[time-nuts] HP10544A Confusion

[Jim Flanagan]

Hi..
I need help understanding a few things in regards to my 10544A oscillator.

I was given an osc about 5 years ago that did not have the oven 
controller.  The
owner at that time had built his own version which did not work well.  I 
completely

removed everything he had done and duplicated the original oven using the
osc schematics that are available.  At that point the osc went on the 
shelf until
a couple of weeks ago.  I decided to go ahead and calibrate the oven 
temperature
in order to select the correct resistor to set the temp at the turning 
point.


Here is my confusion:
I understand that the 10544 oscillators used AT cut crystals, which 
means that

after warmup, I need to tweak the temp for a freq MIN.  Whereas, for an SC
cut xtal osc we would be looking for a freq MAX.  For both xtal cuts the 
turning

point is typically set for somewhere in the 75 - 85 C range.  I see where my
10544 osc is sitting about 1.5KHz LOW at room temp and then increases
in freq at warmup (OVEN temp rising).  I thought that at room temp the
freq (for AT osc) would be HIGH and decrease in freq as the oven warms.
After a full warmup, I would then adjust the temp slowly, watching the 
freq for
a min, at which time, as the oven is made hotter, the freq would then 
start in the

opposite direction(positive).

In my mind, my osc seems to act as though it is using an SC cut crystal...
Is my thinking all wrong here?

I've been studying he classic df/f vs Temp curves and my osc appears to be
opposite of the curves, assuming my osc does use an AT xtal.

I would appreciate someone setting me straight in regards to this..
Thanks
Jim
jf...@tampabay.rr.com




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Re: [time-nuts] HP10544A Confusion

[Bruce Griffiths]

Jim

Where did you get the idea that the 10544A uses an AT cut crystal?
At least some of them used a BT cut crystal.
There are 2 sets of specs for the 10544A.
The specs on the earlier data sheets are worse than the specs on the
later data sheets.

Bruce

Jim Flanagan wrote:
>
> Hi..
> I need help understanding a few things in regards to my 10544A
> oscillator.
>
> I was given an osc about 5 years ago that did not have the oven
> controller.  The
> owner at that time had built his own version which did not work well. 
> I completely
> removed everything he had done and duplicated the original oven using the
> osc schematics that are available.  At that point the osc went on the
> shelf until
> a couple of weeks ago.  I decided to go ahead and calibrate the oven
> temperature
> in order to select the correct resistor to set the temp at the turning
> point.
>
> Here is my confusion:
> I understand that the 10544 oscillators used AT cut crystals, which
> means that
> after warmup, I need to tweak the temp for a freq MIN.  Whereas, for
> an SC
> cut xtal osc we would be looking for a freq MAX.  For both xtal cuts
> the turning
> point is typically set for somewhere in the 75 - 85 C range.  I see
> where my
> 10544 osc is sitting about 1.5KHz LOW at room temp and then increases
> in freq at warmup (OVEN temp rising).  I thought that at room temp the
> freq (for AT osc) would be HIGH and decrease in freq as the oven warms.
> After a full warmup, I would then adjust the temp slowly, watching the
> freq for
> a min, at which time, as the oven is made hotter, the freq would then
> start in the
> opposite direction(positive).
>
> In my mind, my osc seems to act as though it is using an SC cut
> crystal...
> Is my thinking all wrong here?
>
> I've been studying he classic df/f vs Temp curves and my osc appears
> to be
> opposite of the curves, assuming my osc does use an AT xtal.
>
> I would appreciate someone setting me straight in regards to this..
> Thanks
> Jim
> jf...@tampabay.rr.com
>
>
>
>
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Re: [time-nuts] HP10544A Confusion

[Richard (Rick) Karlquist]

Jim Flanagan wrote:



after warmup, I need to tweak the temp for a freq MIN.  Whereas, for an SC
cut xtal osc we would be looking for a freq MAX.  For both xtal cuts the 
turning
point is typically set for somewhere in the 75 - 85 C range.  I see 



Jim
jf...@tampabay.rr.com


The majority of 10811 SC-cut crystals do not have a temperature 
turnover.  Instead they have an inflection point where the tempco is 
minimum, but not zero.  It is fairly broad, so the oven set point is

not especially critical.  If you want to tweak something in the 10811,
better to tweak the resistors that apportion heater power to the
two transistors, to maximum thermal gain.

