IC-905 - Commercial FM ATV Transceiver

[g0mjw]

I thought there were different versions (or settings) for different markets. Perhaps there is a European PAL version and a US/Japan NTSC version?

[G8GKQ]

Hi Darko

While I do not dispute your measurements, the review models that Noel G8GTZ and I were loaned had no difficulty with PAL colour (IC-905 to IC-905)

There was no (or very little) pre-emphasis being applied in the transmitter, so I added a pre-emphasis circuit (and 75 ohm buffer) on the input. Subsequent tests with the GB3SQ repeater showed no sign of the colour being noisier than I would normally expect, although the video level was lower than normal.

However, like you, I formed the opinion that the IC-905 was a product aimed at the black-box Japanese market where a closed community of IC-905 users would be able to exchange NTSC video.

Dave, G8GKQ

[oe7dbh]

Hi Dave

Who knows, maybe I got the NTSC version despite buying it in Austria (Europe - PAL region) ? ---> this is just speculation and guesswork.
The fact is that my IC-905 as it is currently is not suitable for the PAL standard as far as color is concerned.
From the conversation with Icom Europe it turns out that there is only one IC-905 hardware version.
In general it is very difficult to get the important information from ICOM.

I already informed Icom Europe in October 2023 that there was a problem with FMTV modulation.
After several emails with ICOM Europe and ICOM Japan, only the software video hub limitation was removed in
version 1.5 , but no other changes were made.

If there are two or more hardware versions ? , ICOM has the serial number of my device and will certainly see
that I have an unsuitable device for my PAL area.

I have also forwarded my measurements to ICOM Europe and received answers like this:

08.2024.
Sehr geehrter Herr Banko,
vielen Dank für die Analyse.
Unsere Ingenieure sind sicher sehr überrascht von den sehr konkreten Eingaben und versuchen das Beste daraus zu machen.
Fehlende Eingangsimpedanzen kann man bei ausgelieferten Geräten nicht mehr nachinstallieren.
Jedoch alles, was mit Software Verbesserungen gemacht werden kann, wird sicher gemacht werden.
Dazu tragen die einzelnen Eingaben bei, welche von den Benutzern, wie Ihnen kommen.
Dear Mr. Banko,
Thank you for the analysis.
Our engineers are certainly very surprised by the very specific inputs and are trying to make the best of them.
Missing input impedances cannot be retrofitted to delivered devices.
However, everything that can be improved with software will certainly be done.
The individual inputs that come from users like you contribute to this.

10.2024.
Lieber Darko,
vielen Dank für deine sehr detailreiche Schilderung.
Gerne habe ich deine ausführliche Demonstration an unsere Ingenieure in Japan weitergeleitet.
Bleibt zu hoffen, dass es unsere Ingenieure schaffen, die erforderliche Bandbreite überzeugend zu implementieren.
Dear Darko,
Thank you very much for your very detailed description.
I was happy to forward your detailed demonstration to our engineers in Japan.
We can only hope that our engineers will manage to implement the required bandwidth convincingly.

These are the answers from ICOM Europe !! , .....hope dies last .
I have not received a response from ICOM Japan, despite several emails in English and Japanese.







I would be very grateful if one of the readers of this forum would do the same test on 1265MHz with their IC-905 , just for comparison.
1. with FMTV TX transmit -----> IC-905 received
a. with PAL camera ( Composite - FBAS output 1Vpp )
b. with Multiburst signal 1Vpp

2. with IC-905 transmit ------> FM TV consumer Receiver received
a. with PAL camera ( Composite - FBAS output 1Vpp )
b. with Multiburst signal 1Vpp

3. with IC-905 transmit ----> with IC-905 received
a. with Multiburst signal 1Vpp







Missing or incorrect pre-emphasis and 75 ohm impedance:
Yes, that's not quite right but it is possible to improve it from the outside without interfering with the inside of the IC-905 device.
Pre-emphasis function would certainly be possible to change to the correct value with software.
Video 75ohm impedance can be coordinated from the outside.

But in software a wrongly set low pass frequency range is not adjustable by us as a consumer !!!.

