THANK YOU! I own several of the MFJ-1026 units, and completed this modification to all of them. The video was very helpful showing the internal modifications. I used a small piece of the double sided 3M "Command" hanging strips to affix the relay to the circuit board. I also incorporated a suggestion by someone else below. I'll just cut and paste his suggestion from his comment: "When you connect a external relay, you need to set it up so that the normally closed position of the new relay is connected to ground. This will ground antenna during transmit, and it will also ground the auxiliary antenna when the noise canceler is off. This is important because even when the noise canceler is off, the auxiliary antenna is still receiving power from your transmitter or amplifier." That makes perfect sense, and I'm glad he suggested it. Thank you again for the video!
I did the same relay grounding mod years ago, the only difference is I used a a very small screw lamp holder - it's simpler just to unscrew the old bulb and put in a new one. Re the RF sensing circuit... Mine works still, but the T/R Delay knob on the front ceased working very quickly. There's no longer any delay. I'm not bother, as I use the PTT to ground method anyway.
Hi, the relay just connected in parallel with the original, so operating when PowerON Switch is engaged and the unit powered on, does not prevent RF to enter the 1026 unit when Power os Off, and my protection light bulb flashes (160 meter band) (I already burnt one) also if Front Power Switch is in the Off position. - I believe it should be better to take live wire from the T/R RCA and 12 Volts from DC Plug. Pls tell me your opinion about. I had to run short AUX wires, in order to avoid RF feedback to enter the unit, not able to null some distant noises...
@@ThumpMaster6 There's no difference vs. the video circuit, except the source of DC voltage (+12V) that have to be taken directly from the DC socket, not switched off by the MFJ Power Switch. This is protecting the lamp also when the MFJ1026is not in operation. When transmitting, also with MFJ 1026 Off, the AUX socket draws voltage into the box. The Relay shorts this to ground when in TX, also if powered off via the red front switch. Unfortunately there's no chance to attach a picture. Give me an email I'll send you the simple schematic.
Those units are plagued with minor issues due to quality control, there actually excellent for improving signal to noise. My first one you had to hold the phase button in about an eighth inch to get it to work. Had MFJ a simple fixture to test those switches for continuity when applied all the time and shipping cost could have been avoided had the switch been bench tested at the time of assembly. You'll never hear me knock MFJ there 100% customer service satisfaction oriented. In the long run, happy we have them. As amateurs we should be able to figure some of this stuff out like you did. Excellent video, 1026 beats running a mass of delay lines out to a second antenna. Phase Delay's just too cool.
I usually tell folks to treat most of the MFJ stuff as a partially built Heathkit. All the parts are there, just need some final assembly. Their stuff usually works OK once you finish assembly. Adds to the enjoyment, and I don't feel bad about making Mods.
OM - why leave the bulb in the circuit after relay has been added for protection? Bulb attenuates AUX antenna by 3db? Great device, when I have powerline noise most of my gear is useless without this to clean it up.
FYI: The color temp of light (brilliant white) is also a characteristic of light element being heated with RF. WAY BACK when I was first an assistant engineer at a commercial broadcast radio station the chief engineer showed me how the energy received (off air of course) by our AM antenna from another clear channel station a few miles away was by itself enought to fully illuminate a #47 lamp. The color temp from that RF source was very different from what DC or line based AC would produce. Just thought you might be interested in that phenomena.
Do you have a video or schematic on the box you are to interface the tranceiver’s tx/rx control with multiple units like atu, noise cancellor and amplifier? Thanks
I would love to see this as well. Only alternative seems to be the DX Engineering Keyline 3 that only handles half as many outputs. I'd max that out out-of-the-box if I added an amp or another accessory on top of my 1026, a 1708B SDR Receiver TR switch and a digital interface that may require/benefit from a keying line signal.
Nicely done, you explained the problems and your solutions without bashing MFJ products. I own many and have had few issues out of box with any of them. I think you should let Martin know about the issues though. he seems like a sharp fellow.
Hi Mike, there are enough problems with MFJ products to fill the great lakes. Can't believe that they don't know about the quality control issues. Suspect they figure the no questions asked return/repair policy is cheaper than fixing the issues. Don't agree as most folks get fed up and go away costing them business. I am just a glutton for punishment, and I love the challenge of fixing things. Been told I am a strange duck. Suspect it's a correct assessment. Thanks for watching.
Would you suggest replacing the 1A (yellow, original) relay with a higher current one also? If so, any idea what the connections underneath on the board are tied to so if I do replace it, I can know what to solder to the replacement? I have a 6A DPDT 12V tiny relay good for 240 VAC or 1/6 HP motor that would be beefier than the 1A 125V one. The user guide doesn't show the pinouts of the relay on the board.
