NOAA Antenna and OSX Decoding

So I have been using Wefax for getting fax weather transmissions. I really enjoy them and also find it useful in seeing how much QRM I am getting on the ‘wire’ so to speak. Recently a gentleman on youtube by the name of “Tech Minds” published this excellent video

Build a V-Pole for weather sats

Now I loved the instructions on this video and it has been something I’ve wanted to do. I asked “Tech Minds” if i could put the V-Pole adjacent to a 2m/70cm vertical, to which he said yes, so i was then on a mission to build my V-Dipole.

Parts list

PondKraft Rigid Plastic Filter Outlet Pipe 50mm – 1 Metre – Used for attaching Vpole to Mast – £ 6.49

Silverline 868823 Coaxial Cable Stripper – Needed an upgrading in stripping, £5.79

10 Pcs RC Airplane Model Part Stainless Steel Round Rods 3mm x 150mm, for the dipole, £3.78

PremiumX mast base galvanized steel 20-60mm diameter, for clamping the assembly to the mast, £4.45

As i have a number of projects going on, I ordered another reel of coax as well, but think I would of had enough with my existing coax.

Heres what i used

RG-8 Mini Coax Cable 50Ohm Military Spec 50Metre Drum, For connecting dipole to electrical block connectors, £34.96

I already had decent electrical terminator blocks, so didnt need to order those.

I followed the instructions and set about mounting the antenna on the mast – i have to say i found this quite challenging on my own on how to attach the pvc pole to the mast, but sure enough, and with a few ‘oh dear’ (swearing may of been harsher) on dropping nuts/clamps i got it attached.

I then fed the coax from the mast back into the ‘shack’ where I put a PL-259 socket on .

I do love this video, and the guys no nonese approach

the method i use for puting on a PL259 onto coax.

With that i put the antenna via a PL-259 – SO-239 to SMA cable attached it to the RTL SDR Dongle.

Sure enough, i could pick up radio sounds no problem, so all the effort was worth it !

I then set about installing all the necessary software on my HAM computer, following yet another excellent tutorial from Tech Minds

Setting the software up on Windows

I initally tried with the HackRF, but for some reason it wasnt playing ball. Ironically as I knew that a sat should be overhead, i hooked up my other SDR to a basic scanner antenna, and i could hear the sat overhead ! Immediatly i set about setting up my mac for the receiver.

On the mac I used gqrx. The satellite track software is avaiable via macports, but i couldnt find a stable 64 bit version of translation software so used noaa-apt, which whilst not as feature rich, works incredbly well on a mac, as in being actively developed.

I tested with a ‘sample’ NOAA recording, and that produced the required map output ! iwas all set.

I waited patiently for the sats come and tracking and sure enough within an hour i had my first sat pass over ! Whilst the intial result wasnt amazing, it at least proved that antenna, SDR and decoder worked.

My first NOAA decode !

I then looked for future NOAA passes and a good candiate for going directly over was on for 6pm, so i waited and recorded, sure enough, i got a signal and a decode, and whilst the results arent amazing, its a good start in my book.

Second attempt at 6pm

As it was some time before the next pass i set about doing some fettling on the antenna, and found i hadnt got it North-South Aligned that well, so i rotated the antenna and made sure that all the connections were in good form after a full day up in the air.

I’ve not really done a write up of just how good the mast is I use for VHF/UHF, but you can see in the pictures below how high quality it is. All the stages are locking and push up/down without problem, even after rain, they is no fricion on the joints. The locking mechanisim is tough, but gives real confidence the pole isnt going to slip down. I use a ‘light’ guying system as i’ve only got 2 very light weight antennas on the mast (the 2m/70cm and now the NOAA) – any more would be overkill. The guy ropes and ground stakes are incredbly strong and go into the ground some 2ft at a guesstimate, the antenna only ever comes down for the worst weather forecasts.

