SOTA activation FL/VL-101 Tour Malakof

Summits On The Air - vrijdag 16 juli 2021 22:17
For the first time in 2 years I did a SOTA activation again. "Tour Malakof" at 311 meter.

I made 6 QSO's on 40m SSB and 1 QSO on 20m SSB. Conditions were not that good. I was using the mcHF SDR with 10 Watts output. A sloping half wave antenna on 40m, and a vertical half wave antenna on 20m. On a 10 meter fiber pole.

Spot me in the picture below!

QSO's logged
Date: 16-07-2021
Summit: FL/VL-101
UTCCallBandModeRST sentRST recv
By: Erwin PA7N | Permalink | Write a comment

New QRP SDR transceiver!

SDR/DSP - dinsdag 27 juni 2017 23:29
A few weeks ago I ordered a new transceiver. The mcHF. It's a SDR QRP HF transceiver. It's a kit. There are two kinds of kits. One with all pcb's and components and one with the SMD components already placed on the pcb.

I ordered the kit with all SMD components already placed on the PCB. After a few hours of building the transceiver was ready for the smoke test! It worked. No smoke. There was only one push button that caused the transceiver to power off. After some searching I found a short between two pins of the mpu.

The mcHF worked perfectly after fixing the short. There was just one thing that concerns me. In receive mode the current was 410 mA at 13.8V. The linear regulators where getting very hot. I mounted them on a heatsink but they where still getting very hot. Most of the current is draw at the 5V regulator that is in serie with the 8V regulator. The current at the 8V line was only about 16mA. So if you multiply 0,410 x (13.8-5) is about 3,6 Watt of heat disipation. The transceiver itself uses only about 2 Watt (0,410 x 5 V) .

So why not replace the 5V linear regulator with a switched regulator? Noise?!? I bought a drop-in switched regulator (Wurth 5V/1A Farnell: 173010578) and connected it with a few wires to the mcHF board. It worked. The current dropped to 163 mA. (That is less then a KX3!) After connecting a dummy load there was no increase in noise. So that looks good. I still have to build it in the mcHF enclosure and find out if there is still no increase in noise. But so far so good. The mcHF is now a really cool transceiver!

It is not a simple modification as a simple drop-in replacement. The thing is you want the input of the switched regulator connect to the DC power input (12-13.8V) of the mcHF not to the 8V regulator. If you do that the 8V regulator still heats up and the improvement is minimal. But if you connect to the DC input there is no way to turn the mcHF off. I think I need something with a pnp transistor to switch the 5V rail off when the 8V rail is off.

Update 28-06-2017:
Today I put the switching regulator inside the mcHF and the noise level increased to about S1. But worse I found some spurious here and there. With stronger ones every 300kHz (the switching frequency). So I think I have to say: Nice try but it didn't work! :-(
So back to the linear regulators. At least I have something to warm my hands on a cold SOTA summit.

More info about this great open source project:
By: Erwin PA7N | Permalink | 2 comments



woensdag 28 juni 2017 09:44
Hi Erwin,

you've made a great mod! To turn 5V off consider using power P-Mosfet.

73 de S52CQ


woensdag 28 juni 2017 16:18
Hallo Erwin,

Inderdaad een geweldige verbetering, als het inderdaad geen problemen geeft met extra ruis of "spurious". Je hebt de regulator nog op enige afstand liggen zie ik op het plaatje., maar het is veelbelovend.
Ik heb hier in de junkbox ook zo'n ding liggen zo te zien is het dezelfde,, het is een 78ST105VC van Power Trends,, ik zal de datafile eens opzoeken..
Het in-/uitschakelen moet toch op de een of andere manier op te lossen zijn via het ON/OFF signaal van de LM2941, in de junkbox heb ik ook nog wat power fetjes liggen.

73 de Jos (PA3CCE)

Activation summit PA/PA-005 and PA/PA-006

Summits On The Air - zondag 11 juni 2017 21:59
Today I activated two summits in PA. PA/PA-006 Signaal Imbosch 110m and PA/PA-005 Galgenberg (Terlet) 102m.

Both in SSB with a new home brew 50 Watt amplifier. On PA-006 it output was 15 Watt and on PA-005 30 Watt. Reports on PA-005 where indeed a bit better. I used the Yaesu FT-817nd on a 3 cell lithium 3100 mAh battery. The amplifier had its own 3 cell lithium 5200 mAh battery. As with most of my activations I used a End Feed Half Wave antenna on a 10m pole with a home brew tuner.

We walked from a parking place to the two summits and back. Total of 20 km. Nice wetter and beautiful nature.

QSO's logged
Date: 11-06-2017
Summit: PA/PA-006
UTCCallBandModeRST sentRST recv

QSO's logged
Date: 11-06-2017
Summit: PA/PA-005
UTCCallBandModeRST sentRST recv
By: Erwin PA7N | Permalink | Write a comment

Antarctica 13778 km !

Digital modes - woensdag 9 november 2016 22:57
I just made a contact with RI1AND in Antarctica! On the 30m band in JT65 mode. That is a distance of 13778 km!

