[Milsurplus] BC-640 TVI

[WA5CAB at cs.com]

The only people to ever have interference problems with the BC-640 were 
illiterate hams (I assume that they must have been illiterate as they obviously 
never read the Operator's Manual) who didn't know how tune them.  After I 
came home from Vietnam, I had two of them up and running in a town that was 
40-60 miles away from the TV stations serving it.  I never had a single 
complaint.  The comment about "even when turned off" in one of the Surplus 
so-called Conversion Manuals was merely the same BS and general drivel that 
permeate all of those volumes.  

The BC-639 and BC-640 probably hold the all time record for length of 
active service of US military radios.  The last revision that I know of to the 
BC-639 Maintenance Manual is dated 01 May 1975, 31-1/2 years after the Basic 
was published.  Manuals covering the radio sets of which the two radios were 
a part date back to at least a year earlier.  By contrast, probably the next 
longest service survivor (ATC or AN/ART-13) went out a decade earlier.

In a message dated 10/6/2009 8:09:53 PM Central Daylight Time, 
smithab11 at comcast.net writes: 
> Some of the worst  TVI was caused by amateurs  getting into the 21 Mc IF 
> of 
> the TV sets when transmitting on  40 meters(3rd harmonic) and especially  
> 15 
> meters. But the majority of TVI from 2 meters was simply front end 
> overload 
> of the TV receiver.
> 
> breck k4che
> http://home.comcast.net/~smithab11/
> 
> ----- Original Message ----- 
> From: "Jack Antonio" <scr287 at sbcglobal.net>
> Cc: <milsurplus at mailman.qth.net>
> Sent: Tuesday, October 06, 2009 7:19 PM
> Subject: Re: [Milsurplus] BC-640
> 
> 
> |I have to wonder how deserved the TVI reputation of the BC-640 really
> | was.  Was the transmitter really as dirty as claimed, or was TVI the
> | result of running the unit without the proper shields and covers in 
> place?
> |
> | My thinking is that what we call TV channels 7-13 today, were in WWII
> | used a lot for IFF and radar, and if the BC-640 was such a dirty
> | machine, are there reports of BC-640s bothering the receivers of
> | radar and IFF systems?
> |
> | Did the military do compatibility studies during WWII of what systems
> | could or could not be used near each other?
> |
> | Just curious
> |
> | Jack Antonio WA7DIA
> | scr287 at sbcglobal.net
> |
> |
> | Rod Hogg wrote:
> | >Last BC-640 I was around ended up in local salvage yard, in many 
> pieces. 
> It
> | >was used a couple times on 2M, but found it generated more TVI signal 
> than
> |
> 

Robert & Susan Downs - Houston
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