If you want to invest in a good mast system i can really recommend these

https://www.radioworld.co.uk/tfm-40-2_watson_12_2m_40ft_telescopic_fibre_glass_mast_8x5ft_s

https://www.radioworld.co.uk/complete-guy-kit-light-weight

https://www.radioworld.co.uk/9888_3_hook_guy_wire_clamp_non_rotating

With the antenna back up I now wait for the next good pass to try out how good the scan comes out. Its very exciting (for me) and thanks again to Tech Minds YouTube channel who puts really great content !

I’ll upload my pics to my STOATOPIC account as I get more decodes

gqrx receiving noaa 18
gpredict communcating with gqrx
tracking NOAA18 as it flys over my QTH

Tracking pattern

tracking of the pass, i can pick it up from 21:43
Decode in NOAA-APT
Its another fuzzy one!
only the code-strip is visble, but keep trying !

The ongoing quest to reduce QRM – Mains Filter #2

*** PLEASE NOTE PHIL’S OBSERVATION OF MY BUILD (FILTER ORIENTATION) BELOW ***

I was using the origninal picture and refrencing off the *EARTH* location post, and not looking at the label (LOAD/LINE) – I have since corrected – afaik no damage done, but good to get right first time if you are using the same filter (FN2030-16-06 FILTER) which has a different layout and orientation to the one used in the slides

*** PLEASE NOTE PHIL’S OBSERVATION OF MY BUILD (FILTER ORIENTATION) BELOW ***

Back in May I built this filter for my shack, which provided suitably good results for the time and effort employed. Further to that post G8KVM (Personal “Bern”) posted a follow up link to an updated filter here.

The main difference to this filter was it contained multiple and updated ferrite types as well as a mains-filter. I was immediatly drawn to the idea of further reducing the QRM into the shack as the first filter provided good results.

I ordered the following parts

PartSourcePrice
Large Fair-Rite core 0431177081: MouserFarnell16.47

1463420,FERRITE CORE, FLAT CABLE, 25MM
Farnell4.98
FN2030-16-06 FILTER, 1 PH, 16A, CHASSIS MOUNTFarnell15.97
CE-TEK  GR17012  IP65 ABS Enclosure – 170x170x75mmFarnell8.79
PRO POWER  PG-11 BLACK  Nylon Cable Gland PG-11 Black – Single Pack, IP68Farnell0.80
Parts Ordered for updated mains filter

I would like to point out that when ordering the mains filter (2030-16-06) the picture on the site is an AC filter. The once I received had DC on it, although the product code was the same.

I was slightly worried about the filter saying DC on it, where this is receiving AC current from the mains supply. Whilst rated for 250V i was not going to take any risks, so setup a test-bed outside, where it was thankfully dry and sunny.

I set about by first running an unplugged in extenstion, plugging the filter into that, and setting up my voltmeter to read AC from the output terminals. There is only one earth on the casing.

I then went back in doors turned on the power and no popping/arcing/fusetripping was observed. I then checked the output on the voltmeter, and sure enough it was good 240V AC coming out the filter.

I then proceeded to complete the winding for the ferrites.

The cable i used was SEL 10 m 2.5 mm Twin and Earth Cable. This very good solid copper wire. I did have to put on some Electrical PVC Yellow/Green Earth Sleeving to the earth-copper as this is bare when it comes out the original sleeve. I didn’t want to use my electric drill for the twisting of the wire, so done this by hand. Whilst physically demanding, i felt it provided safer and better results.

I was then able to twist the cable thru the torids as per directions. I was rather happy with the results, as it was quite tough to get the cable thru the torid and space it nicely.

Having tested for electrical continuity via a voltmeter, i then proceeded to test with a simple electric lamp which worked perfectly well. There was no issue with the wiring on the toroids or the filter.

I then disconnected my old filter and connected the new filter.

I was immediately impressed that i was now picking out more receive signals on FT8 and Wefax images were incredibly sharp.

I had 4 consecutive QSO’s which had never happended to be before, so was my first time manging a ‘pile up’ of sorts !

