Getting started in AM

[kc4umo]

Hello all.
Name is Buddy. Been enjoying radio for many years. Mostly V/UHF SSB, HF and Oscar communication.
Now I think it is time to tryout AM. This came about a year ago.

I went out and restored couple of Yaesu ft-101's with AM filters. But after spending time listening on different bands I came to the conclusion that the 101 was not what I needed to accomplish this. So set out on a task a while back to find some "heavy iron". What I ended up with is 2 Heath Apache TX-1's. I have finally started to restore one of these rigs. Still looking  for the matching receiver but no luck at the moment. But I am sure there is one out there waiting.

So as being a AM newbie I am open to suggestion and guidance.

[flintstone mop]

Hi Buddy
We have another member we call Buddly.....maybe he will chime in. But welcome to AMFONE. The FT101 is really not that bad of transmitter for AM, driving a linear amplifier.
The Heath Apache always needs mods in the mic circuit to improve audio.
There's quite a mix of modded transceivers driving linear amps and software defined radios and, of course, old broadcast AM transmitters converted to the Ham bands.
Lottsa stuff here to make nice sounding AM.
Fred

[Steve - K4HX]

Welcome. Sounds like you have a good start.

The matching receiver for the Apache is the Mohawk. Unfortunately, it is not a great receiver in general and not a good one for AM reception. Everyone has their favorite receivers and there are many from which to choose. Below are links for two articles covering some of the more commonly found/used receiver and some pretty good explanations on why the receivers are good or bad.

http://amfone.net/Amforum/index.php?topic=4779.0

http://amfone.net/Amforum/index.php?topic=6059.0


I have not nearly the experience with receiver as the two authors above. My favorite receivers for AM are the Hammarlund Super Pro 200 or 400 series. These are 30s and 40s vintage receivers, so things like frequency readout and drift are not as good as some of the newer vintage receivers. But for audio quality, they are hard to beat. The Hallicrafters SX-28 also has excellent audio, although I have not used the 28 nearly as much as the Super Pros.

I'm sure you'll get many other recommendations!     Good luck.

[kc4umo]

Thanks for the welcome Fred and Steve.
I heard a few 101's on the air and they did sound good. Although the guys I have heard on AM sound much better.
I may get the nerve and try one on air.

Thanks for those links Steve. That will come in handy. The Apache is not my radio of choice but I got a good deal on the 2. Seems the Mohawk is almost impossible to find.  I rather not have one shipped over a distance.
I am always looking for more boat anchor gear.

I have never owned but 2 new ham radios in my life. Everything else was purchased used and non working.
I now run a part time business repairing older ham radios. Kenwood 520's to 940's, Yaesu 101's. 221r's. 726's 736's and other models.

It's fun and I enjoy it.

[Steve - K4HX]

Another thing to consider is using a linear with the 101s. A few simple mods on the 101 can make it sound fantastic on AM. If you need the power, a linear capable of over a kW PEP will give you 200-300 Watts of carrier output. Unless your antenna is on the ground, you'll be heard!

[kc4umo]

Yeah I wished I kept ahold of that Johnson Thunderbolt or the henry 2k floor model. Be nice to have them again lol. Guess I will also be in the market for another linear.

Before the spring I plan on stringing up some massive wire antennas behind the shop fromsome 70 foot tree line.  Can probably do it while the folage is back due to winter.  Cant wait too long though. The poison ivy is very thick in there.

A little shop tour

[kc4umo]

couple more

[WQ9E]

Buddy,

Welcome!  You will get lots of great advice here.

The matching Mohawk can be a pretty decent receiver but it won't provide the great audio of the SP-400 and earlier Super Pro receivers.  However under tough conditions the Mohawk will shine and under good conditions it sounds pretty good in the widest bandwidth position.   Heathkit probably made a mistake putting the IF gain control on the front panel and a lot of users run it wide open which results in a very noisy receiver that is prone to overload.  The idea was to allow users to adjust the IF gain for optimal operation under different conditions and, especially for the lower bands which tend to have a high noise floor, set the gain so the S meter just barely deflects on band noise.  Like the Hallicrafters SX-96 family alignment of the final IF is critical for good performance.  Another similarity with the Halli selectable sideband family is until you get used to the receiver the easiest way to tune it on AM is to do so with the BFO on and set to zero and then tune for zero beat.  This is the perfect tuning point on AM and you can now switch to AM mode and instantly choose whichever sideband has the least interference without further tuning.  Also like the Hallicrafters only one sideband is received at a time on AM so the 5 Khz. bandwidth provides equivalent fidelity to a traditional AM receiver with 10 Khz. IF bandpass.

