Tuesday, 27 June 2017

HP & other upgrades @ M0HDF

It has been a while... the available time to the hobby has been spent on on projects and contests and I have not had that much time to update the blog. Here is a brief summary on how I have been up to...

Shack upgrades to High Power
Acom 1000  
Nested dipoles for 40 and 20m
   - DXWire UL & insulators
   - 12turns of RG316 on FT140-43 [choke balun]
   - aircell 5 - vertical section
   - M&P ultraflex 7 - main run from shack to the garden
   -  Spiderbeam 12m HD fiberglass guy belt and clamp set [mast up now permanently]

shack - June 2017

shack RF management [grounding and bonding]
    - Aluminium bonding plate bolted underneath my desk
    - GM3SEK mains choke & TX chokes [shack entry]
I took some time to study the materials from the RSGB, N0AX, GM3SEK, K9YC, G3TXQ, W8JI and spent a bit on the proper ferrites and ground straps,...  This has worked pretty well and clean up my RX. I don't see any RF around either which is great.

400W light-weight dipole choke balun

CQ WPX CW 2017
SOSB[A] 40m HP
37 M8A............728,292 (M0HDF) WORLD - raw scores
10hrs of good fun and plenty of DX for a low wire dipole

RSGB Field date 2017
I had the pleasure to join The Monfort University ARS and their entry on 2017 NFD cw - M2A/P.
An absolute blast and fine group of people.

Hooked up now to my TS590S a panadapter using the crystal radio group mod.

Joined the folks from EA2 for their annual gathering and field day. It was great to meet old friends and new ones. Fine weather, qsos and a great luncheon in EA2 Navarra. Many Thanks to Ignacio EA2BD for all the arrangements and help.

Hopper of next projects
- broadband active RX loop
- 80m loaded dipole
- Raspberry PI / Arduino  .. got some of the bits at home already
- skimmer

73 Angel

Tuesday, 14 March 2017

M8A @ BERU - RSGB Commonwealth contest

The BERU contest is always interesting. I managed to get a few hours at my friend Chris' QTH to work HF with a SteppIR @ 17m and legal power. Conditions proved difficult and it was not help by local QRM everytime I transmitted .

M8A @ BERU - 2017
4 ATNOs :
  -Dom E51KTA - 20m over the pole
  -Iain 9G5X - 3 bands
 - Iain V31GX - 20m
  -5U5R on 15m outside the contest

 -Nigel 3B8/G3TXF - new slot on 40m cw
 -First QSO with CQ zone 1 - CI1AAA @ CP20kw
 -5 QSOs with VK with a low inv V doublet -11m apex on the 40m band

Many thanks to all the DX travellers and people who manned the HQ stations.

73 Angel
M0HDF  / M8A

Thursday, 9 February 2017

RX antenna isolator

I homebrewed and tested the G3BJ RX antenna isolator  last weekend. Implemented as M0VKY

G3BJ RX antenna isolator 

The half size K9AY RX antenna is close to my TX doublet [about 5m]. There does not seem to be much power coupled into the RX antenna when I transmit with 100W on 40m. I measured the DC rectified voltage on a dummy load connected to the RX line at approx 300mV.

Testing RX antenna isolator with 817 and a dummy load connected to TX.

The Aluminium boxes by Bitbox are inexpensive and easy to work with. I might box in them some of my other kits [BBGen,...]

Many thanks to Don G3BJ and Simon M0VKY for sharing this.

73 Angel

Wednesday, 8 February 2017


The ionosphere was kind yesterday and delivered 2 new DXCCs on 20m band.

I got home before sunset and the Italian expedition to Central African Republic was booming here.
After 15min of calling, I managed to the get through with my 100W and doublet around 5 UP.

A bit later I also heard - on the noise -Patrice TY2BP in Benin and as the signal raised a bit, I was able to make the QSO.

I noticed over the last couple of dates that switching off the AGC gives a better SNR - cleaner and easier to copy weak signals. I wound down the RF gain a bit and keep the vol to min or close to min - the Yamaha CM500 I use produce plenty of volume.
I am not sure about the NR2, the audio seems too warble.
My QTH here in the city is very noisy.

73 Angel

Tuesday, 31 January 2017

RI1AND - new slot - 40m digi & low band RX experiments

I worked RI1AND on 40m JT65A a few days ago in the evening. Probably one of the easiest far DX that I remember. Walk in park!. Good signal here -11dB, consistent. He got back to me at the first call.

