don't think that the typical 100 W transceiver is 
   capable of driving a pair to the legal limit. 

As mentioned, these modules will require 50 Volts DC.  
   With their efficiency, I would count on 50V @ 30A 
   per module at the 600 W level.  

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: sedxc-bounces at contesting.com
> [mailto:sedxc-bounces at contesting.com] On Behalf Of Robert Carroll
> Sent: Friday, August 07, 2009 9:37 AM
> To: sedxc at contesting.com
> Subject: [SEDXC] 6 meter amplifiers
> Importance: High
> 
> 
> I would be glad to help out WSB—count me in.  Are others
> interested?  Please let our VP know!  
> 
>  
> 
> 73
> 
> Bob W2WG
> 
>  
> 
> From: James Cummings [mailto:kt4mm at bellsouth.net]
> Sent: Friday, August 07, 2009 7:24 AM
> To: w2wg at comcast.net
> Subject: Fw: 6 meter amplifiers
> 
>  
> 
> Bob:
> 
>  
> 
> As editor of the KARC newsletter I received the following
> email from Mr. Pearcey.  Sounds like there is potential for 
> some nice siz meter amplifiers.  If you could send the email 
> onward to our SEDXC members I think we could help WSB clear 
> out their Channel 2 equipment.
> 
>  
> 
> 73
> 
> Jim C.
> 
>  
> 
> ----- Forwarded Message ----
> From: "Pearcey, Gary (CTV-Atlanta)" <Gary.Pearcey at wsbtv.com>
> To: KT4MM at bellsouth.net
> Sent: Thursday, August 6, 2009 3:20:54 PM
> Subject: 6 meter amplifiers
> 
> Hi Jim,
> 
> I am Gary Pearcey and I work for WSB-TV.
> 
> As you know, we recently vacated 55-60 MHz and moved to UHF
> channel 39. This hopefully will allow increased use of 6 
> meters because of fewer problems with TVI. With this increase 
> of activity might come a desire for QRO and amplifiers.
> 
> We have retired our old transistorized Harris HT30LS
> transmitter and are having trouble finding a home for it.
> 
> It appears that channel 2 is not very desirable due to QRN and skip.
> 
> Therefore, if no one steps forward to use it as a complete
> unit, then we must remove the transmitter and part it out.
> 
> That’s where the Amateur radio clubs come in.
> 
> There are 35 air cooled one-kilowatt amplifier modules, of
> which all but 2 work OK.
> 
> There are some additional 500 watt driver stages as well.
> Even though it is designed for 55 to 60 MHz operation, I 
> believe it is wide enough to cover 6 meters.
> 
> While I cannot guarantee that someone won’t still step
> forward and buy the transmitter as a unit, I would at least 
> like to have a way to possibly donate the amplifiers and 
> perhaps even the six 50 volt DC (208 3 phase)power supplies.
> 
>  
> 
> Please pass this along to the Kennehoochie membership.
> 
>  
> 
> Thank you.
> 
>  
> 
> Gary Pearcey    
> 
> WB4RLW
> 
> gary.pearcey at wsbtv.com
> 
>  
> 
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