Reference Antennas Using Ferrite Baluns Part 1 James Eagleson 2014-01-26 | A quick look at a couple of ferrite Balun designs that could be used for making Reference Dipole Antennas. I cover the original 2m KLM balun that I believe was used on an early version of the 2m Eggbeater antenna but found it to be deficient at frequencies above 250 MHz... as might be expected.I show return loss results for an old HF Balun from my junk box. It turned out to have internal connection problems but seems to work fine from about 80m to, perhaps, 6m.I then did a comparison between the old KLM 2m power balun to a CX2024 unit made for receivers (100mW Max) that covers 10-1000 MHz. While I was unable to duplicate the spec 30dB return loss published by Pulse Electronics, it was good enough to proceed with using it with my adjustable telescoping dipole and showed good results up to about 440 MHz. I should comment that with my directional coupler method of measuring return loss, part of the difference between the spec and measured performance could easily be related to the test setup performance more than the actual balun's performance though a load directly on a BNC connector did show about 30dB return loss.Regardless, when I actually hooked up these baluns to the telescoping dipoles used for the reference antennas I obtained better than 20dB return loss up to about 253 MHz for the KLM 2m power balun and I was able to obtain 20dB return loss at 145, 222, and 432 MHz by adjusting the whip lengths on the unit that used the Pulse Electronics CX2024 balun.When I get the second CX2024 Reference Dipole Antenna made I will complete this project by evaluating each of these antennas in an Over-The-Air (OTA) test for gain and pattern. I'll present those results after I perform those tests.As usual, I am open for comments.
Quick View of a Useful MacDoppler Screen Setup James Eagleson 2022-11-21 | A quick look at how I set up my computer screen when operating Amateur Satellites. The browser is available on the right side to view AMSAT's Satellite Status page but could be set to your Contacts page, Audacity for capturing audio, Quick Time to capture both video and audio, or perhaps the specifications page for the satellite you are tracking.
Preview Daily Satellite Passes Using MacDoppler James Eagleson 2022-08-01 | How to preview satellite passes using MacDoppler... quick plus more detailed methods.
Foam Mini Crow DLG James Eagleson 2021-06-29 | Here is build information and flight footage (7:11) for my foamboard Mini Crow DLG. This is a 19-inch version loosely based on Maurosz Wrona's contest winning The Crow indoor hand launched glider. See jhaerospace.com/product/crow-f1n for availability and details about the original model.My unit is made from a 6mm Depron (foam) main wing, foam plate V-tail, with a Carbon Rod boom attached to a laminated plywood/Depron pod. The video shows some construction details and flight videos. The last flight was in a larger park with a touch of thermal activity aiding the flight.You can contact me via email ( jeagleson945@gmail.com ) if you would like a copy of the PDF plan for my 19-inch "Mini-Crow" version.By the way, I changed the tail section to 1/16th inch balsa wood and added a small vertical stabilizer under the V-Tail for better yaw control. This provided higher launches and longer flights. Unfortunately due to thermal activity and apparent higher winds aloft, my last flight was high enough that my "Mini-Crow" was carried by wind somewhere off into the neighborhood surrounding the park where I fly. Such is the nature of free flight in the city.A good resource for information about free flight gliders check out the National Free Flight Society website at: freeflight.org For a very good Catapult and Tip Launch glider build and trimming video view: youtu.be/Jznb6mHep-8
Super Baby Daddy 30 sec Charge Flights James Eagleson 2020-12-03 | Follow up to my Foam Hoosier Baby Daddy conversion to Super Capacitor power showing results with 30-35 seconds of charge time. (I needed to go to a bigger park with fewer trees!) I probably should mention here that flying Super Cap Planes is similar in many ways to flying with rubber power. The small brushed motors and 45-55mm propellers generally will not harm ones fingers if they get in the way. When something stops the prop, the motor will draw extra current which tends to discharge the Super Cap rapidly making Super Cap planes a safer alternative to typical LiPo/Brushless Motor powered model aircraft for urban park flying.See my earlier video at: youtu.be/cBnEmcDczK0See the DLG version build and flight video at: youtu.be/1YWJy5yIC_0
Hoosier Baby Daddy SuperCap Power Conversion James Eagleson 2020-12-01 | I decided that my beat up Hoosier Baby Daddy was a good candidate for seeing what this good DLG design could do as a Super Capacitor powered plane. This video shows what was required to make the conversion and concludes with several flights that I made to trim the model for powered flight. (Flight video at 3:13)Required parts for the conversion: 1. 8520 (8.5x20mm) quad copter motor 2. 10 Farad (2.6VDC) Super Capacitor 3. 5.5mm Coaxial DC Power Socket The charger I use has a 5.5mm Coaxial DC Power Plug purchased from Amazon connected to a 3 battery box also purchased from Amazon. I use NIMH rechargeable AA batteries to provide 4.5V which charges up the Super Cap to 2.6V in about 25-35 seconds. I generally do initial testing with an 8 second charge then tweak things in with 15-20 second charges. Typically flights will last between 1.5-2.0 times the length of a charge though I have had a few flights of several minutes when there has been thermal activity (see an earlier video in this series).If I use a full 35-40 second charge this model will achieve much higher altitude but I don't try that in my local park because I get tired of getting planes out of trees. I've placed several models more than 40 feet up the 70 foot trees you see surrounding my flying area. I know it is more than 40 feet because I can't reach them with the 40 foot extension fiberglass pole I use to rescue them from plane eating trees. There is a park about 2 miles from my house where full power flights are much safer to launch. There is a short, 1 minute video showing flights after 30-35 second capacitor charge times at:youtu.be/pxMQuwPxSI4Construction video and comments for DLG version: youtu.be/1YWJy5yIC_0
JHA DLG Launch, Pitch Over, Glide Setup on Jumper T8SG 1 James Eagleson 2020-11-30 | To use a DSMX Ultra Micro integrated Receiver/Servo "brick" in my J&H Aerospace Carbonette DLG, I needed to program my Jumper T8SG to work with that receiver. This video shows my step-by-step set up of Switch D on the Jumper to provide 3 conditions during the launch of the DLG which are Launch, Pitch Over, and Glide. (Flight video at 14:22)Some may notice that I have placed the control rods outside the carbon fiber tube going to the tail section. I tried Joshua's original music wire push/pull rods through the tail boom but found it too difficult to connect the "Z" bends in the space provided. It was simpler to place the control rods on the outside of the boom using some 1mm carbon rods with wire tips... at least for me.While learning to launch a DLG I broke the nose portion of the Carbonette 19 a couple of times thus I finally added some more balsa siding to repair the damage. This, of course, makes the unit unusable for rocket launch and adds a few grams of weight to the plane. This makes the overall weight of the plane with battery installed about 43 grams.