You fail to mention that internal relay is enabled during receive, and drops out during transmit. When you connect a external relay, you need to set it up so that the normally closed position of the new relay is connected to ground. This will ground antenna during transmit, and it will also ground the auxiliary antenna when the noise canceler is off. This is important because even when the noise canceler is off, the auxiliary antenna is still receiving power from your transmitter or amplifier.
As I commented, I get RF enetring the AUX Antenna even when the unit is powered off and the bulb protection lamp burned already. I believe this mod should be done taking T/R sense to the relay being connected to 12Vdc directly, not after the Power Switch. This is grounding the AUX also if the MFJ1026 is Powered Off and does not let RF light the lamp Bulb.
For us future modders, where should connections go from the relay to the board? Swap the red + green wires and flip the diode polarity? Different pick ups from the board? And…about the normally closed advice above…how does that change on connecting to the relay? Just got one and I want to add this protection, and I’m using a Radio Shack 275-0248 relay, rated 10A @ 120VAC/24VDC with a 30mA nominal coil current.
You could've used the relay to ground the 1026 input and open the incoming antenna, seems it would be more effective. In doing so, wouldn't you get away from the TX overload issue and the need for high wattage relay contacts?
If my radio does not have an output for sensing TX how do you suggest doing this. Can i make up a simple standalone switch ? is just grounding that pin ok ? Bit confused how a stand alone switch would work. Please excuse my lack of knowledge Thanks
Hi Jason, if you don't have an output for triggering an amplifier, you are likely running barefoot. If you keep the transmitting antenna and the sense antenna at least 100' apart you can probably safely use the internal RF sense and let the unit switch that way. A standalone switch will work, but will be a pain. You could also add a relay that triggers from your microphone line.
Sadly I doubt they will as it is probably cheaper to replace the units that are defective. However it gives them a bad name. But I try whenever possible to avoid buying from the CCP ( Chinese Communist Party) based sellers. I have no issues with the Chinese People, but that Criminal Government needs to be stopped.
Hi Thank you for a very informative and well made video. I messed up mine by accident. I plugged a 13v ac not dc in it and now it does not power up any more with 12v dc. What did I break? If you can steer me in the right direction to fix it , I'd appreciate it.
Perhaps MFJ used the same kind of SO-239 connectors described here: th-cam.com/video/I3QtuozE3vU/w-d-xo.html The partial schematic at 2:03 is essentially the same as the DEO RG-2000 receiver guard. TH-cam won't let me post a link, but you will find its schematic and a discussion by searching for: Receiver Protectors DEO RG-2000 vs. DXE RG-5000
WWII sets would be vacuum tube and a lot more forgiving of strong RF in the receiver. A lot of early sets also had neon lamps across the antenna to absorb nearby EMP from lightning. Those trigger on around 80 to 90 volts.
I've done the mod shown, works great, my 1026 arrived in GREAT condition, excellently assembled, absolutely no complaints, other than the "RF sensing and switching" function and circuitry - stupid that MFJ has included that means of switching, and THEN advises buyers to NOT use it. Seems their design and manufacturing would have been better implemented by adding the extra relay displayed above - and totally eliminating the RF switching circuit that they insist owners not to use... I wonder if there's a reliable means of de-sensitizing the RF sensing circuit so it can actually be used at least at the common 100 watt transmitter levels?
MFJ kind of missed the mark here. I agree the best way is to "hard switch". l tend to treat MFJ gear as a partially assembled Heathkit. Just waiting for me to finish assembly and debug. Being the sick puppy that I am I love problem solving. Keeps me out of the bars.
Checking the sensitivity of the 1026 internal sensor/switching circuit, my IC-7300 will easily trip the circuit at lowest power output, 5 watts. MFJ's problem with this circuit seems to be inability to effectively manage triggering power range at upper levels - perhaps some sort of zener-type device that limits/cuts off tripping power at a specific level - say, about 100 watts. As it is, the sensor feature seems worthless for anything but QRP inputs...
Would you (or anyone) care to supply an actual relay part number since not all of us have great strength in construction. Would relay appreciate it (pun intended) or an eBay listing number perhaps?
I used a standard Radio Shack miniature SPDT miniature 12vdc relay - looks identical to the one used by original poster of this thread - cost was about $5 as I recall. I mounted mine with silicon cement with a thin piece of foam plastic material to keep relay noise to a minimum. It works great.
Would this do the trick? Miniature PCB Relay 12V SPDT ~125VAC/10A -- 30VDC/10A on eBay on item: 132671574308, if I orientate the same way as video that should work yes?
