I really appreciate this video. Since getting my SDR I've been looking for an explanation of the nuts and bolts of making a multi-band antenna for receive only.
Awesome video. Counter poise for those who live in high rise is a great tip. I was always not sure how to make it work on the 18th floor where the antenna wire is mounted!
@2ndPeterVBlack You and me Bro, we're on the same page of the beginners book. My electronics experience doesn't apply to antenna theory (or reality). 👍
This answered a lot of questions I had, thank you! A couple quick questions I still have, as silly as they may sound: 1) When you're cutting those CAT wires to length, do the "dead" ends interfere with the signal (i.e. should you slide them out of the insulation?) 2) What's the difference between grounding to a rod stuck in the earth vs. the ground in a grounded outlet? (I live on the 2nd floor in an HOA + I've also never seen anyone suggest using the ground in an outlet, so there must be a good reason.) 3) When you say "just one wire," referring to the "hot" wire in the core of the run, is this connected to all of the different lengths of CAT wire in the antenna at the same time, or do you have to change the length of the connection based on what frequency you're trying to receive? Thanks for walking through this setup!
Part of the issue with poor reception in the 10, 6, 2, etc meters and is your antenna is in a horizontal alignment. The majority or transmitting antennas in the frequency range are from vertical antenna. A separate wire antenna cut to the higher frequency lengths mounted vertically such improve reception on those bands. Actual shortwave bands 15 meters and above transmit from horizontally oriented antennas. Hope that makes sense.
You can make a 1/4 wave vertical antenna for 2 and 6 meters out of just your coax ..... For 6M just measure 5 feet from the end and peel off the outer jacket then take the braid and push it down over the outer jacket so you end up with a 5 foot section of braid and a 5 foot center conductor .... 2 meters is even easier since it's less than 2 feet long but at that length it's about as easy to build a traditional vertical with a 4 wire ground plane on a SO239 female 4 hole panel connector
A switch is not needed, just connect both band lengths to the coax centre and it's then basically a fan dipole. you can make it for as many bands as you want then. Also, getting your counterpoise out straight in open space WILL improve receive vastly.
Hi Kinda new sdr receiver but using a amplifier is pretty much a must ,l found this out by using the supplied rabbit ear type antennas that come with this dongle, just for kicks I hooked up a amplified channel master beam antenna and quadrupled the reception on am-fm and weather radio frequency , naturally a tv antenna is not to good for short wave or side band so if you can get this to work it’s cheaper than buying a $ 150.00 dipole . With these you don’t need a big costly receiver .
Am I the only one that noticed? 80 Meters is 262.5 feet, not 281with a quarter wave of 65.6. 40 Metets is 131.25 feet not 141 with a quarter of 32.8 feet. The 30 meter measurement is correct. But the 20 is also wrong. Hope this helps someone who is cutting wires to exact lengths or do your own conversions.
Getting 5 Difrent Conversations In One Frequency IS NOT GOOD, Im getting The Same Problem, But I Change The Antenna Settings, I Mix Mach The ANtennas AUntill I Get The reception I Need Or Want, Sometimes I Don`t Get What I Want , But Thats Why Radio And Antenna Things Are Always Interesting Because To get Best Results You Need To Think Outside Of The Box All The Time And Inovate On The Spot. Love The Content
if i wanted to put this in a vehicle, can i ground to the chassis or will that cause problems? if i do a counter poise, will i get RFI off the vehicle? does the antenna have to be straight or can i make deliberate bends to follow the contour of the vehicle?
Nice idea!!! I guess you remove the LNA when you are trying to listen to HF as the LNA you are using is rated 45 MHz - 4 GHz. I just use a single random wire for HF, which is about 25 feet. I pick up 80M, 40M, 20M, and 10M just fine. I don't use an LNA and I use the AC outlet plate center screw as my ground (green wire), as it ultimately connects to a grounding rod outside. If you do this be careful to secure and tape this connection so that is can NEVER touch the blades of plugged in wires (fire hazard). Also be careful how you use the 9 to 1 Balum because if you hook it up when it is not needed, you can loose half your signal. Thanks for your interesting video!!!!
I think it's an SMA connector. At least my RTL-SDR uses a male SMA connector.It looks to me like both the LNA and the SDR have male SMA connectors, and that he is using a female to female connector to bridge between the two.
So essentially making a fan dipole out of a multy strand wire if I am following here. Do you pull the remaining wire out of the shielding (the part not connected to the feed end hookup?) I don't get how that would not become a parasidic antenna to effect your bandwidth...
Confused on some points. 1. If I understand correctly your antenna is basically installed horizontally on the roof, correct me if wrong. 2. Let me know if this is right, It would seem as though you are running a piece of 50 ohm coax straight from equipment antenna input out through your window over to your ground rod. You are opening up your coax at that point to tie the shield of coax to the ground rod while leaving center conductor alone. Then continue coax up to roof antenna start point at one end of house. At that point you separate the coax into center and shield/ground. The shield is left alone while the center conductor ties into your multi antenna common point. From here is where I think your description is very unclear. You mention the full length of all conductors is whatever is the longest wire calculation is. Now from the common initial feed point you go out to the dimension of your second longest calculation and cut open the outer insulator to make the necessary cut on wire 2. Ok, you've made that cut but what about the rest of that same wire that you just cut? Do you pull the "unused" sections of wire out the back end or are you leaving it. Repeat question for each band. It would seem leavening the "unused" section which now lies in parallel and in close proximity might effect antenna performance.
