Thursday, November 12, 2009

New 2 Meter Radio

With all the driving I do with my job, I decided to purchase a new ham radio for my van.  I drove up to Amateur Electronic Supply in Cleveland and picked up the new Yaesu FT-1900R.  The one I wanted was discontinued, but this is looking more and more like it is a better radio.


One thing that has concerned me is that the new mobile 2 meter rigs run 50+ watts.  This one is 55 watts, and the package is so tiny, I was afraid that there wouldnt be enough heat sink to dissipate the kind of heat that a 50 watt final would produce.  Turns out the entire bottom of the radio is finned heat sink, and it runs really cool with no temperature rise.  Could they be running a class E PA in their rigs now?  It would make sense.


Now for the operation of the rig...  For a new radio, it is relatively convenient.  You do need to reference the user manual, however, as programming the radio involves a few keystrokes, especially when you need to use CTCSS to access a repeater.  You can also name the channels so you dont have to remember the frequencies when you tune thru the memories.


Operating the radio is a breeze once its set up.  Power level is changed between 4 steps using a front panel button, tuning can be direct entry via the DTMF microphone (standard equipment), or by turning the tuning knob.  The receiver has a hot .2 microvolt sensitivity, and the transmit audio is nice and clean.  I've made a few QSO's on the radio from the mobile, and I am very pleased with it.


I also started a yahoo group on this radio, and if you have one, you're welcome to join it.  The url is at
http://groups.yahoo.com/group/ft-1900r/

Tuesday, September 22, 2009

E-H Antenna

Because of my limited space for antennas, I decided to do a little experimenting with an E-H Antenna. An E-H Antenna is a tiny HF and MW antenna. Originally designed for AM broadcast stations, these antennas supposedly operate with extremely high efficiency, but come in a very small package.

More information at http://www.eh-antenna.com/

I built one for the 30 meter band. The antenna is about 2 feet long, and have the antenna resonant close to the 30 meter band. According to my SWR meter, it currently runs about a 2:1 SWR on 10.139 MHz. I could get the swr down even lower by adjusting the matching coils. I did a rough tuning on mine, and got it close enough for now.

I've read mixed reports by hams who have built these antennas for themselves. Many say they dont work. Here is what I've found so far:

On receive, it seems to pick up a fair amount of noise, but that could be due to antenna placement. I dont have the antenna up very high, only about 10 feet.
On transmit, it appears to do fairly well, even at this height. Signal reports are about even using WSPR. I chose WSPR as an antenna testing mode because every station "advertises" their transmit power, so I can compare transmit vs receive efficiency easily. There is a difference, as my untuned 20 meter hamstick (going thru a tuner in the shack) consistently runs about 10 dB weaker on transmit than in my receiver.

Although this is not paint a complete picture, it does tell me that it works equally well, (or equally poor) between receive and transmit. When I am able to test the antenna when its up a bit higher, I'll be able to make better comparisons.

Watch for me on the 30 meter WSPR freq. I'll be beaconing using this antenna for awhile.

Sunday, September 20, 2009

10 GHz Mountaintop Operations

Saturday, Sept. 19 (2009) was the first time I have operated from a mountaintop on 10 GHz, and I'd like to share some observations from this particular trip. Because this was the first time I have operated from this location, Blue Knob, PA EN00rg, I'd like to tell you what I learned from this trip.

Mountaintop operations such as this tests the capability of your equipment beyond what I have experienced along the lake. Things such as receive sensitivity, pointing accuracy, etc are tested. On this trip, most of the signals are much weaker then what I experienced on Lake Erie.

One thing that was noticed readily on this trip, although our most experienced operator on site, KB8VAO said that this was a fluke, but the 2 meter band conditions were far better than the conditions on 10 GHz. Typically, signals on 10 GHz are much stronger than on 2 meters. Now I have noticed this up on the lake, but I figured this was caused by the duct over the lake being much smaller, and not able to support 2 meters. However, on the mountain, stations in New England were extremely strong on 2 meters, but almost imperceptible on 10 GHz. Many stations had to be worked on CW because the signals were so light. Most of the contacts were a struggle, especially the ones over 100 km away.

