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1-8 of 8 messages
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Recently obtained Ameco TX-62 transmitter
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by KC2RMT on June 7, 2007
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Hi all,
I am essentially brand new to ham radio. I recently obtained my license, and have just gotten a used ameco tx-62 transmitter. I chose one that can operate on 2 and 6 meters because i have heard 6 meters is used for a lot of neat things, such as signal bouncing off the moon, and it can be used for phone and CW, and doesn't require an outrageously large antenna. Upon receiving it, I did some reading about it, and learned that it uses an 8mc crystal, which i'm assuming is 8mhz. If this is true, how do you vary the frequency that the transmitter operates on? Does it have to do with the loads on different parts of the transmitting tube or do you vary the crystal that you use? If the latter is true, would I be better off obtaining a VFO so I do not have to get a different crystal for every different band i wish to operate on? Pleas excuse my lack of knowlege in this area. Any help would be great!
73, de KC2RMT
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RE: Recently obtained Ameco TX-62 transmitter
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by K3WVU on June 7, 2007
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Wow, this rig is almost as old as I am!
Seriously, I'm not sure that this is the way to go for you, especially if you're new to ham radio. The TX-62 is either crystal controlled, or you can use a VFO, the 621, I believe, if you can find one. It puts out a respectable 75 watts, but you're limited to CW and AM, and there isn't much AM on 6 and 2 meters. Also, with a rig this old, you may be looking at some extensive refurbishment, especially with the capacitors.
You may want to go with something more modern. There are a number of 2 meter FM rigs availavle and also some 6 meter FM rigs. One other option is to find a used ICOM 706 or 706MKII. Both have both 6 meters and 2 meters and can be had for a decent price.
73
Dwight
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RE: Recently obtained Ameco TX-62 transmitter
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by KC2RMT on June 7, 2007
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Heh, thanks for the advice. While I look for another cheap rig to get myself going, I'm still somewhat interested in how this rig is supposed to work crystal-wise. If it takes an 8Mc crystal like all the documentation I have seen suggests, that's awfully far from the 50mhz seen on the 6 meter band. How do you calculate what output frequency you will have with a given crystal in this radio?
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RE: Recently obtained Ameco TX-62 transmitter
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by N3JBH on June 7, 2007
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i know i love to have one them tx-62's fine cw
x mitter. but hey forget the crystals use a vfo. jeff n3jbh
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RE: Recently obtained Ameco TX-62 transmitter
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by KE3WD on June 7, 2007
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>>Heh, thanks for the advice. While I look for another cheap rig to get myself going, I'm still somewhat interested in how this rig is supposed to work crystal-wise. If it takes an 8Mc crystal like all the documentation I have seen suggests, that's awfully far from the 50mhz seen on the 6 meter band. How do you calculate what output frequency you will have with a given crystal in this radio? <<
Most xtal controlled radios don't use the desired frequency as the frequency of the xtal itself, although very simple oscillators and transmitters may to reduce component count.
Typically the xtal oscillator is followed by filtering which strips out one of the harmonics above the fundamental frequency of the crystal. With an 8mHz xtal we could be talking the 6th order harmonic which would be 48MHz. --
BUT, the xtals for the 6 meter Ameco are 8.3333 to 9.000MHz.
The xtals for the 2 meter version of the same unit were from 8.000 to 8.2222 Mhz.
Someone stuck a crystal meant for the two meter radio into the socket of your 6 meter radio.
DON'T TRANSMIT with that xtal in there for you will be transmiting outside of the 6 meter band!
Owner's manual and schematic for free download are here:
http://www.one-electron.com/FC_Ham.html
(BTW "mc" is "megacycles" for "cycles per second" which was replaced with the Hertz terminology to honor Heinrich Hertz not all that long ago)
Nice pixture of the rig here:
http://www.rigpix.com/mischam/ameco_tx62.htm
You should be able to obtain xtals for the rig, or look into finding a VFO for it.
I would heartily recommend that you just put it on the shelf for now, get your hands on a more modern 6 meter rig and use that to learn and perfect your operating skills, saving the Ameco for later on-air use as you collect the parts, resistors and caps mostly, maybe a tube or two, clean the controls, keep your eyes open for the right xtals at hamfests, etc. and one day in the future you can operate CW with it and have some boat anchor fun.
73
.
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RE: Recently obtained Ameco TX-62 transmitter
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by KE3WD on June 7, 2007
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Forgot to mention "multiplier" in my post.
The 6 meter rig multiplied xtal frequency by 6 but the 2 meter multiplied by 18.
As per your question about changing the freq of the xtal, well, you are what we used to call "rockbound" with a rig like that one.
The way to QSY is to have more than one xtal.
Yeah, that got old quickly, which is why the VFO got to be so popular, although many would drift a bit, a problem usually solved with long warmup before operation. Some guys used to leave the rig ON or at least the VFO ON all the time so that it would stay at the same temperature and not drift as much.
There are ways to "rubber" a crystal -- move it slightly left or right of frequency -- by putting a trimmer cap in series with it, some intrepid hams even used to open the xtal case and actually write a big hairy X on the crystal itself with lead pencil to move it down a bit, but that wouldn't be recommended procedure on the 6 meter band, those kind of tricks work best "down low" on 3 or 7 MHz.
HTH
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RE: Recently obtained Ameco TX-62 transmitter
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by N6AJR on June 7, 2007
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somewhere around here I have a sheet of window glass and some " crystal grinding powder, I got from a SK's wife. he used to tweek his own xtals, his dad was a ham and he had been a ham, and also worked as the motorola tech for the city of oakland and had a ton ( litterly 2 1/2 pick up beds full) od parts , which I promplly dietributed to lots of local hams, some of it even went to Kenya whit the helpof a friend.
I still have about 5 pounds of assorted Xtals around here somewhere.
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RE: Recently obtained Ameco TX-62 transmitter
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by WB2WIK on June 8, 2007
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The TX-62 is a fun and cute transmitter but isn't terribly useful in 2007. I had one brand new in 1966, so it's obviously at least that old (41 years).
It doesn't run 75W output power! It runs 75W DC input power, and about 35W output, using Heising modulation for AM, or of course also runs CW. It requires an external VFO to change frequencies, and there was a good and pretty stable matching unit for that, Ameco model VFO-621. It's also only a transmitter, so it's not a complete station -- you still need a receiver.
What makes this a bit painful is that there is *very little* activity on 2m AM or 6m AM at all. It's been replaced by SSB, back in the 1960s and early 1970s. I can count on one hand the number of 2m AM stations I've heard on the air in the past ten years...although I work hundreds and hundreds on SSB. AM is not a suitable mode for moonbounce or much of anything other than local chit-chats amongst people using very old equipment.
The TX-62 at this point is mostly a collector's curiosity piece and not a viable station for daily use.
2m and 6m are both great bands, but all the "weak signal" activity is SSB (and a bit of CW and JT digital modes), and all the "local" activity is FM simplex and repeaters. The TX-62 doesn't do any of this, and again, it's only a transmitter; without a suitable receiver, you can't make a contact with it.
WB2WIK/6
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