> Coax is always a challenge because the shields leak.
FSJ1-50 works for me. Maintaining ham VHF repeaters where I'm putting 100W up
the pipe and looking for -114dBm at the receiver, I have had big improvements
replacing even good coax with heliax and real silver/Teflon connectors.
Of cou
I am reminded of the time before retirement that I put together an RF lab at
Hughes Missile Systems. All of the equipment was housed in a shielded room,
since in addition to all of the garbage generated in our own factory we were
located at Tucson International Airport with all of their comm an
YES 7851 I hope
In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time,
rich...@karlquist.com writes:
FWIW, the HMC832 has FOM of -226. The best synth on a chip
now available AFAIK has FOM of -236. That's 10 dB better.
Rick N6RK
On 12/12/2018 10:46 AM, Dr. Ulrich L. Rohde via
That is almost true, depending on the PhFreq. discriminator
In a message dated 12/12/2018 3:56:49 PM Eastern Standard Time,
rich...@karlquist.com writes:
The TI/NationalSemiconductor LMX2594 and LMX2595 have the best
phase noise floor FOM at -236.
The AnalogDevices/LinearTechnology LTC6952
Am 12.12.18 um 21:56 schrieb Richard (Rick) Karlquist:
The TI/NationalSemiconductor LMX2594 and LMX2595 have the best
phase noise floor FOM at -236.
The AnalogDevices/LinearTechnology LTC6952 has the best flicker at -281.
It requires an external VCO. The LTC6951 with an on board VCO is
almost
The TI/NationalSemiconductor LMX2594 and LMX2595 have the best
phase noise floor FOM at -236.
The AnalogDevices/LinearTechnology LTC6952 has the best flicker at -281.
It requires an external VCO. The LTC6951 with an on board VCO is
almost as good.
Although these are state of the air for a synth
Hi Ulrich,
Analog/Hitite
https://eu.mouser.com/new/hittite-microwave/hittite-hmc832-pll/
Cheers,
Magnus
On 12/12/18 9:44 PM, Ulrich Rohde via time-nuts wrote:
> Who makes it ?
>
> In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time,
> rich...@karlquist.com writes:
>
>
> FWIW,
Googling -236 figure of merit synthesizer yields:
http://www.ti.com/product/LMX2594
On Wed, Dec 12, 2018 at 8:46 PM Ulrich Rohde via time-nuts
wrote:
>
> Who makes it ?
>
> In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time,
> rich...@karlquist.com writes:
>
>
> FWIW, the HMC832 has
Who makes it ?
In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time,
rich...@karlquist.com writes:
FWIW, the HMC832 has FOM of -226. The best synth on a chip
now available AFAIK has FOM of -236. That's 10 dB better.
Rick N6RK
On 12/12/2018 10:46 AM, Dr. Ulrich L. Rohde via time-n
FWIW, the HMC832 has FOM of -226. The best synth on a chip
now available AFAIK has FOM of -236. That's 10 dB better.
Rick N6RK
On 12/12/2018 10:46 AM, Dr. Ulrich L. Rohde via time-nuts wrote:
I did some phase noise measurement and the 8751 is much better then the rest on
the market
Sent from
Hi
I assume 8751 = 7851 (says Bob who makes typo’s in about every second sentence
:) ).
I’m not at all surprised it’s doing better than the radios with SiLabs parts.
They dominate
the market once you get to the “rest of the pack”. Of course those radios are
half the price
(or less) than the
I did some phase noise measurement and the 8751 is much better then the rest on
the market
Sent from my iPhone
> On Dec 12, 2018, at 1:20 PM, Bob kb8tq wrote:
>
> Hi
>
> Just to save others the time digging, the 7851 uses a HMC832 VCO + fractional
> N PLL on a chip as
> the heart of its syn
Hi
Just to save others the time digging, the 7851 uses a HMC832 VCO + fractional N
PLL on a chip as
the heart of its synthesizer. Yet another “way to go” if building a quick and
simple signal source.
===
No argument at all about other parts of the radio having their limits. PA
performance ce
On 12/12/18 9:40 AM, Russ Ramirez wrote:
Don, you mention digital attenuators. What parts do you have experience
with? I am in the midst of a signal generator design for a club build
project. Looking at digital attenuator parts now, but many are spec'd in
the GHz range. Looking to get down to -14
My feeling is
A Because of the low sunspot cycle the large signal performance of the RX is
less a topic, the ICOM 7851 dynamic range, synthesizer and frequency concept is
winning but expensive
B The power amplifier from 100 W to 1500 Watt need to be catching up to the old
Collins tube Amps with
Don, you mention digital attenuators. What parts do you have experience
with? I am in the midst of a signal generator design for a club build
project. Looking at digital attenuator parts now, but many are spec'd in
the GHz range. Looking to get down to -140 dBm from +20, or as close to
this range a
Hi
Usually on HF, the issue is large signal rejection. Phase noise very definitely
gets into that part of things. Other components in the signal chain do as well.