ICOM could also supply the correct 75ohm impedance, already built into the Audio-Video cable that we missed in the delivery ?.


https://oe7dbh.blogspot.com/2024/09/ic- ... imode.html

We are talking about a device costing over 4000 euros, ( for some people that is 3 months salary ) ( and not a Chinese device costing around 200~400 euros )
everything should work properly before the market launch, and all necessary accessories too. China devices have more accessories in delivery.
Actually, it should be in ICOM's own interest to keep its customers happy.
Or am I wrong with my claims ???

[M0DTS]

I don't really have the best test equipment to help you much but...

I see around 3dB roll-off by 5.1MHz using my IC905 in TX with FIL1 Setting.
No noticeable loss at 4.43MHz, colour passes quite well as far as I can tell.
Video input does appear to be ~75Ohm, I get the same Vp-p at the IC905 input as I do into a 75R resistor.

I have other issues with IC905 ATV operation that Icom UK have acknowledged and said they would investigate but never heard anything back:
Flickering Tx Video on the screen, ATV Audio Squelch does not work unless signal is VERY strong, >P5.

Rob

EDIT
That's using a fairly narrow IF Receiver which is non standard, i don't have any 'good' analogue receivers to compare with.

[oe7dbh]

Rob,
thank you very much for your feedback, it seems that there are several problems with the IC905 in the FMTV area.
While I was writing to you, I received an email from ICOM Europe saying:
Please try a factory reset as per the manual. The IC-905 is a computer with analog interfaces, so stored values ​​can sometimes be changed.

I will try that too and see if it helps.

In any case, it is good when customers publicly report their problems with the IC-905 in FMTV mode,
as this is the only way to put pressure on the ICOM software specialists, hardware obviously can no longer be changed.
Dear IC-905 customers and readers, please write here any comments regarding FMTV ( anything that bothers you ) .


viewtopic.php?f=2&t=8337&start=20#p36857

Vy 73 de OE7DBH ( unfortunate FMTV owner of IC-905 )


My initial post regarding this topic: https://oe7dbh.blogspot.com/

[oe7dbh]

...after ALL RESET:

the tip with the all reset was worth its weight in silver !!
Because ?
Because after the reset ( software version 1.15 remained ) in FMTV mode IC-905 lets through 5MHz !! hence also the color carrier which is at 4.43MHz.
The above applies to the transmitting part of IC-905, I'll test IC-905 reception part tomorrow.

So why isn't it worth its weight in gold ?
Because there is still too little modulation, just 0.3Vpp image content ( image is dull but in color ) instead of 0.7Vpp is coming to the monitor or wave monitor.

Test 1.
1Vpp multiburst video signal without 75 ohms on the TX video input & IC-905 video input level 78% ( at 79% no longer wants to transmit )
Including sync pulse, video signal at receiver output is: just under 0.5Vpp ( but should be 1Vpp )

IMG_20241120_160147.jpg (74.82 KiB) Viewed 1113 times

Test 2.
1Vpp multiburst video signal with 75 ohms on the TX video input & IC-905 video input level 94% ( at 95% it no longer wants to transmit )
Including sync pulse, the video signal on the receiver output is just under 0.5Vpp ( but should be 1Vpp )

IMG_20241120_160147 1.jpg (76.58 KiB) Viewed 1113 times

Show me the received wave monitor image of this signal !!
Here you go.....

Reset Ergebniss x.jpg (137.15 KiB) Viewed 1113 times

That is only 50% of the expected-necessary modulation according to the CCIR PAL standard !!
ICOM still has to do something if he wants to have satisfied customers in Europe or the PAL region.





For non-TV specialists: Just that you can compare with other posts below, this is what a perfect TV PAL signal looks like.....

0n.jpg (505.75 KiB) Viewed 673 times

[G3GJA]

Surely, test no.2 is invalid because the 75R is paralleled with the 82R in the input circuit, resulting in the signal source seeing an impedance of 39R (approximately, assuming the OP356 input is Hi-Z) at the video input of the IC-905

What deviation is your receiver expecting to produce 1v pk-pk?