Although band conditions were such that there was a 2 meter opening, and 10 GHz seemed flat in comparison, I still managed to break my old personal distance record and worked Vermont which was just under 600 KM away. It was hit and miss for awhile, signal was quite weak, and had to be done on CW. I think next trip, I'm going to bring some form of headphones. I have found that headphones will give you about a 10 dB advantage, at least for me when working extremely weak CW.

The next week or 2, I'm going to compile an equipment checklist, I forgot to bring my code key, and had to borrow one to make the contact.

I worked about a dozen stations total from the mountain, ranging from 60 KM to 600 KM.

Tuesday, September 8, 2009

PowerSDR-IQ with the SoftRock v9.0 Lite+USB Xtall

I've been running the Softrock Xtall+Lite v9.0 with the individual band pass filter boards for several months before I broke down and purchased the Electronically Switched Bandpass Filter about a month ago. Ever since I got it, I had problems getting PowerSDR to switch the filter automatically. I know the filter works because it works fine using Winrad. Today, I got powersdr-iq working with the filter using a fancy little trick that I discovered.


The first thing I did was to uninstall powersdr-iq. I went into windows explorer and deleted what was left in the installed folder. I then went and reinstalled powersdr-iq.


Now here is where it gets tricky. If there is a .dll file in the installed directory called "ExtIO_PMSDR.dll", rename it to something like "EXTIO_PMSDR1.dll". Then go and download ExtIO_Si570.dll and save it in your powersdr-iq folder. Rename the file to "ExtIO_PMSDR.dll". Run Powersdr-iq. Go to setup > General > USB and UNCHECK BOTH boxes under AVR. Then go to the ExtIO tab, under General and check "PM-SDR Enable". Click the "Toolbox" button. You will get another box pop up. If you have Winrad installed and working with the dll for the Softrock, this box will look familiar. If you need help with this box, here's what you need to do with it.


Under "BPF", check "Enable". Normally the info in the band boxes would have for Band 0 1.8 to 4 mhz. I built my BPF so that band 0 is 50 - 54 MHz, so I changed those numbers. I also changed Band 1 to 3 to 7 MHz. You may not have to do this, but by experimenting with the cutoff freq's for MY individual filter, I found these numbers to work best.


I have posted to the usergroups regarding this problem, but it sure seemed that I was the only one that had this problem. I find that hard to believe, but now that I have this new dll installed, I can fully customize the filters, and they switch just like in winrad, probably because its the same software snippet that Winrad uses!


If you have noticed this problem too, give this fix a try. At the very worst, you might need to uninstall psdr and start over. This is all experimental software, and I'm sure that if youre using this stuff, you've probably uninstalled and reinstalled more than once anyway. Its worth a try. Let me know if it works for you too.

Wednesday, September 2, 2009

1296 update

I had just finished rebuilding my 1296 rig and assembled the modules. I added a 3 pole bandpass filter between the transverter output and the 10 dB gain block that drives the 2 watt PA. When I initially tested, I wasnt getting any power out of the rig, so I proceeded to test for RF at each stage.


I was getting the usual milliwatt or two out of the transverter., but at the output of the filter, there was nothing. I retuned the filter for max output. I lost about 3 dB thru the filter.


After hooking up the low level amplifier, the measured output was about +8 dBm. A little lower than I expected, but it's enough to drive the 2 watt amplifier to a useable output level. A quick check at the 2 watt PA output indicated a healthy output. I then determined that I had the antenna relay hooked up backward, RX line going to the TX port, etc.


Once I got it all hooked up, there was an oscillation, which I cured by shielding the low level amplifier. The output is a little low, i think, but I still believe it is enough to so some good mountaintop work. I believe I can get a little more out of the transverter, however, so I'm sure I can get the power level up to where it should be. I guess the level to shoot for is +10 dBm out of the low level amplifier. So, it looks like I'm capable of getting on 1296 now.

