One season 4m …

Yesterday the 4m TX permission in DL ended for this year. Hopefully we get another one next year. For me it was the first time and it was rather interesting to compare real band opening with the propagation prediction on dxmaps. Unfortunately i missed the big ES in June. I was on vacation and also my transverter was not ready that time. But still i made some QSO.
A frequent “beacon” on the band was DK2EA. We had several short qso and it was always a stable connection although we both used low power and small antennas.
During the ES openings i worked EA, EI, SV and LZ. I also worked some OK stations and some local stations as well.

While i was using my FT-817 as IF TRX last days i hooked up my HiQSDR to the transverter.
The day before yesterday i noticed some band opening to G. I heard the beacons GB3ANG and GM8RBR. You can see the screenshot below. While GB3ANG was rather stable over a long time GM8RBR more in the north was fading in and out all the time.

4m ES 2017-08-30


I also heard GM4ZMK calling CQ. Unfortunately outside the frequency range allowed for TX in Germany. The opening to him was only few minutes.

Find the audio files here:

GB3ANG/B 20170830

GM8RBR/B 20170830

GM4ZMK 20170830 calling CQ

DG3LSM 20170830 local

Now i will disassemble my 4m station and switch to other activities. Hope to hear you on this nice band next year.

Another 4m ES

Last week i met another ES opening and worked LZ1ZP and LZ1ZX. I also heard the LZ2HV beacon and once again SV2JAO/B.
LZ1ZP was extremely strong. Here you can find a short video of his signal in SSB (29MHz = 70MHz with transverter):

LZ1ZP 4m band SSB via ES on Aug/25/2017

Watch this video on YouTube.

Below you find some audio snippets of ES signals i recorded the last weeks.

2017-08-03 4O0BCG/B

2017-08-03 SV2JAO/B

2017-08-25 LZ2HV/B

2017-08-25 LZ2HV/B

2017-08-25 LZ1ZP CW

2017-08-25 LZ1ZP SSB

Another lunch time ES

Today i was lucky again. During lunch i worked LZ1AG and OK1VBN. Heard the beacons SV2JAO/B and 4O0BCG/B. Also 9A/S51DI/P came back to my CQ, but i did not manage to copy the complete call. Sorry! Unfortunately i did not have a 2m rig available since the band was also open on 144MHz.

Almost a antenna feed for 6cm …

Not all things work out… I was searching for some nice feed for a offset dish to be used for 6cm narrow band. In the internet i found a nice version from Russia.
It was announced for the 5GHz WLAN band without dedicated specification of the exact frequency.
For 40 Euro including shipment it was ordered and after only 2 weeks in transit (russian saying tells: For bad children Santa Claus sends the gifts by russian post… ;) ) and 1 week in customs i finally got my russian present.

5GHz horn from Russia


Measuring the input matching shows that its well in the middle of the lowest 5GHz WLAN band.

WLAN horn matching measurement


Far away from 5760MHz. But ok, lets try. First i removed the N connector.

5GHz horn from Russia


The connector with the radiator seems to be a robust construction. I tried to shorten it step by step. Unfortunately it happened what could be expected. The feed can be de-tuned to about 5.5GHz but above that the matching vanishes. Probably the distance to the backside of the horn is too big. So this one was a fail. Fortunately i can still use it for WLAN if i make the radiator a bit longer again. If you want to use the lowest of the 5GHz bands it is really a nice and very solid construction.

MD380 DMR radio

I have a Tytera MD380 DMR transceiver now. Flashed latest MD380tools and database yesterday and hope to make a first qso soon. A mmdvm hotspot is in the pipeline but i still need to connect a transceiver.

TYT MD380 DMR radio

Wideband amplifier

I tested my new assembled wideband high IP amplifier (BX-088) from Funkamateur. The transformers need to be handmade which is a very fiddling task. The cores are really small. I choose for 11dB gain assembly. The measurement shows, that the gain really rapidly drops below the 160m band. The figure fits to what is shown in the documentation. So far i did not measure the p1dB or IM3 behavior.
The points that are interesting for me are 28MHz as LNA for my SDR or as IF amplifier for transverter input on 14/28MHz and usage as pre-amp for 70MHz.

Measurement of Funkamateur wideband amplifier

My first QSO on 4m

Now finally i have my 4m rig ready. It consists of a DF2FQ transverter with some modification to power module mounting and RX amplifier stage.
Currently i use my FT-817 to drive it. I also added a separate drive input which i need for the SDR. With 1mW input on 29MHz it can achieve about 25W output on 70MHz.
So far i did not benefit from ES conditions. Seems it missed all the nice propagation from last weeks. Hopefully there will be another opening until end of August, when the permission ends here.
As antenna i use a Hentenna Quad with direct 50Ohm assymetric feed point. The antenna has some significant Null in the radiation pattern but is a good compomise for the fibre mast at the balcony.
My fist contact was with DK2EA in JO50UF in CW. Meanwhile i also worked DD1VD and DL2VPO locally.

4m band rig on the balcony

4m Hentenna Quad

[Edit 2017/07/23] meanwhile i worked EA1BFZ in IN81SS and today SV2JAO in KN10DN. ES propagation seems to be very short and spotty. You really need to look to the cluster and search the frequencies all the time. 5 minutes later all could be gone. 100km away the conditions can be significantly different.

June DUR from JO54LJ

This year i was on vacation again during the June DUR weekend.
So i took the 23cm transverter + FT-817 + my 16ele Yagi with me to do some aircraft scatter QSO.
My location was balcony on the 8th floor but with decent takeoff towards JO60/61. Takeoff more towards west was slightly better.
Looking to the Airscout software revealed very few planes. This resulted in weak and very short reflections. In the end 3 QSO. Best signal was from DJ5AR this time which was the most distant QSO.
Unfortunately i found no other station for a QSO in the north.

Antenna mounted to rainfall pipe. Baltic sea in the background.

my portable station. You can see the arm of my 3year old co-op “operating” the chat PC ;)

China LNA

I was searching for some simple LNA for microwave reception and found a very cheap board from China. For less than 10 Euro i ordered a LNA board that is specified to work from 50MHz to 6GHz. The gain should be about 20dB at 50MHz and still >10dB at 6GHz. Even if it does not work like that the PCB with shield and SMA jacks is still a good deal. You can find some measurement results below. The original condition makes clear that the gain on the upper frequencies is not good. Touching the bias network with the finger showed slight improvements. So it was clear that there is some problem with the components feeding the MMIC. Exchanging the ferrite bead by a 68nH RF coil gives much better results up to 4.5GHz but still has problems on the highest frequencies. So i tried a 2.7nH i series directly connected to the RF trace in order to avoid the stub that was there before. Now 6GHz is good but there is a resonance at about 3.5GHz. My last attempt was an additional 120nF to ground between the two coils. Thats pretty promising for the microwave bands but below 800MHz the LNA is not usable anymore. So the network still has room for improvement but it is at least clear that the board is usable.

Chinese LNA with german finger ;)

measurement results for different bias networks