[digitalradio] Re: FT-450 on digimodes
Hi Sholto, It is not normal specifications to have 12dB tilt (or more) within the passband of an SSB transmitter. The engineer's response to your measured graph of power vs passband frequency indicates that either the engineer is BS'ing you, or the engineer is unqualified to determine the problem. Bonnie KQ6XA Sholto wrote: Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak as the filter narrows and conversely to drop off sharply as you approach the band edges. That is exactly what your data shows. Your FT-450 is performing within design parameters.
Re: [digitalradio] Re: FT-450 on digimodes
I must say that I agree with Bonnie - this is either a poor radio design or more likely you've got a 'duff' radio. I don't think the SignaLink is the problem. Simon Brown, HB9DRV www.ham-radio-deluxe.com - Original Message - From: expeditionradio expeditionra...@yahoo.com It is not normal specifications to have 12dB tilt (or more) within the passband of an SSB transmitter. The engineer's response to your measured graph of power vs passband frequency indicates that either the engineer is BS'ing you, or the engineer is unqualified to determine the problem.
[digitalradio] Re: FT-450 on digimodes
Hi Sholto, I just read the FT-450 Transmitter Specifications: Audio Response (SSB): Not more than -6dB from 400 to 2600Hz In my view that is not a very impressive specification to begin with :) But, be that as it may, your measured graph of transmit power vs audio frequency indicates about 26dB of response variation (tilt) between 400Hz and 2600Hz. This falls short of achieving Yaesu's advertised transmitter specification by approximately 20dB! So, it would be wise to do your measurement again on both Upper Sideband and Lower Sideband, and compare the two graphs. If the graphs are different, it points to tilt problems in the roofing filter, or other problems in the radio audio-to modulator chain, possibly the DSP. By the way, the hilarious errors in technical language in the reply to you from Yaesu is an indicator that the engineer doesn't have a clue what he is talking about. 73 Bonnie VR2/KQ6XA FT-450 Brochure with Specifications: http://www.yaesu.com/downloadFile.cfm?FileID=2519FileCatID=156FileName=FT%2D450%20.pdfFileContentType=application%2Fpdf Sholto wrote: Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak as the filter narrows and conversely to drop off sharply as you approach the band edges. That is exactly what your data shows. Your FT-450 is performing within design parameters.
[digitalradio] Re: FT-450 on digimodes
I did a quick test only yesterday night at my FT-450 and here are the results: 500 Hz40 W 1000 Hz40-50 W 1500 Hz40 W 2000 Hz40 - 50 W 2500 Hz20 W There is not at all such a big difference for the different tones even though it's for sure not a very even passband for the system soundcard + transceiver. I have to say, however, that I didn't do any precise measuring of the output voltage of the soundcard. This means that it is not correct to make any conclusion to the transceiver passband based on the above figures. 73 Juergen, DL8LE --- In digitalradio@yahoogroups.com, Sholto Fisher sho...@... wrote: Hi all, I picked up a new Yaesu FT-450 over Xmas and have discovered that the transmit passband seems very uneven to me. Using the same settings, i.e. audio drive, USB DATA mode, constant RF POWER selection - a single tone from the soundcard at 500Hz could produce 20W, a tone at 1000Hz 7W, a tone at 1500Hz produces only 3W output and at 2000Hz it is down to 1.8W. The interface is a Signalink SL-1+ and I know it works fine because I have used this same interface (and soundcard) with an FT-897D for years without problem. Has anyone else got an FT-450 on this group and could do a similar test to see whether it is just my rig that has the problem or it is these radios in general? The firmware in mine is 0194. Power out in CW mode is 100W without difficulty. I suppose using PSK31 the problem is not severe but wide bandwidth modes like ALE or MT63 e.t.c., could be a real problem. Other than this the FT-450 seems a very nice little rig and at $616 from AES was too good to resist. The RX is very nice but you need to play with the DSP a bit to get the most out of it. Surprisingly (at least to me) it is superb on AM SWL broadcast too. Thanks es 73, Sholto KE7HPV
Re: [digitalradio] Re: FT-450 on digimodes
