Category: Geen categorie

I recently purchased Xiegu’s newest radio, the G106. It’s a tiny, sturdy and very basic SDR QRP-HF-transceiver. It’s a bit quirky because it can also be used as a broadcast receiver (HF MW and FM, bands preprogrammed). This makes the rig a great travel companion. The quirkiness also comes back in the design, with rounded corners. I.m.h.o. it’s a beautifull and ergonomically well designed radio. By the way, the design reminds me somewhat of the ELAD FDM DUO.

The Xiegu is basic as in ‘it misses a lot of features that high end radio’s have’. For me that’s not a huge problem, although I miss the opportunity to read the SWR while transmitting.

With an interface it can be connected to a computer. The monochrome LCD is very well readable.

For those of you who watched the very early (and mostly negative) reviews: mine just works fine. I’m happy with the rig.

For me the biggest drawback is something very simple: the G106 lacks a tilt stand. As I use the G106 on a table, the lack of a tilt stand is a bit annoying. But also easily solved. I solved the ‘problem’ with after-market tilt stands, sold as ‘laptop stands’ on Ali Express. The ones I bought are self adhevise, made from aluminium and available in black (so they match the G106 ;-).

Attachment is simple: best is to remove the two front feet and replace them by the stands. See the photo’s for the result.

The Xiegu G90 is a manpack style SDR-transceiver, 20 watt and a legendary antenna-tuner. It’s great to use outdoors. But in my opinion the G90 lacks a foldable table stand. I tryed a laptopstand, but found it’s an hassle. I needed something much simpler. So I came with the idea to use two pieces of L-profile and attach them to the front handles of the rig. This would make a simple, lightweight and compact, foldable stand.

It’s easy to make this stand from any plastic (or aluminium) L-profile from a DIY-store. Choose the length of the stands according to your prefered position of the G90 in tilted position. 6 cm worked for me.

By the way: the L-shape of the profile makes the stands more stable than just a flat piece. And: the notch on the top side together with the L-shape secures the position when in use.

Folded back, the stands lay nicely flat to the radio. I used an L-profile of 2 x 1 cm.

You don’t need to drill extra holes in the rig: the stands are attached to the G90 using the holes/bottom screws of the handles.

See the pictures below, they are self explanatory! In my case I choose 6 cm lenght for each stand (in total), the L-profile I used is 2 by 1 cm.

And does it work? Yes 😉

The Xiegu X6100 is a great radio, but gets hot to the touch when used with digital modes. Mine got as hot as 55 degrees Celsius (130 F). Maybe within specs, but for me too much. The root cause is the transceiver’s heatsink. (and off course the heat production inside). The heatsink has an ‘capital I’-profile, with the largest area of the heatsink inside the radio itself! This is where the heat producing components are mounted. The heat tis then transfed to the outside of the X6100. Only the top and bottom of heatsink of the radio are on the outside: this is the only place where the heat is actually dissipated. Or: … should be dissipated. The problem is that these top and bottom heat dissipating surfaces are not very large and have almost no fins. Result: the rig heats up to an unpleasantly high level.

An alternative way to overcome the X6100 heating problem is by adding a fan. Best place i.m.h.o. at the bottom. But a fan consumes power and produces noise.

Another (more elegant?) way is enlarging the effective dissipation surface where it matters most: at the bottom. Preferably easy removable. The heatsink has to be fixed in a reliable way, preferably without drilling holes in the rig itself. By the way: also the back of the Xiegu dissipates some heat and the surface is relative big. However, the back it is not a part of the actual heatsink and just sheetmetal that happens to touch the heatsink where it is screwed on. Only cooling the back of the rig is not a good idea and that is why I did not put a heatsink to the back. But you could if you want, just keep in mind that it will not be as effective.

You can see how I attached the add on heatsink without drilling holes. I used magnets -which I glued on the bottom of the rig- and other magnets in the heatsink. When needed (working digital, that’s when the X6100 heats up most) I can add the auxiliary heatsink easily.

As a prototype I used a standard aluminium heatsink (160 x 25 x 10 mm) I had lying round in my shack. These heatsinks are sold for cooling LEDS. I drilled three 8 mm holes in it and glued 3 strong 8mm diameter Nd magnets flush. Between the magnets I added heat conducting pads (1 mm thickness). I spray-painted the heatsink black on the visible side so it looks niver on a black rig. To the bottom of the X6100 I glued 3, 1mm high same thickness as the heat conducting pads) Nd magnets. This contraption makes the heatsink ‘click’ to the rig nicely and also secures that the heat conducting pads are pressed to the rigs bottom heatsink firmly. This to ensure a goof heat transfer the from the bottom to the add on heatsink. As the add on heatsink has a much larger dissipation surface, its capacity is enlaregd significantly. The rig now stays cool nicely. Because the heatsink itself I used is not very high (just 10 mm) the X6100 can still be used in the tilted position. See the picture below.