Foam Hoosier Baby Daddy James Eagleson 2020-11-12 | I built a 24 inch foamboard version of Bruce Kimball's Hoosier Daddy DLG renamed by Jim Buxton as Hoosier Baby Daddy. I show some of the construction that I used along with 14 and 22 second flights of my, now, beat up glider. (flight video at 4:45)I found the plans for this in the Sept-Oct 2020 issue of Free Flight magazine but a PDF can be downloaded from the www.discuskids.org site. Free Flight magazine is available with membership to the National Free Flight Society (www.freeflight.org).I plan to make a Balsawood wing for this which should allow full discus launch heights. I am a noob as far as such launches are concerned and I'm not certain the foam wing would withstand such a launch. I am easily able to get 30-40 foot high tip launches, however. Cost? About $5-7 of materials. I plan to add a prop and functional 8520 electric motor with a 10 Farad Capacitor to this model in the future after I make the Balsa version. Capacitor powered flight provides performance similar to Rubber power thus places less stress on the foam wings.Also see Super Cap conversion and flight video at:youtu.be/cBnEmcDczK0 See Super Cap fully charged flight video at: youtu.be/pxMQuwPxSI4
4 VHF UHF Equipment, Nets, Resources James Eagleson 2020-10-07 | Part 4 of VHF-UHF Operations & Equipment covers suggested equipment, nets, and resources.
3a VHF UHF HamSatellites James Eagleson 2020-10-07 | The third section of VHF/UHF Operations and Equipment discusses Amateur Radio Satellites.
2 VHF UHF Modes, BW, Noise, Prop James Eagleson 2020-10-07 | The second video about VHF/UHF Weak Signal Operations covering the impact on range by selection of modulation modes, bandwidth, propagation effects. It also discusses VHF/UHF noise levels and noise reduction capability of modern radios.
1 VHF UHF Antennas, Preamps, Amps, Range James Eagleson 2020-10-07 | This first video is about VHF/UHF Range Improvement Techniques covers the use of Antennas, Preamps, and Amplifiers to improve communication range and to control external noise, interference, and multi-path issues.
DIY Cap Powered Crow Thermals Into Tree James Eagleson 2020-08-30 | A brief video showing my DIY copy of Mariusz Wrona's RS20 F1N Hand Launched indoor competition glider thermalling up to about 75 feet then landing in a tree. The orginal glider I bought from J&H Aerospace (jhaerospace.com) flew even better but thermalled away from me some time ago. It has a hot wire cut foam wing that is way more efficient than my hand sanded 3mm Dollar Tree foam board for the main wing. Then again, my DIY version only cost a few dollars to make and still provides a lot of fun.The plane seen in this video has been further modified using a 7x20 brushed mini-quad motor (Banggood) with a 10 Farad Super Cap (also from Banggood). I charge it up with 3xAA NICAD rechargeable batteries placed into a three battery case... both of which are available on Amazon. The battery connections for both the plane and the battery case are 5.5mm coaxial DC connectors. The female connector on the plane is set up to disconnect the motor while charging the Super Cap but connects the motor back up to the Super Cap when the charge plug is pulled out. The battery case I found also has a switch on it so that it is easy to control how many seconds of charge you allow for each charge.If there is sufficient interest, I can upload a build video though I would highly recommend that you purchase the original Crow from J&H Aerospace as a better place to start. I should mention that this is a slow flyer designed for indoor flying so that outdoor flying should be when wind speeds are less that 3 MPH. The original Crow is weighs in at 16 grams and my DIY copies have come in around 24-35 grams depending on whether built for hand launching or capacitor power.
The Crow HLG Indoor:Outdoor Glider James Eagleson 2020-05-22 | This is a follow on video showing a few more flights of The Crow Glider. In moderately calm air this model flies very well. In completely calm conditions it floats even with a very gentle launch. With a single loop, gentle catapult launch (or a "gung-ho" javelin launch) The Crow will easily turn in flights greater than one minute.However, you will notice that The Crow is very sensitive to the cross currents and up and down drafts caused by the trees surrounding this park. I don't think I'd trust flying it on a windy day or if there was any low level thermal activity around. It might just float out of sight!Footnote: My Crow has flown South for the Summer. I tossed up a moderate, ten foot high hand launch. The plane flew about halfway around its usual circle without losing much altitude then started climbing and straightening out as it neared the trees on the SE corner of the park. Suddenly it climbed up over the 60-70 foot redwoods, fluttered around for a bit like it might turn back towards the park but then apparently caught a thermal and was last seen a couple of hundred feet up heading into the neighborhood. Bye, bye!Good Flying Airplane! (Too Good.)
