Wednesday 21 February 2024

OFCOM'S LICENSE VARIATION

OFCOM'S LICENSE VARIATION IS NOW ACTIVE!

As of today, the 21st Feb 2024, OFCOM have announced that the new variation to license has come into effect. Full details are below (click to read the PDF file)...



Wednesday 14 February 2024

IS HAM RADIO STILL RELEVANT?

I spotted this article and thought it was interesting….


73, Tom.


STREAMDECK & FLEX 6300

EXTERNAL CONTROL FOR FLEXRADIO 6300

Because I have a 32-Button StreamDeck and a Flex-6300, I thought it would be a worthwhile little project to link them both together. Needless to say, it wasn't as easy as I thought because the SmartSDR software doesn't have native keyboard mapping, so you can't apply keystrokes to buttons as you might normally do.

It seems that the way you go about this sort of thing is to use a very popular 3rd-Party piece of software called FRstack which virtually every Flex owner will be aware of. FRstack (V3) allows you to assign tasks/events (even multiples with tailored delays in-between) to StreamDeck Buttons.

I should point out straight away though that if you assign certain keyboard characters to a button (such as SpaceBar=PTT), you will end up keying your mic everytime you press the spacebar whether you want to or not (as long as FRstack is running). So it's better to avoid doing that, except maybe the F1-F12 Function keys.


Of course this meant a lot of learning and no doubt a string of cock-ups before making any progress, but thankfully, Erik Carling (EI4KF) had already used his blood, sweat and tears getting the StreamDeck to function properly with FRstack - and therefore with SmartSDR. Without Erik's mighty contribution, I'd still be wrestling with the commands. Thank you Erik for sharing your profile 🙏

Some of Erik's profile worked and some of it didn't. The errors were no doubt due to differences in either our ownership of software or their file paths - who knows? So as it stood, I couldn't make use of Erik's profile BUT it was incredibly helpful in letting me understand the command syntax. The video below by David Deccons was also helpful...


After an hour or so I managed to start a new profile and create an initial layout of my own. Needless to say, it's not perfect and I plan to spend a lot more time refining it, but at least I feel like I've made some good progress tonight.

One good little tip I learned was that it's easy to see a button in someone else's profile (eg EI4KF's), copy it and then switch profiles from the drop-down and go to your own profile and paste the button. It will bring across the icon, the text and the actions. You can then tailor them accordingly. Saves you a bunch of time!

At the weekend I'll try new things and I'll reorganise the button layout after spending time using the SteamDeck with the radio. I already feel like I don't need half of the screens. I might end up creating a separate simple single or double screen profile with JUST the very common button presses that I find myself doing all the time. 

Back soon!

















UPDATE

After all that messing around, I soon realised that multiple presses of the StreamDeck screen took up more time than just moving the mouse and clicking!

So I chose the functions that I change most frequently and put them on the front screen. There's a second screen with other software which gets me launching apps quickly.




KISS huh?  I can see this front panel changing pretty frequently as I start to use it and discover what I like and don't like.

73, Tom, M7MCQ.



UPDATE : 
Here's a list of commands that might be of use to anyone wishing to create more complex profiles than me.

