MAD activity on July 7

Next MAD will be held on Saturday 07/07.

Time to start making plans. I intend to be at YMCA (EM48sq) with my 10GHz as usual. I intend to bring a laptop and try to monitor the 10GHz band on its screen. This should detect even weaker signals that can't be heard by human ears.

I also intend to test a portable PA for 23cm (approx. 20W). Furthermore, I will also bring an omnidirectional antenna for 144MHz ("eggbeater") for liaison frequency of 144.260MHz.

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.

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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):

ARRL June VHF Contest

I was planning on operating my home station in this contest, even decided to install new 55el. looper for 1296MHz on the roof. Discovered that the gutters are full of mess again and decided to clean them immediately and install protective covers to avoid this in the future. That activity took most of the day on Saturday.

This is how clogged gutters look like :-(

Covers installed

Well, that was Saturday. I have jumped out of bed at 5:00am on Sunday (!!) and went to my usual location at YMCA in Westport to work some microwave QSOs.

Of course, this was a contest, so no cellurar phones allowed. I have tried to use my car radio for liaison frequency. While I was there, I have also made several QSOs on 144MHz!

FT-100D

This is how I worked even stations from Texas!

I have also solved how to prevent my 23cm antenna from turning around

Here is the important detail :)

All my antennas on one picture

 

 

 

However, I have still not worked Zack W9SZ on 10GHz from EN50rl. Nice clear sky, no chance for Rain Scatter today .. will have to come some other time and try again.

MAD on June 2nd again

We have achieved some progress with 10GHz transverters, worked KO0Z (EM59bc) over 42.6 miles (68.5km) CW and SSB with full scale signals on all 3 stations. We have also worked W9SZ (EN50rl) on 1296MHz CW over 160.5 miles (258.2km). See pictures below. I have identified couple of issues to be improved before next contest, but overall this MAD was very successful.

MAD activity on June 2nd, 2012

Once again, several members of the SLAMS group from St. Louis will show some "radio-activity" and try to make contacts on microwave frequencies. I will be at the YMCA parking lot in Westport, EM48sq as usual. QRV on 1296MHz and 10368MHz CW/SSB.

Liaison frequency 144.260 SSB. This is not a contest, so cellular phone calls will be accepted.