The Crow HLG Glider James Eagleson 2020-05-09 | This is a video shows the last 20 seconds of the flight of a very popular European indoor, competition grade, hand launched glider. The flight was made outdoors at a park near my house under calm wind conditions (0-2 MPH). The Crow is about 26 inches wingspan but weighs only 15 grams. It's a real "floater" that regularly turns in 20-30 second flights. I've gotten 60 second flights when there is a bit of lift around. The Crow is a slow flyer but can be gently catapult launched to 30-40 feet. I don't try to launch higher than that in this park due to glider eating trees surrounding the 300x300 ft open space. My usual hand launches (javelin-style) get the model up about 15-25 feet. (I'm not as young as I used to be!). The foam wing is most likely not strong enough for regular underhand or Discus launching, on the other hand, I believe Joshua Finn was able to do some side launches at his indoor flying location.JHAerospace.com imports kits to build The Crow. See their website if you are interested. The kit isn't hard to build but experience (and patience) with the epoxy glue required is definitely a plus. Trying to use CA glue will melt the foam wings of this plane.
Nighthawk Tornado 12in Modified to a Capacitor Plane James Eagleson 2019-11-14 | The Nighthawk Tornado ( nighthawkgliders.com ) is an excellent catapult launch glider on its own. Just for fun I decided to convert mine to a Capacitor powered plane using an 8520 electric motor with a 55mm propeller. The 8520 is a bit too fast and powerful for this size glider so I felt that I had to modify the tail from a "V" tail to a standard Vertical and Horizontal stabilizer assembly. Given the extra weight of the capacitor, switch, and motor, there is really not as much benefit to using the "V" tail to save weight. However, those of you who are more skilled with trimming models having a "V" tail might be able to still use that arrangement.My final flight after a 30 second charge went up 60-80 feet, looped around at least six times over more than one minute (I wasn't keeping track) finally ending up about 35-40 feet in a tree about 400 feet away. I ended the video with a look at that tree where I could not even find the plane when I went to retrieve it. I guess I'll have to wait until the leaves finally fall off the trees before I can try to locate it and knock it out with my telescoping, 40 foot fiberglass pole.Update: The lawn mowing crew for the park where this plane was "treed" saw my phone number on the plane and gave me a call. Apparently the brief, strong wind and rain storm we had in mid November blew the plane out of the tree and the mower operator saw it just before running it over. He called and my Tornado lives to fly again. Still works fine.
Aero Drifter Build, Flying as a Capacitor Plane James Eagleson 2019-10-15 | This video shows how I modified Bob DeShields Aero-Drifter Free Flight HLG to use a small motor powered by a Super Capacitor. The plane uses a Spruce fuselage with Foam Plate Vertical and Horizontal Stabilizers and a Sand Paper Shaped 3mm Foam board for the main wing (paper removed). The stabilizers and main wing have trim tabs to allow setting a limit on the free flight circle to match the flying space where I fly this model.I also used clear packing tape on the leading edge of the main wing as well as at the dihedral breaks and wing center to strengthen these areas.By the way, while the Aero-Drifter crashed into the tall pine tree at the end of this video, fortunately it fell through the branches and landed on the grass. An earlier version was "treed" about two months ago but when I was finally able to knock it free from the 40 foot level using a long, telescoping pole, it actually flew free of the tree and landed nicely on the grass. There was no serious damage. I should know better than to fly too high at this site if there is any wind at all. I once modified one of the $8 kids capacitor planes (Banggood) with a 1/16th inch square balsa piece glued along the EPP fuselage to stiffen it up and using sandpaper to shape the wings into more of an airfoil shape only to have it fly up and over these same trees. I watched it make nice circles as it rose higher and higher in a 5-7 MPH wind until it was just a microdot about 1/2-mile away... still circling nicely. Bye bye! Plans for DeShields original Balsa Wood Hand Launched Glider are at: aeromaniacs.com/Freeplans.htm
TYT MD UV 390 on AO85 Satellite James Eagleson 2018-08-26 | I take a look at my new TYT MD UV-390 DMR / Analog FM HT as a ham satellite receiver. During this overhead pass of AO85 I was unable to uplink enough signal to make a contact but the video shows several stations who were transmitting through the satellite. The TYT MD UV-390 can cross band repeat for satellite use but is not full duplex. I have gotten responses on AO91 and AO92 using the UV-390, however.I should mention that I have a typical urban environment with overhead power lines (upper left in video) and a power pole transformer in the corner of my back yard, plus both an ATT and a Comcast Cable TV distribution unit on the same pole. That is the likely sources for the crackly noise heard in the video. I have established that reception is better in a city park about a block from my house or even in my front yard further away from these noise sources.Update: I looked into AO85(Fox 1A) uplink problems and found that the primary issue with that satellite is poor uplink sensitivity due to a broken antenna on the bird. Those able to access AO85 run significantly more power than my 5W into a whip antenna using the TYT MD UV390 HT.
Tracking Ham Sats with MacDoppler - AO92, PicSat, AO7, LEO vs MEO James Eagleson 2018-04-03 | This video provides a look at how the MacDoppler program is used to determine location of various Amateur Radio satellites, previewing where a given satellite will be and its coverage area, and shows the difference in coverage between LEO (Low Earth Orbit) and MEO (Medium Earth Orbit) satellites.