Radio cmdval Parameter
INFOreturns radio information
ENUMINFOreturns radio properties enumeration information
ACC0 turn off, 1 turn on, other toggle setting
AMCARRIERUP* to increase level, DOWN* to decrease level, or carrier level
AMPOPERATE0 turn off, 1 turn on, other toggle setting
ATUParam values are START, BYPASS or CLEAR
ATUMEM0 turn off, 1 turn on, other toggle setting
AUDIOGAINUP* to increase level, DOWN* to decrease level, or audio level
BINAURAL0 turn off, 1 turn on, other toggle setting
CLIENTNEXT to switch clients, or set client station name, returns client station name
CLIENTSreturns list of clients
CWBREAKIN0 turn off, 1 turn on, other toggle setting
CWDELAYUP* to increase offset, DOWN* to decrease offset
CWIAMBICMODEA0 turn off, 1 turn on, other toggle setting
CWIAMBICMODEB0 turn off, 1 turn on, other toggle setting
CWPITCHUP* to increase offset, DOWN* to decrease offset
CWSIDETONE0 turn off, 1 turn on, other toggle setting
CWSPEEDUP* to increase offset, DOWN* to decrease offset
CWSWAPPADDLES0 turn off, 1 turn on, other toggle setting
CWX1 - 12 transmits the CWX Macro
CWXQSK0 turn off, 1 turn on, other toggle setting
CWXSPEEDUP* increase speed, DOWN* decrease speed, or speed value
CWXDELAYUP* increase delay, DOWN* decrease delay, or delay value
DAX0 turn off, 1 turn on, other toggle setting
DEXP0 turn off, 1 turn on, other toggle setting
DEXPLEVELUP* to increase level, DOWN* to decrease level, or DEXP level
FDX0 turn off, 1 turn on, other toggle setting
FILTERSHARPNESSNo param returns CA-ON,CL-1,DA-ON,DL-1,VA-ON,VL-1
CA - CW Auto, CL - CW Sharpness Level
DA - CW Auto, DL - Digital Sharpness Level
VA - CW Auto, VL - Voice Sharpness Level
Note: key value separator can be - or ?
Note: ON/OFF is same as true/false and 1/0, 2 is toggle
param=CA will return only CA
param=CA-OFF will set CA to OFF
param=CA-ON will set CA to ON
combine settings with comma to read or set in single command
param=VA-OFF,VL-2 will turn off voice auto and set level to 2, returns OFF,2
GLOBALPROFILEParam is the profile you are selecting
HEADPHONEGAINUP* to increase level, DOWN* to decrease level, or audio level
HEADPHONEMUTE0 turn off, 1 turn on, other toggle setting
METERINRXMeter in RX - 0 turn off, 1 turn on, other toggle setting
MICUP to set previous, DOWN to set next
MICBIASMic Bias - 0 turn off, 1 turn on, other toggle setting
MICBOOSTMic Boost - 0 turn off, 1 turn on, other toggle setting
MICLEVELUP* to increase level, DOWN* to decrease level, or mic level
MICPROFILEParam is the profile you are selecting
MONTX Monitor - 0 turn off, 1 turn on, other toggle setting
MONGAINTXCWTX Monitor CW Gain - UP* to increase level, DOWN* to decrease level, or level
MONPANTXCWTX Monitor CW Pan - UP* to increase level, DOWN* to decrease level, or level
MONGAINTXSBTX Monitor SSB Gain - UP* to increase level, DOWN* to decrease level, or level
MONPANTXSBTX Monitor SSB Pan - UP* to increase level, DOWN* to decrease level, or level
MOX0 turn off, 1 turn on, other toggle setting
MUTE0 turn off, 1 turn on, other toggle setting
MUTEALLn/a
PANCREATE add Panadapter, DELETE remove active slice Panadapter
PROC0 turn off, 1 turn on, other toggle setting
PROCLEVELUP increase proc, DOWN decrease proc, value of 0, 1 or 2
RFPOWERUP to increase power, DOWN to decrease power, or power level
SLICEUP to previous slice, DOWN to next slice, CREATE to add slice, DELETE to remove slice
SPOTSInfo, Clear, Remove and Trigger Spots
param=info to list all spots
param=clear to clear all spots
param=remove,n where spot index n is removed
param=trigger,n where spot index n is triggered
TRACKASlice B tracks slice A Freq enabled; param = true / false
TRACKREVTrack in reverse direction; param = true / false
TUNE0 turn off, 1 turn on, other toggle setting
TUNEPOWERUP* to increase power, DOWN* to decrease power, or power level
TXFILTERReturns delta between High and Low
TXFILTERLOWUP* to increase offset, DOWN* to decrease offset
TXFILTERHIGHUP* to increase offset, DOWN* to decrease offset
TXINHIBIT0 turn off, 1 turn on, other toggle setting
TXPROFILEParam is the profile you are selecting
VOX0 turn off, 1 turn on, other toggle setting
VOXLEVELUP* to increase, DOWN* do decrease, or level value
VOXDELAYUP* to increase, DOWN* do decrease, or delay value
XVTRSTransverter array of Index, Name elements
-XX-Invalid cmd

