HFU HF Underground
Technical Topics => Equipment => Topic started by: Looking-Glass on July 19, 2018, 0502 UTC
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Been looking at a few You Tube pics of NDB DXing and note that many have the MFJ tuner coupled to the long wire antenna.
MFJ have a good reputation for a quality product so would be interested in finding out from anyone into NDB's and running a filtering system what is the best MFJ product you have found for the NDB band?
I already run a home brew filter for MW spurs and crud (cut off around 530KHz) but still get a high amount of noise on the band.
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MFJ have a good reputation for a quality product
Thanks. Now I have to wipe the soda off my monitor. :P
FWIW, I built this filter: http://www.radiohobbyist.org/blog/?p=1894
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MFJ has a long standing reputation as mighty fine junk...or worse.
Heh, hope you can salvage that monitor...
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MFJ seems to make decent tuners, SWR/power meters, antenna switches and other misc. radio-related accessories. I've used and I do use several MFJ products (read: tuners and SWR/power meters) and they work exactly as they should for ham radio purposes. Are there better meters and tuners out there? Absolutely. Can't comment on their filters although I've read some good reviews (see: eham.net, etc.) on the various SWL/HF ham radio noise filtering systems they sell.
Some of their other stuff seems suspect. I had one of their "apartment antennas" with the big loading coil and wanderer lead, the thing had a bad solder joint and the wanderer lead broke off after only a few frequency changes. I also used to own a MFJ-9406 6-meter SSB transceiver...that was junk too. Overpriced junk at that. Their mobile VHF/UHF antennas are okay, but there are certainly better options out there for that sort of thing.
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I never used a mfj sw tuner thingy but have the Grove TUN3 and it works amazingly well on mw and lower. A good one will have a decent q so as to increase the energy extracted from the antenna and at the same time reduce the energy from off channel signals.
Here's some home brew examples;
http://www.bobsamerica.com/swl.html
scroll down to the preselectors section
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Have several MFJ boxes here that are used for NDB DX. Have had good luck with the 722B Optimizer Filter as well as the 1020C Active Antenna used as a preselector.
Also have the 1026 Noise Cancelling unit but had to modify it to cover LW. Have had some good results with the 956 Tuner, helps cut down some of the spurs.
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Wow, such a variety of responses, sorry about the monitor there Chris, soft cloth and window cleaner should rectify the expulsion of soda!
Main problem I have is getting rid of power line noise, I had a huge problem with MW crud, harmonics and spurs but the homebrew filter fixed that now to try and eradicate, or simply reduce the power line noise, which is all over HF as well as the NDB band.
I had an MFJ-941B ATU until well over 30 years ago and was impressed with it and I kept it for 20 years before giving to a friend, so thought I would give them another go.
Both the MFJ-1025 and MFJ-1026 Noise Cancelling Signal Receiver seem to rate very well with the majority of DXers into NDB DXing on the low band, watched a few You Tube clips from around the world on it.
R4002, didn't know they made a 50MHz transceiver. Will spend some more time on research before a decision is made.
Thanks to Josh for the link re: Grove TUN3, will check it out on my weekend off, thanks fellows... :D
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There is no one magic box that will fix all the noise issues on LW freqs.
If power line noise is your biggest problem, first make sure that the source is not from some device(s)
on your own property. Better to quench it at the source than with some add-on box at your receiver.
If you decide to give the MFJ 1026 a try, it will have to be modified to work on the NDB band...
plenty of info on the internet on how to fix it.
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Wow, such a variety of responses, sorry about the monitor there Chris, soft cloth and window cleaner should rectify the expulsion of soda!
Main problem I have is getting rid of power line noise, I had a huge problem with MW crud, harmonics and spurs but the homebrew filter fixed that now to try and eradicate, or simply reduce the power line noise, which is all over HF as well as the NDB band.
I had an MFJ-941B ATU until well over 30 years ago and was impressed with it and I kept it for 20 years before giving to a friend, so thought I would give them another go.
Both the MFJ-1025 and MFJ-1026 Noise Cancelling Signal Receiver seem to rate very well with the majority of DXers into NDB DXing on the low band, watched a few You Tube clips from around the world on it.
R4002, didn't know they made a 50MHz transceiver. Will spend some more time on research before a decision is made.
Thanks to Josh for the link re: Grove TUN3, will check it out on my weekend off, thanks fellows... :D
I have a Turner T-1000 (same thing as a MFJ-949E "Versa Tuner", made by MFJ in the same factory as far as I can tell...) and it's a high quality piece of equipment. The MFJ-9406 6-meter SSB radio only covered 50.000 to 50.300 MHz (on the analog dial anyway, real coverage was something like 49.950 to 50.325 MHz). I bought it when I was first getting into ham radio and really didn't know what I was doing. Made some DX contacts on it but for the price (I want to say I spent $275 on it) I could have saved up a little more money and bought a proper used 100 watt HF/50 MHz transceiver instead of a little 10 watt radio that only did SSB/CW. They make (or made) versions of that radio in other bands too, I want to say 75 meter, 40 meter, 20 meter, 15 and 10 meter versions exist. They're basically little QRP rigs and apparently are better suited for backpacking HF or field communications. But I'm getting way off topic here :D The MFJ-9406 I had wasn't really a great performer and, being on 6 meters, produced enough TVI to get myself noticed even though I was operating within band legally and at low power.
