After much time doing only microwaves activities, I listened the encourage words from Luis EA5DOM, to try to receive LF and MF . Luis is active in 136kHz and 477kHz in TRX and uses Opera, WSPR and have a SpectrumLab grabber.
Icom IC-R9000 and IC-781 used
On the right the PA0RDT mini-whip antenna
I build a PA0RDT mini-whip antenna and erected it 6 meters over the floor, as receivers I used my Icom IC-R9000 for 136kHz and the Icom IC-781 for 477kHz. I tested Opera, WSPR and Argo for QRSS.
WSPR-2 stations in 477kHz
WSPR-15 signals in 136kHz
Opera32 stations in 136kHz
G3XDV in slow CW QRSS/60 in 136kHz
DK7FC in DFCW in 136kHZ
The most common modes are OPERA32 (32 mins period), wspr15 ( 15 mins period) in 136kHz, and OPERA-8 (8 mins period) WSPR-2 (2 mins period) in 477kHz. The OPERA and WSPR uploads to Internet the receptions as spots and is possible check online the results and distance. This is feature is very nice to compare results with another stations.
wsprnet.org map with the WSPR-2 stations received in 136kHz
pskreporter.info maps with the OPERA-32 stations received at 136kHz
I’m really surprised for the good results and for the nice signals that can be received in this low frequencies with a small antenna. I know that this band some times not are easy for the local QRM/QRN generated by switched power supplies, motors, etc.. but with not much effort is possible get some setup to receive this bands.
I encourage that you try to receive this bands. A good point to start is the 477kHz band. It can be received easy using a base HF transceiver and antenna.
Recently I build a circular polarization feedhorn to try to do EME in 1296 MHz. The hint was that it have very easy to build and cheap. I was looking some designs based in ual mode septum designs from N2UO and RA3AQ but they not are easy to build for me. My idea has been use fireplace pipe and a dielectric depolarizer.
1296 Dual mode feedhorn
To build the feehorn I have used fireplace inox pipe of 150mm and a galvanized reduction from 250 to 150mm. The dielectric depolarizer is a piece of Rogers Duriod 5880. To try to minimize the number of sma connectors, I used a small piece of Suhner .141 as a probe that will connect directly to the LNA saver switch.
Building the RX probe
RX port probe
In the TX port I used a standard N connector. I measured the RL in the lab, but have to measure the RL in the dish for this reason the bottom plate not is soldered yet, it is glued using metalic tape, until the RL is adjusted on the dish.
Measuring return loss
Feedhon on the dish
The wind season is finishing, and now looks a good time to se new challenges. After a lot of years receving weak signals, looks that is a good time to try to transmit to the air my own signals. One of the most nice challenges for a amateur radio is bounce his signals to the moon, and do it in he microwaves segment looks more cool 😉
Prodelin 1251 with 1296MHz feedhorn
Before to transmit something, I’m looking if I can receive signals. My first attempt has been in 1296MHz. I was build a feedhorn for with a bit of junk, use a LNA used before and a AOR AR5000 receiver with the WSJT software.
I1NDP left and HB9Q right signals and WSJT
The result was amazing, receiving nice signals. I was receive the big gun HB9Q with a very loud signal, audible in the receiver speaker!
After some hours finally I was copy this stations:
Now looks that will start to build a more efficient feedhorn and build the transmission side.
Recently a nice activity for the Ham radio community was organizated from the JPL. The idea is that the spacecraft instruments can detect a message transmited by the Ham radio operators, here all the info. Waiting the definitive plot from the JPL here my the plot that I was record using a Rfspace SDR-14 in continuum mode, recoerding the slice from 28.0 to 28.5MHz:
Say HI to Juno
Thanks to the JPL people to this kind of activities for the Amateur Radio community.
The IF output ot the DMC downconverter is around the 1.5GHz, and need a IF output of 432Mhz. Googling a bit I found the mods of OK1VVM that show hoe modify the module. The mod basically consist in replace two capacitators and remove a resistor as described here.
DMC downconverter before the mod
DMC downconverter before the mod
DMC downconverter after the mod
DMC downconverter after the mod
Now I’ m looking retune the DRO locked oscillator modules to 23616MHz to get a IF of 432Mhz at 24048MHz. To get 23616MHz I can use 98.4MHz (x240) and 105.42857MHz (x224). As I have a xtal of 105.43857Mhz I wish use the same in the two units, but have in one unit dosen’t works.
The unit that originally have a xtal of 99.04MHz dont accepts xtals more high than 100Mhz, and the units that originally have a xtal of 105.99MHz dont accepto xtals of less of 100Mhz. Comparing the units, looks that the issue is in the wire inductors located near of the xtal.
DMC DRO locked oscillators opened
DMC DRO locked oscillators
To check the reference inside of the unit exists a SMA located in the upper right that gives the ref freq x4. After modify the coils now and retuning the filter located in the bottom right , the unit that only accepts xtals up to 100MHz locked now can be used with the 105.43857MHz xtal.
DMC DRO locked oscillator test
DMC DRO locked oscillator xtal
Recentlly I purchased some DMC microwave modules tu build a 24GHz transverter. This modules are designed to work at 22 / 23GHz but can work well at 24GHz with a minumum work and be purchased in ebay.
24GHz DMC modules
The set is composed by a DRO locked oscillator, upconverter, downconverter and LNA. The DRO locked oscillator, uses from 90 to 110 MHz as reference. The upconverter uses a 310MHz IF input and outputs over 15dBm ( 30 mW). The downconverter have a IF output of 1.4GHz, and have a second donwconverter to convert from 1.4GHz to 70Mhz. Finall the LNA have over 15dB of gain and a NF over 2.5dB / 3dB
24GHz DMC RX test
All the modules use 8.4V dc except the LO that uses 8.4V and -5V. Googling a bit, I found some info about the modules:
In the middle of 2009 I bought a 26GHz transceiver to use in amateur-DSN. It was to try to receive the 25GHz downlink of the Lunar Reconnaissance Orbiter spaceprobe. After much time without succes and after the confirmation of Paul J Marsh, that he never has received the probe too I decided give a new life to the module and try to use in 24GHz amateud band.
Thales TGTR-26 trasnceiver
The module is a THALES TGTR-26 and googling a bit, looks the some Autralian amateurs are using the module without problems. The first was get a suitable local oscillator , this unit should accept a frequency range from the 10 to 14Ghz. The idea is ise a IF of 1.3Ghz then need a LO over 11.45Ghz. Using the cavity and electronics of a Magnum MC PLS22 that accepts 10MHz input reference and the SRD and output filter of a Magnum MC PLX31 that cover from 10.4 to 10.7GHz, I put all totgether and after retuning the SRD I get a nice brick of 11.36 GHz, pefect to use as LO.
Magnum brick oscillator
The TGTR-26 uses +5V (1A),-10V and +8V to enable the TX branch. One time solved the power issues, the unit was start to receive very well, giving a conversion gain of 29dB aprox. To test the RX branch I was use the Marconi / Aeroflex 6203 microwave test set as signal reference.
RX Test setup
Marconi 6203 tuned at 24.050GHz -90dBm
IF at at 1.3Ghz, signal at -63dBm
After to verify the good results of the RX branch, is the time of the TX branch. To put the transceiver in TX only need aply +8V in the TX pin. The result was amazing, receiving peaks of 32dBm, it can be more than 1.5W! This test has ben used a 10dBm IF at 1.3GHz.
Signal generator as TX IF
TX Signal plot
TX Image signal plot
The unit is suitable for amateur use in 24GHz. Really amazing how this modules that can be purchased in ebay and can be recycled to give a new life.