Saturday, November 14, 2020

The RX888 SDR

Late summer I became aware of the RX666, a Chinese build of Oscar Steila’s BBRF103 design. Basically, a design with a 16-bit ADC capable of sampling 32 MHz, and with a R820T2 chip “thrown in” to allow reception up to 1800 MHz. I did a write-up which you can read here. The antenna connectors were not up to standard, so after a while I returned it for a refund.

The RX888 is very much the same design, but with a smaller PCB and apparently better build quality. Unlike the RX666, the RX888 has an LNA built-in for better sensitivity.

As a MW DX-er I’m mostly interested in how it performs on MW. And for that, three things matter more: Sensitivity, large dynamic range, and a minimum of 1200 kHz alias-free sampling. And of course, software to match.

The RX888 footprint is quite a bit smaller than the RX666. It measures 72 x 83 x 43 mm (excluding antenna connectors) and weighs in at 160 grams – less than half that of the RX666. Heat dissipation panels make up three sides and of course adds to the physical size.


A 16-bit ADC (Analog Devices LTC2208 in this case) is always better than 14-bit or 12-bit ADCs, especially when negotiating the huge signal levels on the MW band. In that respect, the RX888 performs very well indeed, even if the only filter is a 64 MHz low pass filter. The downside, as with the RX666 is sensitivity. Although the RX888 has an LNA built-in, sensitivity figures are still in the lower part of the list, 3-4 dB better than the RX666. I measured -95, -98 and -99 dBm on 500, 1000 and 1500 kHz (AM mode, 6 kHz bandwidth, a 400 Hz signal with 30 % modulation). This is 5-6 dB worse than the Perseus, and 10-12 dB worse than the Airspy HF+. The good part though, is that the ADC is quite forgiving if you decide to use external amplification. A 16-dB preamp from DX-Engineering increased sensitivity by 13-14 dB, which is a massive improvement. I did test this setup on a very high signal level MW band, fed from a beverage antenna, and noted no overloading. If you do, you can always reduce RF gain by 10 or 20 dB.



Available sample rates when using the dlls developed for HDSDR are 2, 4, 8, 16 and 32 MHz. In addition, there is support for 64 MHz sampling rate. SDR Console also supports the RX666 and RX888 and offers a 1-MHz sampling rate in addition.

It does require a USB 3.0 port on the PC, and of course the wider sampling rates, the more it demands from your PC. Since the Cypress driver was already installed for the RX666, the RX888 connected right away.

So, while the Perseus + Jaguar combo is still my choice for MW DX-ing, the RX888 appears to perform very well if some external gain is added.

Ebay prices are in the USD 230-250 range, not much more than the SDRPlay RSPdx but a lot more resilient to large signal levels and only slightly less sensitive. And not very much more than the Airspy HF+/Discovery, but able to sample the entire MW band.


Sunday, October 25, 2020

KONG41 Day Nine: Almost Ready for Departure

 Another DX-pedition is getting close to the end! Conditions overnight were variable to say the least, but a few stations made it through: KFOR-NE 1240, KHIT-NV 1450 and a super strong KUGR-WY to name a few. Mount Loran recordings still to be reviewed, but we did note KYUL Scott City KS 1310 in parallel with KIUL-1240 - a rare station. Maybe there is more.

Yesterday was a dull experience indeed, KAJO-OR 1270 is the only noteworthy station in the log so far. Asia/Pacific: Forgettable.

Dinner last night was a lot more memorable: Västerbotten pie with trout roe instead of the usual löyrom. Followed by fried fillets of saithe, with unbelievable amounts of fried onions and a potato paste. A Niepoort OLO white 2016 went very well with the fish!


For dessert, we.... just couldn't make it. After a long break, we settled in with some port wine. And not just any old port, but a 2014 Niepoort. So, two Niepoorts in one meal!

Today, we dismantled the Mount Loran equipment. Hard physical work, but we've found a good routine so things went smoothly. Especially with the weather on our side.

Speaking of weather: Mild, calm and dry so far today, 4-5 Celsius. Quite a bit of change from previous days, as you can see on the picture below. Wind will increase again late afternoon and tomorrow. Myself, I will be leaving Kongsfjord later today after another fantastic meal, haddock in salsa. Ole will drive to Andøya Monday morning, and OJS will leave for Berlevåg airport a few hours later.

