Hey Joseph. The feed to L6 L5 and L4 is actually the B+ for V1 and is 240v or so above ground. So the broad frequency undiscriminated signal is on the B+ line. Bands 1 and 2 should be very sensitive. I would check for common mode failures in L6 such as an open ground or cold solder joint, feeds to the rotor on the tuning and bandspread tuning capacitor, ensure the contacts and strips on S1 are clean. Check for continuity across coils and switch positions.

@@gixerags750 they work as is

@@i82996 no worries , I have one but I saw some dodgy reviews. ✌️

Great - I'd love to see it. By the way this antenna rocks for me. OK the gain is 0 in all directions, but I am seeing really good DX on FT-8 and FT-4. The only "dark" area is China for some reason. Worked easily Guam Easter Island and Indonesia the other morning. KR3HAB

I will certainly upgrade before I do another video, however I have been pre-occupied with ministry in Asia these past couple of years. Albert

@@i82996 by all means, ministry is far more important than sound! but we want to see these vids! cant get enough. a good sound will be awesome!!

I am 72 currently in Asia working for the King! If you get stuck anywhere you can ask. Also Hallicrafters has an excellent interest group called HallicraftersRadios. I cannot put the link here but look it up.

Hey friend, as my Elmer Dave Casler KE0OG on KZbin says (paraphrased) "with antennas, everything affects everything." I chose this antenna as a catch-all installation that could be put in the back yard away from trees, and with a hinge mount on the 10 foot pole, provide me easy maintenance. As it is a vertical, the gain is one in all directions. Still with that, I am able to FT-8 just about everywhere in Europe, South America, with some middle east, Africa, Japan, Australia, ... everywhere except South Asia and China have been tough even with a 500w linear. I am really happy with it. I might suggest that if you have a pole you could mount, put up a single wire 1/4 or 1/2 wavelength vertical on the metal roof on a shorter wavelength band, to experiment first before sinking so much into the multiband. Dave has a video on his channel "Metal Roofs Vs Antenna (#1043)" which may help. Also you could ask this question to the HyGain engineer who is a very. very knowledgeable expert on his antenna designs and antennas in general. You can surely get to him via MFJ.

Thanks 👍

Hey Antonio, you caught me when I am over in Asia for the moment. Write me your question on the business email for the channel, and I will follow up when I get home next month. I took the antenna down and stored it in the garage and will have to check your question down anyway when I put it back up. I removed the composite top part from the metal tubing to store it, and the radials were removed relatively easily for storage.

I just got back Tuesday and I noticed that the wire from the lower stages is connected to the upper screw assembly that is outside of the tube as inserted. I also noticed some cracks in the composite so I will be reinforcing that with straps. Albert

Thank you for your kind remarks. I probably should say something on the channel, but I have been wrapped up with overseas ministry lately and have not had time for restorations, still waiting for a chance to look into my un-restored HT-37 transmitter. As for the BFO, it is not so strong. I have learned as a ham that the sensitivity knob is always helpful in clarifying the BFO, regardless of the radio (at least tube radio that is). Albert

It is a very hot antenna for me. Close to 2K QSOs.

This video was recorded before any vaccines were available. I do use Sambucol to reduce cold effects.

Well no, after it was put up I have put a lot of work in the transmission center to address some issues I created so that took some time. Also I have been working entirely in FT-8. I use a MFJ-989D tuner and get 1:1 on every band but 6 meters. The antenna + my mostly clear line of sight above 10-15 deg over the horizon results in a powerful DX combo. I have worked around 1000 QSOs since installation and the antenna beats the old EFDP hands down. I have recently worked Kazakhstan New Caledonia Cyprus Algeria Japan New Zealand Australia Malawi but China India and Indonesia still elude. I can hear em though.

The one bugaboo is the antenna tunes about 500khz above the FT8 frequencies and I don’t have a 6 meter tuner. No amount of manual length adjustment with my MFJ 259D can bring it down so 6 meters is a SWR of 3:1.