One of the first things you need to do is replace the lamp with a 240-ohm, half-watt resistor, or you'll be ordering new lamps from MFJ every few days. The lamp actually doesn't offer any real protection. I've been running my 1026 for 7 months using a resistor with no issues. I can't take the credit, however. This mod come from W7DHH, who is a longtime member of our local club and operates the similar MFJ-1025.
But can you run a KW using only that 240ohm half watt resistor? The 1026 is connected between the radio and before the amp so a KW doesn't actually run through it. Would it work that way running QRO with just your resistor and without the extensive mods in this video?
Thank you very much for the video, the light turned on due to the proximity of my antennas with very little power. Now instead, I can use my amp this way and the light never shines, even though the antennas are close together. Connect NC to ground as a colleague put in the comments. I also appreciate that very helpful comment. Greetings 73
Hi Mr. Radio Mechanic! Another great video and thank you for your efforts!! I just ordered the MFJ-1026 as I have a terrible noise problem here at the Home QTH... However, I notice my IC-706 (first gen. series) does not have an External PTT port on it. Therefore, I can NOT plug into the "TR Control" (keying line) in back of the MFJ! Any Ideas on how I can do this since I don't want to rely on the on-board relay as what you warn about certainly makes sense even though I'm not going to use an amp. Thanks again - really enjoy your well-made and informative videos that are really easy to understand! Thank you in advance for you help... 73 (K7GYB)
HI David. The 706 has some interface connections on the back. There is on one of them a keying line to trigger an amp. Just do a search for IC-706 keying an Amplifier and there are several sites that will pop up. When you get the 1026 remember that it takes patience to get the knack of setting it up. And a good sense antenna.
Thank You, Mr. Radio Mechanic for the info. I looked at the schematic for the IC-706 (technical info.) and the 13 pin Din plug in the back of the radio and there are two pins that will be needed which I can use to connect to the RCA jack into the 1026 T/R Control (ground - pin 2; and PTT line -pin 3). Thank you for the follow-up info! It is very much appreciated! Have been enjoying all of your videos! Thank you for the prompt reply. 73 K7GYB
RF will destroy the lamp even without an amplifier. Normal rf from a 100 watt rig will do it as well. I burned out three 50 ma. lamps; then found Steve Ellington's video and added the DX Engineering Receiver Guard INSIDE the MFJ-1026, as well as the relay mod.
Gunde please tell me what happens when you burn the bulb, do you lose receive? I lost receive on my 1026 and the S-Meter of the radio goes down to zero. When I power on the 1026, I hear the relay but I have no receive and the preamp doesn't do anything, none of the controls work. I power it off, the receive returns to the radio like normal. What happens when you blow the bulb, did you lose receive? Thank you so much. No one has answered this question
@@624radicalham With a burned out bulb, (minimal safety feature), you will have no signal in from the external auxiliary antenna. With the main antenna gain fully clockwise; you should receive signals with the 1026 switched on or off. (If you're running through an external tuner, ensure it is bypassed). The auxiliary antenna gain should work with the supplied whip antenna and the pre-amp on, internal jumper in position 1, even with a bad bulb. To get away from this burnt out bulb scenario, I use the DX Engineering Receiver Guard, (DXE-RG5000HD) plugged in between the Aux antenna input and it's antenna. Problem solved after removing the bulb, and shorting its connections. An excellent source of info. is a TH-cam Video by Steve Ellington describing the MFJ 1026. Hope this helps.
@@efrostrup Wow. Interestingly all I ever used is the internal whip which solved 99% of my noise problems and I have no receive on the whip with the jumpers set to the whip. And no difference detected anymore with when I push preamp on or off. Just no receive. I haven't tried the main antenna with the tuner bypassed ... but all this could mean that the RF not only blew the bulb, but also took some FETS in the circuit along with it. Q1 seeming to be a common transistor that blows. And it's near impossible for me to solder SMT boards. This was my worse fear. I can't thank you enough for confirming this. I thought with no bulb no receive.
Thank you so much! I’m in the city and my HF noise level is so high my radio is basically useless! Hopefully Santa will get me a mfj-1026 for Christmas 🎄??? Lol take care! 73 de ve3hip in welland Ontario Canada 🇨🇦
Great video. Gives me ideas for my own build of this circuit. But I must say it's absolutely ridiculous the crappy assembly quality of MFJ equipment. I bought an auto tuner from a ham store (929) and the first unit had charred wires like yours had, and the main coax ground was left unconnected!!! I didn't even power it up and returned it where I bought it to have it fixed. The store told me MFJ will fix under warranty, but I would have to pay for shipping both ways (I'm in Canada..), and pay for labor.. on a brand new unit! Disgusting. So they just swapped me a new unit instead. The 2nd unit had a broken power switch, and bad solder joints on the coax connectors. Fearing getting another unit that might be even worst, I just fixed it myself. All this to say.. I'm never buying anything MFJ again, at least not new/at full price. Given what little there is in the MFJ-1026, I think I'll be better off building my own. :)
I find it harder and harder to source parts, build a board and find an enclosure. I look at these as a kit without build instructions. As long as I have a schematic. But I am kind of a glutton for punishment. The basic electronics design is usually excellent. Just zero Quality Control. Sad.