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Pinto Vortando: Done the source issue some time back, the noise is from the overhead wires passing the house, I once turned off everything in the house and pulled the plugs out of the walls and it's still there.
Electricity supplier came and replaced two cracked insulators on the main power pole (after I complained) near here which did reduce the noise from 25dB over nine down to just eight to nine on the radio meter.
Not coming from my neighbour to the left as the house is empty and power is off at the mains box, house has been empty for months. Neighbour on other side is not the source as we went through elimination of items running early year.
I noticed when wind speed is above 60KMh the noise breaks up and often the 'S' meter drops to a five then suddenly goes back up to 8 or nine on the meter. This suggests still a power line issue.
Two reviews I watched on You Tube said it greatly reduced their power line noise by putting the MFJ-1025 in line and twiddling the settings.
DNR function on the FT-2000D helps to a certain degree.
R4002: Will Googgle and check You Tube for the Turner T-1000, thanks for the heads up and comments.
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That change with the wind is interesting Looking-Glass, I have noticed a significant increase in noise when the wind really gets going, I wonder why it would be lower in your case.
I am fairly close to some power lines, and about 2 miles from a 1000MW (yes, you read that right) hydroelectric power plant.
I imagine the increase in noise during wind in my area is due to partially damaged high voltage hardware being strained.
whoops, went a little off topic there
I have not used the MFJ tuner specifically, but on my loop antenna, tuning can bring a signal right up out of the noise, as opposed to running the same loop untuned. I do not have a tuner that will work with my longwire, but I have gotten about a 10 to 20 db decrease in noise by making the antenna perpendicular to the nearest power lines.
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What I had to do at my present QTH is physically move the antennas away from the house and power lines +50ft away. I have one leg of my Inverted - L going over the creek valley. (Which is fine since minnows, crayfish, and frogs, don't bitch about RFI.) I even had to move the wide-band Diamond Discone antenna since I was still getting power line noise on 2M, MURS, and even 222MHz, FM! WOW!!!! You actually got the power company to come out and do something? Huh, in WV if I even try to complain about power line noise, they say G.F.Y.S. and deal with it. So, I'm always looking for NR here as well, and thus far, distance seems the most effective, but at the cost of distant feed line loss. BTW, I also had an MFJ-9406 10W USB rig. A very fun rig indeed, whether portable, base, or mobile. Got a lot of QSL card requests from that rig's use in the 1990's. Even talked to the UK on a home brew dipole! Ended up selling it to a friend.
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ThaDood: Yes, had the power company here twice, first time they came they rolled up in a van with testing equipment and other assorted tracking gear. I was amused when the technician gave me a handheld radio and told me to tell him when the noise drops.
While I was at the radio he was walking up and down the street hitting the timber electricity poles with a huge sledge hammer, two out of six poles were found to have defective insulators/stays detected when he hit the pole the noise dropped.
Last visit (six months after the first) some insulators were found to be cracked and were replaced and a securing stay was found to be frayed and thus arcing when high winds blew. Hence (ThElectriCat) the variance in hash on the radio during high winds.
They also replaced the pole to house connector/cable to my property free of charge, also checked to see if my house was earthed properly too. Checked all power points in the house for faults too. All in all very good customer service and they rang back a few days later from head office to check with me.
Good part of it all was the noise dropped about three to five 'S' points, but not entirely gone, and it didn't cost me one cent. ;D
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Here is an example of the MFJ 722B filter in action. Early this morning was tuning around looking for NDBs. Conditions were noisy as usual per summertime listening but there was also an annoying power line buzz on top of the usual summer static. Switched in the 722B and it took the edge off of the buzz. Heard a faint signal, turned out to be 344 YGV Harve St. Pierre QC.
That is located on the Gulf of St. Lawrence over 1000 mi from my QTH... pretty good DX for this time of year. The signal was not audible with the 722B out of line. Heard a jumble under the buzz at 382. Switched in the 722B and was able to knock down the buzz and separate the mixing signals... YPL Pickle Lake ON and XU London ON both on 382. The band fell apart about an hour before sunrise so that was the end of it.
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Pinto Vortando: Excellent result from the MFJ-22B, it's worked well. Will Google it later and have a look on You Tube for it also. The little Icom IC R-75 has worked well so far, logged KT Kaitaia, New Zealand on 278KHz for a 319 report.
Interesting toggling between PreAmp-1 and PreAmp-2 or no PreAmp at ll, KT was logged without the PreAmp. Not a bad result considering conditions were poor at the time... ;)