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From: "Talbot Andrew" <ACTALBOT@dera.gov.uk>
To: rsgb_lf_group@blacksheep.org
Subject: LF: RE: Manual and active antennas at LF.
Date: Mon, 12 Mar 2001 16:32:03 -0000
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I think you have later versions of the 1792.  My one only tunes in 10Hz
steps and I know others mentioned on this reflector have 1Hz tuning.
Wonder if the later version is specified down to a lower frequency.

Incidently, returning to an earlier topic, the current Naval standard HF
receiving antenna on board ships is an active whip, made from a 2m
length of 50mm diameter Al pole.   The amp is made from three E88CC
valves in parallel, operating in a cascode / common collector circuit.
A company somewhere is working on a solid state replacement based around
power FETs, but don't know the progress on that.   The amp is specified
as having a 50dBm third order intercept point and by my reckoning could
function as a power amp delivering over 10W.   That's linear !!!
Frequency response is 10kHz to 60MHz.   

Ships do have the advantage of a near perfect groundplane so presumably
they can get away with this sort of antenna to lower freqs than normal.

Andy  'JNT


> C1,4,11 are all marked as 1 not 0u1 on both the cd and the components
> list.  The only difference is that 1 is a polyester 100v 
> whereas 4 and 11 are
> ceramics 50v.  Unfortunately nowhere on the five sheets sent 
> to me by the
> vendor is there an issue or date reference.  Still, with the 
> components
> I had to hand, it now works, if out of spec.
> 
> Thanks to all who took the trouble to send information, it is much
> appreciated.
> 
> 73, Brian
> > >is private and is intended solely for the intended recipient(s).
> >For those other than the recipient any disclosure, copying, 
> distribution, 
> >or any action taken or omitted to be taken in reliance on 
> such information is
> >prohibited and may be unlawful.
> >
> >
> >
> 73 Brian     CT1DRP     IN51QD     41 09 58N  08 39 11W
> http://homepage.esoterica.pt/~brian
> 
> 


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