Storm Alex. QRM

I can report that all the rigging and daily inspections insured that the end-fed antenna stayed up well despite storm alex lashing down wind and rain of epic proportion !

Whilst I have been enjoy several QSO’s on other digital modes (SSTV, BSPK) other than FT8, id thought I do an update on the next steps for the End-Fed antenna.

Whilst my signals are not bad, there is a noise floor present. Whilst I have largely removed alot of sources of QRM from ‘the shack’ (see earlier posts on QRM) my end-fed antenna seems particuarly good at picking up ‘noise’. Maybe its good to state what I think noise is as well.

When I tune the radio, I should be able to, ideally, hear all stations on that frequency (and mode). What noise brings is either man-made or remote interference to a weak signal. For noise that is ‘local’ the weak signals hide in a ‘noise’ band, this can be upto S9 for thinks like washing machines/VDSL/construction equipment.

With the ‘local’ noise its possible to use the an external antenna (lets call that a receive antenna) and transmit on the existing antenna, then between the two ‘phase’ the noise until it is no longer present.

I am going to use the MFJ-1028 noise canceller as I was using this already with my Kenwood and DX-Commander multi-band vertical, but as both a send and receive antenna making using of the ‘T/R Delay’ – The Icom 7300 doesnt come with its own ‘receive only’ port unlike its ‘bigger brothers’ in the Icom range, but is easily adapater to have one via the a plug-in kit from Inrad.

The installation looks simple enough as shown in the video below. I face the challenge that I am also using an external ATU (MFJ-993B) so getting both ports in will mean doing the install slightly differenty.

INRAD RX7300 mod

I have a number of antennas i could use as a receive only, but a recommended ‘noise gather’ is the ‘mini-whip’. I picked mine up off ebay and it arrived in a bout a week.

I have yet to install the miniwhip, but have all the necessary parts, including a rather impressive 4th ground pole ! I will be following the guidance from the following video

I will first try using the mini-whipa and end-fed combo and feedback on results !

Hopefully there will be less bad weather in the coming week allowing more ‘build’ work outside, for now i’m glad my masts have stayed up and we are all staying safe at home !

Until next post – 73 !

Passed the Intermediate Exam!

Having originally booked the Intermediate course and exam back in March events stopped that happening.

Thankfully the RSGB started with the Foundation Level exam in starting on-line exams and rumours of the Intermediate being made available on-line soon started. I had been building my kit for assesement since earlier in the year, and not sure what would happen about the practical assesment carried on with it, albeit at a much slower pace !

In July it was announced that the exams for Intermediate would be on-line so I immediately booked mine. I wanted to give myself enough time to kick-start my learning and give myself the best chance of pasting, but also fit in with everything else I have going on. Post September alot of my time outside of work will be taken up with my MSc and I had already booked a holiday for the bank holiday at the end of August, so went for August 23, first thing in the morning !

All the participants of the exam were given an invite earlier in the week and hooked up. This was a great idea and we was given a nice introduction to our group. Vitally I learned i would need *two* webcams, one on my PC I was using and another to see me from behind. So i set that up via my ipad. I would say if you dont have 2 webcams, use your PC for your main camera and use your phone – you will need WebEx on your phone, but belive that is possible.

In the two weeks upto the exam I made myself a schedule and broke down the notes/exams questions into days. I found this really helped me understand where I need to focus my learning. I had no problem at all on anything related to licencing and safety, most of the challenges come from the maths and equations on theory.

Invaluable advice !

Although the video came out close to my exam and the revision was well underway, the video from Tim G5TM really helped ! I followed his techqnique and it made me much more at ease during the exam. I took my time and went thru the ones i knew for sure and left the ones i didnt until the end, and at worse could take an educated guess – but i was in control (or it seemed!)

In the week leading upto the exam i continsualy tested myself on both the RSGB provided Test Papers and the questions in ‘Exam Secrets’. I cant recall the questions word-for-word but for sure there were many that were very close to what were present, and probably doing the test exams in ‘rote’ method got me over the line to get a pass mark 🙂

The only negative side to the on-line experience was other people making a noise during an exam, as they finished or whilst they worked, there was a level of noise I wouldnt expect during an exam situation. For this i just removed my headphones and concentrated on my exam but listening for anythign that the invigulator might say (rather than just random noises).

I was told immediately of my score and I had passed, so am now just waiting notification from Ofcom so i can apply for my Intermediate licence ! I can wait to setup a working beacon and use 50W on HF, i think it will make a difference on the telephony contacts for sure.

Bad weather in – antennas down !

So in the QTH down in IO90 the met office issued their warning of bad weather. I brought my antennas down as a precaution of lightening strike. Following a couple of messages on the DX-Commander Discord channel the UK Antennas multiband end-fed was mentioned as a comparison. As such I’ve not had the time or opptunity to get it in place, and with the wire at 39 meters long would require some prep on how to get it in place !

planning the long wire across the garden

The advantage of the DX Commanderj is that all the bands are vertical each, even 80m can be done lengthening the wire. With the End-fed finding how to route 36m of wire into the space I have was a challenge.

