[CQ-Contest] ICE 419 Schematic

[Tod -MN]

Dave [and Dave]:

I do not have the schematic. 

I do, however, have a set of scans similar to the ones I did for the
Dunestar 600 that are waiting for me to complete the text and post on my web
site. As Dave, K6LL, notes, the schematic can fairly easily be deduced from
looking at the innards. I have a couple of pictures of the inside of the
419B unit that I used for testing. Pictures of the Dunestar 600 are
available on the Dunestar site as well as fairly detailed specifications.
The ICE specifications must be estimated from curves that are challenging to
read. My scans provide considerably easier to see information since they
were done one band at a time and show bandpass attenuation, in-band loss and
return loss in separate figures. If time permits I will try to prepare a
specification list similar to the Dunestar one.

There is a performance difference between the two brands. There is also a
circuit difference between the two brands. There are some component choice
differences that are apparent from the photographs as well. 

Looking at the ICE unit I deduce that it has tuned transformers shunting the
input and output and they are capacitor top coupled. The Dunestar also uses
tuned transformers for input and output with top capacitor coupling.
HOWEVER, the Dunestar uses taps on the input and output coils to get less
loading on the transformers and resultant higher Q and somewhat better close
in attenuation. 

The primary objective, of course, is to have the sub-harmonic and second
harmonic frequency attenuation as high as possible so 'close in attenuation'
is not a primary thing although usually is indicative of what to expect at
higher and lower frequencies.


If you have the values for the capacitors and you know the typical
performance curves for that filter I would expect that one could come up
with a good estimate for the coils. 


Tod, K0TO



> -----Original Message-----
> From: cq-contest-bounces at contesting.com 
> [mailto:cq-contest-bounces at contesting.com] On Behalf Of Dave 
> Hachadorian
> Sent: Sunday, July 27, 2008 2:55 PM
> To: cq-contest reflector; n3rd at arrl.net
> Subject: Re: [CQ-Contest] ICE 419 Schematic
> 
> You're right. The question comes up every few years, and 
> nobody has ever produced a schematic.
> 
> If you slide the unit out of the case, you can easily see how 
> it is put together. Basically, there are 6 bpf's in series. 
> The ones that are not activated are bypassed by 
> normally-closed relay contacts. The bpf that IS activated has 
> the relay pulled in, putting the filter in line. The discrete 
> components for each bpf are easily visible, and can be easily 
> worked on.
> 
> I have the capacitor values if you need them.
> 
> Dave Hachadorian, K6LL
> Big Bear Lake, CA
> 
> 
> 
> ----- Original Message -----
> From: "Dave Hawes" <dave.n3rd at verizon.net>
> To: <cq-contest at contesting.com>
> Sent: Saturday, July 26, 2008 4:51 PM
> Subject: [CQ-Contest] ICE 419 Schematic
> 
> 
> > This question seems to come up every few years, and it's 
> > been a
> > while, so I'll ask.
> >
> > Can anyone supply a copy of the ICE 419 schematic diagram?
> >
> > I have the external connections, but need to see how it's 
> > wired
> > internally.
> >
> > Thanks and 73 - Dave N3RD
> > _______________________________________________
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