MacDoppler Review Preview Bar James Eagleson 2018-03-12 | A look at the Review - Preview Bar function in MacDoppler Satellite Tracking Program.
FT 991 features Demonstrated during the 01 20 2018 VHF Contest James Eagleson 2018-01-26 | A 5 minute look at some 6m and 2m contacts during the Jan 2018 VHF Contest to demonstrate the latest firmware update for the original FT-991. Shows the effect of DNR (Digital Noise Reduction) and NB (Noise Blanker) on signal background noise and quality when using the two noise reduction tools on the 991. Note that 3 of these stations are in Benecia, Clovis (Fresno area), and Santa Cruz... all of which are shadowed by mountains from my location on the north-east side of San Jose, CA. I also captured a couple of stations working simplex using FM then SSB. This demonstrates the effectiveness of SSB under weak signal conditions (S1 to S3 signal levels).
FT 991 Satellite Tracking using MacDoppler 2.26 James Eagleson 2018-01-12 | A look at using the MacDoppler Satellite Tracking Program (actually v2.26) on a Mac computer to control Doppler shift tuning on my FT-991. The link to the FT-991 uses the USB port on the transceiver. Satellites observed are FO-29 (JAS 2) with its linear translator and beacon and AO-91 (Fox 1B) launched late in 2017 with a cross band FM repeater.
Quick And Dirty Azimuth, Semi-Elevation Antenna Bracket James Eagleson 2017-09-18 | I just made a quick bracket to use with a speaker tripod that I have to use with an ELK 2m/70cm Log Periodic antenna that I have for tracking Low Earth Orbit (LEO) satellites. This is a compromise but much easier on the elbow and arm compared to trying to hand hold the ELK while fiddling with an HT or two while trying to talk through one of the FM or SSB Amateur Radio Satellites.By the way, if you leave the lower bolt in place and remove the upper bolt, you can drill a few more holes using the existing hole in the PVC pipe to guide the drill bit to make a hole in the board just above the hole I show or just below it to allow you to change the angle to more than 45-degrees or down to 0-degrees. Replace the nut on the upper bolt to a wing nut so that you can easly change the angle higher or lower to allow you to better match the maximum elevation range expected from a given satellite pass.I'm certain that this method also would work well with the Arrow satellite antenna with slight modifications. It could also be used on a small TV rotor as a permanent antenna for OSCAR Satellites. I'd use a metal plate for that kind of installation, however. A typical dual band five element beam aimed at the horizon will cover the 0-10 degree elevation orbits fairly well and adding this antenna will add coverage from 10-70 degrees elevation. However there would not be any polarization control using this scheme and the PVC based ELK structure would need to be replaced with fiberglass tubing to provide sufficient ruggedness for a permanent installation.
YouKits FG 01 Antenna Analyzer Used to Test a 40m Whip Antenna James Eagleson 2017-03-27 | A quick look at my evaluation of a portable 40m Whip Antenna with wire counterpoise using a You Kits FG-01 1-72 MHz Antenna Analyzer.
SK 1A Rx and Tx Evaluation James Eagleson 2017-02-24 | A quick but more complete evaluation of the YouKits SK-1A 40m, 4-6W SSB / CW QRP Transceiver. New material starts at 3:05.I provide RX examples including overload by a S9+60dB local net control station near my QTH (about 1 mile away and up the side of a mountain by about 800 feet!).I have added a look and listen to the SSB Tx part of the SK-1A along with a sample of the Tx audio as received on my FT-991 receiver with about S8 signals from the SK-1A transmitter. Note that there was some background static and noise as would be typical for a station receiving a QRP station at any normal distance.I did a two-tone test which showed the unit to have a PEP output of about 4W PEP with IMD products at -26dB below PEP.For less than $200 this unit seems to have good frequency control and accuracy, reasonable TX audio (though it could be improved), sufficient Rx audio to drive an efficient speaker like the MFJ-281 or a Hi-Fi bookshelf speaker to good audio levels. The SK-1A uses a more than 0.5W @ 3% THD audio output IC (LM386).The Double Balanced Mixer / Oscillator is an SA-602 SOIC.The transceiver appears to use a TL592B video amplifier, presumably for Rx gain (I don't have a schematic, however, so this is just a guess). The RF output stage is an IRF510 SOIC in a TO220 package.The CPU is a PIC 16F886 and the DDS (synthesizer) is an AD-9834 which is good up to 75 MHz.
Measuring PEP Power & Occupied Bandwidth on the DSA815 TG James Eagleson 2017-01-26 | I use the Rigol DSA815-TG to measure PEP Power and Occupied Bandwidth of my Yaesu FT-991 HF Transceiver and a newly offered (Dec 2016) CW/SSB 40m QRP rig (YouKit SK-1A).If you try this at home, please be cautious. Check every part of the system before applying more than 20dBm (100mW) to the input of the 30dB Power Attenuator followed by the 10dB Protection Attenuator placed on the DSA815 input port.While up to 100W PEP can be measured using this technique, you MUST use 40dB of Attenuation between the Device being tested and the SA input port!Also note that since I don't yet have the User Guide for the SK-1A there is a possibility that I don't have the unit set up completely correctly during these tests. The 4-6W PEP level shown may be adjustable by some means that was not obvious to me and the Occupied Bandwidth shown is, of course, not really a problem for QRP operation of the unit. Also note that the Occupied BW evaluation is on 40m thus it is Lower Sideband. Thus the lower frequencies on the spectrum shown are actually the higher speech frequencies.
