Probably not dead from the rollover issue as I can’t talk to the receiver via 
the serial port.

Fred Bray

> On Jun 22, 2021, at 2:59 PM, Robert DiRosario <[email protected]> wrote:
> 
> Does this effect All Z3801As?
> I have one of these:
> http://www.realhamradio.com/GPS_Frequency_Standard.htm
> I picked up a power supply and antenna for it but  haven't done anything with 
> it yet.
> 
> > I have a HP Z3801A with a dead GPS receiver.
> Is it dead because of Week-Roll over limits or something else?
> 
> Robert
> 
> 
>> On 06/21/2021 11:54 PM, Art Sepin wrote:
>> Hi Fred,
>> 
>> I apologize if the following smells overtly commercial; it's only intended 
>> to answer your questions and explain where we are in the process of 
>> producing GPS replacement products for legacy timing instruments.
>> 
>> The 6 and 8 channel Motorola VP and 8 channel UT+ will not work as 
>> replacements. Those products have also reached their 1024 Week-Roll Over 
>> limits. The HP Z3801A and Z3805A products only respond to 6 channel commands 
>> and produce 6 channel reply messages.
>> 
>> We have developed single-board clones for the Motorola VP and UT+ products, 
>> as drop-in replacements, that are lower in cost than Synergy's 2-board 
>> Adaptor Board products (Shooting for dropping to less than $190 if component 
>> prices don't go even higher!). The SSR-VP can plug into the HP Z3801A and 
>> Z3805A products.
>> 
>> A different part number SSR-VP designed to drop into HP 58503A and an 
>> SSR-UT+, designed to drop into HP 58503B products, have also been completed 
>> but firmware for those have yet to be tested in actual instruments. With the 
>> proper firmware loads, the SSR Drop-In products should be candidates for 
>> upgrading many other legacy timing instruments.
>> 
>> We had planned for the single board "Drop-In" products to be available near 
>> the end of 2020 but COVID-19 changed things for us. We are now planning a 
>> small production run to satisfy folks that have already been in touch with 
>> us but we need to complete our boot-loader for firmware updates first. With 
>> current work load, I'd estimate 90 - 120 days for HP Z3801A and Z3805A 
>> replacements. If you are interested we can put you on our list.
>> 
>> Apologies for the quasi-commercial intrusion!
>> 
>> Art
>> 
>> 
>> -----Original Message-----
>> From: Frederick Bray <[email protected]>
>> Sent: Monday, June 21, 2021 7:21 PM
>> To: [email protected]
>> Subject: [time-nuts] Z3801A Receiver Replacement
>> 
>> I have a HP Z3801A with a dead GPS receiver.  I understand that it is 
>> possible to drop in an Oncore VP 8 channel receiver as a replacement -- not 
>> withstanding the fact that the Z3801A will only see six channels.
>> 
>> I see that Motorola R5122U1154 8 channel receivers are available.  Does 
>> anyone know whether this will function in the Z3801A?  I'd like to get it 
>> working again.
>> 
>> Thanks.
>> 
>> Fred Bray, KE6CD
>> 
>> 
>> 
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