Topband: 160M Bandpass filter drawing. K0FF

[Hardy Landskov]

Hi All,
I believe the intermods are being created in the toroids and hence have a
spectrum that goes into the 160 band. In that case, a bandpass filter on
the coax line going to the shack will do no good. The filtering must done
before the signal gets to the toroids. This gets messy. In the case of a
2-wire Beverage, a balanced high pass filter must be at both ends of the
Beverage and be the characteristic Z of the two-wire line. You have to
protect both the reflection transformer as well as the transformers at the
opposite end. A 7-pole elliptic function highpass will also reduce BC
stations too if the cutoff is place at 1.7 MHz.
73 N7RT


At 01:23 PM 10/02/2000 -0500, K0FF wrote:
>
>Fred, here is a drawing for a 160M bandpass filter. The first section is a 5
>element Chebyshev lowpass filter and the second section is a 7 element
>Chebyshev hipass filter. Different values are given for the lowpass portion,
>depending if the upper cutoff frequency is selected to be 80Meters or 40
>Meters. Either section can be used alone, but these are designed for use in
>the 50 Ohm side of the matching transformer.
>The drawing is located at:
>http://homepages.dstream.net/K0FF/HomebrewTips/160mBandPassFilter
>
>There are kits available for this type thing, as well as the preamp. Anyone
>interested, contact me off the reflector, I will pass along details as they
>are know to me.
>
>Happy Building, Geo>K0FF
>
>PS comments always welcome.
>
>
>
>
>>
>>Hello Topbanders,
>>
>>
>>I have a problem with a near bc-station working on 177kc. This station
>>poducing
>>interference only on my 2-wire-beverage. Every 5 - 10 kc appearing
>>bc-stations,
>>somtimes with s7. I think my ferrite-cores are saturatet from the strong
>>signal
>>on 177 kc (59 +60db on the ft1000d). I am using FT50-77 and FT50-43
>>cores.
>>What can i do to eleminate my problem?
>>
>>thank you
>>73 Fred, DL7ON
>>
>
>
>
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>


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