Saturday, August 22, 2009

1296 2W Amp Update

I got the 2 watt 1296 amplifier working Friday evening. I have had some problems with it when I was working on it. Let me give you a history before I go on.


The active device is a Motorola SML7008, which is known to work on 1296, but with slightly reduced RF output. This was aquired on eBay as a kit.


A couple weeks ago, I installed the circuit on an aluminum pallet ready to install in the enclosure that I planned on using. After it was assembled, I installed a couple of SMA connectors, connected it to a 20V Dell laptop power supply, terminated the input and put my power sensor on the output.


When I powered it up, the unit oscillated. I tried all of the usual fixes - conductive foam, etc... to no avail. The PC board that came with the kit used single sided material, with 2 mounting holes for the board and the active chip is flange mounted with 2 holes.


The fix was...I installed some flashing on the top side of the board, wrapped it around to the bottom, and screwed the board down against the flashing to the aluminum pallet. This is what eventually fixed the amp.


Now, when I was testing the amplifier earlier, I discovered the transverter power output was a tad bit low. This amplifier likes 10 milliwatts on the input for full output. I'm getting about 2 mW. The output spectrum isnt as clean as I'd like either, so I'm planning on building a 3 resonater filter and will place that on the output of the transverter, and a MMIC amplifier following that, to drive the 2 watt amplifier. I'm guessing the filter will have about 3 dB or so of loss, so the MMIC should work out just fine. I will probably be using a MSA-1105 for the active device. I still need to look up the device specs, gain, etc., but I believe it should work out. Once I get this done, I'll be packaging the thing up and will try some line of sight contacts with it using one of my 10 element yagi's. Of course I'll keep you posted as to how it comes along.

WSPR Beaconing

Along the same lines as PropnetPSK, I ran across another system that looks promising, WSPR. Pronounced "Whisper", and is an acronym for "Weak Signal Propagation Reporter". This is the kind of thing that looks quite interesting, so I downloaded it and installed and ran it for a couple of days.


This looks to be a great mode. It decodes signals up to about -29 dB below the noise floor, uploads the spots to a realtime database and plots them on a google map. Most stations run about a watt or two, with some running a couple hundred milliwatts. This is an USB digital mode. Bandwidth is a whopping 6 hz! It does not take much power to be heard.


There are stations on most of the HF bands, however most are concentrated on 30 meters. Again, I would like to see some activity on bands like 2 meters, as being the extremely weak signal properties of this mode, it would be beneficial in showing enhancements on the VHF bands. So far, I have not seen any activity on 2 meters.


Although this is an excellent mode, I dont have a good working antenna for 30 meters, so my transmitted signals are typically down about 15 dB from others on the band. Until more activity starts to show up on bands above 10 meters, my activity on this mode will be limited, I believe. This is a personal preference, I would operate more if I had a 30 meter hamstick, which I may end up getting at some point, but for now, I will probably keep beaconing on PropnetPSK.