1296 Return Loss Test James Eagleson 2016-12-31 | I evaluate a new ultra precise 50 Ohm Reference Load on both the 046 $20 Return Loss Bridge (RLB) and the $45 Boxed RLB. The video shows the test setup and results over 1240-1340 MHz using the precision load as well as an Interdigital Bandpass Filter for the 23cm (1296 MHz) Amateur Band. I also demonstrate how the DSA815-TG can be used to expand a set of saved traces using the SPAN function, can be moved in Frequency, and can have the Markers moved after capturing and freezing all three traces.Ebay source for Calibration Kits and Loads: http://www.ebay.com/sch/geodebk/m.html?ssPageName=&_trksid=p2060353.m2749.l2654Ebay source for Boxed Return Loss Bridge:http://www.ebay.com/itm/121863951721?
Boxed RF BRIDGE Compared James Eagleson 2016-12-22 | Evaluation of Ebay Boxed 500kHz-2500 MHz RF Return Loss Bridge with comparisons to the Mini-Circuits ZFDC-20-5 Direction Coupler used as a Return Loss Bridge, a $45 Boxed RLB and the $15 046 PCB bridge that I recently purchased on Ebay.Please note that the performance shown may not fully represent the capability of these RLB's since I am not using 40dB Precision Reference loads or attenuators in this video since I do not have any available. I am using surplus Mil Spec loads however. These should provide better than 20dB return loss with most providing 25-30dB over the 0-1500 MHz frequency range of the DSA815-TG.I would recommend either of these RLBs for use below 500 MHz or so with the Boxed unit being the best performer from 500-1500 MHz.The boxed unit is available at: http://www.ebay.com/itm/121863951721The PCB 046 unit can be found at: http://www.ebay.com/itm/332052527822
$15 Ebay Return Loss Bridge James Eagleson 2016-12-17 | I evaluate a $15 RF Return Loss Bridge I purchased on Ebay and compare its performance against the $85 Directional Coupler I have previously been using for Return Loss tests. Available on Ebay:Search phrase "RF Bridge Ukraine"The video shows results for 0.1-1500 MHz as well as 144 MHz, 222 MHz, 432 MHz, and 1296 MHz Antennas.I note an error at 3:59. The annotation indicates that performance is 40dB Return Loss with a 50 Ohm load below 150 MHz. This should have been 50 MHz. This unit is still better than 35 dB Return Loss below 150 MHz, however. Some of the Return Loss error may be due to the quality of the Reference Load that I was using for these tests since its VSWR spec is only 1.2:1 or less at these frequencies. This is a Return Loss of only 21dB or so... not exactly a laboratory grade load.To search Ebay for these units use: "RF bridge 1500 MHz" to find the boxed version (various vendors)."RF Bridge 3000 MHz" to find the board version. Note: The PCB version is marked "1000 MHz" but the actual working range may be higher if truly high precision Reference and Dummy loads are placed on the REF and DUT ports as seen in the spectrum picture shown on the 64dbmcom site.
Basic AM, DSB, SSB Modulation James Eagleson 2016-10-30 | A follow on to my Basic CW, AM, FM Modulation. This video shows the Spectrum and Modulation Envelope patterns for AM, DSB (Double Sideband), and 300Hz+3kHz modulated DSB. You can find a more in depth discussion of SSB at: youtube.com/watch?v=_5kCOpcmApYEquipment used to make this video: Rigol DG4102 Waveform/Function Generator, Rigol DSA815 1.5GHz Spectrum Analyzer, Rigol DS1054Z Oscilloscope.
Basic CW AM FM Modulation Tutorial James Eagleson 2016-10-26 | This video is very basic demonstration using a Function Generator to show CW, AM, and FM Modulation in the Frequency Domain using a Spectrum Analyzer and an Oscilloscope to show these Modulations in the Time Domain. The video also shows how Modulation affects signal Bandwidth.Take aways include:1. CW (using Morse Code) has an approximate Bandwidth of 200 Hz thus is the narrowest mode normally used in radio communications. This mode typically uses On/Off keying to generate short pulses ("dots") and long pulses ("dashes") to transmit using Morse Code... though any other sequence of pulses could be used as long as the sender and receiver both agree on what those pulses mean.2. AM bandwidth is approximately equal to the highest modulating frequency applied times two (Modulation Frequency[max] x 2 ). This is about 6 kHz for normal HF (Short Wave) communications when the modulation frequencies are all below 3 kHz. Distortion may increase this to about 9 kHz in a typical transmitter.3. FM is somewhat wider than AM because it swings the carrier frequency higher and lower with modulation amplitude and often has a modulation index of more than 1. Thus FM will occupy most of the bandwidth of a 20 kHz "channel" when adjusted for a typical 5 kHz deviation.Another tutorial about CW and AM modulation can be found here: youtube.com/watch?v=3I_e7gIyfQg(Note: For purists who look at the video carefully you will note that the "200 Hz" shown in the video is actually more like 600 Hz wide since I had the Spectrum Analyzer set for a 300 Hz receive bandwidth. This, of course, adds to the apparent bandwidth of the signal as the filter sweeps across the signal.)
