Dear Shark RF Team, forum members,

I spent now over 3 days in riddling and ruling out, the root cause of my BER issue. Beside other entries in this and other forums, I came to the conclusion, that my copy of the openspot4pro must have an issue with its RX unit/antenna.

Issue:
High BER of 1-11%, what causes drops outs. This sounds like SIP packet loss and far too loud modulation in combination. Nobody will understand what I say, nor do I understand myself in a Parrot room.

My setup:
FTM 500 ( Settings Bandwidth WIDE, mike gain normal, transmit Power low(5watt)/mid(25watt))
Distance to the OS4Pro between 40cm (in the shack, next to a USB supply/power bank and transceiver shelf), to 2 floors below in the house _10meters distant through walls.

What I tried so far:
I tried the Hotspot next the transceiver with 5W (I can´t set it lower, thats the lowest setting on the TRX), high BER 2-11% , I distant it arround 3m to a neighbor room, BER is arround 0,8%, I rise the power to mid (25watt) to the 70cm antenna, the BER lowers to ₀,3% I put a charger for stationary usage to the os4pro, the BER rises again to ₁%

I also tried a AutoCal, what is quite strange with the FTM500, as there needs to be a FM bandwidth (in menu RX/TX) been set to narrow, what however impacts the C4FM side to be able to be calibrated as "half deviation". It was offset by 100hz. I lerned here in the forum, that does not make a difference on normal aka wide deviation, nor did it help with the BER issue, not even a notch.

