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#1 2012-03-18 09:43:30
- Bseres
- Member
- From: Belleville, Ontario
- Registered: 2012-02-19
- Posts: 25
Low pass filters and bandswitching
I'm working on my multi band cw transceiver and wondering what experiences or suggestions are out there concerning bandswitching the low pass filters. Plans are for a six band 160 to 17 unit using a N3zi dds and Receiver, as well as the 5 watt amp and low pass filter modules. I have a six position 2 pole rotary switch. My question: switch the filters directly, or use little relays? Also, can any of the filter modules work for more than 1 band ( 40/30, 30/20, 20/17)? I hope I hav'nt bitten off more than I can chew with the bandswitching. 14 lengths of rg174 off of the switch if I do it directly. Any suggestions? Thanks
Brent
VE3CUS
Brent
VE3CUS
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#2 2012-03-18 10:25:43
- Bseres
- Member
- From: Belleville, Ontario
- Registered: 2012-02-19
- Posts: 25
Re: Low pass filters and bandswitching
Also, if I go with relays, could I use one dpdt unit to switch moth in and out on a filter, or should I go with seperste relays for input and output?
Brent
VE3CUS
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#3 2012-03-18 18:11:32
- W8DIZ
- Administrator
- Registered: 2008-08-12
- Posts: 317
Re: Low pass filters and bandswitching
Bseres wrote:
Also, if I go with relays, could I use one dpdt unit to switch moth in and out on a filter, or should I go with seperste relays for input and output?
Just make sure that if you use a single relay to switch both I/O, that you have enough separation so large signals do not stray thru the filter via capacitance between relay contacts. - Diz
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#4 2012-03-18 19:11:49
- Bseres
- Member
- From: Belleville, Ontario
- Registered: 2012-02-19
- Posts: 25
Re: Low pass filters and bandswitching
Thanks Diz
It looks like the best way would be to go with a seperate input and output relay then. Would a DIP style relay be ok? The ones I am looking at are rated for 500 mA DC contact rating
Brent
VE3CUS
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#5 2012-03-19 05:56:54
- W8DIZ
- Administrator
- Registered: 2008-08-12
- Posts: 317
Re: Low pass filters and bandswitching
Bseres wrote:
Thanks Diz
It looks like the best way would be to go with a separate input and output relay then. Would a DIP style relay be ok? The ones I am looking at are rated for 500 mA DC contact rating
I would says YES, use the DIP relays, OMRON etc...especially the magnetically latched versions. -Diz
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