VHF Pass Reject Filter Pass Loss and Return Loss on the DSA815 James Eagleson 2016-08-29 | This video shows the block diagrams and equipment recommendations for tuning a single cavity VHF Pass/Reject cavity. Both Through Loss and Return Loss results are shown and you can take a screen shot of each diagram for reference.By the way, when I said -13dB Return Loss indicated "slightly less than 1.5:1VSWR", I should have said "slight over 1.5:1". The Return Loss, of course, is slightly under -14dB which is the level seen at a 1.5:1 VSWR.For a more in depth set of videos about Duplexer Tuning and other similar subjects please see some videos I've produced for Telewave which can be seen on their website at telewave.com/resources/videos
TPI-1001-B Signal Generator/Synthesizer James Eagleson 2016-05-22 | Basic evaluation of the TPI-1001-B VHF/UHF Synthesizer/Signal Generator/Scaler Network Analyzer. I will upload a few more videos showing the performance of this unit for various uses around my Ham Shack.Website: http://www.rf-consultant.com
rf Concepts 3-211 2W/100W PA Preamp Gain Evaluation James Eagleson 2016-05-02 | A quick look at making a measurement of Bypass Loss and Preamp Tuning and Gain for an rf Concepts 3-211 2W input for 100W output 222 MHz Linear Amplifier.Note: The reason I used 30dB of attenuation between the Source (Tracking Generator) and the Device Under Test (Preamp) is not only to provide a good 50 Ohm match to the cables but also to reduce the -20dBm out of the tracking generator to -60dBm into the Preamp. This keeps the preamp from getting anywhere near its compression point so that the gain curve doesn't get flattened out during the test. Example: Specified preamp gain for the rf Concepts 3-211 is 18dB. Thus with -60dBm at its input, the output will be 18dB higher at -42dBm. This is well below the likely 1dB compression point for the J308 in the second stage of the preamp which should be around 5-10dBm at its output.If we put the usual 0dBm Tracking Generator signal directly into this preamp, we would overload it by 8dB since 0dBm + 18dB gain = 18dBm at the output. Even if the TG is set to -20dBm, output from the preamp would be -2dBm which isn't really where we would like to perform this kind of test. Thus we should add at least a 10dB attenuator between the TG and the preamp and I prefer to use about 20-30dB to place the test signal to -50 to -60dBm range. This is still well above typical signal levels experienced over the air but not high enough to impact the preamp significantly.Sorry for the oversight.
FT 991 DNR Samples James Eagleson 2016-02-17 | Several Samples of use of Digital Noise Reduction and Pass Band Tuning with the FT991 on HF bands. Notes:DNR = 1 or 2 drops the background noise reasonably with very little distortion.DNR = 3 or 4 drops the background noise almost completely but it is replaced with what I call the "Babbling Brook" effect common to Digital Noise Reduction (DNR) systems.I find that between use of DNR at level 3 and dropping the RF Gain to slightly reduce the normal background noise by an S unit or so provides a good compromise setting for moderate to weak signals.DNR is generally not required for signals above S8 on the 991 and noise pumping between syllables or between stations in a net situation can as easily be controlled using the RF Gain control. I generally tune around with my DNR set to level 1 or 2.
FT 991 Menu Items 50 100 James Eagleson 2016-02-09 | FT 991 Menu Items 50-100 tutorial. Sorry for the delay but I had a busy Holiday season and some health problems which slowed me down for a bit.I note one error in my commentary. For 222 MHz the 1600kHz split is negative, not positive. Tx should be -1.6MHz.Also check below for a quick discussion of TX Microphone Equalization (Menu Items 119-136). I will have more details about this in an upcoming video.Oh, yeah. It is perfectly OK to Like these videos if you want to. I don't mind. ;-)
UT5JCW 222 1MHz XVTR Kit Part 2 James Eagleson 2015-11-23 | Part 2: UT5JCW 222.1 MHz transverter final assembly, evaluation, re-evaluation using a better heatsink. Hopefully this will help those building this DIY kit to achieve the desired results from their finished kits.
222 MHz XVTR Kit James Eagleson 2015-11-02 | A quick look at the Ukrainian DIY 222MHz transverter kit from Serge, UT5JCW. I purchased it on Ebay. I also show how I mounted the boards into the case supplied. This is Part 1. Part 2 will be uploaded when I finish the unit and will show test results and, hopefully, some on the air contacts with the Monday night 222.100 MHz SSB group active here in the Northern California area. Expect Part 2 in a week or so.By the way, this unit uses a 28 MHz IF thus will only cover 222.0-223.700 MHz with HF transceivers that aren't able to transmit above 29.700 MHz. This does, however, allow use of the unit on both 222.100 plus or minus for SSB use and 223.500 MHz for FM Simplex. By using the Tx/Rx VFO A/VFO B function of many modern transceivers, you also should be able to use repeaters that have inputs up to 223.690 MHZ (29.690 MHz) as well. Since most receivers in HF transceivers actually tune to 30 MHz you can listen to 224 MHz or possibly even higher (my FT991 tunes up to 32.999 MHz, for example).More later...
FT991 Setup Items 30 50 James Eagleson 2015-10-03 | This video demonstrates Menu Setup items 30-50 on the FT-991. Comments, questions, corrections are welcome.