Juergen, Thanks for doing the test. Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak as the filter narrows and conversely to drop off sharply as you approach the band edges. That is exactly what your data shows. Your FT-450 is performing within design parameters. I agree with your comments regarding the sound card interface roll off and I will measure this later today with an oscilloscope. But from experience this sound card (audigy 2) and i/f has been in use with my old FT-897D and I did not observe such a problem. I am quite prepared to believe it is something I am doing wrong but I will need to take more measurements to find out where the error is (if there is one). 73 Sholto. KE7HPV dl8le wrote: I did a quick test only yesterday night at my FT-450 and here are the results: 500 Hz 40 W 1000 Hz 40-50 W 1500 Hz 40 W 2000 Hz 40 - 50 W 2500 Hz 20 W There is not at all such a big difference for the different tones even though it's for sure not a very even passband for the system soundcard + transceiver. I have to say, however, that I didn't do any precise measuring of the output voltage of the soundcard. This means that it is not correct to make any conclusion to the transceiver passband based on the above figures. 73 Juergen, DL8LE --- In digitalradio@ yahoogroups. com mailto:digitalradio%40yahoogroups.com, Sholto Fisher sho...@... wrote: Hi all, I picked up a new Yaesu FT-450 over Xmas and have discovered that the transmit passband seems very uneven to me. Using the same settings, i.e. audio drive, USB DATA mode, constant RF POWER selection - a single tone from the soundcard at 500Hz could produce 20W, a tone at 1000Hz 7W, a tone at 1500Hz produces only 3W output and at 2000Hz it is down to 1.8W. The interface is a Signalink SL-1+ and I know it works fine because I have used this same interface (and soundcard) with an FT-897D for years without problem. Has anyone else got an FT-450 on this group and could do a similar test to see whether it is just my rig that has the problem or it is these radios in general? The firmware in mine is 0194. Power out in CW mode is 100W without difficulty. I suppose using PSK31 the problem is not severe but wide bandwidth modes like ALE or MT63 e.t.c., could be a real problem. Other than this the FT-450 seems a very nice little rig and at $616 from AES was too good to resist. The RX is very nice but you need to play with the DSP a bit to get the most out of it. Surprisingly (at least to me) it is superb on AM SWL broadcast too. Thanks es 73, Sholto KE7HPV
[digitalradio] Re: FT-450 on digimodes
It's hard to believe that the engineer has looked at the scale ... If such a characteristic would be standard I would not recommend the YAESU FT-450 to be used for medium or wider digital modes like Olivia etc. I remember that first tests of the FT-450 complained about poor tx audio performance, but I don't remember the modification on later versions. As it looks my radio (bought in August 2007 in Europe) performs better in combination with the soundcard I have. 73 Juergen, DL8LE --- In digitalradio@yahoogroups.com, Sholto Fisher sho...@... wrote: Juergen, Thanks for doing the test. Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak as the filter narrows and conversely to drop off sharply as you approach the band edges. That is exactly what your data shows. Your FT-450 is performing within design parameters. I agree with your comments regarding the sound card interface roll off and I will measure this later today with an oscilloscope. But from experience this sound card (audigy 2) and i/f has been in use with my old FT-897D and I did not observe such a problem. I am quite prepared to believe it is something I am doing wrong but I will need to take more measurements to find out where the error is (if there is one). 73 Sholto. KE7HPV dl8le wrote: I did a quick test only yesterday night at my FT-450 and here are the results: 500 Hz 40 W 1000 Hz 40-50 W 1500 Hz 40 W 2000 Hz 40 - 50 W 2500 Hz 20 W There is not at all such a big difference for the different tones even though it's for sure not a very even passband for the system soundcard + transceiver. I have to say, however, that I didn't do any precise measuring of the output voltage of the soundcard. This means that it is not correct to make any conclusion to the transceiver passband based on the above figures. 