[time-nuts] Any (relatively) cheap TSIP GPS receivers without WNRO out there?

I have an NTP server that uses a Trimble GPS receiver (Accutime 2000, p/n - 39091-00, ROM 3.06) that has fallen prey to WNRO. Just wondering if there are any Trimble (or other brand) receivers that have TSIP serial comms that are available for a reasonable price? Any help appreciated. Skip

[time-nuts] 5065A phase-noise

Fellow time-nuts, As I have been measuring this, I've been surprised by the behavior differences of my 5065A rubidiums. One of them has a modernization so the 00105-6013 oscillator is replaced by a 10811 oscillator with associated support-board. This retrofit is known as 05065-6097 [1]. Now,

Re: [time-nuts] OCXO Advice

Hi Bob, On 2020-01-11 23:42, Bob Quenelle wrote: > I’d like some advice about the OCXO’s I’m using. They’re UCT 108663-10, > double oven, purchased from the auction site. The attached graph shows the > frequencies of 2 very similar circuits compared to the 10 MHz output of an > LPRO-101. At

[time-nuts] OCXO Advice

I’d like some advice about the OCXO’s I’m using. They’re UCT 108663-10, double oven, purchased from the auction site. The attached graph shows the frequencies of 2 very similar circuits compared to the 10 MHz output of an LPRO-101. At 7.6 hours, the blue line design switches from GPS PLL to

Re: [time-nuts] The difficulty of low noise measurements

In message <643136da-9599-18ca-be85-ffa62ab04...@rubidium.se>, Magnus Danielson writes: >> I have on my ever-growing TODO list to test if serial-BLE adapters >> are any good. Has anybody tried that yet ? >My recommendation is to build on the ESP32, then you can get serial port >to

Re: [time-nuts] The difficulty of low noise measurements

In message <454f3441-6479-cc54-7c1c-55f61b5fa...@earthlink.net>, jimlux writes: >That is an interesting idea. I wonder if you could make a short distance >fiber connection by just having your notional 10MHz source directly >drive the diode, with maybe a series resistor (so you don't

Re: [time-nuts] The difficulty of low noise measurements

Hi, On 2020-01-11 18:57, Poul-Henning Kamp wrote: > At that level of the dungeon, you have a choice. > > You can either bolt *everything*, including the chair you sit on > and the pencil you write with, together with copperstraps to get a > common potential. Mesh Bonding Network [1] > > Or you

Re: [time-nuts] The difficulty of low noise measurements

On 1/11/20 9:57 AM, Poul-Henning Kamp wrote: At that level of the dungeon, you have a choice. You can either bolt *everything*, including the chair you sit on and the pencil you write with, together with copperstraps to get a common potential. Or you can arrange *all* your cables and other

Re: [time-nuts] The difficulty of low noise measurements

At that level of the dungeon, you have a choice. You can either bolt *everything*, including the chair you sit on and the pencil you write with, together with copperstraps to get a common potential. Or you can arrange *all* your cables and other metalic connections (cabinets touching because the

[time-nuts] The difficulty of low noise measurements

Fellow time-nuts, As I now have a hydrogen maser sitting here, it triggers me to measure things. Essentially I try to measure the stability of the maser, and well, that will be very hard since one need very quiet reference sources to do that, but that then triggers the question of how quiet are

Re: [time-nuts] Low Phase Noise Amplifiers

FWIW, at the Arecibo Observatory all our cryogenic LNAs had bias stabilized with active stabilizers based on opamps. Since the opamps do not work at ~15K, bias connections to the drain and gate of the RF FETs were brought out separately from the RF connections, and the opamp circuitry was at room

Re: [time-nuts] Low Phase Noise Amplifiers

A VERY long time ago, it was discovered that simply degenerating a transistor with an emitter resistor makes a worthwhile improvement in 1/f noise. I want to say this was published in 1970 by Dick Baugh of HP but don't hold me to it. Note that the resistor was NOT bypassed: it's purpose was RF

Re: [time-nuts] Low Phase Noise Amplifiers

Am 11.01.20 um 15:36 schrieb Charles Clark: I wonder if adding active bias feedback around the RF transistor to reduce the low frequency current variations would help.  This is the classic PNP bias scheme which can be applied to BJT's or FET's.  I have used it to successfully improve the

[time-nuts] Low Phase Noise Amplifiers

I wonder if adding active bias feedback around the RF transistor to reduce the low frequency current variations would help.  This is the classic PNP bias scheme which can be applied to BJT's or FET's.  I have used it to successfully improve the phase noise on oscillators.  Details from T.T.