I used 25 Watt and a 2 x 7 m dipole at 6m above ground. The band seems dead but with JT65, signals can be seen in the waterfall screen and can be decoded. This is so amazing! :-)

By: Erwin PA7N | Permalink | Write a comment

Activation summit F/VO-073 Le Haut Koenisbourg 733m

Summits On The Air - maandag 15 augustus 2016 15:20
The first summit in France this year. I went here by bicycle. 16km from the camp site. Climbing the last 8km to the top. Climbing about 500m in altitude.

Because of the terrorist threat and the chatteau attracts a lot of tourists, there were some military police with heavy automatic guns checking everyone's bags. I didn't come for the Chatteau on the summit so they didn't check my backpack with all the wires, batteries and electronic stuff what just might be A home brew explosive. (with some imagination). The 10m fibre mast looks like A riffle! But all went well.

Not many QSO's because after 15 minutes it started to rain. Also my internet connection didn't work so I could not spot my self on sotawatch. But after this activation I figured out how to spot via SMS.

QSO's logged
Date: 04-08-2016
Summit: F/VO-073
UTCCallBandModeRST sentRST recv
By: Erwin PA7N | Permalink | Write a comment

Comming SOTA activations

Summits On The Air - vrijdag 5 augustus 2016 00:15
From 4 august till 14 august 2016 I try to do some SOTA activations. I'm in France in the Alsace/Vosges.

I will be QRV in CW on 40m around 7.032 MHz. As I am still a beginner CW OP please be gentle with me. 12-15 wpm with a little more space between the characters will do :-) Please no pile-ups hi!

My equipment:
- Yaesu FT-817ND 1 - 5 Watt output
- 10 meter fibreglass pole
- End feed half wave sloping antenna for 20-30-40m
- QRP Long wire tuner for EFHW antennas
- Internal FT817 battery
- 1900 mAh 10 x AA NiMH battery
- Inline microphone compressor

If 40m doesn't work I will try 30m CW on 10.118 MHz +/- QRM.

Hope to work you!

SOTA sites:
By: Erwin PA7N | Permalink | Write a comment

Flying Pig Rig

QRP - woensdag 20 januari 2016 13:04
Finally I finished building the "Flying Pig Rig" after being in a drawer for years. A 40m 5 Watt CW transceiver kit from Kits and Parts dot com!

It's a single frequency QRP CW transceiver that will fit into a small box. It is lightweight and very power economic. It receives and transmits on 7030.7 kHz. The Flying Pig Rig has a build in keyer. I will use it with my LiPo batteries. With 12.3 volt the output power is 4 Watts! It draws 25mA on receive and 630mA on transmit. Compare that for example to the Yeasu FT-817nd which will draw 300mA on receive and 1.9A on transmit!

I plan to use this QRP rig on some SOTA activations later this year.

More info
By: Erwin PA7N | Permalink | 1 comment



vrijdag 12 februari 2016 10:02
hallo Erwin
thanks for call on 7MHz yesturday..
Your signal was pretty good about 579, via instrunent, and fully readable ewen in QRM...

please , what is your equipment you used in our conntact ???
73de 9a2ki ico
here 100W Dipole up 20m

This weekend SOTA activations

Summits On The Air - donderdag 27 februari 2014 19:36
This weekend (1-2 march 2014) I will try to activate some SOTA summits in Belgium. Depending on the wetter and other activities I will try to activate ON/ON-001, ON/ON-010, ON/ON-011 and ON/ON-013.

I will be QRV in CW on 30m around 10.120 MHz. As I am still a beginner CW OP please be gentle with me. 15 wpm with a little more pause between the characters will do :-) Please no pile-ups!

I'm using a Elecraft KX3. 5 Watt output. 10 meter fibreglass pole. End feed half wave sloping antenna. 5000 mAh LiPo battery. QRP Long wire tuner.

If 30m doesn't work I will try 40m on 7.032 MHz.

Hope to work you!

SOTA sites:

Things didn't work out as planned! In the car, on the way to the holiday park, my wife told me she had booked a different park then what I thought the holiday park would be! (Amazing isn't!) The park she had booked was more to the west of Belgium. There was only one sota summit with more then one point. So no high score that weekend :-( But still a lot of fun :-)

The summit I activated was ON/ON-006 La Croix Scaille. It was 55 km driving. Walked about 2km. After 30 minutes transmitting it started to rain. I had to quit. The new KX3 worked great!

QSO's logged
Date: 01-03-2014
Summit: ON/ON-006
UTCCallBandModeRST sentRST recv
By: Erwin PA7N | Permalink | 2 comments


Ray LaRue

woensdag 26 maart 2014 21:27
I have downloaded your software "PA7N VNA" v0214. I am using a MiniVNA with WinXP Pro. I have a couple of questions.

When attempting to view a parallel resonant circuit using your software, how
does one determine the exact frequency of resonance?

I am currently trying to use the MiniVNA to accurately cut 1/4 wave stubs to frequency and am not sure of the correct proceedure for doing so.
Can you help?