In the case of an oscillator that does have a turnover, you do not
necessarily want to set the oven temperature to the turnover.  Instead 
you want to offset it so that there is a nonzero crystal tempco that 
happens to cancel out the tempco of the oscillator electronics.


Rick Karlquist N6RK

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Re: [time-nuts] HP10544A Confusion

[Tom Van Baak]

See:
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf

/tvb


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[time-nuts] Ashtech Z-12-R Operation?

[Brooke Clarke]

Hi:

I got an Ashtech Z-12-R that powers up and displays the start up screen, see:
http://www.prc68.com/I/AshtechZ12.shtml

But it does not progress or respond to button presses.  Does someone have a pdf 
manual or know how to kick start one of these?


Have Fun,

Brooke Clarke

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Re: [time-nuts] HP10544A Confusion

[Jim Flanagan]

Thanks, Bruce for clearing this up.

I've only seen references on the internet that the 10544 used AT cut 
crystals.  Another
fellow responded with an HP journal article that is a good read on the 
SC cut crystals.
They also referenced the 10544 performance along with the 10811 osc.  
This helps

a bunch.  Take care
Jim

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Re: [time-nuts] HP10544A Confusion

[Jim Flanagan]

Excellent read... Thanks, that helps me out a bunch
take care..
jim

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[time-nuts] time to get a reference clock for the shop

[Pete Lancashire]

By the end of the year, I want to upgrade my shop with a
reference clock derived from GPS. Suggestions on the way
to go now that the supply of old Cell Phone clocks seemed
to have dried up ? I don't mind building a disciplined osc.

Hopefully not too much a loaded question :-) ...

-pete



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[time-nuts] ment to say reference oscillator Re: time to get a reference clock for the shop

[Pete Lancashire]

> By the end of the year, I want to upgrade my shop with a
> reference clock derived from GPS. Suggestions on the way
> to go now that the supply of old Cell Phone clocks seemed
> to have dried up ? I don't mind building a disciplined osc.
>
> Hopefully not too much a loaded question :-) ...
>
> -pete
>
>
>
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Re: [time-nuts] ment to say reference oscillator Re: time to get a reference clock for the shop

[Richard W. Solomon]

The simplest is the N1JEZ variation. I built two of them.
The only problem may be the boards.

You can also get in line for the next Trimble T-Bolt lot.

73, Dick, W1KSZ

-Original Message-
>From: Pete Lancashire 
>Sent: May 29, 2009 1:53 PM
>To: Discussion of precise time and frequency measurement 
>Subject: [time-nuts] ment to say reference oscillator Re: time to get a 
>reference clock for the shop
>
>> By the end of the year, I want to upgrade my shop with a
>> reference clock derived from GPS. Suggestions on the way
>> to go now that the supply of old Cell Phone clocks seemed
>> to have dried up ? I don't mind building a disciplined osc.
>>
>> Hopefully not too much a loaded question :-) ...
>>
>> -pete
>>
>>
>>
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>
>
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[time-nuts] Motorola GPS board with OnCore module questions

[Jim Cotton]

I have a Motorola RF-Audience! module with a GPS receiver
(disciplined time source).

I am not sure how to identify it

Motorola 848504F01 P4, PTRN4307A, Copyright 1996, 4" x 11",
has an OnCore GPS receiver installed.

Front

LED's  9pin "D"BNC
pwr 10Mhz GPS 1PPS   RS23210Mhz


Back

9pin"D"  15pin "D" BNC
PowerGPS/Timing10Mhz

To make it more than a nice looking paperweight, I need:

1.  A manual, or at the least connector pin outs.

2.  Someone removed the OCXO.

   a. part number and source at a reasonable cost to replace the OCXO...

   b. Has someone already hacked a HP 10811, or HP 10544 to this board?

Jim Cotton
n8qoh

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Re: [time-nuts] time to get a reference clock for the shop

[SAIDJACK]

Hi Pete,
 
your best and least expensive path may be to buy a Thunderbolt or  
Thunderbolt package (power supply, antenna etc) from the GPS store in  China.

Search ebay for Trimble Thunderbolt...
 
bye,
Said
 
 
In a message dated 5/29/2009 10:44:36 Pacific Daylight Time,  
p...@petelancashire.com writes:

By the  end of the year, I want to upgrade my shop with a
reference clock derived  from GPS. Suggestions on the way
to go now that the supply of old Cell  Phone clocks seemed
to have dried up ? I don't mind building a disciplined  osc.