* NOTE
- DOWN can be replaced by -1, -2, -5, -10, -20 or -50 to step non-default values
- UP can be replaced by +1, +2, +5, +10, +20 or +50 to step non-default values; You must prefix with the +


Slice / Active Slice Commands
http://localhost:5025/ActiveSlice/?param=
To target specific slice letter use
http://localhost:5025/Slice//?param=
http://localhost:5025/ActiveSlice/?letter=&param=
To target TX slice letter use
http://localhost:5025/Slice/TX/?param=
To target slice index use
http://localhost:5025/ActiveSlice/?index={0-7}&param=

Slice cmdval Parameter
INFOreturns slice information
ACTIVEreturn active state and 1 to set it active
AGCMODEDOWN to next mode
AGCLEVELUP* to increase level, DOWN* to decrease level, or level value
ANF0 turn off, 1 turn on, other toggle setting
ANFLEVELUP* to increase level, DOWN* to decrease level, or level value
APF0 turn off, 1 turn on, other toggle setting
APFLEVELUP* to increase level, DOWN* to decrease level, or level value
AUDIOGAINUP* to increase level, DOWN* to decrease level, or level value
AUDIOPANUP* to increase level, DOWN* to decrease level, or level value
BANDband selections
Set band values like 2200, 160, 40, 20, GEN, WWV
or XVTR0, XVTR1, XVTR2, etc.
CLOSE1 to Close Slice
COPYFROMCopy slice information from slice index 0-7 or letter A-H
COPYTOCopy slice information to slice index 0-7 or letter A-H
DAX0 turn off, 1 - 8 DAX channel
DIV0 turn off, 1 turn on, other toggle setting
FILTERUP to previous filter, DOWN to next filter, 0 - 9 to select filter
FILTERLOWUP* to increase offset, DOWN* to decrease offset
FILTERHIGHUP* to increase offset, DOWN* to decrease offset
FREQUP moves FREQ up by STEP, DOWN moves FREQ down by STEP, other is MHz value
Use 1 - 6 to format exponent length of Frequency; e.g. 2 results in 7.12
FREQEFrequency Entry; Param values are 0,1,2,3,4,5,6,7,8,9,., CLEAR or ENTER
ENTER will set the Slice Frequency to accumulated value
LETTERreturns slice letter and index
LOCK0 turn off, 1 turn on, other toggle setting
MODEUP to previous mode, DOWN to next mode, other MODE setting (eg. AM, LSB)
MUTE0 turn off, 1 turn on, other toggle setting
NR0 turn off, 1 turn on, other toggle setting
NRLEVELUP* to increase level, DOWN* to decrease level, or level value
NB0 turn off, 1 turn on, other toggle setting
NBLEVELUP* to increase level, DOWN* to decrease level, or level value
PANPanadapter settings
CENTER center panadapter on slice
UP increase bandwidth, DOWN decrease bandwidth
SEGMENT zooms to band segment, BAND zooms to band
MIN zooms to min bandwidth, MAX zooms to maximum bandwidth
1 - 1000 sets bandwidth
PLAY0 turn off, 1 turn on, other toggle setting
RECORD0 turn off, 1 turn on, other toggle setting
RFGAINUP to increase gain, DOWN to decrease gain, or gain value
RIT0 turn off, 1 turn on, other toggle setting
RITFREQUP* to increase offset, DOWN* to decrease offset, or freq value
RXANTRX antenna selection or , NEXT selects next in list, PREV selects previous in list
SPLIT1 will attempt to SPLIT slice. Will silently fail if no remaining slices for client. This is not a toggle.
STEPUP to increase step, DOWN to decrease step, or step value
SCANstart scan on scan bank
Set scan bank number 1 - 20
or 0 to get scanning bank number
SMUTE0 - 7 slice number to toggle mute setting
SWAP0 - 7 index or letter A-H letter to swap with active slice, if 2+ slices present use NEXT swap active slice with next one
TX0 turn off, 1 turn on, other toggle setting
TXANTTX antenna selection or NEXT selects next in list, PREV selects previous in list
WNB0 turn off, 1 turn on, other toggle setting
WNBLEVELUP* to increase level, DOWN* to decrease level, or level value
XIT0 turn off, 1 turn on, other toggle setting
XITFREQUP* to increase offset, DOWN* to decrease offset, or freq value
-XX-Invalid cmd
--Slice not found

* NOTE
- DOWN can be replaced by -1, -2, -5, -10, -20 or -50 to step non-default values
- UP can be replaced by +1, +2, +5, +10, +20 or +50 to step non-default values; You must prefix with the +
- DOWN or UP can be replaced by a value to set; You must prefix with the space


Tuesday 13 February 2024

FLEXRADIO 6300 Signature

LATE TO THE GAME?