[Pete, WA2CWA]

I still have my original Apache that I built back in the beginning of time. Took me roughly 30 years to find a decent and unhacked Mohawk. Get the Apache up and running as per design and specs and then decide upon any mods you might want to make. The Apache even in stock form, if audio adjusted properly, can still sound good on AM. The Thunderbolt due to its design, will only get you about 200 to 225 watts carrier on AM on a good day. Not much better then a Valiant. Some of the many current, or recently current imported transceivers, can sound great on transmitting AM and generally have good AM receivers.

[K4RT]

Buddy,

Welcome and FB on having two Apaches. I have received good advice from the hams here while working on my Apache.

Pete's advice to get the Apache(s) running in stock mode as a base point is sound. If you then want to make changes you might try changing the values of the interstage coupling caps in the speech amp circuit to see how it sounds, and do additional mods if needed or desired. I would take it in steps, which is what I did with my Apache - based on the experience of other Apache owners.

I just finished working on the speech amp circuit after studying the W3SCC mod for the Apache and the WA1HLR mod for the DX-100. Other work: Replaced the electrolytic caps in the power supply section and replaced the stock AC line cord with a 3-wire cord and new fuse holder on the rear apron with helpful advice from Rodger and others here. I also moved the AC lead for the VFO filament so it's controlled by the transmitter's main power switch.  I really enjoyed getting to know how the Apache works, including its elaborate band-switching mechanics.

By the way, some months back I had posted a note here about arcing in my Apache. That turned out to be caused by a missing screw for the VFO enclosure that lodged in the wrong place and shorted the HV to ground. Fortunately, no lasting damage from that and some other dumb things I did!

It’s been noted elsewhere here that sometimes we forget to thank those who provide advice and help. So thank you to everyone who offered advice and suggestions as I worked on the Apache, and a big thank you to Terry K7MPP who lives nearby and provided a lot of hands on help troubleshooting and explaining how vacuum tube transmitters and their sub-systems work.

Have fun with your Apaches. Maybe we’ll  have a QSO some day.

73,
Brad

[kc4umo]

Thanks Brad,
Was so cold yesterday evening I did not get much time in the shop. And this morning is a chilling 12 degrees here. So will probably be the week end before I get a chance to get back on it.

I tested the caps with my ESR meter and they check fine but will be the first thing to get replaced. Old caps could go at any time. I also need to check those old molded mica caps.

I pulled the front plate off this past week end and re-strung the dial, cleaned the frequency roll and cleaned the shafts and mechanical parts. The 2 brass belts have been repalced with some sort of leather belts and both were broken.  I made some aluminum belts for temporary use. They seem to work fine but probably want hold up as good as the brass ones.

As soon as I get the front panel back on I will get the caps replaced. Then I will start on some voltage checks and see what is there.  I aalready replaced most of the tubes since some were cracked due to storage. So much to do so little time.

Thanks for all the suggestions.

[W1RKW]

Buddy,
Welcome to the forum.

Another receiver to consider is the National NC300. I have one. It sounds great. It's sensitive and selective.

Love your shop. thanks for sharing the pictures.

[kc4umo]

Buddy,
Welcome to the forum.

Another receiver to consider is the National NC300. I have one. It sounds great. It's sensitive and selective.

Thanks for the welcome. Glad I found this place, been doing a lot more reading than posting.  I was going to get one at an aution one day but got outbid. But will keep my eye open on that.
I do have a National 98.  This is one I found at a trash dump one day.  The guy there knew I liked old radio so he saved it for me.  I did a bit of a restore to the electronics. Cut the old caps open and installed new capacitors inside. I like the old radio so much I left the appearance as is. Which it scratches, rust spots and some dust on the chassis. But it sounds like a new one. I will attach a pic.

Love your shop. thanks for sharing the pictures.

You  are welcome and glad you like it. Suits me and I spend many hours in there.

[WQ9E]

Buddy,

It is great that you saved the NC-98   I have one also and there is something about the size/style that I find very attractive.  I have several more expensive and/or rare National receivers but for style my three favorite Nationals are the original sliding coil catacomb NC-100X with its magic eye tube, the HRO-7 (last of the external power supply HRO receivers), and the NC-98.

As to blemishes, Hank Van Cleef used to post a lot on the original boatanchors mailing list and he referred to a lot of his radios as "blue collar" radios that bore the badges of honor earned in a long working life.  I have quite a few in that category

[Todd, KA1KAQ]

I'll add my welcome to the rest, Buddy - you've definitely come to the right place.