Clive G3GJA / GE8QZ

[oe7dbh]

Next test, now I'm interested to know if this " Factory ALL reset " has changed anything when receiving with IC-905 ?

My home made FMTV transmitter is prepared and the output signal is set to the desired value using attenuators.
The connection between the attenuator and RX is made using a coax cable - Not ON AIR Way .
The following measuring devices are used in this test: PM5570, EV4161, Camera NV-GS10 and Monitor PVM1454QM.
Note: This test still only affects 17MHz bandwidth, in IC905 this is the FIL1 setting.


Hardware configuration: FMTV TX ----> Attenuator ------> IC905 Receiver in Test -------> Monitor or Wave monitor


As a control, first receive with reference receiver....

image (3).png (753.94 KiB) Viewed 916 times

( The reason it is not perfectly linear is half due to the my TX and half due to the Pace receiver )

And now we remember what test signals looked like before the " ALL Reset ", Multiburst namely like this below.....

Unbenannt-Zusammenfügen-01.jpg (234.26 KiB) Viewed 908 times

Now receive again with IC-905, all cables plugged in and signal level adjusted, here hardware configuration....

IMG100257x.jpg (208.93 KiB) Viewed 899 times

Lets goo , TX ON !! ------> Received Video Signal with IC-905 RX after Software ALL Reset......

2xn.jpg (809.42 KiB) Viewed 675 times

YESSSS, YES that is completely different than before the factory reset, now the color is there too, I would say RX site it's almost perfect ( to ~90% ).
( I think: if no deemphasis is inside IC-905 available ?, then the frequency response could be increased linearly from 0dB to 1.2dB via software from 2MHz to 5MHz. )

I didn't know that you have to do a factory reset right after buying a new 4000 euro expensive device to improve the quality. crazy thing , at least something, half of the problem is solved and we have learned something new.


So if anyone here has the same problem as I had, I recommend doing " Factory reset "
on page 10-2 in IC-905 Basic Manual



But that doesn't solve all the IC905 problems !
1. As for the FMTV RX part of IC-905, I'll say YES, we can leave it like that.

2. As for the FMTV TX part of IC-905, we still have too little modulation - too little deviation !
Instead of the "prescribed" 1Vpp we only have 0.5Vpp and you as a customer can't set that with AV-IN video input level !!!
---> the ICOM software specialists have to get involved.
3. And what about missing special AV cables that are necessary for operation and are not included in the delivery ?
For SSB mode, a microphone is included as an accessory --- Why is the special 4pin 600/75ohm AV cable not included for FMTV mode ?
( If the cable is not the right one, a lot of video signal quality is lost ) .


Vy 73 de OE7DBH

[WiSi-Testpilot]

1. Post from Wilhelm, DG2YK

Hello,
my name is Wilhelm.
Today I came across this forum. I have the same problems with my two IC-905s as described here.

One problem has not yet been addressed here:
Below a certain limit, the video on the AV output is switched off. The monitor then produces a blue screen. Occasionally the AV output switches on, even when there is no video signal. This behavior is random and can sometimes be reproduced by switching, see photo.

I want to set up an ATV repeater with my IC-905. This of course assumes that a noisy signal is also allowed through. The repeater will be software-controlled so that the user can influence the content using gesture control, for example. The test image in the attachment was switched on by a hand movement in front of the PC camera. The image from the camera is then displayed at the top left.
Best regards from Germany, Wilhelm, DG2YK

AV-output.jpg (255.78 KiB) Viewed 657 times

ATV-testimage.jpg (86.65 KiB) Viewed 657 times

[oe7dbh]

Hi Wilhelm

I tested today whether the same phenomenon occurs for me as for you.
With software 1.15 that I have in it and after the "factory reset" this is not the case for me.
From strong signal to completely noisy does not switch to blue, and even without a signal the video output port remains noisy ( Plug J1452 )

Audio Squelch test:
without signal = audio squelch threshold at 50%
with signal = audio squelch opens at 50% only when signal image is noise-free and "S meter" is between S0 and S1.
with signal 80% noisy picture = sound carrier still audible ( Squelch open ) but in strong noise.