Yes, the 6300 has been out quite a while already and so it's all old news. But it's new to me and I wrangled another bargain.  I've already had a Flex-1500 and a Flex-3000, so I'm not totally unfamiliar with them. Needless to say, the old Flex radios ran PowerSDR and the 6000 Signature Series run the latest version of SmartSDR, so there's new stuff to learn and enjoy.

So why bother writing about the 6300 when there's lots of comments and reviews already out there? Well that's because most of the stuff on the internet dates back to when it was launched and the fact is, things have altered dramatically since that early firmware and software. Most other reviews are highly technical and I wanted to write something from a more basic point of view.

The 6300 is part of the 6000 Signature Series and offers superb performance at a great price-point. This is not a standalone radio though - it will always need to be connected to a computer in order to operate it. Some view such things in a negative light, but in all fairness, every time I get a new radio, the very first thing I do is hook up an SDR receiver such as the RSPdx or the ColibriNano so that I can have a large scope and waterfall and control the radio from my PC, so having a computer-reliant radio is no big deal to me - it's actually a positive! Yes, we all like spinning a dial and pressing knobs and buttons, but I’ve got the wonderful RGO ONE for that.


The 6300 is a HF/6M 100W DDC SDR with some pretty awesome software and my radio already had the very latest V3.6.8 installed. It can run two panadapters at once - the more expensive versions can run up to eight and they have preselectors which the 6300 doesn't. The sample I purchased included the £400 optional ATU ðŸ‘

Getting the 6300 up and running is a doddle - power, antenna, USB, PC and a network cable. Luckily I have a BT Router in the shack so it's easy to make a direct Ethernet connection. The radio takes about 30 seconds to load up and then you're ready to go. I'd say most people could just get straight into the SmartSDR V3.6.8 software - the basics are pretty intuitive. It's only the more advanced options which get you reaching for the manual.

Of course the performance of great software is dependent upon the performance of the connected computer and for a nice, fluid feel you need to have a decent computer - there's no use trying to get away with a shabby old PC you've had since the 80's, lol. I tried using my cheap Mini-PC and fully expected it to be okay, but it just kinda stuttered along.  Thankfully I have a powerhouse gaming PC (and a fast gaming-laptop that I could use if I wanted to go on a Field Day).

The slimline form factor of the Flex means that it’s easy to find a place for it in the shack - it’s just over a foot square (330x300x70mm). There’s just a single button on the front panel (On/Off) and three sockets for Mic (8-pin), Phones and Key (1/4”).

On the rear you have two antenna ports (SO-239), two USB, an Ethernet RJ-45 socket, Transverter BNC, Speaker socket (3.5mm), Accessory socket (15 pin), Anderson Power Poles and four RCA sockets for ALC, PTT, REM and TX.

The radio has small fans inside and although they're quiet, I would prefer them not to be on all the time. I've read that the PA fan can get quite noisy if you're transmitting at high power levels. Of course with this type of radio you don’t need to have it located right next to your seating position, so if the fans annoy you, you can always move the radio further away.

Rather than have a fist-mic laying around, I decided to use my PC’s desk mic. It’s a Fifine 669 USB mic on a small tripod. It works amazingly well for vocals and is an absolute steal!

With the Flex 6300 you can easily record your outgoing audio which makes setting up your TX audio a total breeze! The SmartSDR software has an 8-Band equaliser which allows you to tailor the frequency response to suit your voice and mic. You can save the settings as a named profiles such as “FiFine DX” or “Heil RagChew”, etc. If you find that your microphone doesn't produce enough 'oomph' you can give it a 20dB boost from one of the menus. You can also switch on or off the BIAS option to suit condenser and electret mics.

