Hi,

With keys loaded, PPS GPS receivers can access the 10.23MHz encrypted P(Y) 
spreading code signals on both L1 and L2.

Without keys only the 1.023MHz unencrypted C/A spreading code signal on L1 is 
available.

The two main benefits for a keyed receiver are

1) resistance to spoofing, since the spoofer can not generate a correct 
“encrypted” signal and 

2) increased resistance to interference/jamming due to having access to 20 
times the bandwidth of C/A divided on two different frequencies.

Further benefit is the somewhat increased accuracy due to dual frequency 
ionospheric compensation.

/Björn

Sent from my iPhone

>>> On 28 Mar 2020, at 23:01, [email protected] wrote:
>> Hi
>> 
>> Just a guess, but I'd bet the answer is no. 
>> 
>> The only reason the SAASM receivers play with L2 is to demodulate the 
>> encrypted 
>> military signal with the proper key. There is no need to do the "fake out" 
>> reception
>> that the old style survey receivers did on L2. With no need to do it (and 
>> likely no survey
>> data interface to report the results) .... no function in the device. 
>> 
>> That's just a guess based on no direct knowledge of what's what with the 
>> device.
>> 
>> Bob
>> 
>> 
>> 
>> -----Original Message-----
>> From: time-nuts <[email protected]> On Behalf Of Tom Knox
>> Sent: Saturday, March 28, 2020 1:29 PM
>> To: Discussion of precise time and frequency measurement 
>> <[email protected]>
>> Subject: Re: [time-nuts] Microsemi XLi SAASM
>> 
>> Hi Mike;
>> Quick question, do the SAASM receives work as simple L1-L2 standard recovers 
>> without the Key?
>> Sadly there is no company more protective of their product information then 
>> Microsemi.
>> Sadly Microsemi is clearly in the camp of stockholder driven rather then 
>> customer driven.
>> I have spent decades looking for a service manuals for the 1050A and 5071A 
>> with no luck.
>> I feel sorry for many of the employees that have worked there for decades 
>> and are limited by the short sighted policies limiting the sharing of 
>> information in recent decades by so many test and measurement companies.
>> Thanks;
>> 
>> Tom Knox
>> 
>> 303-554-0307
>> 
>> [email protected]
>> 
>> "Peace is not the absence of violence, but the presence of Justice" Both MLK 
>> and Albert Einstein
>> 
>> ________________________________
>> From: time-nuts <[email protected]> on behalf of MIKE ELDRIGE 
>> <[email protected]>
>> Sent: Saturday, March 28, 2020 12:00 AM
>> To: Discussion of precise time and frequency measurement 
>> <[email protected]>
>> Subject: Re: [time-nuts] Microsemi XLi SAASM
>> 
>> Steve,
>> There is no jumpers for the antenna voltage.
>> I have 2 saasm units and have many Xli units for parts which I would sell
>> Thanks, Mike
>> Some time give me a call and I can help what I can.
>> Very Best, Mike
>> 
>> -----Original Message-----
>> From: time-nuts <[email protected]> On Behalf Of Steve - Home
>> Sent: Friday, March 27, 2020 6:11 PM
>> To: Discussion of precise time and frequency measurement 
>> <[email protected]>
>> Subject: Re: [time-nuts] Microsemi XLi SAASM
>> 
>> Absolutely, but I’m hoping the XLi, like some of the later receivers, has a 
>> method to select the antenna voltage.
>> 
>> Steve
>> 
>> 
>> 
>> 
>>> On Mar 27, 2020, at 8:06 PM, Dana Whitlow <[email protected]> wrote:
>> You could easily do what you want without modifying the receiver,
>> using a
>> 7805 or similar
>> regulator and a pair of bias tees, inserted in the transmission line
>> from the antenna.
>> Dana
>>>>> On Fri, Mar 27, 2020 at 7:33 PM Steve - Home <[email protected]> wrote:
>>> I wondered if anyone has a user and/or service manual for the XLi SAASM?
>>> Or any of the option modules? The one I received appears to have had
>>> the L2 receiver removed. I’d also like to see if there’s a jumper or
>>> software setting to change the antenna supply voltage from 12v to 5v.
>>> Thanks for any assistance!
>>> Steve
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