Planning on a new camera

​@@i82996Albert, I truly appreciate your wealth of knowledge and how your willing to share. I'm finishing up a Mark-D replaced all capacitors and resistors out of 10% tolerance now I have a few quirks I was hoping you could enlighten me with a path to solve. One is my S meter isn't working like it should I have a long wire antenna and I get strong signal good reception it might bounce to a 3 when people stop talking or music breaks. I have replaced all resistors in that meter circuit including the 56 ohm R-71 to match the 200 ohm meter pot. I have watched your video explaining how the s meter works and understand it is the lack of current flow that works with the meters internal spring to draw the needle toward the right when operating. At rest it parks on the right like it is supposed to. At V3 my voltages seem reasonable 213 at the plate,G2 pin 6, 130,pin#4 G1 -.5 this goes up a little when I switch to broad cyrstal. Thanks again for inviting me into your world, I just retired and have enjoyed radio restoration for over ten years still a newbie but learning everyday I haven't taken one apart to your level yet but have fixed I.F. cans changing components out etc... love the birds in the background, Regards, Paul

@@bertconvey3881 I would remove the zero adjust pot and check it out. With an ohmeter attached run the pot from min to max. The ohms should move smoothly with no breaks or jerks. If there is a problem you may check out my video on the SX-100 Mark 1 where I repaired the pot.

@@i82996 Hello again Albert and thank you for the reply I did take the pot apart and it ohms out working 0-200 ohms. I think it is my alignment being off the crystal frequency. Working with reconditioned Eico 320 and fluke frequency counter. I'll get it when I took it apart non wiper side it had a additional 68 ohms at the pot wired to non wiper side. It seems to give more adjustment to zeroing meter grounding ant. lead as instructed in manual. Regards. Paul

My guess is that there is a problem with the wiring of Switch 1, section 5 (rear). There is supposed to be a jumper between the first lug (Band 1 position) and lug 4 (Band 4 position). It may be open or missing or a cold solder joint. The purpose of this configuration, my guess, was to have a relatively even sensitivity when switching between the bands. This radio was not intended so much for ham communications, but was for radio entertainment across the bands, my thinking. So switching bands should not cause one to reach for the volume or sensitivity control. This switch is supposed to add 680 ohms to the sensitivity pot of 10,000 ohms (roughly 5%) on bands 1 and 4, nothing on Band 2, adds 2700 ohms on band 3, and parallels 2700 ohms with 680 ohms on Band 5 (SW2 Section 1 rear, dropping resistance by about 50%). If the jumper is missing, then L1 choke is open, and V5 behaves as if there is no bias on the cathode, driving the tube harder and dulling the sound. So at 10 on the knob the sensitivity is supposed to be at max with only the above resistances as a bias to the V5 cathode and no sensitivity with the bias at 10000 ohms plus at the zero setting. But in your set, at 10, it is at 680 ohms to the cathode (lower), and at 0 the sensitivity is only the capacitor to V5, which would be higher sensitivity. In bands 2 through 5 the normal connection for biasing is made and the receiver works normally. When the BFO is on, the AVC is grounded off at 150 ohms, which puts biasing on V5 at 150 ohms. So check that jumper. It's my guess.

Merry Christmas and Happy New Year!

The plate voltage is high because the screen voltage is too high. Check the 330,000 ohm R9 again or just replace it, and the wiring around the S-meter including the + and - connection, and smooth function of the S-meter adjust, as well as those resistors in line. Try checking voltages from the B+ all the way through the S-meter to R-9 and to the screen to see if values make sense. Blessings. Merry Christmas and Happy New Year!

@@i82996 Thanks for the clues. I replaced the 330k R9 but haven't chased all voltages along the B+ path all the way to the screens. I will do that next. I like the simple explanation about plate voltage dependency on the screen voltage! Happy New Year to you as well!

