Yes, Paul, I also tested WSPRNET and achieved amazing reach. It’s at the top of the thread.
Thanks for the long chat yesterday!
73 Chris
2 Likes
Finally, 90 km from home, I found a 630m chaser. He’s doing 900W on a 2x40m doublet and is barely audible here at S9 QRM. But he heard me with my auxiliary antenna under the roof and 10W Tomorrow I’ll be working from a summit under hopeful much better condition.
73 Chris
Here are my video answer and thanks to my qso partner Chris DF5QG.
10 Likes
Was this a QSO or a one way transmission? You are close to a full QSO from a summit now.
All you have to do is get your friend to a summit for a 630m CW S2S. Now that would be a rare achievement.
In fact, I should try to work the Sota Database reports to see if, and how many times, its been done before.
3 Likes
I tried it today with him from a summit. My antenna didn’t seem to be working so well, probably due to the insufficient counterweight (2 x 20m of wire on the ground). Or the daytime attenuation in the D layer.
The transverter ran at 12V and then output 12W. At 24V with two 3-cell batteries, it’s 50W, so maybe that’s enough. I’m not giving up.
A friend in Hannover heard me 559 40km away.
73 Chris
7 Likes
Fascinating stuff and a pleasure to follow your experiments!
73 Peter
My 630m chaser is Chris DF5QG, and he often calls in the evenings on 472.6 kHz. He operates crossband and listens on 3560 kHz.
Maybe you’ll give it a try. According to RBN and so he told me, he can also be heard in Great Britain.
Armin, DL6GCA, and Roman, DL3TU, heard him well this evening on 630 m and reached him on 80 m.
We want to expand our activities on 630 m with the goal of as many qsos as possible, especially S2S.
73 Chris
7 Likes
Looking forward to seeing how you get on with this, it’s brilliant work. Wishing everyone involved the best of luck getting 630m QSO’s!
3 Likes
Will give it a try. Would be exciting to receive a medium-wave amateur radio “broadcast”…. It’s ages I have not been on a medium-wave radio….
73, Peter
5 Likes
Thank you for your support.
We plan to publish instructions and a circuit board for a 40m <> 630m transverter with a maximum of 50W and integrated antenna matching.
This will allow us to cover distances of up to 100km during the day and more at night. The digital WSPNet will reach the center of Europe.
EDIT "… the center of Europe, if you a qrv in Germany … 
Stay tuned
73 Chris
11 Likes
…hi Chris, what about using split for operators whose region does not allow operating on 630m.
Great to see what you have been doing with your experiments.
Geoff vk3sq
3 Likes
Chris, you’ve rejuvenated my interest in MW.
Some years ago, I built a 630m transverter using G3XBM’s circuit with limited success. I’m now on with complete rebuild which includes receive converter, a summit friendly ATU and class E output stage. I just hope that when it’s all finished there will be someone else I can communicate with.
73 de Steve.
4 Likes
Steve, I’m glad to hear that.
My transverter is also based on G3XBM’s concept. The decoupling of the RX via the first capacitor in the pi filter short-circuited at TX by the antiparallel diodes, is brilliant.
I get just under 50 watts out at 24 V, and that’s fine for portable activation. I use a switchable toroidal coil with taps as the antenna coil.
Please tell us more about your concept. I will do the same later.
73 Chris
hi Geoff, yes a lot of the transceiver receive well at 472kHz. You can use the coaxial or feed line as an antenna if your local QRM is not too strong.
73 Chris
2 Likes
Chris, it’s still in the development stage. TX follows G3XBM’s design except for a class E output stage which produces 23 W at 12 V and since my ft817 is broadbanded the LO is 3MHz. For the RX side, I’ve tried both fet and ne612 mixers, the 612 seems the easiest approach, but I haven’t heard any stations to do on-air testing.
I was hoping that some TVS diodes that I’ve got from an old modem will short the TX and I’ll follow your approach.
Considering a T200-2 but will it give me enough inductance?
73 Steve
1 Like
Psst, Paul! He already achieved a proper 14 km s2s (DM/NS-121 <> DM/NS-122) on 630 in August 2019 witnessed by a dozen radio amateurs. 
Ahoi
Pom
2 Likes
My approach produces only 12W at 12V. I will rebuilt and check it with more care. My version is more than 6 years old. On 24V it put out 50W. 
That’s what I have done. I will try to onmit the ne612. The loss of the mixer is only -6db and the sensitivity of the trx should suffice. I will see.
I once took 2 of T240-2 with a total of I guess 132 turns with 2 step switches. One for each 10 and the other on there other side of the coil each one. So I can choose 1, 2, 3 … 132 turns. That brings up to 700uH. This is enough for my 10m vertical and 30m horizontal antenna. And I can tune it for best antenna current.
In my new approach I take one T240-52 and hope that it will do it with not more than n=50
Additionally I use an switchable impedance transformer with a FT140-43 for up 180 ohms. When your counterpoise is not the best the total resistance of antenna goes up to this value. The radiation resistance is near 1Ohm so you can imagine your efficiency is about 1%. 
Here are my suppliers
Ferrite-shop Waterpeper 26 2804PR Gouda Netherlands info@ferrite-shop.com
73 Chris
3 Likes
How time flies, doesn’t it? I fondly remember the party with you as a newly minted mountain goat.
Ahoi
Chris
1 Like
Luckily it does, Chris! I wouldn’t know how to stand the nearly 15 years ‘til retirement if time was at the same speed as it was back in my twenties.
Ahoi
Pom
2 Likes
Thanks for providing the back-story; 2019, that seems like a lifetime ago!
1 Like
Antenna counterpoise is crucial at 630m. I learned that today. But see for yourself
73 Chris
13 Likes