[time-nuts] To use or not to use transmission line splitters for GPS receivers

[paul swed]

Lots of comments. Indeed it sounds like a great discussion for pizza and
beer. The more beer the more lively. Did they bring beer?
Fact
I have used a 8 way splitter Sat/TV for 5 years now. Port to port loss is
something like 16 db or 26 db as I recall. It has dc blocking on all but 1
port built in. The loss was as advertised. The cost was pretty high at $7.
To make up for the loss I used a amplifier. A Mar circuit and only enough
gain to cover the splitter loss since the single antenna has 30db of gain
and feed 1/2" hardline. So if all of things discussed are happening its not
at all apparent from the 6 rcvrs on the system. Some old like odetics
austrons some newer like 3801s and Tbolt...Plus I never have to hunt for a
port for experimenting.
There is one catch and this can apply to all splitters some rcvrs need a dc
load so that they think they have an antenna. I think about 430 ohms. As I
say its been 5 years and it just works.
Total investment $10??
Though it doesn't say HP on it.
Regards
Paul
WB8TSL

On Tue, Oct 9, 2012 at 7:14 AM, Robert Atkinson <robert8rpi at yahoo.co.uk>wrote:

> When GPS first started to be fitted to light aircraft it was found that LO
> leakage from some VHF navigation recivers blocked the GPS when the NAV was
> on certain channels. You can buy a BNC "T" adaptor where the leg of the T
> is a 1.5GHz coax stub notch filter. They go on the NAV RX antenna connector.
>
> Robert G8RPI.
>
>
> ________________________________
> From: gary <lists at lazygranch.com>
> To: time-nuts at febo.com
> Sent: Tuesday, 9 October 2012, 8:51
> Subject: Re: [time-nuts] To use or not to use transmission line splitters
> for GPS receivers
>
> I was wondering about that myself, but my guess is the crosstalk would be
> from whatever grunge was coming from the other GPS. Every amplifier has
> reverse parameters, so a small amount of the crud (circuitry noise) from
> one GPS will reach the other GPS. Not much, but some people are nuts about
> time.
>
> This is a bigger problem with radios, where the locals from one radio can
> reach the input to the other radio.
>
> I was also confused on the notion of a transmission line splitter. Is this
> a Wilkinson or something else?
>
> On 10/9/2012 12:40 AM, Azelio Boriani wrote:
> > Crosstalk? With the same signal?
>
>
>
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