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#1 2009-08-22 18:33:12
- wa2mze
- Member
- From: South Florida
- Registered: 2009-08-22
- Posts: 171
Bandpass filters
Is it possible to adjust either of the filter kits (dual or single) so that they cover the entire
band for 160 - 10 meters? (That is that the bandwidth of a single band filter could cover
the entire band). Could this be done by modifying the inductance and or capacitance values?
I suppose in the case of 80 meters, a dual band unit could be ordered for 80(cw) and 75(phone).
It looks like the 20 - 12 meter filters would cover the entire band as is. Maybe increasing the top
coupling capacitor a bit in value would spread out the band width for the 40 and 80 meter filters,
or use a few more turns on the inductors and less capacitance to tune to resonance.
I'd like to build an all band clone of the K2. I'm also considering the PA3AKE filters, I see you have
the toroid kit (but not the required capacitors).
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#2 2009-08-23 07:03:04
- W8DIZ
- Administrator
- Registered: 2008-08-12
- Posts: 314
Re: Bandpass filters
wa2me wrote:
Is it possible to adjust either of the filter kits (dual or single) so that they cover the entire band for 160 - 10 meters.
All my filters are designed for narrow band CW operation, especially the single band filters.
For wide band, use the dual band filters. For wider coverage, double the value of the coupling capacitor between the toroid inductors.
-Diz
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#3 2010-09-19 10:31:52
- ak2b
- Administrator
- From: New York City
- Registered: 2008-08-12
- Posts: 338
Re: Bandpass filters
I did a scan with my N2PK VNA of the 10 meter BPF. Markers 1 and 3 are the 3 db bandwidth and marker 2 is the insertion loss.
Tom, ak2b
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#4 2010-12-23 12:26:14
- wa2mze
- Member
- From: South Florida
- Registered: 2009-08-22
- Posts: 171
Re: Bandpass filters
W8DIZ wrote:
wa2me wrote:
Is it possible to adjust either of the filter kits (dual or single) so that they cover the entire band for 160 - 10 meters.
All my filters are designed for narrow band CW operation, especially the single band filters.
For wide band, use the dual band filters. For wider coverage, double the value of the coupling capacitor between the toroid inductors.
-Diz
Can I request different caps for the coupling when I order then? Also is a BP filter for 60M (5mhz) possible (I guess it would be an 80 meter BPF with smaller caps and less turns). Also, I would think it possible to get more bandwidth with the three section filters by stagger tuning the sections (sorta like the way you aligned an old time TV video IF strip)?
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#5 2010-12-24 06:37:21
- W8DIZ
- Administrator
- Registered: 2008-08-12
- Posts: 314
Re: Bandpass filters
wa2mze wrote:
Can I request different caps for the coupling when I order then? Also is a BP filter for 60M (5mhz) possible (I guess it would be an 80 meter BPF with smaller caps and less turns). Also, I would think it possible to get more bandwidth with the three section filters by stagger tuning the sections (sorta like the way you aligned an old time TV video IF strip)?
Do not want to start customizing my kits...bad business idea.
For 5 MHz, I would modify the 80 meter kits; use less turns on the cores.
-Diz
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#6 2012-09-10 06:11:18
- IANOFPA
- Member
- From: Eastern Shore Maryland.
- Registered: 2012-03-26
- Posts: 14
Re: Bandpass filters
W8DIZ wrote:
wa2me wrote:
Is it possible to adjust either of the filter kits (dual or single) so that they cover the entire band for 160 - 10 meters.
All my filters are designed for narrow band CW operation, especially the single band filters.
For wide band, use the dual band filters. For wider coverage, double the value of the coupling capacitor between the toroid inductors.
-Diz
So if I am reading this right for the dual BPF for 10 and 40 meters for wider band coverage I would replace C5 on the 10m BPF to a 2pf cap and for 40m C6 to a 6pf cap?
Thanks Ian K3HQL
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