874	2007-07-01 11:49:36	David Brainerd	Band Pass Filter Boards
Message	Date	From	Subject
I have designed a Band Pass Filter Board. The board is 1.5" by 3.5". The layout includes 6 bandpass filters that can be up to 7 pole elliptic. The filters are switched by 2 cmos analog data selectors(FST3251). The filters are selected with 3 CMOS data lines which have pull-up resistors on-board to allow either mechanical switches or a processor to be used. The board also has a transformer on the input. My website has all the info include designs for 6 filters which cover from 1.8 to 30 MHz. Click the "BPF" tab on the side. I will sell the boards for $8(USA) or $9(outside USA) postpaid. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>
875	2007-07-01 15:43:04	Bill Heverly	Re: Band Pass Filter Boards
Dave, I might be interested in purchasing your board, except that I can't seem to open your schematics. I installed KICAD and I get an error that the files are not the proper type. Help. Bill Heverly AB3DT -----Original Message-----
876	2007-07-01 16:08:14	Mark Bayern	Re: Band Pass Filter Boards
The schematic I see on his website is a simple .pdf file which is readable with Acrobat Reader Mark On 7/1/07, Bill Heverly < wheverly@ptd.net> wrote:
877	2007-07-01 16:21:19	brainerd@wildblue...	Re: Band Pass Filter Boards
On 1 Jul 2007 at 18:42, Bill Heverly wrote: > > Dave, > > I might be interested in purchasing your board, except that I can't seem to open your schematics. I > installed KICAD and I get an error that the files are not the proper type. Help. > > Bill Heverly > AB3DT > The schematic and layout I posted on the website are .pdf files readable by the acrobat reader. I did use KICAD to design the board but thought the more people could read the schematic if in .pdf format. I you want the KICAD files e-mail me privately. The filters were designed using the AADE filter program and those files are posted. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>
878	2007-07-02 03:52:00	w4zcb77	Re: Band Pass Filter Boards

879	2007-07-03 10:47:06	brainerd@wildblue...	Re: Band Pass Filter Boards

880	2007-07-03 10:55:31	Joe Rocci	Re: Band Pass Filter Boards
David, I think this is the same question I asked in an off-line email, but I'm not sure the answer is what either of us is looking for. Rephrasing: 1) What is the combined worst-case insertion loss of all the filters plus the two switches when the highest loss filter is selected? How about for the lowest loss filter? 2) How off is "off", ie, when a given filter is selected, how far down are the responses from the other filters that are not selected? Joe W3JDR ----- Original Message -----
881	2007-07-03 11:26:37	brainerd@wildblue...	Re: Band Pass Filter Boards
On 3 Jul 2007 at 13:55, Joe Rocci wrote: > > David, > > I think this is the same question I asked in an off-line email, but I'm not sure the answer is what > either of us is looking for. Rephrasing: > 1) What is the combined worst-case insertion loss of all the filters plus the two switches when the > highest loss filter is selected? How about for the lowest loss filter? > 2) How off is "off", ie, when a given filter is selected, how far down are the responses from the > other filters that are not selected? > > Joe > W3JDR > The worst case insertion loss of the board(filters plus switches) was 6dB. The "off response" depends on which filter is selected and whether it is on the high side or low side. I will post the measured responses later today. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>
882	2007-07-03 14:42:03	brainerd@wildblue...	Re: Band Pass Filter Boards
On 3 Jul 2007 at 11:24, brainerd@wildblue.net wrote: > On 3 Jul 2007 at 13:55, Joe Rocci wrote: > > > > > David, > > > > I think this is the same question I asked in an off-line email, but I'm not sure the answer is what > > either of us is looking for. Rephrasing: > > 1) What is the combined worst-case insertion loss of all the filters plus the two switches when the > > highest loss filter is selected? How about for the lowest loss filter? > > 2) How off is "off", ie, when a given filter is selected, how far down are the responses from the > > other filters that are not selected? > > > > Joe > > W3JDR I uploaded 2 sets of measurements made on 2 prototype boards. The production boards are identical except for the addition of pull-up resistors on the 3 select lines. The filters used on these boards are slightly different than the design now posted(the posted designs are slightly wider) but use the same series of parts and the same board layout, so the insertion loss, shapes, and ultimate rejections should be very close. These measurement were made with the DigiKey coils which have a specified Q of 10 min. The Coilcraft Coils I listed in the BOM as alternates have higher Q's (20-40) and according to the AADE filter program should produce lower insertion loss. Note on the Flt001 measurements that Filter 3 and 4 are the 2 open positions on the design and the builder left one open and made the other straight through. Therefore, the "short" filter will show just the insertion loss of the switches. The open filter will show blow-by and leakage. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>
883	2007-07-03 15:23:13	Sam Morgan	Re: Band Pass Filter Boards
brainerd@wildblue.net wrote: > I uploaded 2 sets of measurements made on 2 prototype boards. The > production boards > are identical except for the addition of pull-up resistors on the 3 > select lines. > uploaded where.....? -- GB & 73's KA5OAI Sam Morgan
884	2007-07-03 15:26:39	brainerd@wildblue...	Re: Band Pass Filter Boards
On 3 Jul 2007 at 17:21, Sam Morgan wrote: > brainerd@wildblue.net wrote: > > > I uploaded 2 sets of measurements made on 2 prototype boards. The > > production boards > > are identical except for the addition of pull-up resistors on the 3 > > select lines. > > > uploaded where.....? > -- > GB & 73's > KA5OAI > Sam Morgan > I uploaded them to my website at <http://users.wildblue.net/wb6dhw/bpf.html> Select "measurements" from the left side. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>
885	2007-07-03 20:27:35	Rud Merriam	SDR (was BP Boards)
Hi Dave, I perused the SDR pages on your site. Your focus is on HF. I am interested in VHF, 2m specifically. Is my understanding correct that with a proper BPF front end your design would work on 2m? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://over50.k5rud.us/wiki/
886	2007-07-04 00:38:40	brainerd@wildblue...	Re: SDR (was BP Boards)
On 3 Jul 2007 at 22:27, Rud Merriam wrote: > Hi Dave, > > I perused the SDR pages on your site. Your focus is on HF. I am interested > in VHF, 2m specifically. Is my understanding correct that with a proper BPF > front end your design would work on 2m? > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://over50.k5rud.us/wiki/ > The SDR design would not. The 995x board uses a much faster switch for it's QSD and should work at 2 meters with reduced sensitivity if you subsample(LO at 1/3 freq) and have the proper front end filter. You should be able to put a 144MHz bandpass filter on my BPF board in place of one of the other filters. However, I don't know how much loss the FST3251 would have at 144 MHz. Our measurements only went up to 80 MHz. The loss in the two switches increased from 1.5 dB at low freqs to 2.9dB at 80 MHz. Dave - WB6DHW <http://users.wildblue.net/wb6dhw>