In summary for the time and expense this is a fantastic additon to the shack and makes me confident that in terms of power-line RF and QRM I have done as much as I can in terms of mains-filtering.

Thank you again to GM3SEK fantastic blog posting and G8KVM for pointing me in the right direction to the updated design !

73’s and see you on the airwaves soon hopefully !

— Appendix page update ! 🙂

Following Phil’s comments I powered down everythign and re-opened the filter as its been a little while since I closed it up.

In the picture below, the mains is the cable to the top of the page, this connects to the line filter, then in turn the ferrites connect to the output of the filter. I think I have got this correct based on the source picture !

Source – https://gm3sek.files.wordpress.com/2019/10/capture.jpg – All credits to gm3sek.
Pic of filter following Phil’s observations

Whilst mine isnt as tidy, i think it is correct. Appreciate if you can reply to comment Phil 🙂

Posted in QRM

Kenwood SP-23 & Phonema Upgrade

The main speaker on the Kenwood TS690-S is not a bad one. I’ve been using it now for around 5 months, and although no expert, it has been good in terms of being able to listen to what ever made it thru the antenna and to the audio stages of the transceiver.

However, with the addition of the Auto-tuner and DSP, there is quite a bit which ‘blocks’ the speaker. Whilst not muffled, its ironic that I have such a good DSP and not a good external speaker. I do have a very good mixing desk (Behringer X2222) which I use on ocassion to process and amplify the audio from the transceiver, but ordinarily I keep the radio audio seperate from the synths/drums/guitars. Another issue would be managing the sizeable ground loop between mixer and transceiver as the earth/bus bonding isnt the whole way around the ‘shack’ yet.

This lead me to search for a speaker for the TS-690s. Whilst not an ‘audiophile’ I do understand a little about speakers, housing and acoustics of them. I was very lucky to find a really great condition Kenwood SP-23 from ebay. The item itself is in incredbly good condition. I cant tell if its one month or 10 years old. It looks gorgeous. When findng the SP-23 I also searched for upgrades to it, this is without hearing it, but I’ve come to trust the reputable amateur sites on the internet, for example eHam reviews of the SP-23 talk about the quality *compared to other speakers* – I guess when you buy a speaker you want it to be the best buck for money. The most often given upgrade was to the GPH-K23X speaker and applying Phonema K23A PHITS acoustic coupling. I ordered both immediately and was amazed that these arrived from the USA in just a few days – amazing work from FedEx.

Having had the speaker for several days un-modded I was quite happy with the audio quailty. That said I still dont do enough telephony work to really say how good it was, and other than the internal speaker have no real reference on what ‘good’ is in terms of HF transceiver speakers.

As the kit arrived so quick, i jumped over a couple of other projects to immediatly upgrade the speaker and apply the acoustic foam.

I was really impressed with how well the speaker and foam had been packaged, its quality throughout and is a good sign that this is a quality purchase.

I am always slightly relectant to make changes to orginal equipment, but when I do I make sure i can recover it back. In this case i carefully de-soldered the orginal speaker. I did have to cut a little of the positive wire as it has been wound so well, but it was a minor inconvieane.

I was then able to start trying to work out how to install the new GPH-K23. Reading the instructions it discusses a bracket and furthermore has pictures of ‘clamps’ which are not visible in either the kit or in the existing speaker. I was slightly confused how this could happen, give this speaker is designed for the SP23. In the website for the GPH-K23 is describes a ‘plastic’ front version of the SP23. Mine is very metallic. With that i was somewhat perplexed on how to mount the speaker, especially as I had now de-soldered the orginal speaker just moments ago.

I was undettered by the fact that the instructions and mounting didnt match. There must be a way to do this. I had kept the old parts safely, ready to be placed in the SP-23 box so that they are there for future records and changes if required. I examined the brackets which held in the orginal speaker. The backing card was too small (diameter of hole) and too thick (widness of backing card) to mount the new speaker on.