SmartSDR presents itself very well onscreen and whereas I usually want to change and customise everything, I was instantly happy with the look and the layout - it's fresh, clean, bright, informative and uncluttered. It looks good at many sizes and even when shrunken to accommodate other software, it remains fully usable.

I like how all the commonly accessed options are readily available, while the infrequently adjustable controls are tucked nicely away (but easy to get to). In particular, I love the way you move around the selected band. It's just so easy and intuitive to zoom into a section of the waterfall or to move from one end of the band to the other.  I'd say it's the best I've used to date - I really like it!

The maximum viewable width of the panadapter is 7MHz which is quite generous and way, way more than I'd ever use anyway. I rarely use more than 1MHz. The ratio between scope and waterfall is obviously adjustable and you can even scroll the waterfall backwards to see the history.

It's nice to be able to have two panadapters running at the same time of you want to monitor two bands and have two antennas connected. If you only have the one antenna, then you'd need to be using two bands which were harmonically related or you'd barely see any signals on one of the scopes.

Each panadapter carries its own control panel to the sides, so you have quick access to everything including all the adjustments of the filters. You can also chose which one will be the TX.

A handy little feature of the 6300 is the ability to record the incoming signals and play them back instantly over the air! This is great when you're chatting with someone who is testing a new mic or processor and wants to hear how they are being received at your end. Nifty!

The 6300's filtering is superb and so too is the DSP. In my shack I get some very annoying pulses and hash at various times of the day/night. I've never been able to track it down and it's only made bearable by good noise reduction - thankfully, SmartSDR provides that in buckets. 

Only yesterday, I was tuned into a weak Brazilian station (PP2CC) and it was right where I have local noise - I switched on the WideNoiseBlanker and boom, the noise was completely gone without any effect on the signal. I got the 5,500 miles contact logged and confirmed thanks to the Flex!  Adjusting the TX profile and switching the PROC to DX+ also made a huge contribution to the success of this 10W QSO💚

Don't get me wrong - these contacts rarely happen and you just have to be in the right place at the right time and have all your ducks lined up. But that's the thrill of it all!! I know people with huge linears who can make these contacts all day long - but that is kinda boring to me. Well, each to their own.

If you have a particularly annoying signal, you can use the SmartSDR Tracking Notch Filter to block it. You simply insert the filter wherever the problem is and choose its depth and width. That filter will then notch out the unwanted signal even if you open a second receive-slice. You'll be able to see the notch filter onscreen (and also the unwanted signal behind it).

On traditional radios I like to use the RF Gain to maximise readability of weak signals and in the main, I end up turning it down to improve the situation rather than turn it up. I find that decreasing gain decreases all the noise and allows me to better detect what the operator is saying. 

On SDR machines, it's a little different and I find that I can achieve great results by adjusting the RF Preamp and the AGC. Adjusting the AGC Threshold in particular, can make a huge difference. If the threshold is set too low, you can be inadvertently amplifying the noise! It takes time and practise to get familiar with making these adjustments on the fly, but it's worth it if you want to pull in that distant signal and be able to read it properly.

The SSDR RTX Equaliser also makes a worthwhile contribution to cleaning up the audio on the Flex. Having a set of sliders onscreen makes it real easy to make alterations and hear the difference immediately.


From an operational point of view, I am more than happy to make all the necessary adjustments using a Logitech Master  mouse, but when it comes to transmitting, I don't find it convenient to have to click the onscreen PTT button and then click it again to stop transmitting. This is because I might have moved my mouse-pointer during the QSO.  

To alleviate this problem I'm going to try using a TechnoFix PTT button connected to the 6300's PTT connector on the back.

I originally bought this button for my Elecraft KX3 and it's been a really handy little accessory. It allows you to easily activate the mic and keeps your other hand free to use the mouse or write notes. It's small and easy to hold in your hand and you operate it intuitively without a second thought. Brilliant.

I later attached my Elgato StreamDeck to the radio and created a profile for it which included a PTT button. You can read about it HERE.

