My bad mixing threads here the 1575 filter is in mouser and digikey has them. The 75 MHz is straight from mini-circuits. Regards Paul WB8TSL
On Wed, Dec 2, 2015 at 10:31 AM, paul swed <[email protected]> wrote: > Sorry mouser electroncs. > > On Wed, Dec 2, 2015 at 8:10 AM, Herbert Poetzl <[email protected]> > wrote: > >> 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. >> > > _______________________________________________ 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.