Hopefully not too much a loaded question :-)  ...

-pete



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[time-nuts] time to get a reference clock for the shop

[Mark Sims]

No,  search Ebay for  'thunderbolt gps'...  you will get 10 times as many hits. 
 For 200 bucks you can get a complete, ready to go system.  For $100 bucks or 
so you can get the basic unit and add your own power supply, antenna, etc.  
Seller fluke.l has a pretty good reputation for backing up his sales if things 
go wrong.

-
Hi Pete,
 
your best and least expensive path may be to buy a Thunderbolt or  
Thunderbolt package (power supply, antenna etc) from the GPS store in  China.

Search ebay for Trimble Thunderbolt...
 
bye,
Said
_
Windows Live™: Keep your life in sync.
http://windowslive.com/explore?ocid=TXT_TAGLM_BR_life_in_synch_052009
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Re: [time-nuts] Ashtech Z-12-R Operation?

[Tom Van Baak]

Hi:

I got an Ashtech Z-12-R that powers up and displays the start up screen, see:
http://www.prc68.com/I/AshtechZ12.shtml

But it does not progress or respond to button presses.  Does someone have a pdf 
manual or know how to kick start one of these?


Brooke,

My Z12-T requires an external 20 MHz reference clock; I'm not
familiar with your -R model but it too may require this. It's not
uncommon for high-end geodetic-grade timing receivers to rely
on an external clock (e.g., cesium or maser). The idea is that
all received GPS signals are referenced to a real external clock
instead of an internal or virtual gps clock, or something like that.

So try that first. The quality of the 20 MHz is not important just
to see if it starts working. But clearly, to get good results, you'll
want to lock your 20 MHz to something atomic.

When I got my Z12 I played a bit with how to get 20 MHz. See:
http://www.leapsecond.com/pages/20mhz/

/tvb


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Re: [time-nuts] time to get a reference clock for the shop

[Magnus Danielson]

Mark Sims skrev:

No,  search Ebay for  'thunderbolt gps'...  you will get 10 times as many hits. 
 For 200 bucks you can get a complete, ready to go system.  For $100 bucks or 
so you can get the basic unit and add your own power supply, antenna, etc.  
Seller fluke.l has a pretty good reputation for backing up his sales if things 
go wrong.


I second this.

A Thunderbolt with powersupply, antenna etc. is a very nice way to get 
started. Hacking cell phones is not as good long term as getting one of 
those, and you get fairly well started. Marks software is a nice 
addition to it.


Cheers,
Magnus

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Re: [time-nuts] Ashtech Z-12-R Operation?

[Brooke Clarke]

Hi Tom:

How can I tell if the external clock is working?

I'm using Thunderbolt -> HP 8648A -> Z-12.

Have Fun,

Brooke

Tom Van Baak wrote:

Hi:

I got an Ashtech Z-12-R that powers up and displays the start up 
screen, see:

http://www.prc68.com/I/AshtechZ12.shtml

But it does not progress or respond to button presses.  Does someone 
have a pdf manual or know how to kick start one of these?


Brooke,

My Z12-T requires an external 20 MHz reference clock; I'm not
familiar with your -R model but it too may require this. It's not
uncommon for high-end geodetic-grade timing receivers to rely
on an external clock (e.g., cesium or maser). The idea is that
all received GPS signals are referenced to a real external clock
instead of an internal or virtual gps clock, or something like that.

So try that first. The quality of the 20 MHz is not important just
to see if it starts working. But clearly, to get good results, you'll
want to lock your 20 MHz to something atomic.

When I got my Z12 I played a bit with how to get 20 MHz. See:
http://www.leapsecond.com/pages/20mhz/

/tvb



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Re: [time-nuts] Ashtech Z-12-R Operation?

