[time-nuts] ok, newbie questions

[Bob Camp]

Hi

In a decent location, with a good antenna, you can do just fine with an eight channel receiver. In a poor enough location, a million correlators might indeed improve things over a hundred thousand correlators. 

Are you mounting your antenna outdoors?
Does it have a clear view of the sky?
Do you have any massive reflectors generating multi path in the immediate area? 
Do you need to acquire satellites in under 15 seconds from a cold start, or is 3 minutes ok?

The more of those sort of questions you have the "wrong answer" to, the more you will need a fancier receiver. The HP units pretty much all use not so fancy receivers. They deliver great timing performance when set up properly. If you want to run with an indoor antenna in the basement, they aren't going to work for you. You will need a better receiver. 

Bob


On Nov 26, 2010, at 4:19 PM, W2HX wrote:

> Yes I agree a newer thunderbolt would surely suffice for me and probably also the ocxo in my 8662A synth
> 
> But I am still academically curious about the impact of more channels of satellites? What is the value of these extra sats? 
> Thanks!
> 
> On Fri, 26 Nov 2010 13:01:12 -0500,  wrote:
>> Hi
>> 
>> First option would be to dig into what you already have. There may be a pretty good OCXO in something on your bench.
>> 
>> Any TBolt with a date code past 2001 should have a good OCXO in it. It's plenty good enough for what you are trying to do.
>> 
>> Bob
>> 
>> Sent from my iPhone
>> 
>> On Nov 25, 2010, at 11:48 PM, "W2HX" <w2hx at w2hx.com> wrote:
>> 
>>> Hi all, I am sure my questions have been asked before. Unfortunately, the
>>> mailman style archives are so hard to search through. So forgive me my
>>> transgressions. Happy wil> > answers my questions. Don't need new answers if old ones suffice. (of course
>>> new answers always welcome!)
>>> 
>>> I am looking for a 10 MHz standard for my lab.  Accuracy/stability probably
>>> wouldn't make a hill of beans difference in the stuff I do, so my questions
>>> are more academic and it's just nice knowing I have a "really good"
>>> standard.
>>> 
>>> 1. So from reading about this topic on KE5FX.com I understand that a better
>>> ocxo makes for better phase noise and near-term quality.  I also understand
>>> that some later tbolts had a very good ocxo in them and therefore would not
>>> benefit significantly from an upgrade as ke5fx did using an HP 10811 unit.
>>> I am considering a thunderbolt advertised on ebay by "flyingbest." I will be
>>> traveling to China (mainland, and Hong Kong) on business the last two weeks
>>> in December so I might save some shipping.  Here is a photo. Can anyone tell
>>> me if this unit has a  "better" 10811-class ocxo or "not so good "ocxo? I
>>> also understand that not all ocxo's are created equal, even if they are the
>>> same model number.
>>> 
>>> http://tinyurl.com/2dg2dz3
>>> 
>>> 2. Other GPS DO units seem to differ on the number of satellites they can
>>> receive from simultaneously (channels). Wha> > standard that can see 6,8 or 16 birds? Is noise averaged out? Is
>>> stability/phase noise improved? Here is an example of a 16 sat unit.  Anyone
>>> have any experience with this unit? Good/bad indifferent? It seems they can
>>> be had for about $200.
>>> 
>>> http://tinyurl.com/2ad5kls
>>> 
>>> 3. And then there is the venerable HP units like this one.  I understand
>>> this uses the 10811 ocxo. Other than the better ocxo, is there anything
>>> inherently superior about these HP units to warrant the additional cost? Or
>>> are we mostly just paying for the HP name?  This one is 6 sats.
>>> 
>>> http://tinyurl.com/24tkwdv
>>> 
>>> Lastly, my use of a 10 MHz standard will be for use in equipment like
>>> microwave counters (EIP 548A), Spectrum analyzers (HP 8658B) VNA's (HP
>>> 3577A, 8753C to 6 GHz), synthesizer (HP 3326A and HP 8662A), premium
>>> receivers (Harris 590H), etc., etc. For these purposes, is a GPS DO advised,
>>> or perhaps a rubidium standard? For example, I don't need this to power a
>>> clock. Just a good, clean, stable signal with low noise, low spurs, etc.
>>> 
>>> What's the overall opinion? THANKS !!!!
>>> 
>>> (here's to hoping this message looks better than the first two tests I made)
>>> 73 Eugene W2HX
>>> 
>>> 
>>> 
>>>>> 
>>> 
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> 
> -- 
> 73 Eugene W2HX
> 
>