7QNL and … Michael Jackson!!

Malawi is a religious country. Around 85% of the people are christian, and perhaps the remaining part is moslim. People who know me a bit better know that I do not believe
everything people say to me… but .. what I experienced yesterday (June 5th) was
striking.

It started at a petrol station in Zomba. I took this (see below) picture:
DSCN9576a
You believe this slogan, or not …

We were next to fill up, and … out of the blue Michael Jackson appeared!
DSCN9572a
Michael Jackson is alive! In .. Zomba, Malawi!

As a real paparazzi I took this selfie:
DSCN9575a
7QNL and Michael Jackson v2.0: “Don’t stop ’till you get enough”

7QNL QRX and some tech talk

Today we depart to Salima (next to the lake) and hope to return June 7th around 1300 UTC. I.e. until this estimated time of arrival at the 7QNL QTH there will be no operation.
Yesterday propagation was good. Surprisingly I made quite a few contacts on 12m, even
working Joe 7Q7BP!
RTTY, as already mentioned, works very well and at least Malawi disappears from the 100% needed list on ClubLog concerning 12m RTTY ;- )

I had some requests for 10, 15, and 40m.. The first week (and CQ WPX contest) I was active on these bands. However, last week I replaced the antennas for WARC ones (12, 17 & 30m). I kept 20m alive. Please try to work Ken 7Q7GIA on 10, 15, and 40m instead.

Despite lack of output power (my strategy was to make it for YOU are easy as possible to work Malawi, i.e. producing a good signal abroad) due to the collapse of my SSPA power supply, the pile ups keep coming and coming. On 30m I worked a disproportional amount of JA’s, and … they keep coming ; -)
Output power on 30m is around 65W, but..  I miss the PA ;- )

Below the calculated radiation patterns of the 30m VDA above average ground (0.005/13):
30m-vda30m-vda2
Radiation pattern of the 30m VDA (left 2D, right 3D, click on images to enlarge in a new tab).

Although asking for ‘NA’ sometimes, the amount of responses and signal strengths are low. This morning (June 5th) I worked quite a few NA stations on 30m though.

Although having brought the last MASTER.DTA, my log is full of calls not in ‘the database’. Therefore I have to rely on what I hear in the air, and may sometimes ask for a confirmation in case of weak or QRM’d signals.

Because the pile ups are huge, and I QSX after almost every QSO, most of the times I get portions of the calls. Instead of waiting for another call of the specific caller, I transmit these partials. This is a deliberate strategy to let the crowd know I’m alive and to work
everyone as fast as possible. It takes less time to TX a partial (with one extra over, yes…)
then waiting for the same station to call again, is my experience in ‘the beehive’ (also
during contests btw).

Internet remains unpredictable and slow, but we do the best we can to update everything.
Every day I try to upload the last masterlog to Alex, which he publishes on this site/ClubLog.

To have an idea what kind of internet we have, see picture below (with the RTT’s, when present ;- ) (click to enlarge in a new tab):
ping

When returning Saturday I have one afternoon, evening and morning to operate, because Sunday we have to dismount the antennas. Monday morning is our departure.

Thus .. one more day 7QNL to come on 12, 17, 20 , and 30m!

73, Remco 7QNL / PA3FYM

 

 

 

Good news and bad news…

Good news: when we returned yesterday we modified the 10 and 15m VDA’s into 12 and 17m. The 40m deltaloop was replaced by a 30m VDA (!) The antennas perform very well.
During my first stints on 17m I faced ‘the mother of all pile ups’ in SSB. Incredible…

Bad news: it appears that the switching FETs in my 48V power supply broke.
As a result 7QNL has around 10 dB less output :- (

DSCN9537a
(Unfortunately) broken 48V power supply… No replacement FETs  :- (

Although having less output (around 60W) I encountered a huge pile up (of JA’s) on 30m.

DSCN9540a
30m VDA @7QNL (top is ~16.3m high)

 

Questions concerning QSO’s?

I saw several mails have been sent concerning busted/wrong callsigns
and/or requests/skeds. Yes, I make mistakes! ; -)

Please send these mails to Alex PA1AW at malawihf@pa1aw.nl or qsl@pa1aw.nl
He offered to summarize them in one mail so I can check.
In case of doubt: almost the whole operation is recorded.

We have limited internet access here and are half way through our
data bundle (especially updating this site uses a lot of data).

Now… we are heading for a ‘night game drive’ to DX for wild animals!

73, Remco 7QNL

 

50 MHz HDA

After lunch we had to wait for our boat safari and I thought it was a nice idea
to calculate a 50 MHz Horizontal Dipole Array (HDA) aka 2 elements to be
easily and quickly built when we arrive in Thondwe on Monday.

Within the boundary conditions (Z = 50 + j0 Ohm) the contrapsion converged to an
acceptable radiation pattern and impedance. I tried some other model solutions
(there are many ways to Rome) but that didn’t make much difference.

Of course more elements will improve vertical/horizontal radiation patterns,
but this antenna may be a nice (mechanical) substitute for a HB9CV.

Bear in mind, most Yagi’s are presented in free space with nice radiation patterns.
However, when you put them in the air above real ground,
(vertical)radiation patterns deteriorate significantly!

6m-free-space-6m-abg
Left: radiation pattern in free space, right: radiation pattern @6m above average ground.
Right some ground gain is introduced. A real nice to have : -)
(click on image  to enlarge)

Below the VSWR50 response  (Click on image to enlarge):
6m-hda-swr-response

For co-calculators, here’s the NEC-file.

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