[time-nuts] GPS Antenna Feed Line Decision

Glenn Little WB4UIV glennmaillist at bellsouth.net
Sun Sep 3 23:41:26 EDT 2017

I work with a broadcast station.
We just had a HD FM radio transmitter upgrade done.
In the upgrade package from GatesAir was a GPS antenna with a F fitting.
The provided feedline was RG-223 with a TNC on one end and a SMA on the 
Also provided was a TNC to F adapter.
The new exciter has a GPS receiver installed to provide 1 PPS to the 
There was also another piece of equipment that required 1 PPS and they 
provided an antenna and no feedline with that one.
Either piece would output 1 PPS, so the second antenna was not needed.

So you wonder what the "professionals" had in mind with the adapters.
Low bidder for the antenna??


On 9/3/2017 10:09 AM, Wes wrote:
> On 9/2/2017 4:48 PM, Clay Autery wrote:
>> Thanks for the response...
>> Not sure why you and the other guy both recommended RG-6 75-Ohm cable
>> and F-connectors, when the nominal impedance of literally everything
>> else in the system is 50 Ohm, including the antenna and the HP GPS
>> Distribution Amp....  And then adding N to F adapters?
> As "the other guy" (I think) let me say that the impedance mismatch is 
> immaterial and in my case I have one GPSDO with an SMA connector and 
> another with a BNC and an antenna with an SMA.  So I "adapt" no matter 
> what I do.  Because I understand the cascaded noise figure equations, 
> I know that I don't need an active distribution amplifier to feed just 
> these two devices, so a $5.00 "F" connector splitter is adequate. 
> (https://www.markertek.com/product/201-232/2-way-2-4ghz-90db-satellite-splitter-dc-power-passing-to-one-port)
>> Doesn't make any sense unless one has $$ as a top priority, already has
>> a spool of RG-6 quad shield, etc...  but I specifically stated that $$
>> is not a top priority....  Not really even in the top 5 or 10...
> Then by all means you should use L-band waveguide. :-)
> Wes
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Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

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