If you want to use DIGI modes, SmartSDR makes thing simple. Unlike the old PowerSDR, there's no need to pull in 3rd-party solutions such as Virtual Audio Cables, etc, it's just a case of using SmartDAX which makes the whole process much more simpler than stitching together external programs and making them all shake hands with one another.  It's a similar story for CAT control with Flex's SmartCAT.  There's a video below which helps explain it all...

Click HERE if video doesn't show

I also like the CWT feature where you can send pre-recorded CW messages using the Function keys on your keyboard or even send them LIVE by typing into a text-box while the radio transmits each character that you type. It's worth pointing out here (for those new to the radio) that when keying, you won't hear a sidetone unless you have headphones plugged in. Or you could do what I did and use a tiny speaker…


The software is very well supported by third-parties and there's a plethora of useful add-ons available. It'll be quite a while before you have explored all the various options on this great platform.

Okay so that leaves us with one of the biggest draws of Flex ownership - REMOTE OPERATION. Being an ICOM owner, I am already familiar with radios that have built-in servers (7610 and 705) and the ability to operate remotely, but the Flex  system makes everything just so much easier than other radios. And I'm not just talking about LAN - I'm talking WAN too, so it's easy to operate your Flex from anywhere in the world! You can even share your radio with other operators!


With your laptop and a decent internet connection, you can run SmartSDR and operate your radio with ease. There's usually very little latency - certainly not on SSB. The ease with which you can connect remotely is just staggering. It just works!!
 

Even better (in my eyes) is the fabulous IOS version of SmartSDR by Marcus Roskosch. This is just a fantastic app and it is so good that it's lead to people selling their Flex Maestro!! I have an iPad Pro 11 M1 and I can confirm that the software runs magnificently on it and it looks oh so good. Everything is so fluid and the software includes some amazing tools/utilities.  
 
This is a big plus for most people, but for me in particular, it's a boon! My shack becomes unbearably hot in the summer which makes it a no-go zone. Being able to just pick up my iPad and sit somewhere more comfortable is fantastic. And being IOS software, you just know that it will work reliably and without any glitches.





The software costs around £65 which may seem a little expensive to some, but just consider how much a Maestro would cost you! Below is a video of how the Flex works on an iPhone or iPad.  It's not particularly well shot, but it's informative.


There’s a wide range of really useful tools included with the App and everything’s really well stitched together and functions without a fuss.

 




So, that’s about it for now. I’ve still got lots to explore and I’m enjoying every minute of it. I’d like to discuss the negatives, but I just can’t really find anything of any significance. In my opinion, the Flex 6300 is one of the few bargains available on the secondhand market today. It offers a lot for a little. And now that full remote operation will be permitted on a Foundation License, it's even more attractive.

Leave a comment below.

Many thanks and kind regards,

Tom, M7MCQ.

 

 

 

.


Monday 12 February 2024

HF TROPHY AWARD

 I was the winner of the Bolton Wireless Club HF TROPHY tonight. Now my wife will have to respect my hobby! 😂😂😂








Tuesday 6 February 2024

MX-P50M 50W AMP REVIEW

MX-P50M by BG4IGX


Most hams who love to operate outdoors, prefer to work at QRP levels. Being in the great outdoors usually gives you a fabulous take-off and provides a super-low noise-floor.  10W, 5W, even a couple of Watts can get you across the Atlantic on SSB and that’s something that just thrills me and keeps me interested in the hobby.

Back home however, all the stars need to be aligned for long distance QSO’s to take place. It’s doable of course, but it can be hard work for people at the other end of your transmission, which means that I avoid joining in on any overseas Nets. It’s the main reason that I don’t do much transmitting from the shack. No big deal, cos during Spring, Summer and Autumn it’s easy to setup outdoors. A pleasure, in fact!

I actually have a Xiegu XPA125B amp (boxed and on sale (now sold)), which produces 100W from a 5W input, but it’s useless to me (it came with a radio that I bought (X6100)). The problem with it is that you can’t turn down the power - it’s 100W or nothing!  I’d keep it if I could feed it with 1W and get 25W out. Why?? Because at the end of February OFCOM will be allowing Foundation License holders to use 25W.