Would anyone care to supply an actual relay part number since not all of us have great strength in construction. Would relay appreciate it (pun intended) or an eBay listing number perhaps?
HI Sean, the relay is an old Radio Shack part that they no longer carry. What is needed is a 12 volt coil with very low current draw. I think this one is about 20 mA if memory serves. And fairly heavy contacts. This one claims 10 amps. Probably actually good for around 5 amps. This thing had been in my junk box for 20 years or so.
The Radio Mechanic I know (most of) this because it was already said. What I was asking was a link or an actual part number, I realise its easy for some to transfer the info into an actual part but not all of us are blessed with finer understanding of components.
Would this do the trick? Miniature PCB Relay 12V SPDT ~125VAC/10A -- 30VDC/10A on eBay on item: 132671574308, if I orientate the same way as video that should work yes?
HI Sean, The contacts are fine and will handle the RF without issue. The coil is rated at 37.5 mA which is ideal as it will not stress the switching transistor. Good find.
So, one last bit. The relay has pins 1= Normal Close, 2= Normal Open, 3= Coil 1, 4 = Com 5 = Coil 2. What goes where? Hope this post helps others as well.
I personally called MFJ on this and they said it would handle an amplifier up to 200w.....although the manual says 100w. See the problem here? Also not ALL radios have an external PTT control for the T/R on the 1026.
It might live at the 200 watt level. I run up to 1400. Not a chance of survival. I have not seen a modern HF rig without a key line for an amp. Check your manual carefully. It might be on an auxiliary multi pin connector.
@@baronlund9725 but my question was, why wouldn't you touch it with a 10 foot pole ? that means you do not suggest this peice of equipement to anyone... why ? it did not work for you ? instead, what else would you use ? knowing another ham that bought it does not justify that it is a peice of crap... I just want to understand what you did not like about it ?
ROFL MFJ can make good stuff but all that Stuff suffers from a lack of attention to detail. They shod just ship there stuff with out the screws installed... any how thanks for the video..
HI Bret, There is a pretty steep learning curve. But once you master it, it works like a charm. You do need a good sense antenna thought. This is Key to success. Thanks for watching.
THANK YOU! I own several of the MFJ-1026 units, and completed this modification to all of them. The video was very helpful showing the internal modifications. I used a small piece of the double sided 3M "Command" hanging strips to affix the relay to the circuit board. I also incorporated a suggestion by someone else below. I'll just cut and paste his suggestion from his comment: "When you connect a external relay, you need to set it up so that the normally closed position of the new relay is connected to ground. This will ground antenna during transmit, and it will also ground the auxiliary antenna when the noise canceler is off. This is important because even when the noise canceler is off, the auxiliary antenna is still receiving power from your transmitter or amplifier." That makes perfect sense, and I'm glad he suggested it.
Thank you again for the video!
I did the same relay grounding mod years ago, the only difference is I used a a very small screw lamp holder - it's simpler just to unscrew the old bulb and put in a new one. Re the RF sensing circuit... Mine works still, but the T/R Delay knob on the front ceased working very quickly. There's no longer any delay. I'm not bother, as I use the PTT to ground method anyway.
Hi, the relay just connected in parallel with the original, so operating when PowerON Switch is engaged and the unit powered on, does not prevent RF to enter the 1026 unit when Power os Off, and my protection light bulb flashes (160 meter band) (I already burnt one) also if Front Power Switch is in the Off position. - I believe it should be better to take live wire from the T/R RCA and 12 Volts from DC Plug. Pls tell me your opinion about. I had to run short AUX wires, in order to avoid RF feedback to enter the unit, not able to null some distant noises...
Agreed. But break this down on where the connections should go from the relay contacts out…
@@ThumpMaster6 There's no difference vs. the video circuit, except the source of DC voltage (+12V) that have to be taken directly from the DC socket, not switched off by the MFJ Power Switch. This is protecting the lamp also when the MFJ1026is not in operation. When transmitting, also with MFJ 1026 Off, the AUX socket draws voltage into the box. The Relay shorts this to ground when in TX, also if powered off via the red front switch. Unfortunately there's no chance to attach a picture. Give me an email I'll send you the simple schematic.
