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#1
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My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this??
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#2
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GW1CJJ wrote:
My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this?? Cheers This is a Mk1 (i.e. no mark), right? Not a MkII. Is it OK on FM, but not on USB? And what about LSB and CW? Is the SSB modulation still OK? |
#3
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On Apr 25, 2:30*am, GW1CJJ wrote:
My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this?? Cheers I've got a MkII here with a similar problem, although it's not as severe... about 600~800Hz off from the actual frequency. I'm guessing it could be the age of the reference crystals having an impact (these are frequency synthesised rigs), but without ripping the thing apart, I'm not sure. 1kHz isn't enough to bother me... just use the frequency display as a guide then tune around until you get the target station spot on. 4kHz on the other hand, would be quite irritating. |
#4
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Stuart Longland VK4MSL wrote:
On Apr 25, 2:30Â*am, GW1CJJ wrote: My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this?? Cheers I've got a MkII here with a similar problem, although it's not as severe... about 600~800Hz off from the actual frequency. I'm guessing it could be the age of the reference crystals having an impact (these are frequency synthesised rigs), but without ripping the thing apart, I'm not sure. 1kHz isn't enough to bother me... just use the frequency display as a guide then tune around until you get the target station spot on. 4kHz on the other hand, would be quite irritating. I have the original FT-290 (I presume that is what he refers to when writing Mk1, but I am not sure). In this rig, the synthesizer is running at a constant frequency offset from the tx/rx frequency by the first IF. The transmitter operates by generating FM/SSB/CW at the first IF and mixing it with the synthesizer frequency. As SSB is generated by modulating a crystal frequency using a balanced modulator and then feeding it through the IF filter, I think that if this crystal is off frequency there will be a severe effect on the modulation (as the filter passes the wrong part of the spectrum). That is why I asked if modulation is affected. If it isn't, it is a bit unclear where the frequency difference between rx and tx can originate. (of course, it is easy to explain a difference between actual rx AND tx frequency and the dial display) It could well be that the MkII has a different method of operation. |
#5
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Seems fine on FM Haven't tried on CW (no-one seems to be using thant mode on 2m) Similarly have only worked other stations on USB so not sure about LSB |
#6
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GW1CJJ wrote:
'Rob[_8_ Wrote: ;705288']GW1CJJ wrote:- My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this?? Cheers- This is a Mk1 (i.e. no mark), right? Not a MkII. Is it OK on FM, but not on USB? And what about LSB and CW? Is the SSB modulation still OK? Yes it's a MK1 Seems fine on FM Haven't tried on CW (no-one seems to be using thant mode on 2m) Similarly have only worked other stations on USB so not sure about LSB Ok, next time you work someone in USB ask him for a test what happens when using LSB and maybe CW. (you would have to connect a key or at least a wire using a 3.5mm jack) |
#8
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GW1CJJ wrote:
'Rob[_8_ Wrote: ;706422']GW1CJJ wrote:- 'Rob[_8_ Wrote: - ;705288']GW1CJJ wrote:- My FT=290 is slightly off frequency on TX, it is about 4Khz lower than the display frequency but the RX is spot on display frequency so I have to operate with the clarifier switched on to be able to resolve the other station. Antone know how I can adjust this?? Cheers- This is a Mk1 (i.e. no mark), right? Not a MkII. Is it OK on FM, but not on USB? And what about LSB and CW? Is the SSB modulation still OK?- Yes it's a MK1 Seems fine on FM Haven't tried on CW (no-one seems to be using thant mode on 2m) Similarly have only worked other stations on USB so not sure about LSB- Ok, next time you work someone in USB ask him for a test what happens when using LSB and maybe CW. (you would have to connect a key or at least a wire using a 3.5mm jack) This is an original FT-290 ie the one with the built in battery pack. Everything else on the radio seems to check out OK except a discrepancy between TX & RX frequency on SSB - nothing noticable on FM & don't use CW. Just hoping there is a simple adjustment to net the TX/RX frequencies (& hopefully get these to correspond to the indicated frequency on the display) There isn't. I explained how the transceiver works. That is why I am trying to determine what is the problem with your set. But if you don't like to experiment a bit, good luck finding the problem. |
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