The HP 400EL is not an RMS meter. That would be an HP 3400A. 73, Rob, NC0B
>>> "W7CE" <w...@curtiss.net> 3/14/2009 8:34 am >>> Kevin, The preamp is connected to RX1 in/out. I did some comparison tests between Ant1 and Ant3 but could find no measurable difference. I've thought about moving the preamp out to the antenna, but with my coax loss of about 0.5 dB I doubt if the improvement in NF would be noticeable on 6M. 73, Clay W7CE ----- Original Message ----- From: "Kevin Hobbs" <ve...@cogeco.ca> To: <flexradio@flex-radio.biz> Sent: Saturday, March 14, 2009 6:02 AM Subject: Re: [Flexradio] 5000A 6 meter MDS/NF > Hi Clay > > Thanks for the tests ... very interesting to me as I now primarily stick > to > 6m. I use the 5000A with DEMI 6m preamp in the RX Loop. A few quick > clarifications: > > 1) Was the preamp in the RXin/out Loop or in the Ant Line? > 2) Which Antenna Jack did you use (wondering if there is extra switching > in > any of the 3 paths)? > > > TNX Kevin > > > -----Original Message----- > From: flexradio-boun...@flex-radio.biz > [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of W7CE > Sent: March-13-09 3:06 PM > To: ger...@flex-radio.com; flexradio@flex-radio.biz > Subject: [Flexradio] 5000A 6 meter MDS/NF (was Flex-1500 and multiple > transverters) > > I finally got around to checking the 6M performance of my 5000A in the lab > and thought I'd share the results. I'm using an ARR P50VDG pre-amp spec'd > at 24 dB gain and 0.5 dB NF. I don't have any way to confirm a noise > figure > > that low, but the measured gain is 26 dB. I measured the 500 Hz CW MDS at > 50.125 for all four combinations of internal and external preamps turned > on > and off. The results are as follows: > > Ext/Int Preamp 500 Hz MDS/NF > OFF/OFF -112 dBm/35 dB > OFF/ON -126 dBm/21 dB > ON/OFF -138 dBm/9 dB > ON/ON -145 dBm/2 dB > > MDS was measured using an HP 4396A with an HP 100 dB attenuator as the > signal source and an HP 400EL RMS voltmeter connected to the headphone > jack. > >>From a calibration standpoint, the 4396A/attenuator input signal levels > agreed with the PowerSDR signal level readings 100%. I figure that my > measurement uncertainty is +/- 0.5 dB, with the 2dB NF measurement being > the most uncertain. If I calculate the NF of the receiver using the 26 dB > gain and 0.5 dB NF of the ARR preamp and the measured 21dB NF of the 5000A > (internal preamp on), then I get a NF of 1.6 dB (within my assumed > measurement uncertainty). > > For some subjective on-the-air tests, I compared it to a 756ProIII. For > reference, the measured 6M 500 Hz MDS/NF on my 756 ProIII is -142dBM/5dB > (preamp 2 enabled). Without the external preamp, I can copy signals on > the ProIII that are difficult at best to pull out of the noise on the > 5000A. > > With the external preamp, the 5000A seems to hear slightly better > especially > > on CW with very narrow filter settings. Also the noise blanker on the > 5000A > > is significantly better than the ProIII when local power line noise flares > up. > > For anyone serious about 6M, I wouldn't even consider using the 5000A > without an external preamp. But with one, it looks like it is going to > perform really well on 6M. While we're waiting for the 6M Es season to > start, I'm going to try to make a few 6M EME contacts with it, especially > near the end of this month when E51SIX is on the air from the South Cook > Islands. > > I have my order in for the Flex-1500 and hope that more 6M gain is > provided > on it. It won't be as convenient to use an external preamp with that > radio > and on 6M an extra 20 dB of front end gain will make a huge difference in > performance. > > 73, > Clay W7CE > >> >> -----Original Message----- >> From: flexradio-boun...@flex-radio.biz >> [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of W7CE >> Sent: Wednesday, February 25, 2009 9:20 AM >> To: flexradio@flex-radio.biz >> Subject: [Flexradio] Flex-1500 and multiple transverters >> >> Will the Flex-1500 have a mechanism such as UCB or Flex-Wire to support >> control of multiple transverters (e.g., relay control to select the >> transverter, key out for transmit, and sequencing for pre-amps and >> amplifiers)? Also, is provision made for an external pre-amp for 6M? >> My >> experience with the 5000A is that a pre-amp is an absolute necessity on >> 6M >> (with a 21 dB ARR pre-amp the noise floor drops 21 db). >> >> [GY] We do plan to have a FlexWire control output for the purposes >> stated. >> We will probably have a higher gain preamp in the 1500 at the expense of >> blocking dynamic range. Note that the 21 dB drop in the noise floor is >> probably not calibrated accurately. You will not get 1 dB/dB of gain. >> >> Is it possible to run two copies of PowerSDR at the same time - one for >> the >> 5000A and one for the 1500? >> >> [GY] This is as yet untested but I expect that it will not be a problem. >> People do this now with the SDR-1000 and FLEX-5000 on the same system. >> >> I'm thinking of placing my pre-order this week, but don't have sufficient >> info to determine if it will meet my needs. >> >> 73, >> Clay W7CE >> >> >> _______________________________________________ >> FlexRadio Systems Mailing List >> FlexRadio@flex-radio.biz >> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >> Knowledge Base: http://kc.flex-radio.com/ Homepage: >> http://www.flex-radio.com/ >> > > > _______________________________________________ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: > http://www.flex-radio.com/ > > > _______________________________________________ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: > http://www.flex-radio.com/ _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ -- If this email is spam, report it here: http://www.onlymyemail.com/view/?action=reportSpam&Id=ODExMjI6ODYzNzkzNDU5OnJvYkBuYzBiLmNvbQ%3D%3D _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