Those units are plagued with minor issues due to quality control, there actually excellent for improving signal to noise. My first one you had to hold the phase button in about an eighth inch to get it to work. Had MFJ a simple fixture to test those switches for continuity when applied all the time and shipping cost could have been avoided had the switch been bench tested at the time of assembly. You'll never hear me knock MFJ there 100% customer service satisfaction oriented. In the long run, happy we have them. As amateurs we should be able to figure some of this stuff out like you did. Excellent video, 1026 beats running a mass of delay lines out to a second antenna. Phase Delay's just too cool.
I usually tell folks to treat most of the MFJ stuff as a partially built Heathkit. All the parts are there, just need some final assembly. Their stuff usually works OK once you finish assembly. Adds to the enjoyment, and I don't feel bad about making Mods.
@@theradiomechanic9625 For sure, partially assembled kit.
OM - why leave the bulb in the circuit after relay has been added for protection? Bulb attenuates AUX antenna by 3db? Great device, when I have powerline noise most of my gear is useless without this to clean it up.
FYI: The color temp of light (brilliant white) is also a characteristic of light element being heated with RF.
WAY BACK when I was first an assistant engineer at a commercial broadcast radio station the chief engineer showed me how the energy received (off air of course) by our AM antenna from another clear channel station a few miles away was by itself enought to fully illuminate a #47 lamp. The color temp from that RF source was very different from what DC or line based AC would produce. Just thought you might be interested in that phenomena.
Hi Doc, thanks for the info. Learn something new every day.
Sounds like the Mi Amigo!
Do you have a video or schematic on the box you are to interface the tranceiver’s tx/rx control with multiple units like atu, noise cancellor and amplifier? Thanks
I would love to see this as well. Only alternative seems to be the DX Engineering Keyline 3 that only handles half as many outputs. I'd max that out out-of-the-box if I added an amp or another accessory on top of my 1026, a 1708B SDR Receiver TR switch and a digital interface that may require/benefit from a keying line signal.
Nicely done, you explained the problems and your solutions without bashing MFJ products. I own many and have had few issues out of box with any of them. I think you should let Martin know about the issues though. he seems like a sharp fellow.
Hi Mike, there are enough problems with MFJ products to fill the great lakes. Can't believe that they don't know about the quality control issues. Suspect they figure the no questions asked return/repair policy is cheaper than fixing the issues. Don't agree as most folks get fed up and go away costing them business. I am just a glutton for punishment, and I love the challenge of fixing things. Been told I am a strange duck. Suspect it's a correct assessment. Thanks for watching.
Would you suggest replacing the 1A (yellow, original) relay with a higher current one also? If so, any idea what the connections underneath on the board are tied to so if I do replace it, I can know what to solder to the replacement? I have a 6A DPDT 12V tiny relay good for 240 VAC or 1/6 HP motor that would be beefier than the 1A 125V one. The user guide doesn't show the pinouts of the relay on the board.
as well as ordering a realy i need lapm 1 as mine blew where do yiou get
You fail to mention that internal relay is enabled during receive, and drops out during transmit. When you connect a external relay, you need to set it up so that the normally closed position of the new relay is connected to ground. This will ground antenna during transmit, and it will also ground the auxiliary antenna when the noise canceler is off. This is important because even when the noise canceler is off, the auxiliary antenna is still receiving power from your transmitter or amplifier.
This was very helpful advice! I did exactly what you recommended. Works great.
As I commented, I get RF enetring the AUX Antenna even when the unit is powered off and the bulb protection lamp burned already. I believe this mod should be done taking T/R sense to the relay being connected to 12Vdc directly, not after the Power Switch. This is grounding the AUX also if the MFJ1026 is Powered Off and does not let RF light the lamp Bulb.
For us future modders, where should connections go from the relay to the board? Swap the red + green wires and flip the diode polarity? Different pick ups from the board? And…about the normally closed advice above…how does that change on connecting to the relay? Just got one and I want to add this protection, and I’m using a Radio Shack 275-0248 relay, rated 10A @ 120VAC/24VDC with a 30mA nominal coil current.
You could've used the relay to ground the 1026 input and open the incoming antenna, seems it would be more effective. In doing so, wouldn't you get away from the TX overload issue and the need for high wattage relay contacts?
A friend of mine suggested me that solution too... which one is better ?
It's been five years since this video. Has MFJ made these upgrades during this time?
