DC508 1GHz Counter


henasau@...
 

I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz input is not connected to the circuit. I couldn't find DC508 1GHz manual. I downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's: main board, resolution multiplier and prescaler.


My unit only have two boards:main board and resolution multiplier board. The 75-1GHz BNC connector is not connected to anything. I wonder maybe the difference between DC508 and 508A is in the prescaler board hence 1GHz vs 1.3GHz, just guessing.


Can anyone please confirm if this the case or I am missing the prescaler board in my unit. The main boards appeares to be nearly identical.


Henryk


Dan Rae
 

On 12/13/2014 6:02 PM, henasau@... [TekScopes] wrote:
I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz input is not connected to the circuit. I couldn't find DC508 1GHz manual. I downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's: main board, resolution multiplier and prescaler.

My unit only have two boards:main board and resolution multiplier board. The 75-1GHz BNC connector is not connected to anything. I wonder maybe the difference between DC508 and 508A is in the prescaler board hence 1GHz vs 1.3GHz, just guessing.

Can anyone please confirm if this the case or I am missing the prescaler board in my unit. The main boards appeares to be nearly identical.
Henryk,

I have a DC508A here, and it is a very nice counter by the way. I don't see that the 508 version could exist without the pre-scaler; with the technology of the day 100 MHz was about the upper limit for direct counting so a pre-scaler would have been essential. There would have been no point in making a version without the pre-scaler so I'd guess yours has been removed for some reason.

Option 1 ( and7 ) in the A version has an OCXO timebase.

Good luck!

Dan


 

Hi Henryk,

Option 1 is a better time base for the DC508 so that wouldn't account for
your missing board.
Unfortunately I only have DC508A so I can't help any further.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Saturday, December 13, 2014 6:02 PM
To: TekScopes@...
Subject: [TekScopes] DC508 1GHz Counter

I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz
input is not connected to the circuit. I couldn't find DC508 1GHz manual. I
downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's: main
board, resolution multiplier and prescaler.

My unit only have two boards:main board and resolution multiplier board.
The 75-1GHz BNC connector is not connected to anything. I wonder maybe the
difference between DC508 and 508A is in the prescaler board hence 1GHz vs
1.3GHz, just guessing.

Can anyone please confirm if this the case or I am missing the prescaler
board in my unit. The main boards appeares to be nearly identical.

Henryk
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Posted by: henasau@...
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Christopher Hilton-Johnson
 

Henryk
I think you are missing the prescaler box, which is to the left of the
main board (looking from the front) and mounted on standoffs from the
main board and to the frequency switch. The metal box (with a
perforated detachable top) is about 1/2" deep, 6" front to back and just
fits within the module top & bottom frames. If you want I can send
photos - email me off-list
Option 1 gives you a better spec timebase - but you already suspected
that from the 108A manual!
Chris HJ



I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz
input is not connected to the circuit. I couldn't find DC508 1GHz
manual. I
downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's:
main
board, resolution multiplier and prescaler.

My unit only have two boards:main board and resolution multiplier board.
The 75-1GHz BNC connector is not connected to anything. I wonder maybe the
difference between DC508 and 508A is in the prescaler board hence 1GHz vs
1.3GHz, just guessing.

Can anyone please confirm if this the case or I am missing the prescaler
board in my unit. The main boards appeares to be nearly identical.

Henryk
------------------------------------
Posted by: henasau@...
------------------------------------



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henasau@...
 

Thank you for all replies. It confirms what I suspected. I am missing the prescaler board. Henryk