Microwave Activity Day - May 7th, 2016

This posting comes after long, long period of doing nothing .. I mean nothing for my ham radio hobby. Looks like the overload from my job is finally over and some weekends not spent on job sites are in line now.

We (WA0CNS, N5MU and myself - AF4JF) went to our local hilltop in EM48rq with open view towards West and tested our 24GHz equipment.

Results were not perfect, but promising. My transverter copied 24GHz signal from Harry WA0CNS quite nicely, but Harry didn't hear mine. My station was only a mixer, no PA used today.

It was very interesting to watch how narrow the signal beam from dish antenna on 24GHz actually is. We need to work on aiming system, probably make contact on 10GHz first and then switch to 24GHz. Some more testing still needed.

73 Herbert

AF4JF

MUD 2016

Microwave Update 2016 will take place in St. Louis this year. Click on this link to find more info.

73 Herbert
AF4JF

My Microwave Activity

I wasn't very active since my last posting on this blog ... in fact, I wasn't active at all. Only made several dozens of QSOs on 160m during winter months. My job keeps me busy and often out of town for weeks without end.

Looks like this is about to change soon. I should be able to return to my hobby and work on all my delayed ham radio projects (along with house maintenance, of course). Here are some of them:

• 24GHz transverter
• New 10GHz station with 3ft antenna and TWT amplifier
• Beacon for 23cm

I have obtained two TWT amplifiers. One for my home QTH, another for my portable station. Pictures will be here on my blog site soon.

73 Herbert

MICROSOURCE Synthesizer Issue

I have obtained two MICROSOURCE synthesizers some time ago. Label on that device says:

       FREQ:   10.2 - 13.35 GHz

I was told by several other HAMs that this unit is practically identical to ELCOM unit and can be controlled through a device with 12F675 processor, such as described by Dave WW2R here. The only difference is supposed to be the oscillator type - ELCOM uses "DRO" while MICROSOURCE uses "YIG".

I am not a beginner with ELCOM synthesizers. In fact, I already have a 24GHz transverter based on DFS1201, so I thought that using this new MICROSOURCE unit to generate signal for 24GHz beacon would be piece of cake. Well ...

The synthesizer simply refused to cooperate. I tried to program it for various frequencies above 12GHz, but it always generated 12GHz output signal (note that my counter isn't locked to GPS yet):

I spent hours researching Internet and checking my wiring, switching synthesizers .. nothing. I even contacted Dave WW2R by email, but he didn't have "hands-on" experience with this model. After quite some time I finally remembered that Michal OK1VM published something about this synthesizer on his web site, so I have sent him an email.

OK1VM told me that he has some recent experience with this synthesizer. He also mentioned that although the label on the MICROSOURCE unit says otherwise, it ONLY responds to programmed frequencies in the 11.2 - 12.0 GHz range. So, I have modified my programming to 11.88GHz and here was the result:

OK, the synthesizer works. I can't use it for a small 24GHz beacon, but there are many other ways how to utilize these wonderful devices. 

Again, no matter what the label says, both of my MICROCOM units let me set them to a frequency in the 11.2 - 12.0 GHz range ONLY, exactly as DFS1201 from ELCOM.

So, before you decide to buy such a unit (mine came from eBay), be aware that your synthesizer might have the same limitation as mine does.

Thanks to Dave WW2R and Michal OK1VM for their help with solving this mystery!

73 Herbert

Even more 24GHz Toys

Thanks to recommendations from  Eda, OK1EM, I have obtained some more microwave modules useful for building 24GHz trasverter for ham radio use. These modules are called "DMC" and I have bought them on eBay:

This is a TX-mixer combined with an amplifier. It works well with IF on 432MHz, but requires local oscillator around 23.76GHz about 8dBm. Output on 24192MHz is between 20-40mW. Note that you have to use a filter between the mixer and the amplifier. This module conveniently provides SMA-connection points for such a filter.

This is a RX-mixer. Disregard the 1510MHz label, it works with 432MHz too. We only use the input section that ends with "1510MHz Output", the other section converts the signal to 70MHz and we don't need that, so disregard the cable jumper on 1510MHz.

This is an oscillator. It is based on a DRO element on 1/2 frequency (around 11.8GHz) and a crystal around 104MHz, depends on a model and on output frequency.


DMC modules are more common in EU. Following links show some basic info from web sites of  two HAMs in the Czech Republic. Links open in new window:

OK1EM  and  OK1VM

Please pay attention to block diagrams here and here. Nice and very explaining picture also here.