If my radio does not have an output for sensing TX how do you suggest doing this. Can i make up a simple standalone switch ? is just grounding that pin ok ? Bit confused how a stand alone switch would work. Please excuse my lack of knowledge
Thanks
Hi Jason, if you don't have an output for triggering an amplifier, you are likely running barefoot. If you keep the transmitting antenna and the sense antenna at least 100' apart you can probably safely use the internal RF sense and let the unit switch that way. A standalone switch will work, but will be a pain. You could also add a relay that triggers from your microphone line.
I like your caution. What diode spec should I use on the relay to prevent any back EMF?
I usually use just about any diode that will handle at least an amp and 1000 volts. Nothing special here.
Kit availabe on PCB kit available one ebay assembeled or diy, just bought one works great!!!
I was thinking of buying one but since I haven't I won't you would think they would straighten that out
Great video - I hope the MFJ are having a look into their quality control considering that this unit in the UK is over $300!?
Sadly I doubt they will as it is probably cheaper to replace the units that are defective. However it gives them a bad name. But I try whenever possible to avoid buying from the CCP
( Chinese Communist Party) based sellers. I have no issues with the Chinese People, but that Criminal Government needs to be stopped.
1026 comes with internal shorting clip for use of small whip antenna or remove it and= place on JMP1 all of this is in manual ,
ALL of that is in the VIDEO as well if you watched it
Cute, but why not just build an external box in line with the sense antenna? Wouldn't have to crunch on the board in the MFJ that way.
Hi
Thank you for a very informative and well made video.
I messed up mine by accident. I plugged a 13v ac not dc in it and now it does not power up any more with 12v dc. What did I break? If you can steer me in the right direction to fix it , I'd appreciate it.
Perhaps MFJ used the same kind of SO-239 connectors described here: th-cam.com/video/I3QtuozE3vU/w-d-xo.html
The partial schematic at 2:03 is essentially the same as the DEO RG-2000 receiver guard. TH-cam won't let me post a link, but you will find its schematic and a discussion by searching for: Receiver Protectors DEO RG-2000 vs. DXE RG-5000
In WW2, receivers in tanks used a lamp in the antenna path to protect the receiver from transmissions of nearby tanks.
WWII sets would be vacuum tube and a lot more forgiving of strong RF in the receiver. A lot of early sets also had neon lamps across the antenna to absorb nearby EMP from lightning. Those trigger on around 80 to 90 volts.
This is crazy...I would of had to return it ...Your a smart dude..Good stuff
Just years of experience......Thanks for watching.
I bought one. Gonna see how MFJ did building it. Thanks
I've done the mod shown, works great, my 1026 arrived in GREAT condition, excellently assembled, absolutely no complaints, other than the "RF sensing and switching" function and circuitry - stupid that MFJ has included that means of switching, and THEN advises buyers to NOT use it. Seems their design and manufacturing would have been better implemented by adding the extra relay displayed above - and totally eliminating the RF switching circuit that they insist owners not to use... I wonder if there's a reliable means of de-sensitizing the RF sensing circuit so it can actually be used at least at the common 100 watt transmitter levels?
MFJ kind of missed the mark here. I agree the best way is to "hard switch". l tend to treat MFJ gear as a partially assembled Heathkit. Just waiting for me to finish assembly and debug. Being the sick puppy that I am I love problem solving. Keeps me out of the bars.
Checking the sensitivity of the 1026 internal sensor/switching circuit, my IC-7300 will easily trip the circuit at lowest power output, 5 watts. MFJ's problem with this circuit seems to be inability to effectively manage triggering power range at upper levels - perhaps some sort of zener-type device that limits/cuts off tripping power at a specific level - say, about 100 watts. As it is, the sensor feature seems worthless for anything but QRP inputs...
Would you (or anyone) care to supply an actual relay part number since not all of us have great strength in construction. Would relay appreciate it (pun intended) or an eBay listing number perhaps?
I used a standard Radio Shack miniature SPDT miniature 12vdc relay - looks identical to the one used by original poster of this thread - cost was about $5 as I recall. I mounted mine with silicon cement with a thin piece of foam plastic material to keep relay noise to a minimum. It works great.
Would this do the trick? Miniature PCB Relay 12V SPDT ~125VAC/10A -- 30VDC/10A on eBay on item: 132671574308, if I orientate the same way as video that should work yes?
One of the first things you need to do is replace the lamp with a 240-ohm, half-watt resistor, or you'll be ordering new lamps from MFJ every few days. The lamp actually doesn't offer any real protection. I've been running my 1026 for 7 months using a resistor with no issues. I can't take the credit, however. This mod come from W7DHH, who is a longtime member of our local club and operates the similar MFJ-1025.
But can you run a KW using only that 240ohm half watt resistor? The 1026 is connected between the radio and before the amp so a KW doesn't actually run through it. Would it work that way running QRO with just your resistor and without the extensive mods in this video?