Something like this from Amazon: www.amazon.com/Rakstore-0-1MHz-65MHz-Frequency-Cymometer-PLJ-6LED/dp/B09V4GYCCC/ref=sr_1_104?crid=2RN0Q37K8ZVKU&keywords=frequency+counter&qid=1670096879&sprefix=frequen%2Caps%2C83&sr=8-104 But you will have to find a Hammond box and custom build two of them like I did, because there are two oscillator frequencies in an SX-71. A toggle switch selects the right one.

@@i82996 Thank you very kindly for the response. Actually I have two SX-99s im going to restore this winter and it was my idea to use a programable counter for one of those radios. I just finished restoring a first run S-38. What a great pursuit and past time this is. Cheers and thanks again.

I haven't noticed any issue with the BFO, since I raised the plate resistor from 22K to 100K (see BFO video), which cured the weak injection originally. True a few dB increase in sensitivity might slightly effect the balance with the BFO but the major correction came with the plate resistor.

@@i82996 I just got done changing all mine over. The weird thing the BFO R52 was already a 100k, even though all the others matched run 1 values. I also switched R22, R23, R30, R31 and R32. They had the old run values. Reception is quite good now. My audio output xformer was bad, and I put one in there that matches the 6v6 tube I am using. It really blasts now haha.

The SX-71 was my youth shortwave receiver. It lacked an antenna compensator knob for the first antenna stage that later Hallicrafters models had. So I then,, and now, use an AMECO PCL-P nuvister preamplifier to liven it up very nicely. Also on one of my videos I experimented with the cathode and screen resistance of the second IF amplifier 6SK7 to get the optimum screen voltage, somewhat similar to a commonly available QST mod, which made it a little more sensitive. Lastly, just so you know, this model was notorious for poor dial calibration especially on Band 4. I added a switchable digital counter which switches between the 455 kHz IF offset for Bands 1 and 2 to the 2.075 kHz first IF offset for Bands 2-5, which makes the receiver accurate for frequency readout. However, there is a lot of drift, 10 Khz, the first 45 minutes to the offset should be set after the drift has stabilized. The drift with the counter is odd, rather than be a calibration issue, the receiver literally moves down the band 10 Khz, so that WWV appears initially on 15010 kHz and after 45 min stabilizes at 15,000 Khz. Blessings on your project and 73s KR3HAB.

@@i82996 I'm lucky with my dial calibration as the main dial is all bands spot on. Has been in storage for over a decade so finally got it set up again. Putting an order through digikey for the resistor changes.

Thanks for the tip. Using mainly on FT8. 40/80 is already better than end fed homebrew. Not good FT8 SWR on 10/6 meters.

@@i82996 YOU KNOW i am a 2 year old general license , and had watched a lot of elmers, and kept a lot of contradicting info jotted down. I went with " as short as possible " lmr 400 2 pieces one to the alpha-delta and a piece into my house. I use a ldg at-100 pro tuner and it's almost always on " bypass " getting one to one.

do you have photo's of the 4:1 you took out ??? I have made a few 4:1 and 1:1 using txlabs video , really good desing and step by step . by any chance did they use a air balun or good torroids ?

I haven’t done it yet, but the secret sauce is 8 mm tube or stubs. Fits nicely.

The SX-99 has a 6SA7 mixer tube that combines oscillator with mixing the incoming signal with the IF frequency available through the IF transformer on the plate. The best tap point on the mixer tube is the cathode so the tap does not drag the oscillator. It is important to install a buffer circuit, which is a custom PC board along the lines of the buffer circuit that Mr. Carlson's lab used on a Hammerlund install some years back. The video is still there on his channel.