Tuesday, August 18, 2009

10 GHz & Up Cumulative Contest Part 1




Part one of the 10 GHz & Up contest was August 15 & 16th, 2009. I operated Sunday for a couple of hours on Lake Erie along with WA3TTS and KB8VAO at grid EN91kt. I would have stayed all day like they did, but I was on call at work for 13 radio stations, so I cut it short, just in case.
Although I only operated from about 9AM - noon, I managed to work 10 stations. A large number of VE3's were roving across the lake, into Michigan and around to Ohio. Unfortunately, I did not work them all at every stop, as I left around noon.
Veteran microwave operator, KB8VAO operated the lake both Saturday & Sunday. I dont know how many QSO's he had, but I'm sure he did quite well, as the band was even better on Saturday than Sunday.
Mike, WA3TTS worked 20 QSO's on Sunday. He spent all day there, and this was his first time out on the lake operating with any real seriousness. Mike was up on the lake last year during a microwave activity day running a milliwatt or 2, but his receiver was confirmed working perfectly. Now that Mike has had a taste of some 10 GHz operation, I'm sure he will be quite active in the future. Mike is also planning on building a beacon for 1296 and 10 GHz.
This was a really fun event. It adds a new dimension when you get to operate with other microwaver's. Steve coordinated the operation because he was running the most power and was the most experienced among us. I have to thank Steve because if it wasnt for him, I dont believe we would have done as well as we have.
Now for the 2nd part of the contest, there is talk that Saturday, we operate from Lake Erie again, and from Blue Knob, a mountain in south central Pennsylvania. I have never done a mountaintop operation before, so I'm sure that will be an interesting operation. From what I hear, the long haul DX possibilities are nothing short of incredible, so I cant wait to do something from there. I went to the mountain last summer to check it out, but havent operated the mountain. You can see for miles in every direction, so no doubt, 10 GHz will go a long way from there.

Wednesday, August 12, 2009

Software Defined Radio

Something I've been playing around with, on and off over the past few months has been Software Defined Radio, or SDR for short. A few months ago, I ordered a kit receiver from Tony, KB9YIG. He has been continuing the "Softrock" series originally sold by the American QRP Club. The latest "Softrock 40's" currently are synthesized, and are controlled totally by computer. The theory is a bit deep as to how these work, but for simplicity, I'll say that the sound card in a computer does all of the demodulation of the signals.


This opens up a whole new world of radio. Here, a small pc board, which costs about $50 will tune the HF bands thru 6 meters, and do it so well, it rivals almost any radio on the market. The features of the radio is only limited by the software used in conjunction with it. Using this radio, and a program called "PowerSDR", the receiver will tune, general coverage from 1.6 MHz thru 30 MHz, or from 3.5 MHz thru 52 MHz. It will also receive all modes, USB, LSB, CW, AM, FM and DRM. Using external software, the receiver will receive all of the amateur digital modes (PSK, SSTV, Olivia, Hellscreiber, etc), and with Dream software, will also decode shortwave DRM Broadcasts.


Tonight, I listened to Radio Canada International for about an hour, running Dream, listening to their digital broadcast. They did a commentary, News, etc, which is what you would normally hear on a government operated shortwave station, but they also played some music - Gospel, Jazz, etc. I will say, the quality was almost as good as FM broadcast quality. Absolutely no noise whatsoever, and the frequency response and distortion were exceptionally great!


Of course, the receiver will listen to the analog AM broadcasts, as well as SSB and CW with no additional software.


The display shows a panoramic view of the frequency domain (It looks like a spectrum analyser), and by using different sound card sample rates, you can see anywhere between about 50 KHz to about 200 KHz of spectrum using 48K thru 192K sample rates respectively, provided your sound card is capable of the faster rates. I usually run the 48K rate, as the 96K rate my sound card sounds choppy.


Originally, I purchased this device as an aid to finding rain scatter signals on 10 GHz (with the appropriate converters), however, this is just so cool, that I have been using it as a general coverage receiver.


I just purchased a electronically switched bandpass filter kit for the input of the receiver. The way I have been using this so far has been by changing out little monoband filter boards that cover sections of the HF spectrum. The kits, including the bandpass filter are mostly surface mount devices, and the parts are extremely tiny. There are special techniques for building with these components. I'm finding my eyesight isnt as good as it used to be when I was younger, as I've been having trouble seeing what I'm doing. I can only work on it for about half an hour at a time till my eyes get "buggy".


The link to this really cool project can be found at http://www.wb5rvz.com/sdr/
Hope you try one of these, you'll have a blast with it! They also make a version that transmits also.

