I just purchased an Icom Transceiver and was also told that I'd need an antenna tuner to get it to work well with a longwire for shortwave. So I also purchased a MFJ 941D Versatuner today. I only plan to use the IC-R745 as a receiver. My only available antennas at this time are all longwire type. So my question is how do I hook the radio and the tuner up the correct way? There is a connector on the back of the MFJ marked "wire" so my antenna must hook up there. I'll wait for an answer, it must be very simple but I want to connected them together properly. Many thanks!
Longwire Antenna Setup with MFJ 941D
- Thread starter SatHunter
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A manual tuner will be a hassle to use and I would recommend a 9:1 balun at the end of the antenna outdoors then run coax from that to the radio. You can sort of diddle the controls on the tuner to peak receive but you will seldom if ever get a better signal to noise ratio doing that. Instead you will increase signal and noise together and if the tuner is indoors next to your radio the antenna wire will also have to be inside and that invites noise and RFI from electronics inside the house.
ka3jjz
Wiki Admin Emeritus
It would be a lot more helpful if we knew the exact model of the Icom you got, and also about the 'longwire type of antennas'. That term is very sadly misused and misunderstood. I suspect you really mean some random wires (of no particular length)...a transmatch may help if the antenna is too short for the frequency you are trying to hear, but if you have some size to these wires (say 80-100 foot or so), you will probably not notice much improvement with the tuner, as prcguy suggests.
There are many different types of wire antennas, and some are more specialized in terms of frequencies they cover or the direction they favor. There are numerous books by the American Radio Relay League, and it's UK sister, the Radio Society of Great Britain, that can teach you about this. Antennas are both a science and an art; you have to put some effort in to learn what works best in your environment
Mike
There are many different types of wire antennas, and some are more specialized in terms of frequencies they cover or the direction they favor. There are numerous books by the American Radio Relay League, and it's UK sister, the Radio Society of Great Britain, that can teach you about this. Antennas are both a science and an art; you have to put some effort in to learn what works best in your environment
Mike
Thanks to both of you for taking the time to reply. As I thought this dinosaur of a tuner would be a waste of time so I ordered a nooelec 9:1 balun v2 this morning and will follow your installation instructions. As far as the transceiver it is an Icom 745.
It have 2 wire antennas: one is 75' long and the second one is approximately 55'. My favorite band is 20m. I get really good reception on my Yaesu FRG-8800 with the shorter antenna. Looking forward to adding the balun to see how it might improve my reception.
It have 2 wire antennas: one is 75' long and the second one is approximately 55'. My favorite band is 20m. I get really good reception on my Yaesu FRG-8800 with the shorter antenna. Looking forward to adding the balun to see how it might improve my reception.
KB2GOM
Active Member
Grounding the balun might help as well. I have a similar setup to you. Check this; it might prove useful.
Jock gets a good grounding!
Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post: Getting grounded – at last! By Jock Elliott, KB2GOM Readers’ comments are among the best things about writ…
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W0JOG
Member
You guys sure enjoy spending money, don't you? The long wire, properly grounded, and with ANY tuner designed for it (read the owner's manual?) will perform about as well as any other. As I have written, I have MFJ's differential-T tuner, properly grounded, and it will tune anywhere from DC to light, should i want it to. I just want it to match the radio to the resonance I ask of it. It ain't rocket science. But you'll save asking a lot of questions and wondering about a lot about radio if you'd read Two Hundred Meters and Down, by Clinton DeSoto and see who figured all this stuff out in the first place and what they learned. Available from the American Radio League, and I'm sure, others.
Read it.
73 de W0JOG
Read it.
73 de W0JOG
Sure it will perform for transmitting as well as many other end fed wire antennas, but having the wire run into the home to the radio and tuner brings in man made noise that you can't get rid of. Not to mention the hassles of bringing in a hot antenna wire through a window or wall.
Leaving all the wire outside and terminating with a 9:1 balun feeding coax to the radio is a classic SW/HF receive antenna that works great and avoids house born RFI in most cases. Had the OP not purchased the tuner and got a 9:1 balun or made one from scratch would have saved considerable $$ if that is the intent of your post.
Leaving all the wire outside and terminating with a 9:1 balun feeding coax to the radio is a classic SW/HF receive antenna that works great and avoids house born RFI in most cases. Had the OP not purchased the tuner and got a 9:1 balun or made one from scratch would have saved considerable $$ if that is the intent of your post.
Thanks for pointing this out - it is a great article! A couple of questions - does the ground rod have to be copper? Does it matter which side of the 9:1 balun you connect the antenna to and the ground to? I bought V2 in a case and the 2 terminals aren't marked.Grounding the balun might help as well. I have a similar setup to you. Check this; it might prove useful.
Jock gets a good grounding!
Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post: Getting grounded – at last! By Jock Elliott, KB2GOM Readers’ comments are among the best things about writ…swling.com
KB2GOM
Active Member
I don't think the ground rod has to be copper, but it certainly does have to be conductive. As to the terminals, it probably does matter, but if you can't tell which is which, run the experiment: try it one way, then switch, and see if you notice a difference. That's what I would do . . . in my very non-expert way.
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That is excellent advice - thank you! I can't wait to try it out. Tonight will be without a ground but I'll get a decent one set up tomorrow. This will be the first time trying my system with a balun. No one sells SMA cables, adapters or connectors here so it's Amazon to the rescue to get this show on the road...
You have to be very careful about adding ground rods, NEC requires any additional ground rods be bonded to the house main ground with no less than 6ga copper wire. This is because of different ground potentials around your property and if the new ground rod is closer to your neighbors house than your existing ground rod and your neighbors house is of a different feeder from the power pole, you could be in for a shock.
I ran across this problem as a teenager living with my parents in Colorado where my bedroom was on the opposite side of the house from the electrical panel. I drove a ground rod outside my window to ground my CB and SW antenna. Turns out this new ground rod was about 30ft from my neighbors electrical panel and I had about 90 volts AC between my CB antenna ground and my own house ground. If I grabbed any cable attached to my antenna and touched a radio that had a third prong ground plug, it would shock the heck out of me. I got visited by the FCC once and the field engineer got a serious shock disconnecting the antenna from my radio during the inspection, but that's a story for another day.
Problem with bonding a new ground rod to the existing ground is it could bring in all kinds of noise from stuff in the house as that ground is common to your computers and other high RFI making devices. You also have to realize HF or SW reception is driven by signal to noise ratio and not just raw signal level. You should experiment by grounding and ungrounding the antenna to see if just the signal is increasing or if the signal and noise are increasing by the same amount when you ground the antenna. If just the signal increases and the noise stays the same, congratulations, you have a very rare type of improvement. Most of the time the signal and noise increase together and do not improve signal to noise ratio, meaning there is no actual improvement.
I ran across this problem as a teenager living with my parents in Colorado where my bedroom was on the opposite side of the house from the electrical panel. I drove a ground rod outside my window to ground my CB and SW antenna. Turns out this new ground rod was about 30ft from my neighbors electrical panel and I had about 90 volts AC between my CB antenna ground and my own house ground. If I grabbed any cable attached to my antenna and touched a radio that had a third prong ground plug, it would shock the heck out of me. I got visited by the FCC once and the field engineer got a serious shock disconnecting the antenna from my radio during the inspection, but that's a story for another day.
Problem with bonding a new ground rod to the existing ground is it could bring in all kinds of noise from stuff in the house as that ground is common to your computers and other high RFI making devices. You also have to realize HF or SW reception is driven by signal to noise ratio and not just raw signal level. You should experiment by grounding and ungrounding the antenna to see if just the signal is increasing or if the signal and noise are increasing by the same amount when you ground the antenna. If just the signal increases and the noise stays the same, congratulations, you have a very rare type of improvement. Most of the time the signal and noise increase together and do not improve signal to noise ratio, meaning there is no actual improvement.
KB2GOM
Active Member
Two thumbs up on signal-to-noise! The point is to improve what you can hear, NOT simply how much the signal strength changes. In fact, I've had situations where the signal strength -- as measured on the meter -- dropped, but the intelligibility of what I could hear increased.
In fact, if you are listening to a single sideband signal, sometimes reducing the RF gain (if you have that control on your radio) drops the noise floor so you can hear more of the signal.
You can achieve something of the same effect if you have an attenuator on your radio.
jhooten
Member
Hang me as a heretic but for receive only you do NOT need a tuner to be able to receive with a long wire.
KB2GOM
Active Member
True. A preselector, however, may help receive in certain circumstances.
Indeed you were right! The manual tuner brings in a ton of noise, the same effect that I get with my Yaesu active indoor antenna. Plus the MFJ controls appear to be dirty or badly worn causing a lot of static when changing inductance or using the fine tuning knob. I FINALLY got my 9:1 balun yesterday and set it up last night. I first tried it on my SDR setup - what a world of difference! I look forward to trying it on some of my radios today. I'm not sure how to connect it to my portables. Most only have a whip antenna but a couple of my Tecsuns have a phono plug antenna jack
How true you are! The seller was very emphatic that the transceiver would be a dead duck without the manual tuner but the truth is after experimenting over the past week all the tuner did was bring in a lot of extra noise. The s-meter went up while flipping through the settings but it was due to horrible interference (buzzing and a loud hum). I thought my power supply was part of the problem so I disconnected it and connected the Icom to a car battery. The noise was still there! So my power supply is fine but the tuner is only good for one thing - generating terrible noises that you can only get rid of by disconnecting it. Now the radio does much better on its own! Can't wait to get some PL259 to SMA adapters so I can try my various antennas with the 9:1 balun.
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