@@624radicalham Since the 1026 cannot handle more than 200 watts, it MUST go before the amplifier.
@@Species-rj9si So none of the mods in this video are needed then?
@@624radicalham The replacement of the lamp with a resistor is the only mod that I would make.
@@Species-rj9si I appreciate that comment, seriously. From a common sense perspective that's what makes sense. Thanks
Thank you very much for the video, the light turned on due to the proximity of my antennas with very little power. Now instead, I can use my amp this way and the light never shines, even though the antennas are close together. Connect NC to ground as a colleague put in the comments. I also appreciate that very helpful comment. Greetings 73
Hi Mr. Radio Mechanic! Another great video and thank you for your efforts!! I just ordered the MFJ-1026 as I have a terrible noise problem here at the Home QTH... However, I notice my IC-706 (first gen. series) does not have an External PTT port on it. Therefore, I can NOT plug into the "TR Control" (keying line) in back of the MFJ! Any Ideas on how I can do this since I don't want to rely on the on-board relay as what you warn about certainly makes sense even though I'm not going to use an amp. Thanks again - really enjoy your well-made and informative videos that are really easy to understand! Thank you in advance for you help... 73 (K7GYB)
HI David. The 706 has some interface connections on the back. There is on one of them a keying line to trigger an amp. Just do a search for IC-706 keying an Amplifier and there are several sites that will pop up. When you get the 1026 remember that it takes patience to get the knack of setting it up. And a good sense antenna.
Thank You, Mr. Radio Mechanic for the info. I looked at the schematic for the IC-706 (technical info.) and the 13 pin Din plug in the back of the radio and there are two pins that will be needed which I can use to connect to the RCA jack into the 1026 T/R Control (ground - pin 2; and PTT line -pin 3). Thank you for the follow-up info! It is very much appreciated! Have been enjoying all of your videos! Thank you for the prompt reply. 73 K7GYB
It would have been nice to include more detailed information on the 2 relays. Mouser? Digi-key? Part numbers? NO or NC?
Cheap radio shack relay from my junk box, part number unknown. NO for the ground connection, NC for passing the antenna through.
The lamp is then tied to the NC, and goes open on key down, and the common of the relay is the antenna lead, and the NO goes to ground I presume
It's a shame really, MFJ has an awesome product line, but they have No quality control. And they use the cheapest connectors and parts available..
There’s no reason to annoy us with Harley sounds, ridiculous.
I get more comments for than against. No one is forcing you to watch.
RF will destroy the lamp even without an amplifier. Normal rf from a 100 watt rig will do it as well. I burned out three 50 ma. lamps; then found Steve Ellington's video and added the DX Engineering Receiver Guard INSIDE the MFJ-1026, as well as the relay mod.
Gunde please tell me what happens when you burn the bulb, do you lose receive? I lost receive on my 1026 and the S-Meter of the radio goes down to zero. When I power on the 1026, I hear the relay but I have no receive and the preamp doesn't do anything, none of the controls work. I power it off, the receive returns to the radio like normal. What happens when you blow the bulb, did you lose receive? Thank you so much. No one has answered this question
@@624radicalham With a burned out bulb, (minimal safety feature), you will have no signal in from the external auxiliary antenna. With the main antenna gain fully clockwise; you should receive signals with the 1026 switched on or off. (If you're running through an external tuner, ensure it is bypassed). The auxiliary antenna gain should work with the supplied whip antenna and the pre-amp on, internal jumper in position 1, even with a bad bulb. To get away from this burnt out bulb scenario, I use the DX Engineering Receiver Guard, (DXE-RG5000HD) plugged in between the Aux antenna input and it's antenna. Problem solved after removing the bulb, and shorting its connections. An excellent source of info. is a TH-cam Video by Steve Ellington describing the MFJ 1026. Hope this helps.
@@efrostrup Wow. Interestingly all I ever used is the internal whip which solved 99% of my noise problems and I have no receive on the whip with the jumpers set to the whip. And no difference detected anymore with when I push preamp on or off. Just no receive. I haven't tried the main antenna with the tuner bypassed ... but all this could mean that the RF not only blew the bulb, but also took some FETS in the circuit along with it. Q1 seeming to be a common transistor that blows. And it's near impossible for me to solder SMT boards. This was my worse fear. I can't thank you enough for confirming this. I thought with no bulb no receive.
Informative. Thank you.
Very nice video! Please, how do you make t/r control outing your radio to mfj-1026?