Saturday, August 8, 2009

Absorptive SWR Bridge for the Microwave Bands


A number of years ago, I built an antenna tuner with a very simple SWR meter built in. This SWR meter worked using the Wheatstone Bridge theory, and the indicator was an LED. This meter worked well on HF using 2 watt transmitters. It had occured that since most microwave work is at similar power levels, why one of these meters wouldnt work on VHF and above.

I therefore built a meter similar to the one I used. I found an article on W1GHZ's site, that was very similar to what I was using. Here I thought this was a new idea for a microwave reflectometer, but Paul thought about it before me. I did, however use his circuit, and I also made a few modifications to his circuit to make it better. The schematic is shown. Click on the image for a larger view.
Basically, this is a wheatstone bridge. The three 50 ohm resistors, along with the output port, which if the impedance equals 50 j0 ohms, there will be a null across the 100 ohm resistor, and therefore no diode current. If however, the resistance is anything other than 50 ohms, an imbalance occurs, and RF will be present across the 100 ohm resistor, as well as across the diode. The imbalance current is read on the meter, and can be calibrated as SWR. One feature that is inherent with this type of meter is that it always presents a load near 50 ohms to the source, preventing any kind of burnout of the PA. The disadvantage of this type of circuit is that it cannot be left in the circuit, as it will have approximately a 6 dB loss.

The resistor with the "*" can be found experimentally, or replaced with a potentiometer of about 10 K or so to adjust the meter for a full scale reading with no load connected. To measure forward power to calibrate the meter, remove the antenna or output connection. To measure reflected, simply reconnect the antenna or device being measured. The power handling of this device is quite low, so don't transmit into the meter running more than a couple of watts for very long. My meter will calibrate with 1 watt applied. This meter will work using standard leaded resistors and chip capacitors up thru 432 MHz. To make the unit null on 902 MHz and above (probably thru 2304), you must replace all the resistors with chip resistors. Remember, any path carrying RF should be made with 50 ohm stripline.

My present meter is using the standard metal film leaded resistors, and the null is very good on 432 mhz. I use sma connectors for the guzinta and the guzoutta. I used what I had available as far as the resistors and caps are concerned. I have leaded resistors but no leaded caps, so I used all chip caps for mine.

This device can be used from HF - SHF, but it is a QRP meter. I wouldnt load more than 5 watts into this device.

If you have any questions on this meter, please leave a comment. I will try to answer any questions you may have. I hope that some of you may find this device useful, as it makes antenna tuneup easy, and protects the final of your radio while youre tuning!

Monday, August 3, 2009

1296 amp, and other things....

Today I built up my 2 watt amplifier for 1296 (23 cm). Basically, the board was built, I just mounted it to an aluminum pallet and built a small brass enclosure, mounted sma connectors and power connection.

I tested the thing out using a reduced voltage. I hit it with 12 volts, the unit takes 20 - 24 volts. Turns out it needs like 15 - 16 volts for it to start working, and of course, I had nothing coming out. A phone call to Mike, WA3TTS confirmed that I needed more voltage. I have a couple of old Dell laptop power supplies that are good for about 20 volts at 2 - 3 amps, which should work ok running this amp, which I will use. I will set that up another day, because I need to make this idiot proof, cuz....well, lets say, I've been known to be an idiot sometimes! ha ha... Dont need 20 volts on the transverter or the IF radio.

I also installed Windows XP on my shack pc. It had Vista in it, and I found that my software defined radio did not work in Vista, and besides, this computer is REALLY slow running Vista. Now everything is working again. Just set up Propnet-PSK again, but I have it set up as a lurker station on 10 meters. I'll get the PTT RS-232 working in the next day or 2.

I also volunteered to help out with a local public service event here in New Middletown tomorrow (tuesday). Theyre having a village "party" at the village park, and it kicks off with a parade. I'm to help organize the parade and provide communications for the parade. I did this last year too. Its one reason amateur radio exists, to provide communications as a public service. I therefore am helping to justify our frequencies by helping out in local events.