10:15:02 c4fmct: got header
10:15:02 c4fmct: got header
10:15:02 c4fmpkt: header
10:15:02 dst: *****FCDoZ src: DL2TIM
10:15:02 dl: ul:
10:15:02 c4fmct: voice call started, dst: *****FCDoZ dgid: 0 src: DL2TIM id: 20f86cc60f05b1e2
10:15:02 c4fm4dmrcon: new call, cid 20f86cc60f05b1e2
10:15:02 c4fmct: invalid fich
10:15:03 c4fmpkt: got unknown aprs radio code 34
10:15:04 c4fm4dmrcon: call start, using ids dst 310997 src 2632107 for this prv call
10:15:04 c4fmpkt: got unknown aprs radio code 34
10:15:05 c4fmpkt: got unknown aprs radio code 34
10:15:06 c4fmpkt: got unknown aprs radio code 34
10:15:06 homebrew: ping sent
10:15:06 homebrew: pong received
10:15:06 c4fmpkt: got unknown aprs radio code 34
10:15:06 c4fmct: invalid fich
10:15:07 c4fmpkt: got unknown aprs radio code 34
10:15:08 c4fmct: got terminator
10:15:08 c4fmpkt: header
10:15:08 dst: *****FCDoZ src: DL2TIM
10:15:08 c4fmct: call ended, dur 5.6s ber 2.8% loss 0.0% rssi -59
10:15:08 c4fmcall: tx confirm
10:15:08 modem-tx: start
10:15:08 c4fm4dmrcon: call end, timeout: 0
10:15:09 modem-djq: emptied, closing
10:15:10 modem-tx: end
10:15:11 homebrew: ping sent
10:15:11 homebrew: pong received
10:15:12 dmrct: [0] prv voice call started, dst: 2632107 src: 310997 id: bc320d213ce0bdd3
10:15:12 c4fm4dmrcon: new call, cid bc320d213ce0bdd3
10:15:13 c4fm4dmrcon: call start to dmr id 2632107, using src callsign 310997 for this prv call
10:15:14 modem-tx: start
10:15:16 homebrew: ping sent
10:15:16 homebrew: pong received
10:15:17 dmrct: [0] call ended, dur 5.6s ber 0.0% loss 0.0% rssi 0
10:15:18 c4fm4dmrcon: call end, timeout: 0
10:15:18 net-chk: ok (45 ms)
10:15:20 modem-djq: emptied, closing
10:15:20 modem-tx: end
10:15:21 homebrew: ping sent
10:15:21 homebrew: pong received
10:15:21 c4fmct: late entry
10:15:21 c4fmct: voice call started, dst: *****FCDoZ dgid: 0 src: DL2TIM id: 59e600dc7f122431
10:15:21 c4fm4dmrcon: new call, cid 59e600dc7f122431
10:15:21 c4fmct: invalid fich
10:15:22 c4fmpkt: got unknown aprs radio code 34
10:15:22 c4fm4dmrcon: call start, using ids dst 310997 src 2632107 for this prv call
10:15:23 c4fmpkt: got unknown aprs radio code 34
10:15:23 c4fmct: invalid fich
10:15:24 c4fmpkt: got unknown aprs radio code 34
10:15:25 c4fmct: got terminator
10:15:25 c4fmpkt: header
10:15:25 dst: *****FCDoZ src: DL2TIM
10:15:25 c4fmct: call ended, dur 3.5s ber 6.4% loss 0.0% rssi -59
10:15:25 c4fmcall: tx confirm
10:15:25 modem-tx: start
10:15:25 c4fm4dmrcon: call end, timeout: 0
10:15:26 homebrew: ping sent
10:15:26 homebrew: pong received
10:15:26 modem-djq: emptied, closing
10:15:27 modem-tx: end
10:15:29 dmrct: [0] prv voice call started, dst: 2632107 src: 310997 id: ccfbdf7df3ab8a65
10:15:29 c4fm4dmrcon: new call, cid ccfbdf7df3ab8a65
10:15:30 c4fm4dmrcon: call start to dmr id 2632107, using src callsign 310997 for this prv call
10:15:31 homebrew: ping sent
10:15:31 modem-tx: start
10:15:31 homebrew: pong received
10:15:33 dmrct: [0] call ended, dur 4.6s ber 0.0% loss 0.0% rssi 0
10:15:33 c4fm4dmrcon: call end, timeout: 0
10:15:35 modem-djq: emptied, closing
10:15:35 modem-tx: end
10:15:35 c4fmct: late entry
10:15:35 c4fmct: voice call started, dst: *****FCDoZ dgid: 0 src: DL2TIM id: 70565f748e55c836
10:15:35 c4fm4dmrcon: new call, cid 70565f748e55c836
10:15:36 c4fmpkt: got unknown aprs radio code 34
10:15:36 homebrew: ping sent
10:15:36 homebrew: pong received
10:15:36 pwr: batt 93% est. 27h59m 4029mv usb 0ma cpu 32.2°C chg 0ma
10:15:37 c4fm4dmrcon: call start, using ids dst 310997 src 2632107 for this prv call
10:15:38 c4fmpkt: got unknown aprs radio code 34
10:15:38 c4fmpkt: got unknown aprs radio code 34
10:15:39 c4fmct: invalid fich
10:15:40 c4fmpkt: got unknown aprs radio code 34
10:15:41 c4fmpkt: got unknown aprs radio code 34
10:15:41 homebrew: ping sent
10:15:41 homebrew: pong received
10:15:42 c4fmpkt: got unknown aprs radio code 34
10:15:42 c4fmct: got terminator
10:15:42 c4fmpkt: header
10:15:42 dst: *****FCDoZ src: DL2TIM
10:15:42 c4fmct: call ended, dur 6.9s ber 5.7% loss 0.0% rssi -59
10:15:42 c4fmcall: tx confirm
10:15:42 modem-tx: start
10:15:43 c4fm4dmrcon: call end, timeout: 0
10:15:44 modem-djq: emptied, closing
10:15:44 modem-tx: end
10:15:46 homebrew: ping sent
10:15:46 dmrct: [0] prv voice call started, dst: 2632107 src: 310997 id: b8f1440b2627f567
10:15:46 homebrew: pong received
10:15:46 c4fm4dmrcon: new call, cid b8f1440b2627f567
10:15:48 c4fm4dmrcon: call start to dmr id 2632107, using src callsign 310997 for this prv call
10:15:49 modem-tx: start
10:15:51 homebrew: ping sent
10:15:51 homebrew: pong received
10:15:54 dmrct: [0] call ended, dur 7.5s ber 0.0% loss 0.0% rssi 0
10:15:54 c4fm4dmrcon: call end, timeout: 0
10:15:56 modem-djq: emptied, closing

`
Group C4FM voice call from modem
Sent as DMR private call dst 310997 src 2632107
At: 10:15:21 (00:03.5s B6.4% -59dBm)
(late entry, DN mode 2)

Group C4FM voice call from modem
Sent as DMR private call dst 310997 src 2632107
At: 10:15:35 (00:06.9s B5.7% -59dBm)
(late entry, DN mode 2)`

Signal is quiet on frequency:

and there is no RF interference:

To rule a missconfig on the OS4pro out, I also made a factory reset, on the hotspot, and on my transceiver, no difference.

Luckily a OM friend of mine owns 6 Openspots (model 1 and 4 pros), and is quite experienced with them. Two of them are Openspot4 Pro as well, so we did a whole set of tests to compare the BER rates, at his shack with his FT-3D (handheld C4FM). in different distances, with/out power supply, different power sources. It could be reproduced, that my copy of the op4pro has ALWAYS a much higher BER/dropouts, than his two os4pro hotspots badest up to10% . His ones were aorrund BER 0,2% what is cleary in tolerance range.

As my hotspot is only 5 days old, I want to fully return it. It seems clearly defective.
(my order reference is: S0031874)

vy73!
Tim