Hi Max.
Yes, I will post my findings here as soon as I feel I know what I am saying. Both VHF/UHF and as well as VLF and LF experience. But, I do not want to rush and draw wrong conclusions.
BTW the reference clock was 4.8 ppm off in my unit at arrival. Easy enough to adjust in SDRC.
73 / Ingolf
RX-888 deliveries
Re: RX-888 deliveries
Many thanks Ingolf. Be interested to hear your opinions.
73
Max
73
Max
sm6fhz wrote: ↑Wed Sep 30, 2020 6:09 am Hi Max.
Yes, I will post my findings here as soon as I feel I know what I am saying. Both VHF/UHF and as well as VLF and LF experience. But, I do not want to rush and draw wrong conclusions.
BTW the reference clock was 4.8 ppm off in my unit at arrival. Easy enough to adjust in SDRC.
73 / Ingolf
Re: RX-888 deliveries
Hi all.
I did some experiments with active cooling of my RX-888. I placed two 40x40x20mm, 12V fans on top of the top cooler of the RX-888 and fed them with reduced voltage (from a USB outlet of laptop) for lower acoustic noise. They fitted very nicely on top of the cooling fins and were easy to fasten into the correct position with small screws.
Room ambient temp +23C. Running 32 MHz sampling BW.
No fan attached: Stabilize at +43C case temperature close to the main cooling fins. Delta T of 20C up from room ambient. Cooling fins on the RX-888 facing upwards.
Fan running at 3.8V: Stabilize at +34C case temperature. Improvement of 9C. Very low acoustic noise. (the 3.8V comes from a 18 ohm resistor in series with the +5.0V from the USB outlet)
Fan running at 5.0V: Stabilize at +31C case temperature. Improvement of 3C more for a total of 12C down. Higher acoustic noise than with 3.8V.
Lowering the sampling BW to 1MHz reduced the case temp to +30C when using +5.0V on the fan. Not much of an decrease, actually surprising.
Is it worth the effort? Possibly, semiconductors inside will run at a lower junction temperature and thereby increase their life span.
If a FW using 64 MHz sampling will show up for the RX-888, it may be a good idea the use such a active cooling.
73 / Ingolf, SM6FHZ
I did some experiments with active cooling of my RX-888. I placed two 40x40x20mm, 12V fans on top of the top cooler of the RX-888 and fed them with reduced voltage (from a USB outlet of laptop) for lower acoustic noise. They fitted very nicely on top of the cooling fins and were easy to fasten into the correct position with small screws.
Room ambient temp +23C. Running 32 MHz sampling BW.
No fan attached: Stabilize at +43C case temperature close to the main cooling fins. Delta T of 20C up from room ambient. Cooling fins on the RX-888 facing upwards.
Fan running at 3.8V: Stabilize at +34C case temperature. Improvement of 9C. Very low acoustic noise. (the 3.8V comes from a 18 ohm resistor in series with the +5.0V from the USB outlet)
Fan running at 5.0V: Stabilize at +31C case temperature. Improvement of 3C more for a total of 12C down. Higher acoustic noise than with 3.8V.
Lowering the sampling BW to 1MHz reduced the case temp to +30C when using +5.0V on the fan. Not much of an decrease, actually surprising.
Is it worth the effort? Possibly, semiconductors inside will run at a lower junction temperature and thereby increase their life span.
If a FW using 64 MHz sampling will show up for the RX-888, it may be a good idea the use such a active cooling.
73 / Ingolf, SM6FHZ