I have also gotten a nice dish antenna right for 24GHz, made by MACOM. It even comes with a radome.

Open antenna with a feed

This shows the entire assembly

One more 23GHz antenna assembly from eBay - I am going to use this with my "small test station" (described here). This little antenna has a circular waveguide feed.

---

Following device is not directly related to 24GHz, but it will be used to adjust oscillators for all microwave bands. Following picture demonstrates a temperature regulator (works with a temperature sensor and a relay that controls power for a heater plate):

More 24GHz Equipment

I have obtained this on eBay. Seller said "23GHz Low Band Unity Transceiver", so I hope to get it to work or maybe just salvage some parts or modules. Seems to have a SMA connector for LO. That is followed by a filter, amplifier and power divider with two more amplifiers, one for RX another for TX paths.

RX and TX path seem to have separated IF connectors (they look like MMX from GPS). Following pictures show the TX section with PA and WR42 waveguide port and RX section starting with WR42 and IF amplifier with filter.

Update from the eBay seller (thanks a lot!):

-----------------------------------------------------

1 Ground A GND 0V 0V Ground
2 +13 VDC A IX_13VDC +13+1V +13V +13V
3 +5VDC A IX_5VDC +5.0+0.25V +5.0V +5V
4 -5.25 VDC A IX_NEG5P25VDC -5.25+0.25V -5.25V5.25V
5 Ground A GND 0V 0V Ground
6 Spare A N/A N/A N/A Spare
7 RX Temp Sensor A XI_RX_TEMP 0 to 5V N/ARX Temp Sensor output
8 Ground A GND 0V 0V Ground

OK1EM sent me a picture of the unit without all the metallic parts. I don't have to remove all these to see what's beneath them. Thanks, Eda!

Starting New 24GHz Project!

I am going to assemble new 24GHz transverter and a small 24GHz beacon. Here are the parts that I have collected so far:

THALES transverter unit

ELCOM Synthesizer (upper-side L.O. injection)

Rear view of the synthesizer

Frequency Multiplier (x2), 1mW out

Microsource Synthesizer

(driven by YIG)

Identical synthesizer outside of its case

(this one will control the 24GHz beacon)

Small PA for the 24GHz beacon



Finally 24GHz QSO !

My first 24GHz 2-way QSO with John WB9PNU happened on Saturday 10/22/2011 at 9:36am local in EM48tm:

AF4JF

WB9PNU

I have written some more info on SLAMS web site. You can also find some more pictures from the event there.

First 24GHz Success !!

We have tested my new "24GHz-xverter-to-be" in WB9PNU's lab. John's spectrum analyzer definitely shows a need of a waveguide filter, but otherwise didn't reveal anything bad. Output power on 24GHz seems to be comparable with John's xverter (John uses harmonic mixer x4 from 6GHz and 144MHz IF, I am using different mixer x2 from 11.88GHz and 432MHz IF).

Important is, that we have heard each other today! I have to make a little change on my receiving preamp, but we are generally ready for first field test on Saturday 10/22 during SPRINT Microwave contest.

Both stations on the test bench

(IF radios are FT-817 on both sides):

My station detail:

Let's hope for first QSO this coming Saturday!

Not too many news ...

Well, I am quite busy with my job duties. I only managed a few ham-radio related accomplishments since my last posting here. I also bought fantastic paddle on eBay .. it's a HiMound Iambic Keyer:

Yes, it came with the base .. looks funny, but feels good! I bought this paddle for outdoor use on hilltops during our microwave events and intended to fasten it directly to the tripod, but probably will keep the base attached to the paddle now.

I am almost done with my first 24GHz transverter - just a harmonic mixer using ELCOM synthesizer (posted here earlier). Following pictures document it:

This one shows how simple it is - 12GHz coming in from the left, through the SMD capacitor, to the BAT15 antiparallel diodes and out the box on the 24GHz side. Well, there also is the IF signal of 432MHz coming in through the trace from the bottom. This works both ways, transmit and receive. PCB artwork was designed by DB6NT. Parts were magnified a little, real size is approx. 1/10" for the diodes and little smaller for the SMD capacitor. Smaller board is the new PIC controller for the synthesizer.



This is top wiew of the transverter box .. the 12/24GHz trace is on the bottom side at the right, below the empty space in the enclosure above.

All pieces are assembled, time to put everything together. That will take me a day or two, so I anticipate my very first 24GHz QSO to be made very soon, probably next week!