[time-nuts] Trimble Thunderbolt, any easy way to create 500 MHz

johncroos at aol.com johncroos at aol.com
Wed May 15 13:05:45 EDT 2013

Re: Trimble Thunderbolt, any easy way to create 500 MHz
Richard -

I can think of several ways to do this, but "easy" depends upon your skill set and the equipment you have. Actually - none of these are easy!

I have done a lot of synthesizers and sources over the years and here are some thoughts; hopefully helpful.

1. A straight class C multiplier chain. If you use push pull odd order multipleirs and push push doublers to cancel out the fundamentals, the inter stage filtering becomes easier. Requires discrete old-fashioned RF Design methods and perhaps a filter design program. X5 filter, X2, filter, X5, filter will do it, with low power bi-polars, but the filters have to be multi-pole to keep the spurs down. 

2. Use one of the modern phase lock loop chips with internal VCO from National, Analog Devices, and others. The down side is that most of these require an associated PIC or similar processor to load - even for one frequency. However for one with the required software skills this would most likely be the lowest cost and most straight forward approach.

3. Cook up your own PLL with discrete pre-scaler, phase detector and loop amplifier. Easier than #1, harder than #2 except for the software advantaged.

4. Mix down to IF PLL - eliminates the high speed counters but required a low output multiplier to create a reference line near 500 MHz. Complex.

Any of the PLL schemes will have fewer non-harmonic spurs and some makers web sites have tools to help with the design of the loop filter.

-73 john k6iql



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Sent: Wed, May 15, 2013 12:00 pm
Subject: time-nuts Digest, Vol 106, Issue 72

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Today's Topics:

   1. Re: Trimble Thunderbolt, any easy way to create 500 MHz
      reference from one? (Richard Solomon)
   2. Re: A Time-Nut's Worst Nightmare (Tony Finch)
   3. Embarrassing stuff... (Burt I. Weiner)


Message: 1
Date: Wed, 15 May 2013 08:16:59 -0700
From: Richard Solomon <w1ksz at earthlink.net>
To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] Trimble Thunderbolt, any easy way to create
	500 MHz reference from one?
Message-ID: <5193A6EB.60203 at earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

There are a number of phase-locked oscillators over on the "evil empire" 
that might do,
but if you need exactly 500 MHz, you might not find that one so easily.

I found one that had outputs of 72.5, 725 and 7,975 MHz that locks to my 
useful for checking Frequency Counters, Service Monitors and the like.

73, Dick, W1KSZ

On 5/15/2013 5:14 AM, Chris Wilson wrote:
>    15/05/2013 13:13
> Is there any fairly easy way to multiply the output of a Thunderbolt to
> have a 500MHz reference at about 4dBm? Thanks.


Message: 2
Date: Wed, 15 May 2013 16:29:28 +0100
From: Tony Finch <dot at dotat.at>
To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] A Time-Nut's Worst Nightmare
	<alpine.LSU.2.00.1305151622280.19357 at hermes-2.csi.cam.ac.uk>
Content-Type: TEXT/PLAIN; charset=US-ASCII

Ed Palmer <ed_palmer at sasktel.net> wrote:

> Part of me thinks it's cute, part of me wants to kill it.  :-)
> https://www.tindie.com/products/akafugu/vetinari-clock

Amusing! Reminds me of the Chronophage:


Note that the Wikipedia article is incorrect when it says the clock is
entirely mechanical: the clock depends on a computerized regulator which
is responsible for stopping the spring from over-driving the pendulum, and
for the erratic ticking, and for keeping it in sync with MSF every five

f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at first.
Rough, becoming slight or moderate. Showers, rain at first. Moderate or good,
occasionally poor at first.


Message: 3
Date: Wed, 15 May 2013 08:54:45 -0700
From: "Burt I. Weiner" <biwa at att.net>
To: time-nuts at febo.com
Subject: [time-nuts] Embarrassing stuff...
Message-ID: <384165.26368.bm at smtp106.sbc.mail.bf1.yahoo.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed


I'm sure it's nothing compared to what I did many years ago to my 
Singer FM-10C Synthesizer.  You tell us your story and I'll tell you 
mine.  You're among friends.  Every time my life flashes before my 
eyes it's mostly embarrassing stuff.

Burt, K6OQK

>From: David Hooke <dhooke at gmail.com>
>Subject: Re: [time-nuts] three cornered comparison tools
>Hi All,
>I've managed to blow up the DAC output on my TBOLT; it now has about
>0.5V 42kHz ripple on it. I think I know how I did this, but it's too
>embarrassing to share in public.

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net


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