Well, I havent been doing that much radio wise lately, as the blog shows. The 1296 rig is still my current project, but its time to start packaging the rig, and putting the system together. Once the 2 watt amp is working, then I'll need to rebuild my 30 watt amplifier, then we'll be pretty well set up. Of course I'll keep you posted! 73 for now...

Tuesday, July 14, 2009

10 Element 1296 Yagi Works!

Just finished building and tested a 10 element yagi for 1296. This antenna replaced the larger yagi that did not appear to work. This one received the source just fine. Being it is only 21 inches long (boom length), it did not perform like the 4 foot long antennas that I had tested earlier, it still seems to have the gain and directivity that I would expect out of a 10 element yagi.

The software that I used to design this antenna suggests that the antenna can be lengthened without having to change the current element lengths or spacings. Therefore, I'll add another segment to this antenna at a later time to increase its size to something that should be more useful.

This antenna was a new design, as I used very small diameter elements (1/16 inch). Most yagis on 1296 use 1/8 inch elements, which in my opinion might be a little large for this band. Although the software can design working antennas with different diameter elements, I went with 1/16 inch aluminum to keep the weight down, and I'm thinking the thinner elements might provide a little more gain.

The next step is to get these antennas tested for return loss. I still have no idea how they perform in that manner, and do not have the instruments to test. I did run across an article online telling how to build a directional coupler that works from 2 meters up thru 1296, which I just might decide to build. I think I have all the necessary parts to build it.

Sunday, July 12, 2009

1296 Antenna Testing

I just finished doing some tests on my 3 1296 yagi's. The first was a WA5VJB wood boom yagi, the second, was designed on VK5DJ's calculator, the third was a loop yagi. Knowing that the loop yagi works reasonably well, it was the antenna to beat.

This test was done in a rather unscientific manner. The signal source was a 48 MHz oscillator using ambient radiation from its open enclosure, located about 50 feet away from the antenna under test. The 27th harmonic was weak but quite noticable in the receiver. I did not use any metering to determine gain from one antenna to another, but just compared them all "by ear". I have no way of determining the return loss of the antennas under test. The "antenna range" was not ideal either, located between 2 metal structures about 50 feet apart. I was able to notice decent directivity and antenna gain between the antennas I tested. I figure that the directivity would give some indication of gain. Anyway, here are the results of this test:

The WA5VJB 10 element yagi compared favorably to the 19 element looper. Directivity and apparent gain were too close to call which one was the winner. The 18 element yagi that was designed using the VK5DJ calculator could barely hear the signal source. I therefore measured the dimensions of this antenna, and realized I had built this antenna for the satellite portion of the band (1268 MHz). I will be redesigning another antenna using this design, but tuned to the proper frequency.

Keep in mind, this was a very unscientific test. I meant to do this to see if there was a noticeable difference in the performance of these antennas. Because I built the VK5DJ antenna some time ago, I hadnt realized it was built for the satellite portion of the band. I will run a new test on this antenna once it is built.

I printed out 2 different designs using the VK5DJ Antenna Calculator. One was for a 10 element yagi, the other for an 18 element model. The element lengths and spacing are identical for the first 10 elements, which suggests that a 10 element version could be built, and later the antenna extended to at least 18 elements at a later date. Therefore, I will construct the 10 element version, then will extend it at a later date, if the 10 element version checks out.

Monday, June 22, 2009

1296 MHz Station

Finished building another 1296 MHz antenna last night. I have been experimenting with yagi antennas for the 23 cm band lately. Planning on doing some antenna comparisons this weekend. The new antenna was designed using the VK5DJ calculator. This particular antenna has 15 elements on a 3 foot boom. Over the winter, I built one of the WA5VJB "Cheap Yagi's", but have not been able to test it yet. I hope to be able to compare these two antennas over the weekend. This latest antenna was built on a 1/2 inch diameter round boom and is of all metal construction. The "Cheap Yagi", as with all of these antennas was built using a wood boom, in this particular example, I used a 3 foot 1/2 inch wooden dowel for the boom, and brass brazing rod for the elements. When I'm able to check the return loss on these antennas, I'll post the info here. I have a low power signal source that I can use to do relative gain measurements on these antennas. It will be interesting as to how these antennas compare to eachother.