Thank you so much! I’m in the city and my HF noise level is so high my radio is basically useless! Hopefully Santa will get me a mfj-1026 for Christmas 🎄??? Lol take care! 73 de ve3hip in welland Ontario Canada 🇨🇦
Great video. Gives me ideas for my own build of this circuit.
But I must say it's absolutely ridiculous the crappy assembly quality of MFJ equipment. I bought an auto tuner from a ham store (929) and the first unit had charred wires like yours had, and the main coax ground was left unconnected!!! I didn't even power it up and returned it where I bought it to have it fixed. The store told me MFJ will fix under warranty, but I would have to pay for shipping both ways (I'm in Canada..), and pay for labor.. on a brand new unit! Disgusting. So they just swapped me a new unit instead. The 2nd unit had a broken power switch, and bad solder joints on the coax connectors. Fearing getting another unit that might be even worst, I just fixed it myself. All this to say.. I'm never buying anything MFJ again, at least not new/at full price. Given what little there is in the MFJ-1026, I think I'll be better off building my own. :)
I find it harder and harder to source parts, build a board and find an enclosure. I look at these as a kit without build instructions. As long as I have a schematic. But I am kind of a glutton for punishment. The basic electronics design is usually excellent. Just zero Quality Control. Sad.
Typical MFJunk, you have to repair brand new equipment to make it work.
SUPER good gouge!! Thank you. Lane ku7i Las Cruces, New Mexico
Thanks for the mod. Works fine.
Your Welcome, Thanks for watching.
Would anyone care to supply an actual relay part number since not all of us have great strength in construction. Would relay appreciate it (pun intended) or an eBay listing number perhaps?
HI Sean, the relay is an old Radio Shack part that they no longer carry. What is needed is a 12 volt coil with very low current draw. I think this one is about 20 mA if memory serves. And fairly heavy contacts. This one claims 10 amps. Probably actually good for around 5 amps. This thing had been in my junk box for 20 years or so.
The Radio Mechanic
I know (most of) this because it was already said. What I was asking was a link or an actual part number, I realise its easy for some to transfer the info into an actual part but not all of us are blessed with finer understanding of components.
Would this do the trick? Miniature PCB Relay 12V SPDT ~125VAC/10A -- 30VDC/10A on eBay on item: 132671574308, if I orientate the same way as video that should work yes?
HI Sean, The contacts are fine and will handle the RF without issue. The coil is rated at 37.5 mA which is ideal as it will not stress the switching transistor. Good find.
So, one last bit. The relay has pins 1= Normal Close, 2= Normal Open, 3= Coil 1, 4 = Com 5 = Coil 2. What goes where? Hope this post helps others as well.
Good video. Things to look out before I plug it in and give it some "RF".
73....Karl
VK7HDX
I personally called MFJ on this and they said it would handle an amplifier up to 200w.....although the manual says 100w. See the problem here? Also not ALL radios have an external PTT control for the T/R on the 1026.
It might live at the 200 watt level. I run up to 1400. Not a chance of survival. I have not seen a modern HF rig without a key line for an amp. Check your manual carefully. It might be on an auxiliary multi pin connector.
i woulds of sent it back to MFJ, you should not have to repair it from new that SUX .. jeff ..
Jeff, I have always looked at MFJ to be a Heathkit without instructions. Enjoy the Challenge.
I wouldn't touch that product with a ten foot pole.
why ? and what ever else would you use then to get rid of noise ?
I know another ham that just bought one. You have to lesson very carefully to know if it's doing any good or not.
@@baronlund9725 but my question was, why wouldn't you touch it with a 10 foot pole ? that means you do not suggest this peice of equipement to anyone... why ? it did not work for you ? instead, what else would you use ? knowing another ham that bought it does not justify that it is a peice of crap... I just want to understand what you did not like about it ?
It means it's not worth the investment. At least not so far.@@Aleziss
@@baronlund9725 so any other suggestions to get rid of noise ?
MFJ has a quality control problem. I have an MFJ unit that was not right from the factory and too expensive for this kind of crap from MFJ.
ROFL MFJ can make good stuff but all that Stuff suffers from a lack of attention to detail.
They shod just ship there stuff with out the screws installed... any how thanks for the video..
Hi Matt, they engineer the items well. Just loose it on the assembly end. But I just treat them as a Heathkit without instructions.
Very good video I want to bie one, this is good to know. KC2NXP
HI Bret, There is a pretty steep learning curve. But once you master it, it works like a charm. You do need a good sense antenna thought. This is Key to success. Thanks for watching.
Why must we listen to an engine being throttled at the beginning. It's annoying and irrelevant.
It's a Harley. How can it ever be annoying.......
Actually I listened again. It's not a Harley so yeah Annoying.....LOL
@@clems6989 I agree
Meaning I like it