73 Juergen, DL8LE --- In digitalradio@ yahoogroups. com mailto:digitalradio%40yahoogroups.com, Sholto Fisher sholto@ wrote: Hi all, I picked up a new Yaesu FT-450 over Xmas and have discovered that the transmit passband seems very uneven to me. Using the same settings, i.e. audio drive, USB DATA mode, constant RF POWER selection - a single tone from the soundcard at 500Hz could produce 20W, a tone at 1000Hz 7W, a tone at 1500Hz produces only 3W output and at 2000Hz it is down to 1.8W. The interface is a Signalink SL-1+ and I know it works fine because I have used this same interface (and soundcard) with an FT-897D for years without problem. Has anyone else got an FT-450 on this group and could do a similar test to see whether it is just my rig that has the problem or it is these radios in general? The firmware in mine is 0194. Power out in CW mode is 100W without difficulty. I suppose using PSK31 the problem is not severe but wide bandwidth modes like ALE or MT63 e.t.c., could be a real problem. Other than this the FT-450 seems a very nice little rig and at $616 from AES was too good to resist. The RX is very nice but you need to play with the DSP a bit to get the most out of it. Surprisingly (at least to me) it is superb on AM SWL broadcast too. Thanks es 73, Sholto KE7HPV
Re: [digitalradio] Re: FT-450 on digimodes
Hello Sholto, In the Yaesu FT-450 Yahoo group photo files there are a series of receive BW scans I took with my 450, with a couple of 857 scans thrown in for comparison. If it has a narrow CW filter, the 857 IMO wins on filtering and its audio DPS works extremely well as an adjunct to accessory filters. The 450's SSB response seems by comparison rather peaky, just as the plot linked here indicates for transmit. Unfortunately, the 450 lacks the ability to move the carrier closer to the filter skirt. I have not done 450 output power measurements vs audio frequency, but it sounds like a worthwhile experiment. I will say that where we use wider modes for MARS, such as 1K MT63 and Olivia 1K 32 tone (very nice weak signal performance) I have not noticed the 450 being less effective than a Harris RF350 (300 Hz - 3000 Hz BW). But I have not looked, either! Cortland KA5S [Original Message] From: Sholto Fisher sho...@probikekit.com To: digitalradio@yahoogroups.com Date: 1/8/2009 12:45:20 PM Subject: Re: [digitalradio] Re: FT-450 on digimodes Juergen, Thanks for doing the test. Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak ..
Re: [digitalradio] Re: FT-450 on digimodes
Cortland, Thanks for the info. Can I ask what firmware version is on your 450? Presumably the tx filter is implemented by DSP on these models and it may just be a software issue which in time may be fixed. The version here is 0194. Regarding the rx filtering I am quite happy with the rig. Using a software spectrum analyzer (MultiPSK) the rx passband looks fine. I had an FT-897D with both a 300Hz and 500Hz filter and while the 450 DSP CW filter is not quite as effective I still find it surprisingly good on CW and general receive. In fact at this point I feel it has a better receiver than the 897. Certainly the contour is a big help on some signals and the NR seems not quite as weird sounding as the 897 was. The manual notch is also very impressive and much more useful than the 897 auto notch. CAT control on the 450 is much better too, it is more responsive than the 897 and works very well with HRD and OmniRig. All in all I am quite happy with it and if one day a software update comes along and fixes the lumpy tx passband it will be a bonus. 73 Sholto KE7HPV Cortland Richmond wrote: Hello Sholto, In the Yaesu FT-450 Yahoo group photo files there are a series of receive BW scans I took with my 450, with a couple of 857 scans thrown in for comparison. If it has a narrow CW filter, the 857 IMO wins on filtering and its audio DPS works extremely well as an adjunct to accessory filters. The 450's SSB response seems by comparison rather peaky, just as the plot linked here indicates for transmit. Unfortunately, the 450 lacks the ability to move the carrier closer to the filter skirt. I have not done 450 output power measurements vs audio frequency, but it sounds like a worthwhile experiment. I will say that where we use wider modes for MARS, such as 1K MT63 and Olivia 1K 32 tone (very nice weak signal performance) I have not noticed the 450 being less effective than a Harris RF350 (300 Hz - 3000 Hz BW). But I have not looked, either! Cortland KA5S [Original Message] From: Sholto Fisher sho...@probikekit. com mailto:sholto%40probikekit.com To: digitalradio@ yahoogroups. com mailto:digitalradio%40yahoogroups.com Date: 1/8/2009 12:45:20 PM Subject: Re: [digitalradio] Re: FT-450 on digimodes Juergen, Thanks for doing the test. Now I am confused because I contacted Yaesu and sent them this graph of my measured transmit passband: http://www.projects andparts. com/misc/ ft-450tx. gif http://www.projectsandparts.com/misc/ft-450tx.gif And this is what the engineer told me: Your graph shows the typical audio roll off expected. The bass band deviation for the FT-450 is 300-2500. You would expect the dBWs to peak ..