Also, is there manual online for the use of your software?

Thank you for your attention. I appreciate your time. I look forward to any comments you may have.
Warm Regards, and 73,
Ray, W4BYG

Cleveland, TN


dinsdag 6 mei 2014 22:45
Hallo Erwin.Iwouldlike to let you know that for all of the KX3 Sota and digital users that are bumping into the radiostemperature limits, I have designed a CoolerKX replacement heat sink. You may contact me by email for information. 72, Fred

Ik heb een prijs gewonnen!

QRP - zaterdag 22 september 2012 15:06
Ik heb een prijs gewonnen! Een aanmoedigingsprijs voor meedoen aan de Marathon van de Benelux QRP Club. Met een score van 58712 eindigde ik op de vijfde plaats (van de zes). 10 Euro!!!

De wedstrijd heet Marathon omdat hij een heel jaar duurt. Van 1 juli tot 1 juli. De bedoeling is dat je zoveel mogelijk verbindingen maakt met een zo laag mogelijk vermogen en met zoveel mogelijk verschillende landen. Nu kijken of ik daar het komende jaar overheen kan komen.
By: Erwin PA7N | Permalink | 5 comments


PA3GNZ, Tjeerd

donderdag 27 september 2012 21:35
Enthousiast berichtje.

Volgend jaar een plaatsje hoger?

73, Tjeerd

Webmaster BQC

Bert PA1B

donderdag 27 september 2012 23:05
Hallo Erwin, gefeliciteerd met het mooie resultaat. Leuk stukje met een mooie foto. Je hebt een mooie set.
Het is heel leuk om mee te doen in de marathon. De marathon zet aan tot activiteit. Als signalen heel sterk zijn kan je je vermogen in dezelfde verhouding reduceren. Dat levert weer meer punten op. Op 14 MHz kan de propagatie heel goed zijn. Maak je ook wel eens verbindingen in een contest? Die mannen willen iedereeen werken ook al heb je geen oorverdovend signaal. Veel plezier 73, Bert

Ray LaRue

zaterdag 27 april 2013 20:24
I am trying your software for the MiniVNA. I have been using F4CLB's software for a couple years.

Question: Is it possible using your software to measure at the base of a vertical antenna shorter than a 1/4 wave and interpret directly the needed inductance for it to be resonate?

Conversely can an antenna longer than a 1/4 wave be measured with your software and the MiniVNA, directly indicate how much capacitance is needed to resonate it?

Your attention is appreciated.
Ray, W4BYG
Cleveland, TN USA


woensdag 4 september 2013 11:21
Wat ontzettend leuk voor je. Moet wel veel werk zijn geweest om daar een heel jaar mee bezig te zijn. Maar goed gedaan hoor. Wie weet ga je er dit keer wel overheen.

Hennie, Amsterdam
Massage Amsterdam, Jiskmassage

paolo petrini

maandag 25 november 2013 13:38
I downloaded pa7minivna and I tried to compile it on ubuntu 12.04 64 bit with lazarus 0.92 (1.0 does non install)
and as a first error I get:
/usr/lib/lazarus/,24) Fatal: Can't find unit iconvenc used by LConvEncoding

any idea?

73 de Paolo IW1ACL SA4BHT

Reverse Beacon Network

Antenna - vrijdag 24 februari 2012 13:12
Een poosje geleden had ik al eens een Magnetic Loop antenne in elkaar geknutseld. Die was toen gemaakt van koperen buis. Maar nu heb ik er één gemaakt van 15mm coaxkabel. Ik had hem vandaag even binnen staan en aangesloten op de FT-817. Even een paar keer met 2.5 Watt op de 20m band CQ geseind en via het Reverse Beacon Netwerk gekeken of ik ergens te horen was. En inderdaad, dat bleek het geval. De eerste rapporten kwamen uit Europa maar toen ik de antenne een kwart slag draaide verscheen er ook een rapport van VE2WU. Dat is Canada! Ongelooflijk toch! Zo'n kleine antenne, binnen op zolder tussen de rommel en muren. En met slechts 2.5 Watt.
Hiernaast de foto's van de Magnetic Loop antenne. Diameter is 0.8 meter. Het inkoppellusje is een zogenaamde afgeschermde- of Faraday lus. Volgens de berekeningen zou deze loop een rendement moeten hebben van 35%. De bandbreedte zou dan 12 kHz moeten zijn. Ik meet echter dat de bandbreedte 22 kHz is. Het rendement zou dus nu rond de 15% zijn.


By: Erwin PA7N | Permalink | 1 comment


Pascal ( ON5RA )

vrijdag 13 juli 2012 12:37
Beste OM,

Ik heb zopas je software gedownload voor het gebruik van de miniVna.
In het verleden maakte ik al gebruik van deze tool, nu heb ik de laatste versie gedownload.

De setup is volledig geslaagd onder Windows 7, enkel de instellingen balk onderaan komt niet te voorschijn. Ik heb al mijn resolutie aangepast maar tevergeefs.

Heb je enig idee wat ik fout zou hebben gedaan?

Alvast bedankt !