Minifilter-B Cap question

[Tony]

I am in the process of building my Mobo v4.3 and have reached the
Minifilter-B stage. Of the capacitors that are supplied, how do they
map to the cap filter values in Loftur's spreadsheet? If I need two
caps to get to the non-standard value, which two do I use. I am
concerned with running out of some values of the supplied caps and
wonder if someone has gone through this process before.

Tony W2HWW

[W9...@aol.com]

Hi Tony

 

Hope this helps.

 

BAND C1/C2 C5/C6 C7/C8 C11/C12 C13/C14 C17/C18 C19/C20
160M 860
820+39
1100
1000+100
1800
1000+820
755
680+68
1800
1000+820
755
680+68
420
80M 390 640
470+180
772
390+390
578
390+180
844
820+27
336
330
220
60M 220 505
470+27
680 345
120+220
680 390 OMIT
40M 308
270+39
390 900
680+220
242
220+22
820 509
470+39
188
180+8
30M
220
200
180+18

 

Larry

[Tony]

Larry

Thanks for the info, Yes it is very helpful.

Tony W2HWW

[VK5ZAG]

Take care that the caps you received are correct value
some of those supplied by Art had wrong values.
Also the 20m "B" filter was subject to change
and was unusable with the original values.
Regards 73 Eric VK5ZAG

[Tony]

Thanks for the heads up. I have a AADE L/C Meter that I can use to
check the cap values.

With regard to the 20M "B" filter values, I am assuming the Loftur
tweaked values are the latest. Do you know if the filter input/output
impedance is 50 or 200 ohms? I have seen both values mentioned in the
documentation. I may want to use Elsie or some program to simulate
the filter.

Tony W2HWW

[The Silver Fox]

Here is the inventory of parts that I ship for the Mini B filters.
73,
Alan - W6ARH

http://mobokits.stormwarning.org/
http://wb6dhw.com/For_Sale.html
311-1097-1-ND 3 CAP CERAMIC 8.0PF 50V NP0 0805 Tape 1-1
478-1307-1-ND 3 CAP CERM 18PF 5% 50V NP0 0805 Tape 1-2
709-1172-1-ND 2 CAP CER 22PF 50V NP0 0805 Tape 1-3
478-5017-1-ND 5 CAP CER 27PF 100V NP0 5% 0805 Tape 1-4
478-1312-1-ND 2 CAP CERM 47PF 5% 50V NP0 0805 Tape 1-5
490-1596-1-ND 2 CAP CER 75PF 100V 5% C0G 0805 Tape 1-6
478-1317-1-ND 4 CAP CERM 120PF 5% 50V NP0 0805 Tape 1-7

478-1321-1-ND 3 CAP CERM 270PF 5% 50V NP0 0805 Tape 2-1
490-1622-1-ND 3 CAP CER 1000PF 50V 5% C0G 0805 Tape 2-2

PCD1004CT-ND 1 INDUCTOR FIXED SMD .47UH 20% Tape 3-1
PCD1005CT-ND 3 INDUCTOR FIXED SMD .56UH 20% Tape 3-2
PCD1006CT-ND 3 INDUCTOR FIXED SMD .68UH 20% Tape 3-3
PCD1007CT-ND 4 INDUCTOR FIXED SMD .82UH 10% Tape 3-4
PCD1009CT-ND 4 INDUCTOR FIXED SMD 1.2UH 10% Tape 3-5
PCD1010CT-ND 1 INDUCTOR FIXED SMD 1.5UH 10% Tape 3-6
PCD1012CT-ND 4 INDUCTOR FIXED SMD 2.2UH 10% Tape 3-7