The SX-99 drifts in AM and CW and SSB due to two factors. Certainly a warm up of the tubes and LC circuits in the oscillator section (L7 through L10 and associated mica trimmers) are changing the resonant frequency somewhat due to temperature change until operating temperature is reached. Also suspect is the .01 mfd C17 in the oscillator circuit was originally a paper capacitor. I have replaced it with a poly capacitor (drifty as well) and on one radio I found a 10,000 pf (,01 mf) mica cap in one unit to put in to help. The problem with drift after warm up is because all these capacitors are not what are called NP0 capacitors with low temperature co-efficients (low drift). additionally the mica trimmers are simply two small sheets of metal separated by a mica dielectric, which is hinged by the metal on one side. The movement of the metal with the turn of the screw is non-linear. When the screw is almost out, the change in capacitance is small per turn, and when the screw is almost in, the change is very high (relatively, we are talking 3-30 pf trimmer values). So when there is temperature change the metal slightly expands or contracts and that affects drift as well. Ways to address the drift cheaply: 1) turn the set on 45 min or more before using, 2) find a mica or NP0 and replace C17. C16 is a mica, but if you can find a NP0 for that. The trouble is getting voltage ratings high enough among today's NP0s. If you can find silver mica caps at a hamfest to replace C-19, C10, and C21 that would help as well. Make sure the rectifier is strong on a tube tester, as well as the 6SA7. The C18, C23, and C24 mica caps are probably OK. If you have a capacitor leakage tester I would suggest testing them for leakage. Occasionally mica caps fail. If you haven't re-caped the unit, please do so. Check R68, R8, and R30 for tolerance. Even with all these measures I could never achieve better than .15-.25 khz per minute over one hour of drift, and typically the first 10 minutes of warm up results in a 10 kHz drift. The curve flattens after 10 minutes but never gets totally flat within an hour.

Hello Mic. I don't have an S20 schematic but I looked on the SX-32 schematic, which is as early as I have, and the tuning caps are directly connected to ground. All the radios I worked on, the SX-71, SX-99, and SX-100 did not electrically isolate the tuning caps. Only the SX-71 had non-metallic washers (but the screw went directly from the bracket to the chassis), and the washers provide mechanical isolation to keep tuning caps from experiencing vibration from audio sound or other sources; that radio was a cut above in quality. By the way, you may or may not realize it, the stator on a tuning cap is electrically isolated from ground and connected to the tuned circuit. The bracket and rotor assembly are grounded. Blessings and 73, Albert

@@i82996 I was focusing on the mounting hardware but removing it I see it had a soldered braided connection to the chassis and it shows its the stator that is isolated..interesting! Thx for your time and input!!

@@micjam1986 If you could send a "clip" image of the relevant part from the schematic I am interested. Use the "business email" on my channel. Albert

@@i82996 I will try

Relax, the switch can be refurbished. 1) you will have to take the front face off. I assume you have the case off now. Remove the knobs, disconnect the S-meter, noting the positive, and gently pry the lamp cases off the front face behind the glass. I should say use a liberal amount of WD-40 or some other "loosener" before attempting to remove the knobs. I would go to Ebay and search on Hallicrafters and buy the special wrenches in the blue folder used for Hallicrafters set screws on the knobs if you don't already have them. Once the face is off, you will see the nut holding the sensitivity knob in place. It should remove easily. Desolder the wires to the knob and then remove the control. You will see tabs on the control which can be gently pried open a little at a time (like rotating a tire to put on lug nuts, you don't pry any one up all at once but work around the control. Air blow out the inside of the control first and see if it frees it up. If not use an electronics cleaner such as Super HFE (Use a mask - really rude stuff) or CRC QD cleaner and see if that frees it up. Lastly if still frozen, WD-40 Specialist Spray and Stay Gel Lubricant can be used to free it up. My bet is just removing the control will free it up. If you get stuck send another comment. Blessings, Albert KR3HAB

@@i82996 Albert Thanks for the quick response. I have a Hallicrafters SX-101A on the bench at the moment, but I can move it aside. I have the Bristol Wrench Set. In fact, I used it two days ago to take the tuning knobs off of my SX-42. The snap ring had popped out of the grove, making tuning very fatiguing. I don't have any of those chemicals, but I will get one and follow your advice. 73 Paul AA1SU

See you on the air!

