On Tue, Dec 01, 2015 at 08:33:05PM -0500, paul swed wrote: > Digikey was a strike out with 1 filter for 86 cents but > order was 1000 units.
Sorry, but could you point me to the filter in question please, I couldn't find anything on digikey, but probably I was searching for the wrong keywords. Thanks in advance, Herbert > Mouser however has a wide assortment very reasonable and > by the single units. > Hardest thing will be soldering them. > Regards > Paul > WB8TSL > > > On Tue, Dec 1, 2015 at 8:29 PM, paul swed <[email protected]> wrote: > > > Hello to the group have indeed done the 1575 down to 35.42 to 75.42 and > > upconverter trick. > > Thats what I used for 2-3 years now and thought it was time to move beyond > > that approach. Especially due to the earlier conversation on old receivers > > and that they should still work just fine if you do not care about the date. > > > > I actually have 2 versions of the 35 to 75 converter. One using an odetics > > down converter and another using a starlink gps receiver. Both have 35.42 > > MHz IFs. Old stuff you can get a soldering iron into. > > > > No intention to put this on the tower and mini-circuits makes a good BPF > > for the 75 MHz IF. Since I will believe the actual antenna has a 1571 > > filter in it I was thinking of skipping it down in the shack. > > > > Will see what digikey and mouser has in the way of filters and if > > inexpensive may buy one. I keep thinking I may actually have one also. > > Thanks again everyone. > > Paul > > WB8TSL > > > > On Tue, Dec 1, 2015 at 7:53 PM, Alex Pummer <[email protected]> wrote: > > > >> for 70MHz it does not hurt to match the cable to the filter at the > >> antenna unit [down converter] end and also match the filter at the > >> receiver upconverter end, the cable will pick up enough noise to overdrive > >> the 70 something receiver's input [ the "outside" field will drive a > >> current in the cable's shield, but not in the center conductor, that > >> current causes noise voltage between the two end of the cable's shield > >> which will end up at the input of the receiver, therefore it need to be > >> filtered out before it hits the mixer......also the down converter's LO's > >> reference is sensitive to the noise which the cable will pick up [ will > >> cause phase noise ], therefore it needs to be filtered ..... > >> That down up converter system is an interesting project but it is not > >> that simple as it looks > >> 73 > >> KJ6UHN > >> Alex > >> > >> > >> On 12/1/2015 2:57 PM, Bob Camp wrote: > >> > >>> Hi > >>> > >>> Here’s sort of a backwards look at it: > >>> > >>> Do you *need* an IF filter in the downconverter? By that I’m asking > >>> about a > >>> filter better than a simple LC tank. Did they put the filter in the > >>> downconverter > >>> or in the main box? I would think that putting a fancy filter up by the > >>> antenna > >>> would have been a less likely thing to do than putting it down in the > >>> main box. > >>> > >>> Bob > >>> > >>> > >>> On Dec 1, 2015, at 9:48 AM, paul swed <[email protected]> wrote: > >>>> > >>>> Thanks everyone. The Meinberg is nice and maybe available from Ebay by > >>>> Alex's link. But its 35.42 much as the Odetics down converter. I am > >>>> looking > >>>> to create a 75.42 Mhz IF. > >>>> Mini-circuits makes just the right parts. But had several IF bandwidths > >>>> available. > >>>> So will go with the 2 or so MHz filter as suggested. > >>>> > >>>> I have the typical GPS better quality high gain antenna 1/2" Heliax > >>>> feed to > >>>> a low noise gain block that makes up for the loss of a 8 X splitter. > >>>> I may add a 1575 filter ahead of the 10 db amplifier and then hit the > >>>> mixer. I think I have a filter. I actually question that I need the > >>>> filter > >>>> or 10 db amp. May build without it to see what happens. Can easily add > >>>> it. > >>>> The LO will be a mini-circuits dsn-2036 followed by a 10 db amp to drive > >>>> the mixer another mini-circuit DBM. The IF drives a bpf-a76+ and then > >>>> will > >>>> follow that with 30 db of gain at 75 MHz. > >>>> At least thats my thinking. > >>>> Regards > >>>> Paul > >>>> WB8TSL > >>>> > >>>> On Tue, Dec 1, 2015 at 1:36 AM, Magnus Danielson < > >>>> [email protected] > >>>> > >>>>> wrote: > >>>>> Hi, > >>>>> > >>>>> This is a side-track to Pauls original question, but maybe a nice > >>>>> little > >>>>> point to make now that Peter touched on the subject. > >>>>> > >>>>> To elaborate a little on C/A and multipath surpression. > >>>>> The multipath surpression of the receiver depends on code rate, > >>>>> bandwidth > >>>>> and correlator spacing. P-code is able to surpress more, and the C/A > >>>>> code > >>>>> errors look about the same as the P-code, but scaled accordingly. > >>>>> Increasing the bandwidth helps to reduce the C/A errors, but taking the > >>>>> next step of using narrow correlators further reduces the error. This > >>>>> is > >>>>> shown already in the classical Spiliker book, but further readings from > >>>>> Novatel could be nice. > >>>>> > >>>>> Increasing the bandwidth and narrowing the early and late correlator > >>>>> taps > >>>>> both have the effect of reducing the time over which energy goes into > >>>>> the > >>>>> E-L difference, and hence reducing the impact of multipath into the > >>>>> solution. > >>>>> > >>>>> Cheers, > >>>>> Magnus > >>>>> > >>>>> > >>>>> On 12/01/2015 06:00 AM, Peter Monta wrote: > >>>>> > >>>>> What should the IF pass band bandwidth be? > >>>>>>> > >>>>>>> > >>>>>>> For GPS C/A with wide correlator, about 2 MHz; if you want Galileo > >>>>>> BOC and > >>>>>> (eventually) GPS L1C, or legacy C/A with narrow correlator, about 8 > >>>>>> MHz; > >>>>>> for GPS P code about 20 MHz. Books on GNSS software receivers will > >>>>>> detail > >>>>>> the many tradeoffs available---if you're starting out with a > >>>>>> proof-of-concept lab receiver, go for 8 MHz. > >>>>>> > >>>>>> Cheers, > >>>>>> Peter > >>>>>> _______________________________________________ > >>>>>> time-nuts mailing list -- [email protected] > >>>>>> To unsubscribe, go to > >>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>>>>> and follow the instructions there. > >>>>>> > >>>>>> _______________________________________________ > >>>>>> > >>>>> time-nuts mailing list -- [email protected] > >>>>> To unsubscribe, go to > >>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>>>> and follow the instructions there. > >>>>> > >>>>> _______________________________________________ > >>>> time-nuts mailing list -- [email protected] > >>>> To unsubscribe, go to > >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>>> and follow the instructions there. > >>>> > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >>> > >>> ----- > >>> No virus found in this message. > >>> Checked by AVG - www.avg.com > >>> Version: 2016.0.7227 / Virus Database: 4477/11098 - Release Date: > >>> 12/01/15 > >>> > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