[bg]

Brooke & Tom,

>> Hi:
>>
>> I got an Ashtech Z-12-R that powers up and displays the start up screen,
>> see:
>> http://www.prc68.com/I/AshtechZ12.shtml
>>
>> But it does not progress or respond to button presses.  Does someone
>> have a pdf
>> manual or know how to kick start one of these?
>
> Brooke,
>
> My Z12-T requires an external 20 MHz reference clock; I'm not
> familiar with your -R model but it too may require this. It's not
> uncommon for high-end geodetic-grade timing receivers to rely
> on an external clock (e.g., cesium or maser). The idea is that
> all received GPS signals are referenced to a real external clock
> instead of an internal or virtual gps clock, or something like that.
>
> So try that first. The quality of the 20 MHz is not important just
> to see if it starts working. But clearly, to get good results, you'll
> want to lock your 20 MHz to something atomic.
>
> When I got my Z12 I played a bit with how to get 20 MHz. See:
> http://www.leapsecond.com/pages/20mhz/
>
> /tvb

My Z12 does not eat 20MHz. (5MHz to 10MHz works IIRC)

Look for manual and other documentation around the below URL:

  ftp://ftp.magellangps.com/Reference Stations/EOL/Z12 Marine Ref. Sta/

Outside of the timing community, I suspect rubidiums are more common
external sources than CS/H-masers.

--

Björn


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Re: [time-nuts] Ashtech Z-12-R Operation?

[Magnus Danielson]

b...@lysator.liu.se skrev:

Brooke & Tom,


Hi:

I got an Ashtech Z-12-R that powers up and displays the start up screen,
see:
http://www.prc68.com/I/AshtechZ12.shtml

But it does not progress or respond to button presses.  Does someone
have a pdf
manual or know how to kick start one of these?

Brooke,

My Z12-T requires an external 20 MHz reference clock; I'm not
familiar with your -R model but it too may require this. It's not
uncommon for high-end geodetic-grade timing receivers to rely
on an external clock (e.g., cesium or maser). The idea is that
all received GPS signals are referenced to a real external clock
instead of an internal or virtual gps clock, or something like that.

So try that first. The quality of the 20 MHz is not important just
to see if it starts working. But clearly, to get good results, you'll
want to lock your 20 MHz to something atomic.

When I got my Z12 I played a bit with how to get 20 MHz. See:
http://www.leapsecond.com/pages/20mhz/

/tvb


My Z12 does not eat 20MHz. (5MHz to 10MHz works IIRC)


It should be configurable in 1 to 21 MHz in what appears to be 10 kHz 
steps. I'll will experiment with them.


I think the Z12T bypasses the PLL lock and just buffers up the incomming 
20 MHz and feeds it to the ADCs and DSP.


I racked Z12 is probably just a Z12T, which would make sense.


Outside of the timing community, I suspect rubidiums are more common
external sources than CS/H-masers.


Ionsphere, diffrential GPS and position ref stations use everything from 
OCXOs to hydrogen masers.


Cheers,
Magnus

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Re: [time-nuts] Ashtech Z-12-R Operation?

[J. Forster]

>From a friend:


1. At one time, Ashtech receiver manuals could be downloaded as PDFs
from Ashtech's website.  Now, some Ashtech receiver manuals appear to
be downloadable from
.
For example, see
,
,
,
.

2. GPS receivers require firmware updates in order to keep up with
changes in the GPS signal structure, NAV message content and format,
etc.  The latest update posted at

is dated July 8, 2003.  You may have to pay for a firmware update.

3. Remember that Ashtech was merged into Magellan long ago (in the
early 1990's IIRC), and that Magellan was merged into Sagem pretty
long ago (circa 1996??).  Little or no support may be available for a
Z-12 now.

4. That said, the Z-12 was an excellent receiver -- the best available
at its time.


-Chuck W1HIS

===

-John











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[time-nuts] Trimble T'Bolt Firmware Versions

[Stan W1LE]

Hello The Net:

So far I have experienced 2 different versions of the T'Bolt firmware.

I have  revision 3.0 of 27 June 2002 ( mfg date: 29 August 2006)
and 2.12 of 24 April 2000 (mfg date: 23 August 2000).

Using Lady Heather to compare, both versions perform similarly, when 
satellites are available.

version 3.0 performs better under a forced manual holdover.

I use a single active (patch) antenna outside at gutter height and a
Symmetricom 090-58537-01 GPS Active Smartsplitter, 1 X 4
to feed RF to the 2 T'bolts.

There looks to be a version 2.22 T'Bolt firmware also.

Have folks experienced other versions of firmware ?

Stan, W1LECape Cod   FN41sr




z

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Re: [time-nuts] Ashtech Z-12-R Operation?