So, that's it from the KONG41 DX-pedition. New updates in September 2021!



Saturday, October 24, 2020

KONG41 Day Eight - King Crab Mania!

 Signal levels varied but were quite high overnight, though not much of interest was noted. As for Asia/Pacific: Another boring day. Tonga-1017 had a short, early peak, and that was it. Replacement of battery and SSD on Mount Loran was done in very unpleasant conditions - strong gale force winds and constant rain. No fun at all!

All the more fun to prepare the second of the KONG DX-pedition signature meals, the King Crab! As usual, served with carbonara and a 2017 Le Buissy red wine. Although a little less meat than expected in each leg, the crab tasted wonderfully, baked on a bed of salt with spices.

Scissors for opening the legs...

Jim Solatie and Pia were supposed to enjoy the meal with us, unfortunately due to Covid-19 travel restrictions they were not able to enter Norway, so all they got were some photos. Next year!

It should be noted that we tried a Manzanilla 2017 sherry for some salty snacks as starters. Our ranking is on the photo below.


However, we found an excellent Mas Amiel for the dessert, chocolate pudding with custard.

Weather turned out as forecasted - gale force winds and heavy rain showers most of the day. 3-4 Celsius, so most of the snow on lower grounds is now gone. It will be windy and rainy today as well, so another wet challenge is awaiting Ole and OJ at Mount Loran. Below is today's morning view. By the way, tomorrow will be the last KONG41 update. Mount Loran will be dismantled tomorrow as well.




Friday, October 23, 2020

KONG41 Day Seven - And an Hour Worth Seven Days

Unsettled or disturbed conditions is very often boring. And sometimes not. As we hinted yesterday, very interesting things happened during a western daytimer opening that lasted less than an hour. Some of the signals were almost local-like. Best catches of the day were both on 810: KBHB Sturgis SD and some minutes later KTBI Ephrata WA. Lots of less usual and rarely heard stations were also heard, some to mention: KDFD-CO 760, KATL-MT 770, KUYO-WY 830, KJJR-MT 880, KOGA-NE 930, KVSH-NE 940, KFCD-TX 990, KFIO-WA 1050, KOKK-SD 1210, KOLY-SD 1300, KRCM-TX 1380. And we're still searching.

Just to give you an idea of which signal levels some stations had, this is KGFX-SD 1060.

The recordings from Mount Loran and the local 340-degrees beverage took all our time yesterday, so little focus on Asia/Pacific. Tonga-1017 had a great signal for several hours, but nothing else of interest really.

Yesterday was our annual dinner at Kongsfjord Guesthouse-day, after a quick sauna. Excellent baked halibut. LA9VFA Olav had a 2-hour drive on slippery roads to join us for dinner, much appreciated!



The weather on Wednesday was quite nice, not much precipitation, calm and just above freezing. Overnight the wind increased a bit and changed direction. A bit milder, but more rain. It may be quite windy today. Below is today's morning view.



Thursday, October 22, 2020

KONG41 - Day Six

Wednesday: Geomagnetic warnings! Aurora! Return of the Chinese!

The spectra from Mount Loran tells how much signal levels varied throughout the night and until lunchtime. Often, disturbed condtions can give some very surprising loggings, however, as far as we know, not this time. We did note WMEJ-MS 1190 though, along with WBNS-OH 1460 at 01:00. Otherwise, only the usual stations.


Asia/Pacific DX was not good at all. The Chinese stations were on very early, and nothing of interest was noted. A couple of 1-kW NHK-2 stations were ID'ed at the 15:40 close-down. So most of the day was spent listening to IQ recordings from previous days and weeks.

While doing the daily Mount Loran battery and SSD replacement routine, we took a detour into Berlevåg where the fish shop sold fish cakes right out of the frying pan. We grabbed a few (for each) and headed back to Kongsfjord for a delicious lunch.

We had enough fish cakes when we started making dinner too, so for starters we re-fried them (sliced in halves) in bacon fat, and served with bacon slices and fried fresh ginger, grated carrots with fresh ginger and lime. A Calle's Riesling was the selected wine.

The main course was another leftover, as we had reindeer sirloins from the day before, served cold, with mashed potatoes and carrots, sauce with chanterelle and the rest of the lingonberry jam. The wine was a López de Heredia Rioja from 2007.

