| Author |
Message |
    
Triple1
| | Posted on Friday, December 05, 2003 - 12:09 pm: | 
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Love my Yaesu FT-840,But as you all know Ham rigs are a little weak in the am department.
Is there mod limiters on this radio or what would I have to do to improve the modulation.
It's not to bad using a cobra hand power mike and setting the compression on, but it could be better. Note if you are not carefull with the setting a backward swing happens.
Thanks in advance
Triple1 |
Bruce
| | Posted on Friday, December 05, 2003 - 2:50 pm: |
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I run my ft-840 on 10 meter am ( 29.0-29.2 )On AM I have found that the internal speach prosser works fairly well but a external one on AM if used carefully can add punch also. one i use is the Ten-Tec 1551 it is small cheep only requires to be built into a box and powered. There is one made for this radio that is installed in the base mike but 10 times the price.
http://www.tentec.com/amaccyKit.htm ( # 1551 )
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Sqwirl2001
| | Posted on Friday, December 05, 2003 - 4:24 pm: |
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In order to use this rig on AM,it requires the YF-112A filter.Nothing you can do will make it work without it due to the fact the radio comes from the factory with narrow filtration on transmit.The filter gives it the neccessary 6KHZ transmit bandwith.This info can be confirmed from Yaesu tech support as I had the same problem.
73 KC7OV |
Sqwirl2001
| | Posted on Friday, December 05, 2003 - 4:32 pm: |
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In addition,the same goes for the current models of Yaesu rigs as the FT-920,FT-100d |
Bruce
| | Posted on Friday, December 05, 2003 - 8:21 pm: |
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I have all 3 filters in mine and as i said it works fine on AM but a bit of processing dosnt hurt |
Stickshift
| | Posted on Saturday, December 06, 2003 - 5:05 am: |
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Bruce,
I've been seriously thinking about getting my ticket. In a previous post on another thread, I stated my disliking of code. I've decided that I don't want to wait for the FCC to drop the code issue. I've been listening to HF for years and just recently had a chat with a local who is licensed. He pointed me in the wright direction! I've been considering the FT-840 for quite sometime now. It is a very nice rig for the price! I've heard several while listening on my Heathkit HR-10B and Radio Shack DX 390. Impressive sound for a small price! Haven't heard much on am though. Most of what I have been hearing on 10 am is tube equipment. As for ssb, the FT-840 has my vote for an inexpensive rig! 
73's
stickshift |
Bruce
| | Posted on Saturday, December 06, 2003 - 12:44 pm: |
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Its a FINE radio its been made a long time not high on the technolgy list is simple has only realy need fetures but a good example of KISS I bought a radio shack DSP filter for mine and it does help on weak signals. i HIGHLY recomend the AM filter with it this radio becomes a great short wave radio. Now there are other radios that cover VHF/UHF too newer technolgy but none sound like the 840 it just has a nice real radio sound to it. AVOID FT-100 not FT-100D and PRE 1980 radios without WRC bands like 17 meters bad buys unless given to you.
Bruce |
Stickshift
| | Posted on Saturday, December 06, 2003 - 2:47 pm: |
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Thanks for the info Bruce! Yes, as you stated, the audio quality of the FT-840 is very nice. This radio is basically the same as the FT-747. I've seen a few 747's in the $300 to $350 range. I've even seen a few 840's go for that on ebay. Once in awhile they can be had for a few dollars more with the fm board and filters installed. I will keep looking! My FT-757GX seems to be a boat anchor now. I've hooked a dummy load to it and get very low transmit power (less than 1 watt). It needs some attention from a good tech. I will hold on to it until I can reach that "good tech" status. Until then it isn't hurting to have it around as a decent reciever. As for the license, I hope to work on code and brushing up on other areas during my Christmas vacation. I'll keep you posted!
73's my friends
stickshift |
Dimstar
| | Posted on Saturday, December 20, 2003 - 2:54 pm: |
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Stickshift I own a FT 840 that I use on AM quite often. I use a Astatic D-104 mic with the gain on the mic opened just a bit and the gain on the rig set between 9 and 10 o'clock with the processer in the on position. I run the rig through a FL 2100 Yaesu amplifier and I get pretty good audio reports. Make sure the gain is not too high or you will sound distorted and the ALC will kick in too much. My FT 840 is not modified, but you can directly run audio through the balanced modulator and your transmit audio will sound almost broadcast quality. The 6 kc AM filter is a must. AM is a great mode to run and here in the northeast, it is very active. Try this link http://www.amwindow.org/tech/htm/plastic.htm It will show you how to set up a modern rig for AM. W2HIY has a 2 band eq that will work nicly with the FT 840. I use it on Both my 840 and My FT101 which has the transmit audio mods done with good results. W2hiy has a web site and also has other audio products that might interest you. Also look up G4FON and try his code tutor. Its the best freebe code tutor out there! 73 and good luck on AM Ed www.amwindow.org ( another link too!)
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Tech8541
| | Posted on Sunday, December 28, 2003 - 9:28 pm: |
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the 840 is a great radio. there is no am 'limiter' for this radio. i could not find one by the schem and contacted vertex/yaesu tech support and they confirmed that there was no adjustment for amc nor a 'limiter'.
this radio -will- hit 100% modulation, so don't think it is undermodulated. it just does not meet what most cbers want. |
Bruce
| | Posted on Monday, December 29, 2003 - 11:37 am: |
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My 10 meter am useage of the ft-840 clearly shows if you use a good mike even the stock one the radio sounds JUST FINE on 29.0-29.15 mhz the AM sub band on 10 meters. My Modulation meter easly goes close to 100% with the stock mike i even tried a D-104 cranked wide open all it did was allow the guy on the other end to hear the rattle of fans in the room and drove the mod meter up a bit. Bottom line nothing wrong with this set on AM or SSB or CW but the FM add on board is a bit hoaky. |
Triple1
| | Posted on Saturday, January 03, 2004 - 1:05 pm: |
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OK guys,In responce to my own question.Yes,I have the am filter,etc.To help the am modulation in these types of radios,the right microphone is the key. What I have found is the Heil mobile hand mike was what I was looking for. It has dual elements,non power. Place it in the DX position and it gives sound simular to D-104. Very strong audio in the am department.Works equally well on SSB.Think I'll buy the Heil desk mike now.
Later
Triple1 |
Pig040
| | Posted on Sunday, January 04, 2004 - 10:32 am: |
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I have the Heil Goldline with the two elements (4&5) in it I have it buckled up to my Kenwood, tried many other mics this one works the best on my rig. |