Not an expert here by any means. I'm having a hard time wondering why you would run a ground wire to a grounding rod. Wouldn't running a grounding wire to your computer case work just the same? I mean it is grounded by the electrical outlet which goes to a grounding rod anyway. Even the RTL-SDR is connected to your computer which I would think would be grounded as well connected to the usb port. Like I said, I'm not an expert in electronics and I am not arguing. I'm just fully ignorant on this and am genuinely curious. I am new to this hobby as well. Love the video by the way. Lots of good info here.
Not necessarily, I mean it be better than nothing, but the number one issue is one if the house is wired correctly to begin with, the only other issue is induced noise. Do to all the Switch mode power supplies each operating at there set frequency. I’m pretty sure home grounds could induce some noise in the front end. I’m not 100% certain on that but yea. Next is good grounding. vs poor. The ground is a apart of the circuit, and it’s not just any type of circuit it’s an RF circuit. I’m still an amateur with RF circuits believe me my friend it’s complex like DC circuit that doesn’t involve high frequency switching easy, get into RF circuits, especially tuned RF circuits, you’ve got to pay close attention to your components tolerances, and under stand how heat,cold, and even other stuff like stray capacitance, inductance, parasitic oscillation, not sure if (parasitic capacitance is the same as stray) your question isn’t ignorant at all my friend! You just had a question that well in detail is complex to answer!
Sometimes I wonder... You have your dream computer Ryzen 9 with 32gb of DDR4 safe and sound in your house.. But you plug a SDR on it with a XXX meters wire outside and one night you forget about it and there is a lightning storm.. It sounds like a perfect recipe to get a deep fried Ryzen 9 with a side of DDR4.
@@HamBandit yes but if there is water in the lines, there is a ground point at every valve. There are hundreds of Ground points going all the way to the tower.
@@HamBandit ...As long as there is water in the system there will be ground points at every main valve and fire plug for miles. I have used it for electronic trouble trouble-shooting when commercial ground or transformer ground was suspect... A Great work around and zero noise.
As someone who designed and built conductivity measuring equipment for the oil patch I measured a -lot- of liquids for conductivity (the reciprocal of resistivity) including tap water. It can vary from almost distilled water to not very good ( about 200 ohm - meter). Unless you have salt water in your pipes. Several years ago a friend came over seeking advice about short wave antennas. I supplied him with wire, coax, BNC connectors, a wall mount lightning arrester with 6 AWG wire, and lots of hand waving advice. The next time I was over to his house I checked his installation. Everything looked very good, except that he had clamped his ground to the water outlet just below his arrestor. I had emphasized that a good ground was not negotiable and was very leery about how good it was. He insisted that he had read a lot about grounds and that it was good. OK. About a month latter we had a thunderstorm. He called and asked me to come over. He sheepishly lead me to the back of his house where about 3 feet of siding was blown out. Lightning had taken the path of least resistance to an inside wall plug. There was about 6 inches of wire was still connected to the pipe. What happened? All the pipes were PEX. He lost his receiver, a PC and a television, all running off the same circuit.
1. Your list of .25 wave. Are all of the ends touching at the coax you run to the roofline? You said to bust the list into 2 groups and make 2 runs. Trying to understand the connection. Thought maybe your box was a selector for EACH wire length. 2. Why did you need a selector box on your grounding rod at all?
no switches involved. Simply cut the wires to length. tie them all together at the end. include a small balun if you like. amazon has small baluns 1:9 for coax connection. the box you see is a pass through connection introducing ground to the shield of the coax to help with Noise. no switches involved
@@HamBandit thanks. I plan on doing this today actually. I know it needs to be a straight line but my roofline might not be a full 36 to the peak. Up to the peak and down the other side is enough but that's with the 30deg angle. Thoughts on that?
@@IntoTheWild70 you can bend the wire no more than 90 degrees so feel free to turn the wire just don't let the wire come back on its self thats bad.no more than 90 degrees on the bends. You should get lots more signals. Just after dark is best time to get peak signals. Good luck.
@@HamBandit Help my roofline sucks. Lol. Built cable but don't have a good place. Here are my options. 1. Has a tin roof 1/2 of the distance. 2. Will be near the power line into the house. 3. Will be on ground 4. Might have to go vertical on a pole of sorts. Thought of pvc with wire in middle
@@IntoTheWild70 thats a bad situation to worse. You would be better off with a magloop antenna. Your metal roof will react bad to the wire and the power line will give you noise. Try vertical if you can but watch my video on chokes it will help with the noise if you do go vertical with the wire. If your up for a newer idea watch my magloop videos and see if that be a better direction for you to try. Hope that helps you .