Looking at the parts I had and the design of the case, there was a possibility to use the ‘brass’ clamps from the speaker back to hold the new speaker in place. I tried out the existing screws to check a good fit, and sure enough i was able to use the brass/copper mounting plates to hold the speaker in place !

Looking from the front the speaker looks very centrally located.

The foam fitted really well in the speaker, i was very impressed with the cutting and density of the foam. Getting the case back on required some real effort to it fitted, but on it went and back in the stack it went !

Now, i think its very subjective on how good something sounds, so here it is in action.

Sp23 listening to broadcast radio and the 40 meter band

I for one was very impressed and felt the additonal parts did bring something to the speakers audio clarity. I would recommend that anyone that does have the SP-23 to get the coner and baffilng. I had to choose between one or the other, start with the baffling !

The Quest to Reduce QRM – DSP & New PC and more in progress !

  • bit of a longer post today so grab a cup of tea is recommend, else scroll through the page until you get to the bit you want to know about

Several weeks ago I was browsing the local 2nd hand radio shop where my TS690 came from, and amazingly they had the DSP-100.

Kenwood DSP-100 – finding chicken teeth is easier

The DSP-100 is one of the first ever Digital Signal Processors. Kenwood were pretty ahead of the game when they released it. You will see all the filters and features you see in this unit in most modern transceivers, but this is (I guess) about 20+ years old, and are hard to come by. I dont mind saying this unit, 2nd hand was £333 ,which is only £40 different of what I paid for the TS690S, but what it brings to the radio is RF filtered and processed. The promise of ‘hi-fi’ quality SSB, AM, CW and RTTY was too good to pass up. And it looks gorgeous too 🙂

When I first set it up with my TS-690s I connected in my xggcomms Kenwood interface I started running into issues. I honestly believe this is no fault of the xggcomms device, but moreso on how the RS232 signal from the DSP-100 unit is processed and fed into the transceiver. Its fair to say whilst I was overjoyed in having the DSP, alot of what i do requires a good CAT connection to constantly adjust the frequency (FT8 & WSPR), so I reverted back to the Xggcomms interface only and started investigating.

Upon searching, other people had experience similar, but not identical issues. The key to fix this was the IF-232C. This translates the serial input into signals at the correct levels for the DSP & the TS690s.

Up until now I have been using a laptop, which had become increasingly over burdened with USB dongles/hubs coming out of it, also getting the computer to be ‘RF Friendly’ and grounded proved a challenge. The only way i could see to easily and reliably RF was via the USB port, and this little lenovo laptop computer already had *alot* coming out of the USB ports.

With that I decided to get a dedicated full-size ham-radio PC. Nothing expensive or new, in fact I was looking for ‘older’ models with a native DB9 Serial interface so USB to Serial issues would no longer be a problem. This HP Elite 8200 met the specification needs for what I would be using the computer for and was a reasonable price/availablity. I could add all the audio inputs and outputs to the native connectors and also use the on-board serial (or so he thought…)

HP Elite ports – native Serial Port and audio on-board

Having migrated PC i went about installing first the apps I know, namely Fl Digi and FL Rig. I have been using these for sometime for WeFax and love getting the images in. The good thing about reducing the QRM, i can visually see it has been reduced, as I will show later.

I did run into some issues with communicating with the PC, the Serial Port settings had to be changed on the PC also, by now I had also discovered i had ordered the wrong cable from RS Electronics, but have a replacement on the way. I went back to using a USB to RS232C interface for now, which after some tweaking worked. I’m sure I’m not the only person who would still setup a IF-232C, so here are the settings I used between my PC and the RS232C.