What I wanted was an amp which would provide me with 25W comfortably without putting strain on it. I looked at the Neptune  50W but, for the amount of use it would get, it was more than I wanted to pay (and I couldn’t find any used models anywhere).

And then I read some reviews of the MX-P50 made by Sun Xiao in Shandong, China.  Being a very happy owner of a fabulous radio from China (FX-4CR), I'm not one of those "Let's hate China" brigade, so the MX-P50 seemed to fit the bill. It was just a case of finding a used one for £100 or less (my tight-ass budget).  Because it’s worked for me before, I contacted someone who owned one and he agreed to sell it to me. Perfect!

With the 80-10M MX-P50 being able to produce 45W from a 5W input, I knew that it would be positively coasting along at the 25W limit I’d be setting, so longevity shouldn’t be an issue. If it doesn’t work out for me, I can easily sell it and recoup my money.

When it arrived, I could see that it had not really been used. It had been a backup amp to a HardRock/Hermes setup and had spent most of its short life in the box. The amp is really very compact and light - great for those who want to take it with them on a Field Day.

Apparently, it works well with a range of radios including the FT-817, KX3, IC-705, etc, but people using more obscure transceivers may experience issues. 

The amp’s power cable was fitted with Anderson Power Poles and the interface cable was terminated with a 3.5mm stereo jack plug. This was perfect for my Icom IC-705 and worked straight from the get-go.

I know I'm drifting a bit here, but I think it's important to realise that amps can send current back into your radio if a spike is generated by the relays during switching. This current might be small, but it can cause damage to your radio's keying circuitry. This isn't a problem unique to the MX-P50M - it can happen with any generic amp.

I'm guessing that most people ignore this potential problem (or just aren't aware of it) and probably get away with it, but I don't want to put my radios at risk, so I use a buffer device from a guy called RADIODAN in the USA. He calls it an RBI-1 (Relay Buffer Interface) and it can be adapted to work with virtually any radio (although he sells specific interface kits anyway). It will work with any radio that has a keying output which goes to GROUND when transmitting.

 


Using this relay buffer provides peace of mind and is (IMHO) a very worthwhile accessory for all your QRP radios - all you need to do is make up a different lead for each keying connection type - for example on many radios it will be a simple 3.5mm jack, while on others it will be phono (RCA) or even something like a multi-pin DIN.

There is also a 'mod' which can be carried out to prevent spikes into your radio involving you opening up the amp, cutting a couple of wires and soldering few small components. It's detailed HERE in this video where the construction method is better explained. The mod was designed by Kevin Loughin and his video can be found HERE. When I opened up my amp, I discovered that the previous owner had already carried out the mod.
 

So, back to the amp itself. When connected to power the MX-P50M circuit is live all the way through to the relays even though the Power Toggle is in the OFF position, so don't switch the amp off thinking that it's not draining any power from your battery - it is - only a tiny amount, but it's there.

With all the connections made between the MX-P50M, the RBI-1 and the IC-705, I switched the amp on, set the radio's power to 1W, switched to CW and briefly stabbed the key - the amp worked! I sent a few more dits and dahs before switching over to RTTY mode and keying the mic to send a more sustained output. Everything went well.

Now it was time to insert a Power Meter so that I could find out how much power into the amp would result in 25W out (to the dummy load). With the meter inline, I observed the following results...


The power-out reading on the radio pretty much mirrored the power-out on the meter (x10), so that was great. It altered slightly on different bands, but not a mile off. So 2.5W in, 25W out 👍

So there you have it, a nice little amp which is just perfect for UK Foundation License holders and their QRP radios. I'll post more about it in March when the license conditions officially change.



73, Tom, M7MCQ.


MX-P50M HF POWER AMPLIFIER


Specifications


Frequency Band : 80m 40m 30m-17m 15m-10m
Operating Modes : SSB CW AM,  RTTY and FM-Reduced duty cycle
RF input : 5W
Output power : 45W+
Band mode : Manual
Power requirement : 13.8V 8A ,  RED “+” BLACK “-”
Cooling method:passive air cooling
Antenna connector : SO-239 50Ω
Size : 155*100*35 ( mm )D*W*H
Weight : 0.55Kg