Over the last 3 weeks I have been doing some low band RX experiments.
I homebrew a half size K9AY, following F8AFC dimensions. I terminated with a 550ohm for 40m and the transformer was built with a FT140-43 and 8:24 turns - opposite windings.
I used JTDX JT65A+JT9 in SWL to listen to the bands over 24hrs and swap directions beaming East to West.
Then, I swaped to the inv V doublet [tuned to 40m] and listened in both 40/80m.

80m SWL JT65+JT9 - doublet antenna

    - K9AY:
           - 3-4dB more noise beaming East than West [SDR]
           - definitely directive
           - NA blocked by the tall house behind my garden [due the ground installation]
           - Choke balun @ feedpoint or shack end did not help, if anything the opposite.
            - passed the 40dB common mode current disconnecting the loop vs. BC station
     - Doublet @ 11m apex seem to hear better than the K9AY.
     - Doublet tuned for 40m worked well as a RX 80m band
     - Many long DX spots follow nicely the sunrise/sunset enhancements [higher angle] per explanation in propagation chapter in ON4UN
     - SA is heard well in 40m... probably due to the slightly lower roof line and opening between 2 houses back of my garden.
     - I don't hear JA that well
     - Above 295deg West coast NA - nothing either!- aurora grilled.
     - ON4UN Low band DXing bible - best ham book I got and the absolute reference

107 countries heard in the last week

Last weekend I had a go at building the G3BJ receive antenna isolator, rather than buying the KD9SV system as I had originally planned.
The relay I found in my parts bag was not good and I have ended up "copying with pride" M0VKY implementation. Parts are now on its way and hopefully, I will be able to build it this weekend.

What next:
The K9AY and TX doublet will be in close proximity - within 5m. I want to check whether the mutual coupling leads to increased noise in the RX loop and how well the 2 work together in contest environment.
I will build a flag/pennant and compare with the other two. I am hoping that with the antenna being above the ground might listen better [less blocked signals] and nearby house QRN.

I found these experiments a well worth exercise to find out how well your station RXs. You can also compare the spots with other neighboring stations.

73 Angel  

Monday, 21 November 2016


New special contest callsign arrived just in time to go on the air on the CQ WW CW this coming weekend. Many thanks to the RSGBCC which processed the application very quickly.

Looking forward to it. All the gear is pack now for a 80m entry

73 Angel

Saturday, 5 November 2016

RSGB convention 2016 and more Low band thoughts

I attended the RSGB 2016 Convention in October with my friend Chris G3SJH. It was also great to meet Iain M0PCB from the Vulture Squadron Contest group - G9V, David G3YYD and John G3VPW. These were the lectures I attended:
 -Diagnosing & Reporting RFI problems John Rogers M0JAV
 -The IOTA Challenge from Sub-Antarctic Waters to High Arctic Cezar Trifu, VE3LYC
 -80th Commonwealth Contest (BERU) celebrations Iain M0PCB & Bob G3PJT
 -Contesting from VY2ZM on Prince Edward island Jeff Briggs K1ZM
 -DX fun without spending loads of money! Nick Henwood G3RWF

Quite a lot of focus on the VDSL QRN issue in the RFI presention from John R - which I suffer on 30m. The presentation from G3RWF resonated a lot with my holidays with radio and simple antennas for /P operation.

Lately I have been reading ON4UN Low Band DXing The book is excellent, very well written, and "the reference" for any low band operation "business"...I specially enjoyed the propagation chapter - as well as following KY6R blog and his 160m quest.

The short [16m] inv V doublet @ 11m height has proven an efficient antenna for EU and mid distances.
Efficient means that most of the TX power is being radiated out rather than "heating" the ground, loading elements and nearby lossy objects. It does not mean effective to work DX - low angle radiation  [ref. ON4UN Vertical antennas chapter]
Nonetheless, the simple doublet allowed me to get over 500k points in the CQ WPX CW SOA40 LP and gave a significant boost to my DXCC 40m band count to 96.

On a few occasions I have also extended the doublet by 4m + loading coils [inv U] to operate on 80m - but this is more of a compromise in this band with higher losses.

This week I have been playing with the idea of setting a top loaded 80m vertical in the garden.
I used EZNEC Demo for the first time following some of the examples in the ARRL tutorial, where previously I have used 4NEC2.... and learnt a few tricks along the way [Virtual wires are great!]

80m top loaded vertical
The loaded monopole would be in close proximity to buildings with its near field compromised and low angles blocked in any case + the limited garden space [10m x 5m] and effort to bury the radials, I am not convinced is worth the trip.

I still have in mind to build the front end receiver saver to be able to put a RX dedicated antenna in the small garden when I free up a bit of time

Looking forward now to the CQ WW CW contest at the end of November and some beach operation from the Mediterranean sea and SOTA activations during the next holiday.

73 Angel