Screenshot of Windows PC Running Windows 10 and USB Prolific based RS232 connector

Incase its hard to read on the screen, heres the tabulated form

SettingValue
Bits Per Second4800
Data Bits8
ParityNone
Stop Bits2
Flow ControlHardware
AdvancedLeave FIFO Buffers at max and on
Table of Settings for the RS232 Port on Windows for Kenwood TS690S and IF232C

In the FL Rig for the Serial port the settings are as follows (Select TS450S as the transceiver) :-

SettingValue
Baud4800
2-StopBitsEnabled
PTT via CATEnabled
RTS/CTSEnabled
Retries..Byte intvDefaults
Init (Click)Connected
FLRig Settings
Kenwood DSP-100 with the IF-232C

Now I dont mind saying that I’m still learning, so understanding what filter to use when is very much a case of ‘try it and see’, but i will show a comparison between before I started all the QRM clean up and the acculmation of what I have done so far *plus* the use of the DSP-100.

WeFAX – local QRM is quite clear with the ‘banding’ visible across the otherwise clear image

As you can see in the above image, there is alot of QRM in the picture, the ‘banding’ consistant across the image, in this case probably caused by the Ethernet over Power adaptors, is very clear.

Here is a scan today, same antenna, but will all the additonal work to reduce QRM and the DSP in Receive mode filtering.

Reduced QRM, what you do see is from a fan running because its hot today 🙂

When less electical items in the house are running, namely fans, washing machines and the like here is an example image. Again, this is the same antenna, same external line filters/chokes and the DSP and recent QRM work outcome.

The ice-chart from Hamburg

The ice-chart from Hamburg is the equivlant for me as the last row on the eye-test exam. The letters on it are incredbly small and the details/dots equally so. Whilst with a zoom there is some slight distortion (so more to be gained!) there is a total absence of the QRM which was so present in the first WeFax image shown.

I am adding a MFJ-1026 to the mix now (Thank you Nevada radios, you are doing a great job during the lockdown !) and I cannot thank Steve from Xggcomms enough for the assistance he has given me. I asked Steve for some help on how would I go about connecting both the xggcomms and mfj-1026 at the same time, as they need access to the T/R Control line present on the ACC-2 port. Sure enough Steve was good enough to reply on how to do this, by way of opening up the connector and adding a connection to pin 13 and ground (I used pin 12 for ground).

From Page 22 of the TS690S user manual

I had recently performed an inventory of all the wires/cables,etc I had, so it was easy to find the phono socket I required to connect the back of the MFJ-1026 phono socket to the ACC2 DIN plug.

I first tested the connectivity between socket and plug, to ensure it would work correcly before opening up the xggcomms. I am generally unhappy about opening working equipment in that I could break it and make it unoperational, but as Steve had already offered his support should anything go wrong, i bit the bullet and went for it. Needless to say, it wasnt an easy job for me who doesnt do this type of soldering reguarly.

I had already pre-tinned and checked the continuity between socket and wire on the phono socket, so was confident that as long as I was careful I would be able to add the necessary wires to the respective pins.

I dont mind saying that upon putting the shielding on and checking before plugging in that i found that the case (which should be grounded/seperate) ended up being ‘shorted’ and no resistance was shown on the voltmeter. Undeterred I undone the case and carefully applied a small piece of masking tape across the top pins ‘tucking’ between pins to give some isolation. I apologize i didnt take a picture of this. This had the required effect and that when the casing and flexible connector were restored, the isolation between pins had been restored.

Having completed the cable, the next step is to install an external auxiliary antenna for the MFJ-1028 to match against. I considered several ideas, as in just using a simple end-fed piece of wire, to a range of ‘small’ antennas from Russia that attracted QRM to be used in this way. In the end I decided to get another DX Commander. Whilst I wont totally multi-band this will all 6 elements (in particular 80m requires alot of space) I can setup the 2nd vertical ‘auxiliary’ about 2~3 meters from the ‘transmit’. With this I should be able to ‘phase out’ both any local QRM as well as distant QRM meaning I should not only be able to get out more cleanly, i should also be able to hear and filter those very feint remote signals that currently sit ‘below’ the noise table.

As ever, I will keep posting with my battle with QRM, which I think I am winning one week at a time.

