G2 Ultra 8" fan and some observations unrelated

[Joel1]

Hi,

I'm thinking of replacing my stock fan for a quieter one. As I was looking and also looking at the schematic, I see a PWM fan controller with all the required signals going to the fan connector. Does anyone know if PWM fan control is actually implemented? If it is, I would replace the stock fan with a PWM version.

Also, as I was poking around, wrt to some of the mods I have seen,

My G2 Ultra came with a metal barrel TRS jack and no ferrite clamped onto the TRS audio cable.

On the 10Mhz ref input, mine has J22 and J24 jumpers already installed.

I am currently using an XLR mic plugged in through the TRS jack. Initially I was getting reports of poor audio. I turned off the 20db boost and tweaked the mic gain a bit, now all works fine. I have been on the 15 and 17M bands which seemed to get the most attention wrt audio issues.

[laurencebarker]

The PWM fan connector will adjust the fan speed to suit the temperature of the Raspberry pi, not the PA - and the PA is the part that generates most heat. So it won't help I'm afraid.

[Joel1]

Bummer on the fan, guess I won't go that route.

Thanks

[DO7DV]

I am very sensitive to fan noise. In fact, I prefer passively cooled electronic devices.
My goal is for them to be completely silent.
If that is not possible, I prefer air cooling with large diameter fans running at low speeds.
The operating point of the fans must be optimized to ensure adequate airflow,
static pressure, and low noise at low speeds.
For this reason my computer systems are always equipped with Noctua fans,
they do well for me in this regard. But they are expensive.

The fan of the Anan 10E (revised) is too loud for me to have it right next to me all the time.

Now I got my hands on a Anan-G2 with its 120mm fan.
The G2 is not as loud as the 10E (revised).

oem_fan_small.jpg (477.68 KiB) Viewed 236 times

From my point of view, there is room for improvement:

I assume the aluminum block with through-holes is relevant for cooling the transceiver,
especially the PA part.
I also assume the more "computer like" electronics on the top of the transceiver have other
characteristics of heat output. They definitely have to be cooled as well.

The built in 120mm fan blows directly on the Saturn Board with the CM4 module.
Nice those components are being kept cool this way. But the PCB blocks the airflow into the lower parts
of the receiver completely.

120mm_oem_fan_small.jpg (649.49 KiB) Viewed 236 times

I put a dummy 140mm in its place to see if it would fit and it does. The Saturn board is then still
blocking air flow to lower transceiver parts, but at least the fan could spin slower.

140mm_fan_pos1_small.jpg (624.53 KiB) Viewed 236 times

Actually there should even be a second 140mm that could be placed next to the first one.
Both 140mm fans together probably would move more air than the current 120mm at much lower speeds,
lower noise output and the PA part would have better cooling, because air would actually be pushed
through the holes in the Al-cooling block, into the lower parts of the transceiver and from there
out from the case, sideways left and right.
There is enough space for a design like this. (I did not have a second 140mm fan at hand)

140mm_fan_pos2_small.jpg (649.52 KiB) Viewed 236 times

The first thing I will do to my own G2 is to swap the fan for a Noctua NF-A12x25 G2 PWM or even NF-A12x25 G2 LS-PWM model.
Those are designed to run at full speed with 12V and should be controlled via PWM.
If there is no PWM signal, they just run at full sped.
If there is less than 12V, they run at decreased speed.
With the LS version my Anan-G2 probably would not be cooled sufficiently for long transmission operation,
but for receiving it could fine.

I do not want the new fan to pull much more current than the built in one (0.20A),
because I do not want to destroy the driver on the Raspberry CM4.
I will measure the current draw of the new fans, when I get them.


This topic is so important to me, I also wrote an email to support@apache-labs.com,
but I did not get a reply yet.

[w-u-2-o]

Unfortunately, thermal design has never been Apache's strong suit.

In particular, there has never been a model that has included proper air flow through the unit. The mechanical designs seem primarily focused on low production cost.

I've not seen a G2 in real life, but in the photos appear to show that the fan inlet is on top, and there are vents on the sides. Typical of Apache thermal designs, the internal arrangement does not provide for good air flow over the main heat sink. The lowest impedance path is directly out the side vents rather than through the holes in the heat sink. The heat sink design has no fin stock to promote good heat transfer to the air.

The large aluminum slab (also used in the 8000) has proven to be a better heat sink than the designs that use the extruded enclosure as a heat sink (e.g. the G1, 7000, etc.).

[DO7DV]

I have to admit: The lower board covers the Aluminium-slab almost completley, so air cannot be pushed through.
Are there any pictures of a completley disassembled Anan-G2?

Still, there would be many ways to improve thermal performance and noise output.