Tom, Another question is will the surplus equipment have the same value to the hobbyist?  I have a lot of old gear like spectrum analyzers, scopes, signal generators, etc that was outdated and sold for cheap.  I keep wondering if the same economics will apply to the equipment that is for instance, currently selling for 40k, 50k or even higher, meaning will it drop to pennies on the dollar like I paid for my 8566B?  For some reason I don’t think it will.  If it does, it will be because some board that is impossible to repair went to smoke.

HI

Simple answer is: That depends.

A number of systems are going to network based sync. That moves the “good stuff” back to a central location. The local “mini tower” will
have some pretty basic parts in it. The number of mini whatever’s goes way up compared to an old style system. The number of central
bunkers is way down relative to an old style system.

Many systems are indeed going to much tighter holdover numbers. That is requiring either a much better OCXO or an Rb as a holdover
clock. The bad news is that the GPS functions and the tuning as well often move into the firmware in the base station. The GPSDO
as we know it goes away. The OCXO has no EFC so it’s utility outside a SDR setup is somewhat limited.

The world of telecom is a pretty big arena. Roughly 99% of what we see as “telecom” standards are actually cellular base station devices.
The comments above are thus targeted at that market. The stuff above will shrink the size of the wireless part of the market. As a percentage
the rest of the telecom world will go up as a result. We will see more unusual stuff in the 5,6,7,8,9 era and less wireless related precision
standards.

Lots of fun !!

Bob

Jerry that is indeed the likely reality. As more and more components become
integrated into super chips it becomes impossible to repair or replace
them. They are custom and proprietary to a company. Best of all the
supporting software will be a subscription and of course since the company
no longer supports the equipment the $1000/year subscription will no longer
be available.
So the experience you and I have had of getting pennies on the dollar or
$/pound simply will not occur again. Thats what my crystal ball says at
least.
Not to be all down though. You can buy some pretty reasonable things these
days scopes network analyzers and such. I just like my power sucking HP and
Tek gear.
Regards
Paul
WB8TSL

On Wed, May 31, 2017 at 8:53 PM, Jerry Hancock jerry@hanler.com wrote:

On 5/31/17 8:47 AM, Tom Knox wrote:

In general, higher data rates don't have as stringent close in phase
noise/ADEV requirements - if you look at published jitter specs, they
use phase noise from something like 10kHz to several MHz.

We encounter this all the time with deep space telecom, where
historically, they'd do radio science with the carrier.  When you're
sending 8 bits/sec, you need a good quiet carrier so your receiver loop
bandwidth can be small (to improve SNR). When you're sending 100 Mbps,
not so much.

Higher carrier frequencies make things like Doppler more important -
some of the high rate point to point links actually have problems with
tall buildings moving in the wind. As a result, the modulation schemes
and detection methods are moving towards more highly adaptive techniques
which don't require as good performance for the oscillators.

Hi

The flip side of this is that the number of hardware junkies is not increasing. The
world is moving to software as the way to do things. As we all move on, our giant
piles of stuff will have to go to somebody (or the landfill). Most of this stuff is built
to last a long time. There are a few exceptions (Cs tubes). I’d bet that the net
result is a pretty good availability on all these gizmos for a very long time. You may
not be buying 3 year old stuff, but there will still be stuff to buy.

Bob

I think there will be fewer useful parts.

The reason is integration.  In the old days they would buy off the shelf
equipment like a GPS receiver that was inside its own box and was cabled to
something else.  A better newer design would be to use a "GPS Chip" can
route the output not using a cable but with PCB traces.  An even better
design is to move the GPS on-chip And one day you get a "cell phone tower
on a chip"  THAT day may never come but you get the point.  The trend is
that the sub-parts will be be separable.

Going back a few years in technology.  I bought a broken 1950's vintage
Hammond organ (no, not a classic B2) because I wanted to build a guitar
amplifier.  The dead organ has good transformers, tubes and tube sockets
and so on.  In other words it was built entirely from generic parts that
could have been used to build their day to build any kind of audio
equipment.  50's vintage guitar amps used the same parts, just wired up
differently.

You can no longer to this with audio gear.  Just try taking an AV receiver
apart so you can build your own iPod.  Today all the parts are specialized
and there are few generic parts in most phones, TV sets and the like.

The good news is that making you own specialized parts is now much easier.
FPGAs are cheap and the actual designs are in software that can be pushed
around for free over the Internet, kept on GitHub or whatever.    As an
example I needed a logic analyzer.  These used to be big expensive beasts
but today one can use a generic FPGA development board and somefware for
less than the cost to ship the beast via UPS.

In short, my prediction:  Less surplus gear but better ability to get new
gear so less need of the old stuff.

On Wed, May 31, 2017 at 8:47 AM, Tom Knox actast@hotmail.com wrote:

--

Chris Albertson
Redondo Beach, California

So sync limits are going down. 4G-TDD has a node to node limit of 3µs / node to UTC of 1.5µs. 5g is looking at ± 500 / 400 ns node to node but hasn’t really been deployed on a large scale that I know of. I don’t know that much about the workings of 5G to comment.

The density of traffic (think how many cell phones would be in a mall or a stadium event. ) are requiring more nodes but that cover small geographic area.

This is providing economic motivations to separate the eNode B (cell radio) in to two units. The analog radio and ADC / DAC into a head unit that gets mounted on a pole ( RRH ) and then a base band unit (BBU) that will take the radio I/Q data streams and process them into network traffic. The BBU can process the data form a number of RRHs, The sync between these to units needs to be very tight, MTIE of ± 100ns is so far the leading contender for MTIE limit. This is called the CRAN model.

There are a couple of different factions that champion how to achieve this in the industry. Some say PTP and the use of transparent switches. Others say the use of syncE to transfer frequency with PTP on top to transfer time. Others champion non ethernet solutions.

Another thing that is affecting deployment  is the cost of deploying GPS antennas. An average for one carrier in Asia was about 12000 USD to instal an antenna and maintain it for three years. In there network they would see 9~10% of the nodes serviced by GNSS would have some fault directly relating to the GNSS cable / Antenna.  They are using PTP / IEEE 1588 as a way to distribute sync.

The old way of doing things was to have 3 / 4 good clocks in the core of the network (Cs) and the sync flows out to the edge. ITU G.8261 has test cases that are to simulate 10 hops between the master / slave. Yes, 8261 is really for frequency but the test cases are also used of phase because it is what we have.  Now most operators are interested in putting smaller masters at the edge. Rather than serving 1000’s of clients, serve less than 100, maybe a low as 16. The edge master will have a local GPS reference but will also use PTP / syncE / BITS as a backup to when GPS fails.  If all sources fail we are seeing hold overs in the 4~8 hours.

Keep in mind a carrier will have a huge number of clocks. I visited a cell operator in Asia that had over 1e6 clocks in there network. The size of the networks are staggering.

So what dose this mean? Carers do not want to deploy Rb, are looking at other tecnologies to extend the stability of OCXOs and TCXOs.  I don’t know how far out 5G service is. Its not 100 % clear to me how the deployments will actually happen, depend if the base station MFGs will get CRAN up and running. We should have surplus Rb etc up until G5 is fully deployed. 10~15 years after that it will be OCXO and other switching equipment, that will probably be up to the community to support.