Webcam – some lessons learned !

So having got my webcam up and running with streaming, i had to migrate the streaming server to another PC (in this case a macbook) and relocate the USB cable going into it.

I resumed my daily antenna observations with the inclusion of checking over the camera and re-routing the cabling from the camera so it would be ‘free’ from the mast allowing more length into the ‘shack’

Come the afternoon I’m now perplexed why i can TX and seem to get out well, but RX is non-existant, apart from 18m, which seems odd. I walk the path backwards of changes, of which there have been a couple in the shack with the QRM bonding and all, to try and work out why my reception is so bad.

As i work thru the devices directly connected to the transceiver, no change in reception. I then go out and check the mast, no problems there. I unplug all the connections between mast and and tuner. No change ! What on earth can it be !

At my whits end I relocate the macbook and suddenly see the usb cable from the mac to the camera, albeit on the 2m/70cm mast, it now does have a different ‘vector’ from mast head into the shack.. could this be the source of my problems.

Low and behold, unplugging the mac and the webcam suddenly the channels come alive again. I had created a USB transmit antenna blocking pretty much everything.

I set about removing the camera and cable from the 2m/70cm mast and tidying the cables I had previously disconnected. Full filtered resumed, minus the webcam 🙁

After all this I remembered the advice from the ARRL and Youtube videos “EVERY THING IS AN ANTENNA, EVEN IF YOU CALL IT SOMETHING ELSE”. Hence why my issue had occured, i saw it as a USB cable, but it was an antenna, and blocking my HF.

I probably can fix this, but I’m already battling QRM and I want to reduce issues, not add new ones, so for now the camera stays off, but I was glad of the experience and I could fix and understand the issues.

Posted in QRM

The Quest to reduce QRM – Bonding

The never ending quest to reduce QRM continued after following the ARRL Grounding and Bonding book and the excellent ‘clean up your shack video’ from RSGB i have been planning to try out what is discussed.

The excellent RSGB ‘clean up your shack’ video

For my ‘shack’ i used the following components, other things like voltmeters and screwdrivers I already had.

ItemCost
GTSE Twin Pack Aluminium Foil Adhesive Duct Tape14.99
Digitus Assmann DN – 19 Earth Equipotential Bonding19.99
Items for bonding

The objective here is to ‘bond’ all the radio equipment together so it has a common earth, therefore not creating a ‘earth loop’ via the earth pin. Also it gave me the opputnity to fix things down and generally tidy the ‘shack’ radio desk up, as I would have to remove everything from the table.

The first step was to apply the duct tape. I check first that it did conduct before sticking it down ! I got the idea to try tape as I didnt want to spend on metal plates and the ARRL book some temp setups use tin-foil and baking trays – so thought this was a good compromise.

The next step was to attach the ‘earth’ bar. I put it at a ‘safe’ location to the back of the table away from where human contact should not be possible and also to give better accessability to the various earth taps on each component. I measured it up and pre-sunk the holes to screw into to make fixing a little easier

I then set about attaching all the earth, or in this case bonding, wires to the bar and positoning my KPO distribution to a place on the table. This had previously been loose and somewhat annoying and potentially dangerous. I measured up the location, pre-sunk some holes and set about attaching.

With the grounding bar connected to the distribution board I set about adding the devices. I checked for voltage first and kept the wires coiled nicely onto the now metal surface.

Comfortable that the right voltage was making it to the distribution board and the position of the feed & choke to the transceiver was good i set about adding the other components to be bonded together.

So i have completed ‘bonding’ all the HF equipment together. I will add more metal tape to the small shelf the laptop sits on and source a USB bond, which I think for the rig will complete the RF bonding of all the devices. I’ll continue to work around the ‘shack’ with more tape and bus-bars to further reduce the RF loops which go through the common ‘mains’ ground, but i’m satisfied with the measurements on the rig for now.