FT991 MENU Setup: Items 1 through 30 James Eagleson 2015-09-12 | I cover Items 1 through 30 in the Setup MENU portion of the FT-991 in this video. This includes such things as Fast, Mid, and Slow AGC time settings, "My Call" Indication display time, Main Screen Display Color settings, LED and TFT Display brightness adjustments, Peak Hold time for the S Meter and Po, SWR, and other meter functions, Noise Blanker adjustments (width, Rejection, Threshold), Touch Screen Audio Beep level, Time, GPS / RS232C settings, and 232 Time Out settings.I will upload items 31-60 in the Setup MENU shortly until all settings have been covered, at least as far as I have been able to determine. Yaesu's manual is somewhat 'terse' in describing these functions in their User Manual and leaves some of the Abbreviations used for the user to figure out.Please hold off any questions until all four videos (or so) have been uploaded but I would be glad to hear any inputs concerning things that other users of the FT991 have figured out.By the way, a good video about manual memory management for the FT-991 can be found atyoutube.com/watch?v=bdQTYmwWaWI&ab_channel=MLandSshopA quick example of Analog FM vs C4FM (DN mode) can be found atyoutu.be/mwfknb0VCM4
FT991 FM C4FM Occupied BW James Eagleson 2015-09-08 | A quick look at standard Narrowband FM (12.5 kHz as currently defined), narrow Narrowband FM (9 kHz as implemented in the FT991), and C4FM 'digital' voice.
MFJ 916B Duplexer James Eagleson 2015-03-13 | My IC-706 has both 2m and 70cm coming from the same output port. In order to use two antennas, one for 2m and one for 70cm, I purchased an MFJ-916B Duplexer to allow me to use only one feed line for both long yagi antennas. This video shows the 916's performance and modifications that I made to allow use of this indoor unit mounted outdoors on the mast. Since I live in California I may be able to get away with this though I'm not sure I'd recommend using the sealing technique that I used in parts of the country with more severe weather. MFJ also offers the MFJ-916BM for mast mounting which comes in a weatherized box which is recommended for more typical weather locations.I also noted that the unit that I purchased doesn't really cover the 222-225 MHz Amateur Radio Band very well. It has about 3dB of through loss on that band. I played around with the coils a bit to see if I could correct for the 3dB rolloff but saw no improvement. Possibly there is a capacitor tolerance issue with my particular unit since I see that disc ceramic capacitors are used in the 916B. I'm assuming that ceramic disc caps are used for their higher voltage rating compared to cheaper surface mount caps. The 916B is rated for use up to 100W and my IC706MKIIG only puts out 50W on 2m and 30W on 70cm.For more information on Antenna Duplexer/Diplexer designs check out W2AEW's video at: http://www.youtube.com/watch?v=wv79DSqVi9w&spfreload=10
2m 70cm Diamond X 30 Base Antenna James Eagleson 2014-10-23 | I received a 'freebie' Diamond X-30 2m 70cm Base Station omnidirectional vertical antenna from a local ham. This is Part 1 of my evaluation of this antenna where I check Return Loss on both bands. Part 2 will follow when I get some time to set up a field test for looking at the actual gain over a reference dipole when it is mounted on the top of a mast as well its pattern at 2m and 70cm when it is when mounted on the side of a mast (or tower leg) at various spacings. Whether we use a dipole array or a collinear antenna, a side mounted antenna will have a pattern that will be affected by the spacing between the antenna and tower leg or mast upon which it is mounted.
MFJ 2702 DC 1GHz Ant Switch James Eagleson 2014-10-21 | A quick evaluation of the MFJ-1702 UHF connector two position RF Antenna switch. I look at the through loss, port-to-port isolation, and return loss of this $35 switch over its specified 0-1GHz range. The 2702 uses UHF connectors thus is really best used below 450MHz but a 2702N version is available for use on frequencies up to 3GHz.You can compare the present results with my earlier video about Return Loss of UHF vs BNC vs N connectors elsewhere in this playlist. Also check WIKI for similar information about UHF connectors. They have a very good description of the issues of PL-259 style connectors at what we now call UHF frequencies, which is 300 MHz and up. While the manufacturer of this switch has made an effort to use a good connector design, UHF connectors used on cables, the antenna, radio and adapters in my test setup will still have Return Loss issues due to the impedance variations inherent in these connectors. Thus my recommendation not to use UHF connectors above 250 MHz or so.One final note about the switch: Make sure you move the switch knob fully to the left or right. It can be placed into a partially connected condition if you don't do this. You may have noticed this partially connected condition briefly during my receiving demo section (S3 initially seen instead of S9+60dB while switching to the port to receive the sample signal).(P.S. I noticed upon reviewing this video that I really shouldn't do my morning gardening chores just before making a video. Thus you will note some dirt on my hands. Call it multitasking.)
Repurposed 2M Yagi - 2M9JNN James Eagleson 2014-09-26 | This video shows how I took various pieces from old VHF antennas to make a 2M9JNN antenna that Mike, K6MYC, designed for me using Antenna Optimizer to meet gain, size, and pattern goals that I need in my urban location.I hope to upload a future video showing the design goals, AO and Cocoa NEC evaluations that Mike and I did when we found the original design to be at 143 MHz instead of 144 MHz. Essentially I didn't sufficiently clarify that I was using insulated elements on top of the boom rather than UN-insulated elements mounted directly to the boom, which is what Mike used for the original element lengths.Once the antenna was mounted on my roof with 50 feet of Belden 9913 coax plus about an 8 foot section of RG8x to get around the antenna rotor, Return Loss proved to be better than 20dB or about 1.2:1 VSWR.