For dessert: Selected cheese with slightly roasted sourdough bread. Papillon Roquefort, Chévre, Gruyere and Parmesan were served with a Dow's 2006 Vintage Port. We have lots more cheese. And port...

Weather was a bit cooler than yesterday, hovering around zero and down to around -5 as the afternoon turned into night. Another starry, starry night. And what happened in the night will be told tomorrow. Interesting things...

As usual, a morning picture from today, as you can see the weather is very nice and the temperature is positive again. Friday and Saturday will be very windy and rainy. Today by the way, we're eating out!



Wednesday, October 21, 2020

KONG41 - Day Five

Signal levels towards North America varied quite a lot overnight, with a clear dip around 04:00. It didn't really recover until early afternoon (!) with very strong signals from Alaska and Hawaii around 13:00. The morning signal levels were low towards Asia/Pacific as well, but the dead band allowed signals from the Pacific islands and Hokkaido. In fact, the Chinese power houses, many of them incredibly dirty, didn't begin to dominate until 14:00. The image below shows how Newstalk ZB-1035 is the first signal visible, then at 13:00 it's quite dominant, before the highly un-synchronized CNR1 network starts to fade up - 3-4 hours "behind schedule".


Lots of New Zealand stations were noted, but the noise floor is still on the high side, so few below 1000 kHz. The NHK-2 close-down at 15:40 brought few stations of interest as Hokkaido stations with their generic non-QTH ID dominated too much.

Solar weather is a bit unsettled now, so we're hoping for more surprise openings towards North America and the Pacific.

It's not all live DX-ing though. Playback revealed WCRA Effingham IL 1090 from a while ago.

Time for one of the KONG signature dishes: Reindeer sirloins! For starters we had Bruschetta with Meinklang red wine. The main course was sirloins served with mashed carrots and potatoes, sauce with chanterelle and lingonberry jam. For dessert: Cloudberries in whipped cream. With the meat we tested a 1996 Chateau Musar. We may not go with that one again. With the cloudberries we had another round with Tokayer, and a Grappa at the end to clean up our taste buds.

Weather: The same, the same... occiasional rain showers, 2-4 Celsius, calm. The photo below is pretty much like yesterday's except this morning we had a snow shower coming in.




Tuesday, October 20, 2020

KONG41 - Day Four

Nothing spectacular to report the last day. Signal levels were generally high on the trans-polar paths, but more interference than usual (or wanted) due to higher signals from Europe/Middle East as well. 

Pacific came early yesterday as well, with New Zealand mixing with UK at 09:00. The hope for a nice NHK-1 opening at 10:00 was lost due to increased noise levels.  The 1-kW Asahikawa relays in Enbetsu and Wakkanai (792 and 927 kHz) were nice and strong, also Aomori 963 and a few others. The noise levels were on the high side for the rest of the day.

Checking early night with Jaguar, one can see how WLQV Detroit 1500 changes from day power/pattern to night power/pattern. I would suspect they use two transmitters. The day transmisson is about 3 Hz high while the night transmission is about 8 Hz low. The drifting at the start of the night transmission might indicate a warm-up drift. WLQV is 50 kW days, 10 kW nights.


The main use of this feature is to spot stations with high daytime powers before they power down or power off.

Dinner was a bit the same as yesterday. The starter was different though, duck liver paste. The main course was leftovers from the lamb, cooked in Barolo with chopped vegetables thrown in. Then for dessert, another round of chocolate mousse with cloudberry jam. The duck liver paste was served with a 5 puttonyos Tokay Aszú from 2013. A Lopez de Heredia Rioja from 2008 went very well with the modified Barolo dish. Another round of Banyuls for the dessert.

We do test a few beers during our stay. Below is a selection...


Yesterday's weather: It warmed up a bit so the snow and sleet turned into rain. 3-4 degrees Celsius, some dry periods. This morning's view from the living room:



Monday, October 19, 2020

KONG41 - Day Three

Monday! How time flies. Sunday started off nicely with a few daytimers closing down, such as KUYO-WY 830, KQLX-ND 890, KKOJ-MN 1190 and KDOM-MN 1580. Signal levels were good all Sunday, but night reception was a bit disturbed from snow-induced noise. After checking the Mount Loran recordings, the WNJC 1360 test was heard at 05:41.