[Brooke Clarke]

Hi:

Holding down the ^ (up arrow) while turning on the power switch sets it to 
factory defaults.  I also have the external 20 MHz into the Ref Freq input.
Now it's tracking sats and displaying the GMT time correctly and a position 
good to 0.0001 minutes of Lat and Lon., i.e.:

39:11.4065 N
123:09.8448 W
248.63 m WGS84 (there's bobble of 10 or 20 meters on the elevation.

Thanks very much & Have Fun,

Brooke

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Re: [time-nuts] HP10544A Confusion

[Bruce Griffiths]

Page 20 of that issue is blank.
This page has  useful info on the 10811A.

Bruce

Tom Van Baak wrote:
> See:
> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf
>
> /tvb
>
>
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Re: [time-nuts] HP10544A Confusion

[Bruce Griffiths]

Jim

A couple of references from HP  authors (R Burgoon, RL Wilson) that
mention the 10544 using a BT cut:
http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F10313%2F32746%2F01537287.pdf%3Fisnumber%3D32746%26prod%3DCNF%26arnumber%3D1537287%26arSt%3D%2B406%26ared%3D%2B410%26arAuthor%3DBurgoon%252C%2BR.%253B%2BWilson%252C%2BR.L.&authDecision=-203


http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F10313%2F32746%2F01537288.pdf%3Farnumber%3D1537288&authDecision=-203


Bruce

Jim Flanagan wrote:
> Thanks, Bruce for clearing this up.
>
> I've only seen references on the internet that the 10544 used AT cut
> crystals.  Another
> fellow responded with an HP journal article that is a good read on the
> SC cut crystals.
> They also referenced the 10544 performance along with the 10811 osc. 
> This helps
> a bunch.  Take care
> Jim
>
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Re: [time-nuts] Ashtech Z-12-R Operation?

[Bruce Griffiths]

Tom Van Baak wrote:
>> Hi:
>>
>> I got an Ashtech Z-12-R that powers up and displays the start up
>> screen, see:
>> http://www.prc68.com/I/AshtechZ12.shtml
>>
>> But it does not progress or respond to button presses.  Does someone
>> have a pdf manual or know how to kick start one of these?
>
> Brooke,
>
> My Z12-T requires an external 20 MHz reference clock; I'm not
> familiar with your -R model but it too may require this. It's not
> uncommon for high-end geodetic-grade timing receivers to rely
> on an external clock (e.g., cesium or maser). The idea is that
> all received GPS signals are referenced to a real external clock
> instead of an internal or virtual gps clock, or something like that.
>
> So try that first. The quality of the 20 MHz is not important just
> to see if it starts working. But clearly, to get good results, you'll
> want to lock your 20 MHz to something atomic.
>
> When I got my Z12 I played a bit with how to get 20 MHz. See:
> http://www.leapsecond.com/pages/20mhz/
>
> /tvb
>
>
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Tom

An injection locked oscillator with high level subharmonic injection
also works well.
Just use the appropriate topology for the oscillator and injected signal.
The injection locked oscillator acts like a first order PLL with built
in phase detector and loop filter.
The one drawback is that the phase shift with respect to the injected
signal is determined by the oscillator tank detuning.
A low Q tank is used so the phase shift tempco will be relatively small
if low tempco tank components are used.

Bruce

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[time-nuts] Austron 2100

[Claude Houde]

Hello !

Here is a follow up on my previous thread on the Austron 2100F.

After getting the unit I found out that the power supply is dead.

I was able to start up the receiver with my lab power supply.

It seems to work, but the keyboard bounces terribly, randomly filling 
the display with the last key pressed.


An older thread on that subject pinpoints the 1uF bypass on the display 
keyboard as the culprit, I will change all the electrolytics and 
tantalums and will keep you informed if I see an improvement in 
performance afterwards


I will again need your help to finish the repair job:

   * I bought Brook Clark's manual on CD, but in all flavours of the
 2100 the power supply is shown as a black box, without any
 details.  Mine has an SG3524 PWM controller driving a T03
 transistor, with a Lambda over voltage protection and a small
 DC-AC converter for the EL back light. Is there any known
 schematic of that beast ? I can of course reverse engineer it
 (after all it is an important part of the fun, isn't it ?) but I
 would rather avoid the extra work if I can.
   * If someone is using a 2100 in the north east part of the continent
 , like New-England, Quebec, etc., what type of antenna should I use ?
   * On my receiver both sides of the case were damaged, on the right
 side the handle is broken, and the left one it is bent inward, so
 much that I'm afraid of breaking it if I try to straighten it. I
 would be interested in buying either a junker receiver that has a
 nice case or just the side panels.
   * What is the general feeling about the disappearance of LORAN-C ? I
 read some documents, seem that the US coast guard wants to drop
 the service.