G5RV jr Mod for 75m Operation James Eagleson 2014-06-09 | Modifications to a G6RV jr antenna to allow 80m operations. I used my Rigol DSA815-TG with a Mini-Circuits ZFDC-20-5 Directional Coupler to evaluate the antenna resonances and find the best matching points when using an MFJ-945E Antenna Tuner.Comments:The tuner matches the radio to the antenna system which includes all connection cables, ground returns, the MFJ-945E unit itself, coaxial cable feed line, coaxial cable current choke (multiple loops of coax), twin lead matching section, and dipole elements.One misspelling I caught: Bypased should be Bypassed on the last three slides.Doing the original tuning evaluation using the spectrum analyzer, tracking generator and directional coupler allows a very low power method of checking tuning as well as determining how critical the tuning is for several different settings of the Ind, TX, and Ant tuning elements of the antenna tuner unit.
Reference Dipole Relative Gain and Pattern James Eagleson 2014-03-01 | I got a few hours of sunshine between rain storms here in CA (rain is good) and took a few Dipole and OmniAngle antenna patterns in my back yard. This video shows the method I used and the results I obtained.Some notes:When I suggested that 15 feet was about 4 wavelengths what I should have said was about 4.6 meters. (15 feet / 3.28 feet/meter = 4.57 meters.) As noted in the video this is about 2.3 wavelengths since the 2m band wavelength is 2 meters. (4.57 meters / 2m = 2.28 wavelengths.)When I discussed moving the test antenna (OmniAngle) up and down on the mast this will not change the distance between it and the reference antenna much but will change the phase of any ground or obstacle reflections significantly. If there are no reflections the effect of changing the height will make much less change in signal level. I changed the height about 18 inches which is about 1/4-wavelength which should change the phase between direct and reflected signals quite a bit depending on the relative strength of the relection compared to the direct signal.I will reinforce my comment about antenna gains at this point. The 1dB point (or 3dB point) of any two antennas will depend on both antennas unless one of them is much more broadband than the other. Thus I estimate that the two, more or less identical dipoles will have similar frequency response so that 1dB points are really indicative of 1/2dB per antenna. Thus the true 1dB points would be where the two antennas show 2dB down.However, if the reference dipole is used centered up on a narrower test frequency such as I did in the evaluation of the narrowband OmniAngle antenna, the dipole's loss will be flat over the entire frequency range since its 1dB points fall well outside of the frequencies being evaluated.Please note that Aluminum siding or Stucco house walls are essentially reflectors since both have large metal surfaces. Stucco is generally applied to a chicken wire mesh or, in some cases, metal lath. Also be aware that many houses these days are have metal, not wooden frames in their walls. And don't forget that many garden or patio walls and cement driveways, especially here CA earthquake country, will have Rebar or metal mesh reinforcement.
Reference Antenna - Part 2a Dipole Modification James Eagleson 2014-02-12 | Due to rain I did something that I could do indoors. I modified my recently finished reference dipole to allow it to tune up to 450 MHz instead of the 440MHz that I had measured in my earlier video.Essentially, I found almost 1/2-inch that I could use to shorten the antenna to raise its upper end frequency.This video shows what I did and shows the results that I obtained.
DSA815 on Battery Power James Eagleson 2013-12-29 | A quick look at the CyberPower 1000PFCLCD UPS used for uninterruptible power or to allow use of the Rigol DSA815-TG (and other equipment) at a field site (portable). The unit tested is the one recommended by RigolNA for use with their Spectrum Analyzer. It has low EMI and converts to a regulated 120VAC Sine Wave.With the DSA815-TG alone I found that the time available from a full charge to the point where the unit alarms to indicate that cessation of operation is imminent was about 80 minutes. With the DSA815-TG, DG4102(Arb Gen), and the Owon DS7102 O'Scope the unit provides about 39 minutes battery operation before these units should be switched off or AC power restored.This video shows the LED display functions available with the unit but does not cover the ability to use it with a computer using windows since I am using a Mac.Update: I corresponded with Cyber Power about whether one could use one of their DC to AC Inverters in place of the CP1000FCLCD. Essentially the CP1000 produces an actual Sine Wave ("adaptive sine wave") while the Inverters produce only a "simulated sine wave". Since I don't know how 'clean' the AC power to the DSA815 or other equipment needs to be, I'll stick with the CP1000.The CP1000 battery can be replaced with a spare, previously charged CyberPower RB1290 battery (12V 9AH) to extend the battery powered time to 160-180 minutes when used with the DSA815 alone. It is likely that any field work I would use this for can be done using my laptop or tablet computer on its own internal battery and my Owon DS7102V also has a battery built in that should last long enough for most tests. The RB1290 battery is available on Amazon for about $35 and some less expensive versions also seem to be available. However, I'd stick to the CyberPower battery to ensure that the CP1000 charging and battery monitoring circuits work correctly.
UHF BNC N Connector Return Loss Compared James Eagleson 2013-12-12 | Just a quick look at BNC-UHF, BNC-BNC, and BNC-N Adapter Return Loss at HF, VHF, and UHF to determine their suitability for use at Ham frequencies up to 1300 MHz.Summary: 'UHF' connectors should be used below 150 MHz. BNC and N connectors are shown to be good up to the 1500 MHz limit of my Rigol DSA185-TG. By similarity we can assume that TNC, essentially a threaded version of a BNC, will have similar performance since it is still part of the 'NC' family of connectors.Those paying close attention to the traces will notice why BNC connectors, though otherwise good at these frequencies, should probably only be used for test setups where quick connect/disconnect is required. During the video you will note that when i dropped the BNC connectors on the desk (3:16) and while I was handling the BNC adapter stack up (3:56) there was some obvious contact problems generating a spike in one case and contact noise in the other. That is why TNC connectors are used as a smaller diameter alternative to Type-N connectors in mobile applications instead of BNC connectors.Comments and questions welcome.