Based upon a number of comments I will stick to radios. Clock is running nicely though…

@@i82996 I’m still proud of you

I went back and looked at the schematics. As I recall, the "white dial" versions were exclusively Run 1, but there were Run 1 black dials as well, I think. I don't have a good schematic of Run 1, but Run 2 has 400 volt .05uF caps off the cathode of several tubes and after that, probably Run 3, they were upped to 500 volts for runs 3 and 4. Look for that as a dead give away. Run 4, the only difference I can recall, had the 15 meter band painted on the bandspread dial. There was a service bulletin for Run 1, due to leakage across the primaries to secondaries on T7 and T8. That was fixed by redesigning (or was it re-supplying from a vendor or both) the IF transformers in remaining units of Run 1 - basically this caused the first runs off the factory line to be problem prone. Also R-41 was upped to 1 meg in the bulletin, and is the value in Runs 2 through 4. If your set has anything other than 1 meg for R-41, you have a Run 1. You will need to get into the mixer subchassis and the IF transformer cans and verify everything - especially DC leakage across the micas (yes the mica caps sorry its lots of trouble). When you screw back on the IF cans be very, very careful not to over-torque the screws or you will tear the screw right off of the can.

@@i82996 Wow... thanks for the info... that will be a big help. I thought that perhaps there might be some serial number info that would distinguish between them.

@@johnwaldburger8822 not that I know of.

Thank you friend

Radios are disconnected when not in use.

Soooo close. I used fast blow fuses (not looking at the purchase) so again waiting on slo blows. Higain 80-6 meter vertical.

I hate to hear about the slug. Without the 15 meter band it is either run 2 or 3, more likely 3.

@@i82996 Did you complete the resistor changes for the different bands? Is there a way to tell the 2 from the 3, or is this done just following the schematic.

@@speter60 I replaced nearly every resistor, but that is mostly, but not all me. Some were out of tolerance to the extent that all were suspect as heading towards end of life. I sent you a more detailed reply plus documentation of my rebuild via [email protected] .

I forgot to mention: when you screw back on the IF cans be very, very careful not to over-torque the screws or you will tear the screw right off of the can. They are very fragile.

Terry, the antenna and ground is as important to the radio itself for performance. I dont know your situation, but in my experience, for general coverage receivers like this one, I work hard to have a long wire antenna at least 20 feet off the ground, and I install a 9:1 balun to a coax leading to the lightning protection at the entrance to the house. Then I bring the coax into the shack in the house to a receiver antenna tuner which tunes the antenna. For grounding, I have an 8 foot rod in the ground bonded to the lightning protection at the house, and at the antenna itself out near the woods with another rod there. This is still not best practice, but my setup is pretty noise free and gives excellent reception on all bands. If you go for an Amateur Radio License, you will find that any antenna built well for a transmitter will work well on the amateur bands but may not be best on shortwave bands in all cases. The ground is so important for noise free reception. Now the kicker: my long wire is an inverted L, proceeding up from the balun at the ground to a 20 foot high turn to horizontal where it continues another 100 feet. The receiving pattern is fairly omnidirectional at most frequencies with a few dbs favoring the axis of the horizontal portion of the antenna. I know the manual for the SX-100 talks about a dipole, but for shortwave reception only you want omnidirectional reception as much as possible and dipoles are highly directional. In fact a bad long wire antenna should work better overall for shortwave listening than a dipole. 15 feet is way too short a length to receiver much, and an antenna tuner such as a MFJ-956 or 959c is essential to hear anything with any length of antenna. Blessings, Albert KR3HAB

Your comment tells me I need to do a video tailored to the shortwave listener for antenna designs. If your backyard is not easily converted to antennas there are alternatives. Albert

Thankfully there is still RNZ but it is a bit early in the morning here for light listening.