Pacific stations arrived early, the carrier from Tonga-1017 was visible from 06:30 and very well readable at 09:00. New Zealand arrived early as well, but so did the rest of the Asian continent so they weren't easy to pick.

Tonga, while still alone on the frequency

As the day passed, the snow shower activity eased off a bit, and spending time outdoor was quite pleasant. 

KONG HQ to the right, neighbours including the guesthouse to the left. Facing west.

As evening drew nigh, we did our usual unusual-beer routine, before settling at the dinner table. Starters was salmon tartare, consisting of smoked and fresh, sashimi-quality salmon, together with red onion and chive. A Knewitz Riesling Eisenerz accompanied this course very well.

The main course was a lamb thigh, baked at very low temperature for a very long time - 7 hours in fact. An excellent meal with mashed root vegetables and a spicy sauce. We chose Italian for the red wine, a Langhe Nebbiolo 2018.

Dessert was M&M... Magnificent and Massive! Chocolate Mousse with a cloudberry jam on top. Wow. A 2008 Banyuls didn't make it worse! All this bought us into instant and deep hibernation mode, from which we only just recovered!


Weather report: Snow and sleet showers which eased off during the day (and a starry starry night followed). Temperatures still just on the "red" side during the day, a few degrees below at night. Almost dead calm. We appreciate that.




Sunday, October 18, 2020

KONG41 - Day Two

 A somewhat uneventful night sort of peaked at 06:00 with loggings of rare WBHR Sauk Rapids MN 660, and new (to me) WVAL 800 from the same city. WREY-MN 630 also noted. Good signals from Minnesota and the eastern Dakotas - more suprising was that at the same time several Colombians were audible, and even Radio Monumental, Chacuí Paraguay 1080. And then KKMO-WA on 1360. Propagation which we, with directive beverage antennas, call unfocused.

WVAL-800 is a good example of "seeing the station" with Jaguar software. With CKLW being the huge channel dominant, it is useful to use the Jaguar Spectra tool to see which other stations are visible, but maybe buried in the dominant station's signal. As luck would have it, WVAL came from virtually nothing to a good signal a few minutes around the full hour, and then faded away.


The Spectra tool view also gives a good impression of how many stations are actually on the frequency, but not audible. Since stations tend to have small, and often stable offsets from the nominal frequency, one can make qualified guesses about station identity.

Ole arrived around noon after an arduous journey on snowy and icy roads. DX-peditioning is not for the faint of heart! Later on we did another trip to Mount Loran for battery and SSD replacements, and finishing antenna repairs. Frequent snow showers and slushy roads.


Dinner time! Fried salmon with carbonara. The white wine came all the way from New Zealand, a 2018 Yealand Sauvignon Blanc. For dessert we enjoyed a blueberry pie with custard, and of course Amaretto!

Weather is much the same, snow showers with clear skies in between and temperatures just below freezing.

Saturday, October 17, 2020

KONG41 - Day One

 OK, so here we go again! We were doing some math yesterday, and found out that over the past 24 years we've actually spent more than a year together on this location! Starting off with extremely basic equipment, and little comfort, the journey has been spectacular indeed.

Anyway, I picked up OJ Sagdahl at Berlevåg airport on Friday afternoon, and we headed directly towards our Mount Loran remote, battery-powered Perseus/Jaguar/1000-metre beverage setup. After replacing the battery and the SSD, we discovered that "something", most likely a reindeer, had messed around with the antenna. The antenna lead to the transformer had been torn off, so the last four nights of recording were total silence. After half an hour, the damage was repaired, and there was no sign of the reindeer so it probably got away unharmed.

Mount Loran remote setup, Kjølnes lighthouse in the background. Facing East.

Not too much to report station-wise - KGMI Bellingham WA 790 isn't too common though. Tonga-1017 and Marshall Islands-1098 were heard with moderate levels.

Early in the evening Ole Forr reported that he's on his way from Andøya, a 12-hour drive even in summer conditions. Now: Icy roads.

We were only two for dinner this first day: The usual self-composed Bjarne-style fish gratin. We were supposed to have chocolate pudding with custard for dessert, but there simply wasn't room for any more.

Ole told us this morning he decided to rest a bit in Karasjok before doing the last 280-km leg. We will head out towards Mount Loran later today to pick up the latest catches and do final antenna repairs. And with that, below is the usual morning picture from Kongsfjord. Temperatures just above freezing in the day, at or below at night.