Friday, June 19, 2009

kd0ar audio captured in a video

I found something that is WAY too cool. N0SSC captured me on video while he was making a contact on satellite AO-51. I've always been curious to see how I sounded on the satellite, and I seem to have been hitting it good that day!
The url to the YouTube video is at http://www.youtube.com/watch?v=ywECT739etI

Wednesday, June 17, 2009

More PropNET info

I spoke of PropNET in a previous post. Allow me to direct you to more information and the maps it generates to show where the propagation is happening. First, the display info can be had at http://propnet.org/index3rp.shtml . This link will allow you to set up the band and area of the country you are interested in. When you have that set up, click the "Catches" link just under the table.

Now for the software which you'll need to participate in this project. You can find the software here: http://sourceforge.net/project/showfiles.php?group_id=250959&package_id=306760&release_id=671918

leave a comment on this post if you have problems, or twitter me at http://twitter.com/kd0ar if you need more information.

Tuesday, June 16, 2009

PropNET PSK

I discovered something rather interesting a couple days ago, called propnet psk. Basically, it used psk31 to beacon, looking for propagation. The way it works is a special soundcard based program is used, you set it up for the band you want to beacon on, and input info like your grid square, power, antenna height, etc. It builds a special code to let others know your operating conditions. The beacons if heard by other beacon ops gets posted automatically to a website, showing areas of propagation. Currently there is activity on 30 meters, 10 meters, 6 meters and 2 meters. 10 meters is the most popular right now, but would like to see more of this going on 2 meters.

This could be a really good indicator of 2 meter band openings if there were more operators on this mode operating on 2 meters.

Monday, June 15, 2009

WA5VJB Cheap Satellite Yagi

Well, I was a bit bored tonite. I've been having trouble with the 2 meter portion of my satellite antenna lately. I think water got into the balun and screwed it all up. So, I've been working on replacing the VHF portion of the antenna with a 3 element version of WA5VJB's Cheap Yagi.

This antenna is an interesting design. It uses half of a folded dipole (Kinda like a 'J' shaped element) for the driven element. With the driven element alone, the SWR and feed resistance is VERY low, but when the reflector is brought real close, the SWR goes down. The spacing is strange, something like 8 inches between the driven and reflector, and the director is about 18 -19 inches in front. I'm not sure how this works, but apparently it does.

When I get the VHF portion done, I need to build the UHF one, and tune it to 432 MHz and sweep it to see how flat the SWR is between 432 and 436 MHz. The current antenna has horrid performance on AO-7, but it seems to receive well on AO-51's downlink.

Will keep you up to date as to how the antenna is coming along. My analyzer's battery is dead and is charging now, so looks like I'm done playin for tonite.

Sunday, June 14, 2009

10 GHz short range experiment

Today I took part in a shortrange experiment on 10 GHz. Because I have not made a contact in a long time, Steve, KB8VAO came over, calibrated the gear, and he ran mobile on 10 GHz. Yes, mobile, running a 10 slot alford slot antenna on a magnet mount on his car. I was able to work him over a 2 km range. Range was poor because of the trees in the path. The experiment did, however accomplish a couple things. 1. Because his rig is phase locked to a stable, calibrated source, I was able to determine that 10368.1 MHz corresponds to 144.128 MHz on my IF rig.

Second, I was able to determine that my 2 watt amplifier was working properly, as his rig runs 8 watts, and we had similar copy even over the weaker paths.

I was running the offset dish on my end, tripod mounted in my driveway, DB6NT transverter (g2 model), into a DEMI 3 watt amplifier.

I believe Steve was running a DEMI transverter with an 8 watt PA into the slot, trunk mounted.
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