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Re: 2M Shari Kit
#programing
It appears that the Pi is in communication with the CH340 USB to UART converter in SHARI but the CH340G is not in communication with the SA818.? Look carefully at your solder joints at terminals 16 and 17 of the SA818 (terminal 1 is at the bottom left corner of the SA818 when you can read the silksreen on the board).? Make sure there is a good connection from the pad on the board to the wall of the castellated hole of the SA818.? Also be sure the solder joint is not bridged to the shield of the SA818,? Use an ohmmeter to check for a short to ground from these terminals..
Also check the solder joints at pins 8 (VBAT) and 9,10 (GND) Steve - N8AR |
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Re: Two SHARI's, one Pi
Hi Mike,
According to the hamVOIP website, there should be no issue as far as the software. But we need to consider a potential hardware issue.? The Pi3 and Pi4 are rated to supply 1.2 amps +/- 10%? total current to the USB ports.? On the devices I measured, SHARI required about 500 mA when in transmit.? But this could vary quite a bit depending on the actual voltage delivered to SHARI which is dependent on the Pi power supply and the IR losses in any cable used to connect SHARI to the Pi.? Also individual characteristics of the final power amplifier transistor will cause the TX current to vary, unit to unit.? ?The current is not an issue for one SHARI but for two that are transmitting at the same time (they will do this for sure on the hour unless the cron job is modified) the current could approach the 1.2 amp current limit.? Moreover, as we discovered while testing some BRIAN devices, there is probably a higher startup current transient on TX which would be enough to trigger the USB current limit in the Pi. The bottom line as I see it is two SHARI devices on one Pi will probably work but no guarantees. Steve - N8AR |
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Re: Removing "Squelch Crash" when using SHARI
#CTCSS_reverse_burst
#programing
The frequency has to be entered as 439.0500.? Four numbers after the decimal point.??Enter Tx Frequency (xxx.xxxx):
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Removing "Squelch Crash" when using SHARI
#CTCSS_reverse_burst
#programing
There is a discussion on the HamVOIP ARM-allstar list about how to remove the 'squelch crash' when using SHARI.? This is typically done using CTCSS with reverse burst.? For this to work, the radio you are using to talk to your SHARI must support reverse burst.? The SA818 used in SHARI can be programmed to send/not send reverse burst but that command is not included in the 818-prog program that we have been using to program SHARI.
It turns out that the default setting for the SA818 in SHARI is reverse burst turned on.? I use a Kenwood TH-F6A and hear no squelch tail with it turned on. I have modified the 818-prog program to include the capability to set reverse burst to off/on.? When using the program '0' means no CTCSS reverse burst and '1' means send CTCSS reverse burst.? The new program is called shari-pixx-prog and has been uploaded to the File section of this group.? If you want to experiment with reverse burst, you can upload it to the /usr/local/sbin folder of your Pi using WinSCP.? After you upload it be sure to make it executable by right clicking on it from within WinSCP and checking the three executable boxes (boxes labeled X).? You run the program the same way you run 818-prog. Steve - N8AR |
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Re: File updated in [email protected]
Steve,
I have run the DRA818's as low as 3.0V but have not gone the other way..They run fine at 3.0...Or at least the one I did run there did. |
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Re: File updated in [email protected]
Hi Lawrence,
Thanks for the suggestion.? I have not investigated the Dorji DRA818 transceiver modules because the specified input voltage is 3.3 - 4.5 volts while the NiceRF SA818 is rated for 3.3-5.5 volts.? SHARI would require a circuit to lower the input voltage of up to 5.2 VDC from the Pi.? In BRIAN I use a series diode to drop the voltage about 0.9 VDC since the BF888S is normally powered by a 3.7 VDC battery. My examination of the SA818 revealed that there is an internal 3.3 VDC regulator which powers the RDA1846 transceiver IC and the CPU which controls it.? The driver and PA are powered directly from the input voltage.? I am wondering if the Dorji module does not employ a regulator and thus the 4.5 VDC limit because the RDA1846 is specified for 3.3 to 4.8 VDC.? Have you powered the Dorji module from as much as 5.2 VDC (the official Pi 4 power supply output) and/or have additional information as to the Dorji circuitry and input voltage specification? Steve - N8AR |
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Re: File updated in [email protected]
I have used the DORJI DRA818(V/U) series of Transceiver chips. I believe they are pin for pin compatible to the SA818. Because the DORJI are wide-band only, they would lend themselves to Amateur radio.? The only narrow band operations in the Ham-bands that I know of is someone who has actually ordered a brand new MOTOROLA repeater. You may find the DORJI more cost effective.. Information is here if anyone wants to know.
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Re: File updated in [email protected]
The current batch of SA818 VHF and UHF modules that we acquired arrived with the Channel Selection feature enabled.? The previous batch were programmed to wideband and ignored this setting.? All SHARIs shipped before March 15th were from the permanent wideband batch.
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Re: volume question on the shari
#programing
Hi Jed,
Set the volume to 8 when programming SHARI. Steve - N8AR |
Steve-N8AR
Larry Macionski