Amateur Radio

​M0KWR

My interests and activities 

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M0KWR 
Radio just for fun

My interests and activities in Amateur Radio 

Ham Radio is a licensed radio service. Operators take an exam to get their operating licence and most importantly their call signs Acquiring your licence is not difficult and there are plenty of ways to study with plenty of material available
on line.
I have been licensed as a radio amateur for over 14 years. I still find it a fascinating past time with many so many aspects of the hobby to keep you interested.

Amateur radio clubs/societies are providing training acquiring the licence. Contact your nearby amateur radio operator will help you or recommend a local club.
I made some major changes to the shack this year with a new Icom Ic7700. 

Noisy HF Bands what can you do?

Using your transmitting antenna for receiving, this can often make the noise problem seem worse than it really is.
                                ​Try a dedicated receiving antenna.                                

 Antennas for 160 - 80 meters

         Noisy HF Bands 

Receiving Antennas

Wellbrook ALA100LN

Todays antennas. 1/1/18
My antennas are always changing but today when I wrote this I only had 2 antennas. 
I have a 240 ft 160 mtr inverted V doublet @ 40ft  and a  40 mtr inverted V dipole dipole @ 30ft.


For receive on 160 mtrs I purchased the Wellbrook Loop. A bit pricy I thought but I gave it a go and purchased one.
 
The Wellbrook loop stopped working a while ago for no apparent reason. I now use my home made version of the welbrook loop.  Obviously somthing (RF) has blown the amp in the wellbrook even though I take every precaution to protect it.


My final summary of the Wellbrook Loop.
It does work very well but doesn't last long if subjected to strong RF feilds. £180 for 10 months makes this the most expecive receive anntena I have purchased so far.

To combat the ever increasing noise level on 160 meters I replaced my old 160-meter coax receiving loop with a Wellbrook ALA100LN large aperture loop.  

Receive Loops and filters

Scott G8EQY made up a couple of filters and this was added to the receiver antenna socket. This did suppress the AM signals although you do get a small amount of signal loss when in line. It did considerably reduce the multiple images from 1332khz transmitter.
My SDR Play suffered from overloading from this AM station. It was so bad it was almost unusable without the filter.

Hombrew receving Loop 

Loop info link
The home brew Loop preamp was installed in a spare plastic box  so I could try it out. Its still in the same box ater 6 months. The results have been very good and it is camparable with the the wellbrook loop. After the recent loss of the Wellbrook loop due to RF this has become my main 160 mtr receiving antenna and its working very well. I have now changed the wire loop configurstion into two loops at 90 deg to each other. This is still only one peice of wire about 8 meters long. The performance of this configuration of loop was a major inprovment on the signal to noise ratio and it continues to supprise me with it performance. I have now hooked up to my KiwiSDR where it is working very well. Topband performace is the best I have had on any of the loops i have tested.
Something seriously worth considering if you are installing a receiving antenna

Front End Receiver Protection

Produced by Peter OK1RP

Click the picture to visit his web site.

Original design by
 Gary, KD9SV


when you have put up a receive loop or mini whip or any other receive only antenna for that matter you want to make sure you don't transmit RF into your receive antenna and then into your radio causing expensive radio damage. This is a serious thing to consider with receive antennas. To avoid this problem some form of switching is required to stop RF getting into your radio or receiver.
A good protection circuit to eliminate the possibility of blowing out Your receiver's front-end while using these auxiliary receive antennas specially on low bands.

I was discussing this RF problem with a local Radio amateur G8EQY who has facilities to hand to produce the cicuit board for this project. The following week Scott gave me the finished and built circuit board ready for testing. Totaly unexpected and an amazing quality job. See the pictures of Scotts completed project. The relays used are HJR1-2C L-12V DC which have an  operate/release time: 6/4ms and these work very well.
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OK so what does it do? In simple terms it disables your receiver antenna before switching your transmitter to TX. Connect your foot switch or TX button to the box/panel then connect your transmitter PTT line to the box. The coax through the box is cutting off your receive antenna before your transmitter goes into transmit. I use this to protect my SDR Play and FT2000D. The FT2000D & TS2000 have a receive antenna sockets. All my transmitters are connected through the box and one PTT button is in use.
You could always use a light bulb Hi Hi.

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KiwiSDR: Wide-band SDR + GPS cape for the BeagleBone 

The KiwiSDR is a software-defined radio that attaches to a Seeed BeagleBone Green (BBG) embedded computer. It is available as the board alone or a more complete version including BBG, GPS antenna and enclosure with the software pre-installed on the BBG.
SDR.HU
Link to my online KiwiSDR 
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 Due to our bands ever increasing noise I am looking for alternative ways of reducing the pain of all this disturbing interference.
I have been using Scott’s (G8EQY) version of the wide aperture loop Welbrook loop and it’s been great up to now. The noise has increased slowly and its reached a point where if I  am to continue working the lower bands I have to find a way to receive the bits I do want without the bits I don’t want.


I have been playing around with different lengths of wire on the loop and rotating the antenna to null out the VDSL (OFCOM PLEASE NOTE) which is totally wiping out the top of the 80 meter band. (To see this go to my SDR and take a look at 3.700 MHz to 4.700 MHz is totally blanked out by noise.


My 260 foot doublet makes this part of the band unworkable. Just out of curiosity I decided to try a piece of wire c8 meters long configured as two interlinked loops. This was a bit of a shock. I thought I had done something wrong as the noise level was on the stop but the signals were still good.


I connected this to my newly acquired KiwiSDR (http://kiwisdr-m0kwr.ddns.net:8073) and I was impressed by the performance of the receiver. The only down side is you have to learn how to get the best out of the internet interface. Most people will click and forget because they don’t hang around long enough to learn how to drive it. Once you understand the interface it’s very very good and I can hear people I would normally have missed on my doublet.
  
Landing at Leven Airfield.Filmed by Phil M0VEY
Day out to the Hornsea Rally. Departed Peterborough Conington Airfield landed at Leven Airfield north of Hull. Picked up by Phil, Rog and Nick. 
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Copyright Kent Royce 2017