As to the Apache TX and its companion Mohawk RCVR, it's tough to find a better looking example of late 50s/early 60s nostalgia. I've got a set here and love them. If you're not too fussy about audio, they work fine. But I've gotta say, as much as I like mine....listening to the stock Mohawk for anything approaching a half hour or more may make your ears bleed. It only receives one sideband, and doesn't do that as well as it can with a few fairly simple mods (the S-meter blows, too). WA2PJP basically built a set of these recently using new components and incorporated a few changes which make a world of difference. Been after him to write them up, hopefully he'll get to it someday soon.

The Apache is another matter. It has nice iron and can be made to sound pretty decent without major surgery. I'm of the belief that if your mods require a Sawzall, you're probably better off just getting something else that produces closer to what you want.

As to receivers that sound great out of the box, I'm with Steve/'HX on the older Hammarlund Super Pros. They're wonderful sounding rigs and a knob twiddler's delight. Others include the SX-28, NC-240D, HRO-60 and a few more. Again, the trade off is overall performance and features - they don't perform like a newer radio.

There have been some great sounding FT-101s on AM, so I agree: don't give up on it completely. Though you might want to run an outboard receiver. Best bet? Get a few of each. 

[WBear2GCR]

Actually, you can get tanfabulous results using a very inexpensive I/Q "receiver" that goes into a computer, and runs free SDR software. Two ways, straight up as a receiver and as a pick up off the IF of a boatanchor receiver!

Fwiw, I run an R-388 on AM, and it does it wonderfully for me.

The Apache - watch for bad solder connections. Kit builders were highly variable in their skill levels. Remove the clipper in the modulator. Mods to be found here and in the technical info section, upper left corner of this page.

[kc4umo]

WQ9E,

I like old blemished radios. It just completes the look of age to me. I very seldom repaint anything electronic. Like my first 6 meter rig I built, with a wooden case.

Thanks for the Welcome Todd. I am finding tons of info here.
At the moment I have apache all over the shop lol. Pieces here pieces there. Man when you disassemble  these stuff is everywhere. Glad I have two of them. I am starting to like these beast.

Wb2gcr
I look into SDR before. But never went any further.  Think at the time I was more interested in knobs and not buttons so to speak. But now I do have interest in it.
Something I did end up doing was getting into PIC programming.  I went out and bought some chips, 3 programmers and a friend of mine sent me some boards he created for DDS vfo.  My plans were to take radios like the old Siltronix and convert them over to DDS VFO with a display where the analog dial is at.
Bad thing is Carl passed away a couple months ago before sending me the schematics of his design.
Sure miss him already

Anyway I will ramble all day if you let me.
I really like this forum here. A fine group from what I have been reading.

[N2DTS]

A long time ago, I went through most of the popular vintage AM receivers, and over time, got tired of the faults, limitations, poor audio, and reliability.
Fun to play with, not so fun to use as a main receiver.

When I operate, I want an easy to use receiver with the tools to make copy easy.
I also want to know what frequency I am on, where the transmitter is, and where people I am talking to are.
I also want all modes, great fidelity, sync detection with selectable sideband.

After going through a lot of old receivers, I settled on the r390a for a while, then built a homebrew receiver that was better for AM and sold the R390.

I then went SDR and can not go back to just a regular receiver.

There are a lot of choices in all price ranges, and one of the best ones for the price is the peaberry V2.
Its only 2 bands (any 2 bands), but it includes a transmitter (2 watts) and only costs $150.00.
It works with 3 programs at least, maybe 5, but I have not tried them all.

Next up is the sdr-iq, 500 Hz to 30 MHz, works quite well, and better then any boat anchor.

Besides a very good receiver, its a great tool.

Its fine if you want to play with the old stuff, and even use it for the good tube audio on some models, but I always run the sdr as well.

Its a frequency standard, a mod monitor, a band scope, an all mode hi fi receiver with great filters.

 

[kc4umo]

Still looking a bit into SDR.
In the mean time I just got the front back on one of the TX-1's I was working on. Got all controls functioning. Let it run on the table for 2.5 hours and checking for heat and other things that may fail due to it's age.  Have a 4 day week end coming so will spend some time checking voltages and so forth on it. I did a quick tune up and did see the meter come up in tx mode. But saw no signal on the spectrum analyzer. But was only a quick test. So going to start with voltage checks around the crystal / VFO oscillator.

I am sure I will start a new thread in the correct forum for this.