Thanks to all !

Claude


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Re: [time-nuts] Austron 2100

[Chuck Harris]

Hi Claude,

As the author of the article on key bounce, I must say that the
1uf caps are not bypass, but the actual timing capacitors that
determine how long the keypad chip waits before declaring that
the key has stopped bouncing.  They are a very high quality cap,
and won't be bad.  The problem is the keypad has gotten noisy and
it takes longer to settle than it did when it was new, hence the
change in the keybounce time constant.

I don't think you will need to replace the capacitors in the
2100F, they are high quality wet tantalums.  Check them, but
you will probably not find any that are bad.

Do not mess around with the small stack of circuit cards that
is off by itself.  Those capacitors are critical!

The 2100F is very sensitive.  It is designed to work with a loop
antenna that is a transformer isolated 3 foot square loop made
from electrical conduit boxes, and aluminum tubing... copper would
do fine, as would steel.  There is one turn of 5 conductor antenna
rotor cable inside of the loop.

-Chuck Harris

Claude Houde wrote:

Hello !

Here is a follow up on my previous thread on the Austron 2100F.

After getting the unit I found out that the power supply is dead.

I was able to start up the receiver with my lab power supply.

It seems to work, but the keyboard bounces terribly, randomly filling 
the display with the last key pressed.


An older thread on that subject pinpoints the 1uF bypass on the display 
keyboard as the culprit, I will change all the electrolytics and 
tantalums and will keep you informed if I see an improvement in 
performance afterwards


I will again need your help to finish the repair job:

   * I bought Brook Clark's manual on CD, but in all flavours of the
 2100 the power supply is shown as a black box, without any
 details.  Mine has an SG3524 PWM controller driving a T03
 transistor, with a Lambda over voltage protection and a small
 DC-AC converter for the EL back light. Is there any known
 schematic of that beast ? I can of course reverse engineer it
 (after all it is an important part of the fun, isn't it ?) but I
 would rather avoid the extra work if I can.
   * If someone is using a 2100 in the north east part of the continent
 , like New-England, Quebec, etc., what type of antenna should I use ?
   * On my receiver both sides of the case were damaged, on the right
 side the handle is broken, and the left one it is bent inward, so
 much that I'm afraid of breaking it if I try to straighten it. I
 would be interested in buying either a junker receiver that has a
 nice case or just the side panels.
   * What is the general feeling about the disappearance of LORAN-C ? I
 read some documents, seem that the US coast guard wants to drop
 the service.

Thanks to all !

Claude


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Re: [time-nuts] Austron 2100

[J. Forster]

The official 2100F antenna is a square shielded loop, roughly a 3' x 3'
meters, made of aluminum tubing roughly 3/4" OD. I think it's aluminum
conduit as the connections are made to the coil inside the conduit loop
via an electrician's box in the middle of one side. Opposite the conduit
box, there is an insulating segment, so the loop is not a shorted turn.

Before I got an official loop, I drove 4 nails in a roughly 4' x 4' square
into the 2x4 studs on the gable end of my attic and made a loop by winding
a few dozen turns of #16 wire on the nails. The ends of the coil were
connected to a piece of RG-58 and hence to the 2100F. Pretty crude, but it
has worked just fine in the Boston area for 20 years+. I never bothered to
put up the official loop. It could be shielded by wrapping with copper or
aluminum tape.

The LORAN signals I get are whopping and are easily visible on a 'scope
w/o any preamplifier.

If there are a lot of thunderstorms, the unit does occasionally loose lock
(1 or 2 times / year)

Best,
-John

==

> Hello !
>
> Here is a follow up on my previous thread on the Austron 2100F.
[snip]

> * If someone is using a 2100 in the north east part of the continent
>   , like New-England, Quebec, etc., what type of antenna should I use
[snip]




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