I have made a draft and took some measurements, and in combination with some sorta beam poless and mast, think I have a working configuration !

Will post as soon as the good weather has passed, really excited to try out a new antenna

Shelves for the shack

Well its been busy and for the last few weekends very mixed weather here in the UK with masts going up and down due to the winds and more recently forecasts for thunderstorms ! having just passed a mini heat wave here in the uk, it seems the weather, albeit the wind is still blow a bit, has calmed down somewhat !

With that I have been tidying up in the shack some more whilst I coudlnt transmit. One thing I was not happy about was the amount of vertical stacking on the TS690s.

The TS690s – keep it ventilated !

I had a room re-jig and moved all the book-cases to allow an additonal desk to put the associated radio equipment on. This got the same earthing/bonding treatment i had done for the orginal table, which is giving a good common ground amongst the equipment.

A well-breathable TS-690S and DSP100

I’m much happier that with moving the printer and giving room for the equipment it gives a better layout to operate it. I can quite comfortably operate the transceiver from my computer, or if i want to get close and use it direct, have plenty of room.

I have been doing antenna fettling and this weekend and general mast tidying, but thats for another post when i figure out how to show some other developments as well 🙂

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 ongoing quest to reduce QRM !

*** THIS POST CONTAINS INFORMATION ON BUILDING A MAINS RF FILTER – IT IS NOT AN INSTRUCTION. IF YOU BUILD THIS IT IS AT YOUR OWN RISK ***

So I never knew just how much can be done to reduce QRM and where it comes from ! Having bought some ferrite rings and having mixed results, I found this excellent site from M0NWK who thanks to his equipment and setup can really demonstrate how the chokes work, heres the site which also includes a link to the video here

My build was slightly different, as I cant wire in a main tripper, I can wire in an extension in from an existing outlet, I was pleased to see that someone had already asked this question on M0NWK’s page.

I kept the same ferrites as M0NWK but a smaller box and bought a mains filter to which the ferrite-wound would attached.

Heres my part ilst, I use Amazon Prime alot because things arrive quickly and via decent couriers, if I wanted to get this done in less time I could of sourced cheaper, for example the 6 Way Mains Connector can be bought from Richer Sounds cheaper, but I dont know how quick they deliver or who they use.

PartSourced FromUnit Price
Roundcable snap-it core,300ohm 25mm dia
Stock no.: 4669164 (*2)
RS Electronics14.76
sourcingmap Dustproof IP65 Junction Box DIY Case Enclosure Gray 100mm x 100mm x 75mmAmazon6.89
White 3183Y 3 Core 2.5mm 25 Amp PVC Flexible Cable Cut To Length Flex (10 Meters)17.99
Masterplug Heavy Duty 13 Amp Rewireable Plug, 57.5 x 48 mm, Black4.99
Tacima 6 Way Mains Conditioner and Radio Frequency Interference Filter41.92
Permaplug by Masterplug Two Socket Trailing Socket, without Plug and Cable, 13 Amp, White4.04
GTSE 10 Pack of 12 Way 30-76 Amp Electrical Connector Block, 165mm Length, White Terminal Block Electrical Connector Strips 15.49
Heat Shinkalready had
Table of parts used in the construction of filtered mains feed

I started with stripping back some of the 3183Y Flex to bare out the live, netural and earth wires to wind around the ferrite. The heavy gauge of the wire made this quite a challenge, certianly being able to open the ferrite made a big different in creating a well fitting wire to the ferrite. I used cable ties to keep the ferrite and the wires stable.

The Terminal block comes in a massive pack, but its really good quality and will undoubtedly have many uses in the future, so worth having around. I attached these to the ferrite and wires, but not before attaching heatshrink to the wire going into the terminal. This not only looked good but kept the cable tidy.

I then set about measuring the thickness of the coax to make suitable sized holes into the box. I went in thru one side and so the mains feed and outward to the filter strip plug, nicely gapped so the terminal connectors in the box had a good seperation from them.

When drilling the holes I used a regular drill, but fettled the holes with a small round file to get the edges smooth and remove all the excess produced from the drilling.

The choke in its box – right side is the feed in, left side goes to the power strip with further mains filtering on.

Before plugging into expensive radio equipment i tested on a B&Q light to ensure it would turn on and off/and light. (The lid is back on at this point) As this was my first time using this I kept one hand in my trouser(probably short) pockets, but the lights came on and no problems. I then set about putting it into the mains outlet and to connect the additonal filter

Mains filter after the RF filter which supplies the transformer

You will see the parts list contains 2 ferrites, the 2nd one went onto the back of the radio power supply feed directly

Ferrite on the input voltage to the transceiver

As this is 12V DC and whilst can give a nasty poke, a box isnt necessary here.

I went back to the LW frequencies that had previously been plauged by a ‘buzz’ that had now completely gone ! I went onto 80m and 40m and weak stations were getting thru and loud stations were BOOMING.

Whilst this was a fair amount of work, I’m satisfied it has helped reduce my QRM further.