Once the synthesizer is no longer the weak link in the chain, spending more
to improve it (vs spending on the other components) probab
On 12/11/18 3:26 PM, Bob kb8tq wrote:
Hi
As I said, just how rational using these parts in a radio …. not at all clear
to me.
Back when I went to school, stuff that was this noisy was not in the “greatest”
category.
That was a *very* long time ago.
Oddly enough best performance synthesizers h
Hi
As I said, just how rational using these parts in a radio …. not at all clear
to me.
Back when I went to school, stuff that was this noisy was not in the “greatest”
category.
That was a *very* long time ago.
Oddly enough best performance synthesizers have gotten better. (as the posted
prese
yes
In a message dated 12/11/2018 5:29:23 PM Eastern Standard Time,
k8yumdoo...@gmail.com writes:
Ulrich,
Is it OK for us to forward the URL for your "Noise" paper to others
outside the time-nuts group?
Thanks,
Dana K8YUM
On Tue, Dec 11, 2018 at 9:24 AM Ulrich Rohde via time-nuts <
tim
You can solve the spur problem by using the signal to lock an oscillator.
Some added phase noise but the oscillator can be very pure otherwise. Many
years ago I wrote an unsuccessful proposal for a synthesizer using that idea,
since the spectral purity spec was too tight to use synthesizer ou
Ulrich,
Is it OK for us to forward the URL for your "Noise" paper to others
outside the time-nuts group?
Thanks,
Dana K8YUM
On Tue, Dec 11, 2018 at 9:24 AM Ulrich Rohde via time-nuts <
time-nuts@lists.febo.com> wrote:
>
> https://badw.de/fileadmin/members/R/3685/6_4_18_UNI_BW_June18-safe.pd
Am 11.12.18 um 20:30 schrieb jimlux:
On 12/11/18 10:23 AM, Richard (Rick) Karlquist wrote:
On 12/11/2018 9:13 AM, djl wrote:
Rick: I've spent some time with the dds blocks. We found them to
generate lots of low level spurs, making lots of "birdies" when used
as local oscillators in receiver
On 12/11/2018 11:30 AM, jimlux wrote:
Most of the Silabs parts are available in an I2C programmable version
rather than the factory programmed flavor.
That's for clarifying that. The web site is hard
to navigate. I see that the phase noise is not
even close to an HP 8662 and the VCXO
On 12/11/18 10:23 AM, Richard (Rick) Karlquist wrote:
On 12/11/2018 9:13 AM, djl wrote:
Rick: I've spent some time with the dds blocks. We found them to
generate lots of low level spurs, making lots of "birdies" when used
as local oscillators in receivers.
We had better results using:
https:
Hi
There are I2C versions that can be set to “any frequency”. That’s what people
are using
for synthesizers in radios. Again - one can debate just how good an idea this
all is.
Bob
> On Dec 11, 2018, at 1:23 PM, Richard (Rick) Karlquist
> wrote:
>
>
>
> On 12/11/2018 9:13 AM, djl wrote:
On 12/11/2018 9:13 AM, djl wrote:
Rick: I've spent some time with the dds blocks. We found them to
generate lots of low level spurs, making lots of "birdies" when used as
local oscillators in receivers.
We had better results using:
https://www.silabs.com/products/timing/oscillators.
I was
Hi
I don’t know if it’s expected / surprising / alarming, but a lot of pretty well
respected
amateur transceivers have the SiLabs parts buried in the heart of their
“synthesizer”
section. Cost (obviously) is an issue in any design. That said, they seem to be
“good
enough” that the designers do
Rick: I've spent some time with the dds blocks. We found them to
generate lots of low level spurs, making lots of "birdies" when used as
local oscillators in receivers.
We had better results using:
https://www.silabs.com/products/timing/oscillators.
These may be used with GPSDO clocks for accur
Another gold mine. I used to work for Agilent/Keysight so I
am very familiar with their signal generators. It
will be interesting to see the R&S viewpoint. The DDS
stuff is very valuable. I have been considering using
a DDS eval board with a low noise 1 GHZ reference to
make a poor man's signa
https://badw.de/fileadmin/members/R/3685/6_4_18_UNI_BW_June18-safe.pdf
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