Hi The “antenna in a window” approach does indeed work. I’m running one right now as a matter of fact. I also have other antennas outdoors to compare it to. Even though they are not ideally located, they are a lot better than the window mount. Some sort of outdoor mount, even if it’s not at the top of the roof should be a pretty high priority. In any case, view to the south (in the northern hemisphere / for GPS) is key.
====== These are reasonable splitters: https://www.ebay.com/itm/Mini-Circuits-ZB8PD-2-Power-Splitter-Attenuator/121938456381?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 <https://www.ebay.com/itm/Mini-Circuits-ZB8PD-2-Power-Splitter-Attenuator/121938456381?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649> There are a lot of similar models out there. The main criteria is “cheap” when I go shopping for them. $20 to $30 for eight ports isn’t to bad. No need to make anything from scratch. The connectors alone could cost more than the entire splitter …. ======= There’s no need for this to cost a ton of money or to get overly fancy about it. Outdoors is good. A lightning arrestor (and grounding) comes along with that. Timing wise, you can get a lot of antenna for not a lot of money. Hitting 4mm x 8 mm 95% error ellipses is not at all required.(but it can be fun ….). Bob > On Mar 12, 2019, at 3:37 PM, shouldbe q931 <[email protected]> wrote: > > Hi Bob, and others that responded off list. > > On Mon, Feb 25, 2019 at 2:15 PM Bob kb8tq <[email protected]> wrote: >> >> Hi >> >> On a GPS distribution system the issue of 75 vs 50 ohm cable is pretty > much a >> non-issue. A lot of people have run 75 ohms (like Trimble on the TBolt) > and had >> no problems from this. > > This is what I thought, thanks for the confirmation. > >> The “TV” splitters are generally spec’d to 2 GHz, so well beyond GPS > frequencies. >> Again, it should not be an issue. There are also cheap multi-port > splitters on the >> auction sites. > > Some hints on what to search for would be appreciated. > >> DC blocks *are* a good idea. DC loads may or may not be needed. It’s a > try it and see >> sort of thing. Some have been known to simply drop a 50 ohm load on one > port of a >> 8 way splitter and let that be the DC load. You *can* run into issues > doing this …. >> (one device feeds 12V and another is a 3.3V feed …. smoke results …). > Cable TV >> DC blocks are dirt cheap …. > > Some DC blocks have been ordered. > >> Ideally you want the antenna as high as you can get it. In an urban area > with various >> constraints, that may or may not be very high. Coax losses plus splitter > losses should >> be considered when designing something like this. An amplifier ahead of > the splitter >> is not at all unusual. > > To begin with I'm just going to use one of the "puck" antennas in the > window that it is currently in, at which point I'm expecting to discover > that the loss through the TV splitter means that more gain will be > required, or a lower loss splitter. > >> With the arrival of world of low cost multi-band GPS devices … put up a > multi-band >> antenna. At the very least L1 / L2 (including Glonass coverage). Ideally > L1 / L2 / L5. >> Much easier to do it right the first time. > > The longer term plan is to get a L1/L2 (and possibly L5) antenna and roof > mount it, but stage one is just to get the same feed to the different > receivers. > >> Bob > > While I'm moderately good at fitting most connectors onto cables, making a > wilkinson splitter PCB or managing to cut coax to exactly the right length > do make on out of co-ax its a little bit beyond what I can get away with in > the workshop kitchen. > > Cheers > > Arne > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