25/5/20 – additon

I’ve since connected the virtual earth directly to the transceiver. This is what the guidelines say to do, and I’m not about to analyse the deltas between the bus-bar and the virtual ground. When I have more experience of measuring and using the Virtual Ground I’ll see if this can be changed, for now i’m following the instructions so the wire from the ‘bus bar’ to the ‘virtual ground’ are directly connected between Tranceiver and Virtual Ground.

Posted in QRM

Adding a webcam to the mast

Having had a webcam available to me for some time since I now use a mac which has an in-built camera, I thought I’d put it to good use.

linux desktop now acts as a fancy router, main desktop for me ia iMac Late 2013 model !

There are a number of really good mast-webcams on the Internet/Youtube, so thought I’d give it a try myself. The webcam is a cheap-er Logitech one as I know that some of these cameras can get very expensive (4K/remote control,etc). Im not 100% this from Argos is an identical one, but its a smilar price/looking and all powered via USB.As I’m not sure of the longevity of the camera given its outside, something on the cheaper end of the webcam market is in order !

there was alot of usb cable to go up, or not as the case maybe !

The mast is approximately 10 meters tall and has my 2m/70cm J-Pole on it. It is well rigged and secured with a heavy duty mast vertical and ground stakes which are very well driven into the ground. I do take it down when the weather is predicted to get quite bad, but i can still reach Poole and of course my DRM hot-spot for chatting on Talk Groups via the Internet.

mast with camera and J Pole – one element is wavign around but after checking all is good on 2m and 70cms

The first challenge is that a regular webcam comes with around a 1 meter cable attached to it. I needed a good quality cable that would introduce as little loss as possible. Here the RS USB 2.0 Active Repeater Cable comes into play. I actually ordered 3 of these and to start with did attach all 3 to make sure the cables are not too tight or pulling, but 1 does the job nicely, and I’m left with two very high quality usb repeating cables for other projects.

For software I used free streaming software provided Open Broadcast System, namely OBS Studio which is available here It was very easy to setup and integrates easily with you-tube.

well rigged mast ensures that it will stay up until i wan it to. The USB cable doesnt interfere or go near coax until the feeder.

I entered in the required Token for streaming from YouTube and sure enough the webcam was on air !

The mast cam – for as long as the camera lasts !

I was really thankful for WY7W for checking the camera out and also sharing his amazing webcam video as well – i have to admit i was just ever so slightly envious of his amazing QTH 🙂

Well I’m hoping the camera holds out, be interesting to see how long it last

— additional 25/5

I’ve since had to remove the webcam due to QRM from the USB Cable. When i find time/have reduce all the other QRM in the shack i’ll re-introduce the camera, for now it sadly has to stay off.

Streaming with DXCommander on 80m

Was browsing my youtube recommendations when I saw Calum was live streaming, tuned in and could hear everyone, which was really amazing to hear Calum and everyone else coming out the radio live.

Calum was ace in putting out some calls for M7’s – given the amount of people that call into his CQ’s, it was so nice that there was a gap for us on lower power (10W) to try and have a QSO.

I put in my call and Cal took his time, but i was just too quiet, see the video below.

https://youtu.be/1_jMJL7WLJ0?t=3932
A very faint M7ALU

Listening i can barely hear my voice, with M7 being just about audiable and i can recognize the gaps of how i would say ‘Alpha Lima Uniform’. Its a shame i couldnt get on the log book, but nethertheless provided a very exciting and good evening enjoying Calum and using the DX Commander as well.

Hopefully the restrictions on exams will soon be lifted and the extra wattage will help me get out that bit more. Fingers crossed !

Kanga DX Direct Conversion 40m Receiver Kit – Stage 3: VFO & VFO Buffering – Tuning and use of oscilloscope

So having got the lab somewhat tidy (pics and a full reveal will come soon !) i can continue working on my 40m Receiver Kit – having wound the toroid and secured it previously, the next step was to add the components and buffer around the tuning circuit.

