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

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.

DUR Contest May 2017

Just before the May DUR competition i got my new 6cm Transverter working. Before I faced some problems with the multiplier chain.
Murphy made that saturday afternoon i burned the control circuitry of the SMA bistable relay – poff. So i had to exchange it with my own sequencer circuitry that needs some highside FET switch to do that job.
I used a dual-band ring feed i made for tests and connected it to a old 60cm dish. The result you can see on the photo below. Very beta version ;) The PA is still missing and therefore i had only about 250mW.

I also wanted to take 3cm with me. In order to limit the amount of equipment i decided to minimize effort for 23cm. 13cm is out of order at the moment anyway. That means only using the former Wimax patch antenna for 9cm.

The following result i can claim:
23cm 12QSO 772P
13cm —
9cm 4QSO 481P
6cm 2QSO 351P (x2)
3cm 4QSO 489P
Sum 2444P

Next steps for 6cm will be adding driver (ordered from China) and the PA (10W, already here) as well as creating some better feed suitable for the mesh dish.
My goal is to operate 23/13/9/6 with one mesh dish.

This time i had a neighbour in JO61XA. DM4SWL was operating few meters away on 23cm FM only. Thanks for taking the foto !

6cm rig

after May 2017 DUR test

Sequencer with Attiny assembled

Attiny2313 + Uln2003 + highside FET switch for PA + lowside FET switch for RX-TX relais and a few bipolar Low Power stages on a two-layer board. The PTT input can be either high-side or low-side active. It also has lock input to connect several transverter to one antenna system. Via the driver IC a pulse relais and a fan can be controlled. There is also a Tx inhibit output that can be used with Yaesu tranceivers.

Schematic:
Attiny Sequencer Rev2 schematic
The circuit has two PTT inputs and two Error inputs (decoupled by diodes). A active high PTT input is available as well. There is a highside FET switch that can be used to drive a PA and a lowside FET switch that can be used for an RX/TX relais. The TX inhibit signal is available to drive the inhibit input of Yaesu transceivers. The active out is used to signal a sequencer in TX mode. This can be used to lock other sequencers via the error input. The ULN2003 driver is currently configured for another RX/TX relais, a fan which is running until 30s after releasing the PTT, another low active signal parallel to TX-inhibit (as PTT for TRX without TX inhibit) and output signals for a pulse relais (bi-stable RF relais). The serial interface (also used for ISP) is unused in the application. It might be possible to connect a temperature sensor for example.
The missing connection from Q4 to R7 is a print error.

The design was done with KiCad which is a open source PCB layout system. The code for the microcontroller was written in C. The 2k program memory are almost full now but one might be able to optimize. If you are interested in the design data let me know. I also have some spare PCB left over.

I wonder what else could be implemented with this PCB with the small program memory size. Feel free to give some ideas.

GPS 10MHz reference

Since some time i own a DF9NP GPSDO. Currently i only use it to lock my signal generator but i also want to use it for my microwave transverter OCXOs. When connecting a SMIQ signal generator and checking the signal output at 6GHz i noticed some +-50Hz jitter under the poor reception conditions at thelocation of this signal generator. So i want to look a bit closer into that topic. In China i ordered a Neo-M8N module that can be configured to provide a 10MHz clock at its timepulse output. I tried to compare it with the GPSDO and the OCXO of my SMY-02 signal generator.
Of cause the digital clock has significant jitter because it is generated by a CPU (specified with +-10ns).

Neo-M8N clock output at 10MHz

The picture of the timepulse at 10MHz shows, that it seems that comparing the clock to a stable oscillator over a relatively short period could be sufficient for adjusting the frequency of this oscillator to the GPS.

GPSDO, M8N, OCXO

The screenshot shows the oscilloscope triggered to the GPSDO (green). The output of the M8N module (yellow) shows the jitter and the adjustment range within 60 seconds (yellow shadow). The third (blue) trace comes from my SMY-02 which was locked to the GPSDO. The SMY signal shows some slight jitter compared to the reference. To me it is not clear if the cause is the reference or the locking in the generator. The clock from the M8N module shows significant adjustment of the clock frequency within the 60 seconds shown compared to the GPSDO which has a TCXO that is slowly compensated by the GPS inside the reference.
Looking to the signal in frequency domain shows this picture:

Neo M8N spectrum

There are rather close sidebands that require narrow band adjustment of a oscillator eventually locked to this GPS clock. Wideband the spectrum is noisy as well.

M8N phasenoise at 10MHz

Finally i took a short video showing the the scope triggered to the 10MHz OCXO reference of the SMY and comparing the GPSDO and the M8N output. The OCXO is slightly off 10MHz and therefore the picture is moving all the time. You can also see that the M8N is slowly adjusting compared to the GPSDO output.

9cm transverter

9cm Transverter

The above shows my 9cm transverter. It gives about 5W in 3400MHz. The boxes are rather old but still work fine after adjustment of all currents. The PA has 46dB gain which makes a attenuator necessary. 

transverter component side

This photo shows the assembly side with the RF transistors. The other side carries the filter cups aß Well as some other larger components.

transverter top side

The small box ist the oscillator/multiplier and the other one the transverter.

OCXO G8ACE phasenoise & startup

G8ACE OCXO at 103.5MHz

103.5MHz oscillator briefly measured with R&S FSP30..

PN Plot G8ACE OCXO

I think above 1kHz the PN figure is determined by the FSP oscillator.
Does someone have a better measurement of such an oscillator, especially above 1kHz up to 200kHz ? Unfortunately i do not have a better PN testset.

The following picture shows the cold-start behavior of the OCXO from room temperature to 60 degree celcius. The X-axis shows time in seconds and the y-axis frequency in Hz.

G8ACE OCXO Startup

Attiny RX/TX sequencer

Sequencer for Transceiver and Transverter sequence control made around a Attiny2313. It can switch a RX/TX relais lowside, a PA supply highside, has “active” and a “TX inhibit” outputs. Furthermore there is a input to lock the PTT from a second sequencer (switch on the RX/TX relais only). There is an extra 7bit output driver that is in that example used to drive a pulse controlled RF relais.

MMC 2016 JO61VB

This time no operation from hill. Just a few QSO from home. HiQSDR + ME2HT-PRO + PA + DK7ZB Oblong. Few hours of operation saturday evening and sunday afternoon. 78 QSO and about 18000 points claim.
The screenshot shows the great Tucnak log.
tucnak_marconi16
Some signals look very awful on the band…
marconi16_2
I will not tell who it was ;) Hopefully the signal can be improved.