By the way: the heat is -off course- also transported to the top side of the rig and -for a part- to the back. The effective area of the top is even tinier then the bottom because of the buttons. I did not put a heatsink on top, but one could do so. Beware: if your X6100 has the paracord carrying handle you must ensure to keep some space between the handle and the top heatsink. Because when the paracord handle rests on the top-heatsink, it more or less acts like a blanket, hampering the heat dissipation on the top of the rig!

And, does it work? Yes, by adding the heatsink the X6100 stays cool, even when using digital modes. Also: with the heatsink added, the X6100 can still be used in the tilted position.

Psuedo voice: just an idea for a radical different approach to digital voice over limited channels.

One of the reasons I started this blog and gave this website its name is that I want to share an idea I have for HAM-radio (and other radio communication). Starting point is that on HF ‘voice’ or ‘phone’ needs a relatively large bandwidth compared to many digimodes. Sometimes you just need the excellent SNR-handling and/or narrow bandwidth of digital modes to get the message through. Some digimodes can do this. Voice not.

There are experiments to encode and send coded voice digitally (like freeDV), but that is still a bandwidth-hungry mode compared to -say- PSK31 or even MT63-500

Here my idea of ‘pseudo-voice’ steps in. Psuedo voice is (no surpise!) not real voice, but is in essence it is a series of code-labelled words. That’s why it has the potential to be used in narrow bandwidth channels. They basic idea is you just transmit short codes that represent whole words or even whole sentences. How? First let a computer algorith (AI??) convert speech to ‘words’ and then label each word (or standard sentence) with a unique and (as) short (as possible) code (a so called ‘label’). Then only transmit the sequence of labels. After receiving the labels, they can be converted back to words/sentences (and speech) by using a special look up table: a dictionary. This concept only works if both sides use with the same ‘label dictionary’. that associates the same labels with the same words.

For each type of communication you can develop a seperate tailor-made-dictionary. Like a dictionary for EMCOM, a RAG CHEWING dictionary, et cetera. It’s all about standardisation.

The basic idea behind pseudo voice and its use of dedicated dictionaries is that a meaningfull basic conversation in a normal language only needs a vocabulary of about thousand words (the so called ‘language level A1’). If the conversation is limited to just a few topics (like EMCOM) even less words are needed. Higher laguage levels need more words, complicated grammar and therefore larger dictionaries. By the way: a normal conversational speech speed al level A1 is about 120 words per minute, some of these words form standard sentences that can also have their own label.

Pseudo voice could work ‘like real time’ voice if we use a digimode that does 120 labels per minute. If a label constists of max 5 characters, we would need (netto) max 600 characters per minute = max 10 characters per second. Which small band digimodes can do that? A lot!

More and older/less matured musings:

So: what if each word (and regularly used sentences) has it’s own, short and unique digital ‘label’? And this label is -obviously- shorter than the word itself. You could pair words and labels in a specially written dictonary, that consists of carefully selected words and sentences. Lets say a ‘dictionary HAMQSO’, or a dictionary ‘EMCOM’. Then you could use a speech-to-label engine (STL-e, a variant on the speech-to-text engine) to code speech. And vice versa with a label-to-speech engine (LTSe) . A 120 wpm speech could than be converted to a much lower wpm datastream of ‘labels’.

For use in radio we could -instead of sending real voice- use a STL-engine loaded with a certain dictionary, and send a series of short labels (characters) using a narrow digimode. Say MT63-500 (speed: 5 cps). Labels receveived can be converted back to words (/sentences) and speech using a ‘label to speech’-engine also loaded with this dictionary. Hence ‘pseudo voice’.

NB The sound quality of the pseudo speech is independent from noise in the analog radio channel (as long as the labels are decoded properly): the sound quality depends solely on the quality of sound clips in the LTS-engine. It could be anything from low level computervoices to hifi-speech clips. There are many possibilities to optimise the system to ones needs. One could even have qso’s between diffent foreign languages as long as the labels refer to the same content-dictionary in your own language. ;-). You could use the voice you like (male/female) on the receiving end.

One could use pseudovoice in circumstances where normal HF voice communication is difficult or even impossible (like in situation with low power, compromise antenna’s, bad snr, bad propagation, QRM, etc) and where dedicated digital modes work still OK.

In short: in essence not that the voice itself is digitized and then transmitted, but the use of a dedicated dictionary that labels words (or whole standard sentences) and transmit corrsponding short codes. And vice versa.

For-pupose-dictionaries (aimed at specialized communications) could be developed; for HAM, Emergency, tactical engagements, etc.

Only sending labels (i.e. maximal shorted codes) would greatly reduce HF bandwidth needed (albeit at the cost of a limited dictionary). It doesn’t produce a real conversation, but it comes close (pseudo 😉 ) And it is better than nothing!

That’s why I called this webpage ‘pseudo-voice’.

By the way, I may have coined the idea in this blog, but that doesn’t mean I am building or developing it. I am not an engineer or programmer by any means. So I am not able to bring this idea to life in the real world. But it would be nice to hear from you what you think about this idea and even how to bring it forward in the HAM-community. Please post your comments!