I would like to point out (maybe again) that one thing that i think is very much missing from this kit is a schematic of the ‘blocks’ of the decoder. At this stage it would be very much helpful to understand what components and how the modules worked together, in particular when we get to the stage of the ‘decoder’.

Capactors, IC’s and variactor Diode !

I found getting most components on the ‘push-thru’ was easy enough, the only components which presented a ‘challenge were the NPO and Polystyrene capacitors. As you can see the round circles for C27,C28 and C30 are ’round’ enough when the capactiors are verticle.

Capacitor mounting

On the first attempt i tried the ‘test’ method of using a radio tuned to 7Mhz and got nothing at all. It also didnt help that I didnt know what i would be looking, or in this case listening for. I took a break and came back to it the next day.

visually looks fine, but actally a dry join on the trim.

Tracing my work I found that i had left a slight dry join on the trimmer. As i have now aquired an oscilliscope I thought it was the perfect use to find the frequency and adjust it.

We have a 7.5Mhz frequency!

I was so happy to even see a signal on the oscilliscope and also the read on the frequency was not so far out from the 7Mhz. I was lucky enough that the oscilliscope probes come with tuning screwdrivers which are the ‘safe’ type required to tune the trim. I set about tuning to 7Mhz !

Close to 7Mhz

On the scope i could the frequency to read between 6.90nnn and 7.000nn. I thought about trying to see if I could hear anything on my handheld standard (AM) and my transceiver which has more modes (including CW & PSK) as well as specific filters.

7Mhz = beeep

I was very happy to pick up a clear signal on 7Mhz. What was interesting also was that where i have the probe into the VFO / Decoder board, it had turned the ‘wire’ into a small resonant circuit – in fact I could turn my VFO into a theramin ! After 15 minutes of playing wooping noises I set about completing/and tidying the kit up.

I’m really glad that the receiver is going so well – its been all the work I thought it would be but its now very satisifying, esp as its gets more complex.

QRM & Power Line Adaptors

So last night (11/5 – 12/5) Turned into a bit of a QRM mission. Not exactly sure how, but found myself really getting trying to find the source of a specific hum, as I am gradually reducingt the amount of interference/QRM I am picking up. I started with taking my little AM radio (D-328) around the house buzzing very present. What I wanted to rule out was the utilitys nearby and the garage. Being 1AM and wandering around with a pocket radio should make for amusing footage on the overnight security video from the garage today 🙂 Anyhow, I could pick none up.

I returned home,sure enough the ‘buzz’ was back. So as it was quiet in the house (trust me, we are 24/7 shop here!) i started going thru the fuse box, its an older one, but still thankfully a trip/RCD (?) type box where I can easily flip the circuits. Sadly the circuits are not labelled, which I find quite unprofessional, apart from the ‘light’ fuse. I started flipping fuses and on the 5th one the buzzing on the radio stopped, as did all the mains power to my study and I think the front part of the house.

I set about unplugging everything in my study with the mains back on, hum still there. So I started to research/googling hum between 50 and 500Khz – it seemed so precise, I figured it must be some form of ‘man made’ interferance.

Here is a video of what it sounds like :-

So you can hear it all the way up from 50kHz to a very loud abrupt end at 500kHz. I set about googling as to what that could be, and sure enough found th GM4FVM page on ‘power line adaptors’. I’ve been very careful to remove and limit the use of ethernet in the house now, so suprised that this had caught me out. I immediatly removed the BT Ethernet over Power adaptors I had. This is the result

A longer video with manual AM tuning and a ‘sweep’ of USB

If you are patient enough to have watched the whole video, i congratulate you 🙂 But you can hear the big difference between what a power line adaptor can do to HF/RF in a shack, i.e. completely destroy all but the strongest signals.

This morning I tried out WSPR, the results on receive and transmit speak for themselves :-

wspr map is somewhat busier…

So now its time for work but I think i have taken another big step in reducing QRM in my shack

Next Steps – reduce this hum MORE and MORE