PCD1013CT-ND 1 INDUCTOR FIXED SMD 2.7UH 10% Tape 4-1
PCD1015CT-ND 2 INDUCTOR FIXED SMD 3.9UH 10% Tape 4-2
PCD1261CT-ND 1 INDUCTOR 5.6UH FIXED 10% SMD Tape 4-3
PCD1262CT-ND 1 INDUCTOR 6.8UH FIXED 10% SMD Tape 4-4
PCD1263CT-ND 2 INDUCTOR 8.2UH FIXED 10% SMD Tape 4-5
PCD1020CT-ND 1 INDUCTOR FIXED SMD 10UH 10% Tape 4-6
PCD1021CT-ND 1 INDUCTOR FIXED SMD 12UH 10% Tape 4-7
PCD1022CT-ND 1 INDUCTOR FIXED SMD 15UH 10% Tape 4-8

478-1311-1-ND 5 CAP CERM 39PF 5% 50V NP0 0805 Bulk 1-1
478-1313-1-ND 5 CAP CERM 56PF 5% 50V NP0 0805 Bulk 1-2
478-1314-1-ND 4 CAP CERM 68PF 5% 50V NP0 0805 Bulk 1-3
478-1314-1-ND 4 CAP CERM 68PF 5% 50V NP0 0805 Bulk 1-3
478-1322-1-ND 5 CAP CERM 330PF 5% 50V NP0 0805 Bulk 1-4
490-1613-1-ND 5 CAP CER 680PF 100V 5% C0G 0805 Bulk 1-5

490-1615-1-ND 11 CAP CER 100PF 50V 5% C0G 0805 Bulk 2-1
490-1605-1-ND 16 CAP CER 180PF 100V 5% C0G 0805 Bulk 2-2
490-1607-1-ND 8 CAP CER 220PF 100V 5% C0G 0805 Bulk 2-3
478-1323-1-ND 7 CAP CERM 390PF 5% 50V NP0 0805 Bulk 2-4
478-1324-1-ND 4 CAP CERM 470PF 5% 50V NP0 0805 Bulk 2-5
490-3311-1-ND 5 CAP CERM 820PF 5% 50V NP0 0805 Bulk 2-6

SAM1041-50-ND 1 CONN HEADER 100PS .100 DL R/A AU xx

wire 30 30 gauge magnet wire xx

T30-6 18 Toroid xx
T37-2 12 Toroid xx

[Larry]

50 ohms. I believe. Mike Collins tweaked the values if you are working off then BOM I gave you. That is the newest BOM and should be correct.

If your kit came from Alan Hill there should be no issues.

Larry

-----Original Message-----
From: Tony <apl...@comcast.net>
Sender: mobo...@googlegroups.com
Date: Tue, 29 May 2012 10:54:55
To: MOBOKITS<MOBO...@googlegroups.com>
Reply-To: mobo...@googlegroups.com
Subject: [MOBOKITS] Re: Minifilter-B Cap question

[Mike Collins]

On 5/29/2012 1:54 PM, Tony wrote:
> Thanks for the heads up. I have a AADE L/C Meter that I can use to
> check the cap values.
>
> With regard to the 20M "B" filter values, I am assuming the Loftur
> tweaked values are the latest. Do you know if the filter input/output
> impedance is 50 or 200 ohms? I have seen both values mentioned in the
> documentation. I may want to use Elsie or some program to simulate
> the filter.
>

Hi Tony,

Looks like Eric, Alan, and Larry have you pointed in the right direction.

The latest MOBO design used 50 ohm filters and were designed using
Elsie. The filter files may still be archived. They started off as Ham
band only filters using the PA3AKE H-Mode filter bank design but were
widened to slightly overlap each other to have SWL coverage too. The
initial cap and inductor values were selected from standard values.
Some reduction in the input and output shunt caps were made to account
for the buss capacitance of the switched bank.

The filter topology gives better attenuation to the upper cutoff of the
bandpass. This is a main requirement due to the aliasing of the QSD
type design. The lower rolloff helps reduce the BW also and cut
broadcast band overload.

The MOBO design with the filter miniboards gives flexibility to try
other design. Feel free to come up with another filter topology to play
with. Would be nice to have someone post values for a Ham band only set
too.

73, Mike Collins KF4BQ