Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Alberto, many thanks but I need just to "calibrate" (I should say invent) a S-Meter for a BITX20a QRP Radio, and possibly double check the sensitivity in some very relaxed way. My equipment: - MiniVNA Pro with a 2 signal generators from approximately 0 to -60dBm (not clear if they have an additional 12 or 18 dB attenuator inside). Obviously it is not calibrated nor checked. - The 2105 - Dummy load and VNA calibration set (short, open and 50Ohm dummy load) - several SMA/BNC adapters (probably not enough ones) I need the typical -73dBm and something in the -112dB range to be satisfied. I don't know if and how much the MiniVNA is accurate, I should ask some ham in ARI to double check it. Toto I have a feeling we are not in Agilent anymore... Giuseppe Marullo IW2JWW On 1/10/2014 4:50 PM, Alberto di Bene wrote: On 1/8/2014 11:13 PM, Alan Melia wrote: /Hi Alberto it is quite interesting to continue that test with no attenuator but the shells of the coax plugs connected together. I would guess with the gear you have the resultant would be at least 120dB downbut this is not the case for all signal generators!/ Hi Alan, quite true. I performed the test you suggested, using as generator a Rohde&Schwarz SMDU that has a calibrated output down to -140 dBm, so it must be well shielded... I used 10 MHz as frequency, and, given that the settings of this forum do not allow HTML (why ?) these are the links to the screen captures stored on my Dropbox account. As selective voltmeter I used the ELAD FDM-S1 receiver together with, guess what... Winrad :-) This is what I see with the Hatfield attenuator set to its maximum, i.e. 100 dB : https://dl.dropboxusercontent.com/u/15089947/hatfield-100dB.gif Setting it to 0 dB gives this result : https://dl.dropboxusercontent.com/u/15089947/hatfield0dB.gif So you can see that the difference between the two measures is just 88 dB, not the theoretical 100... And it is almost all to be attributed to internal leakage of the attenuator, because, excluding the attenuator, and just connecting together the two BNC shells, leaving the center pin unconnected, gives this : https://dl.dropboxusercontent.com/u/15089947/hatfield-shells.gif So the Hatfield attenuator IMHO can be fruitfully used only if you do not pretend from it the utmost precision at high attenuation settings. 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
On 1/8/2014 11:13 PM, Alan Melia wrote: /Hi Alberto it is quite interesting to continue that test with no attenuator but the shells of the coax plugs connected together. I would guess with the gear you have the resultant would be at least 120dB downbut this is not the case for all signal generators!/ Hi Alan, quite true. I performed the test you suggested, using as generator a Rohde&Schwarz SMDU that has a calibrated output down to -140 dBm, so it must be well shielded... I used 10 MHz as frequency, and, given that the settings of this forum do not allow HTML (why ?) these are the links to the screen captures stored on my Dropbox account. As selective voltmeter I used the ELAD FDM-S1 receiver together with, guess what... Winrad :-) This is what I see with the Hatfield attenuator set to its maximum, i.e. 100 dB : https://dl.dropboxusercontent.com/u/15089947/hatfield-100dB.gif Setting it to 0 dB gives this result : https://dl.dropboxusercontent.com/u/15089947/hatfield0dB.gif So you can see that the difference between the two measures is just 88 dB, not the theoretical 100... And it is almost all to be attributed to internal leakage of the attenuator, because, excluding the attenuator, and just connecting together the two BNC shells, leaving the center pin unconnected, gives this : https://dl.dropboxusercontent.com/u/15089947/hatfield-shells.gif So the Hatfield attenuator IMHO can be fruitfully used only if you do not pretend from it the utmost precision at high attenuation settings. 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Hi Alberto it is quite interesting to continue that test with no attenuator but the shells of the coax plugs connected together. I would guess with the gear you have the resultant would be at least 120dB downbut this is not the case for all signal generators! The result is usually particularly poor with "video" generators, and often laughable with function generators. This is were many LFers get confused calibrating receive equipment. Alan G3NYK - Original Message - From: "Alberto di Bene" To: Sent: Wednesday, January 08, 2014 8:50 PM Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs On 1/6/2014 2:13 PM, Giuseppe Marullo wrote: /I would like to know the specs for this attenuator, especially the maximum frequency, if any good folk has a ballpark idea... I was not able to locate any info about it./ I too have one, bought cheaply a couple of years ago on eBay. I tested its accuracy with a calibrated RF generator and a Selective Voltmeter, both from W&G, at a frequency of approximately 10 MHz. Up to roughly 70 - 75 dB attenuation, it is reasonably accurate. Beyond that value, the internal leakages dominates, and you can forget to have an attenuation of 100 dB, when you set it to the maximum... 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
On 1/6/2014 2:13 PM, Giuseppe Marullo wrote: /I would like to know the specs for this attenuator, especially the maximum frequency, if any good folk has a ballpark idea... I was not able to locate any info about it./ I too have one, bought cheaply a couple of years ago on eBay. I tested its accuracy with a calibrated RF generator and a Selective Voltmeter, both from W&G, at a frequency of approximately 10 MHz. Up to roughly 70 - 75 dB attenuation, it is reasonably accurate. Beyond that value, the internal leakages dominates, and you can forget to have an attenuation of 100 dB, when you set it to the maximum... 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
David and all, following my post I was directly contacted by Peter (G4BCH) from Pascall that kindly forwarded to me the datasheet of the Dinosaur. Should anyone need it, just contact me off list. >Giuseppi, with any old attenuator its worth a DC resistance check to see if one of the attenuator sections has not been fried over the years. Should be easy enough to fix if somebody has Once I will receive the attenuator (somewhere lost in the Mediterranean between Italy and Greece) I will do some checks, I just need to scale down the signal generator of the MiniVNA Pro, by far not high end equipment but really fun to use. Not to mention I was pleasantly surprised someone still cared to address my request, both from the list and from the vendor. Giuseppe Marullo IW2JWW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Alan, good point I'd forgotten Pascall inherited this attenuator, I've a
vague recollection of using Hatfield ones decades ago and suspect the
spec was similar to:
http://ijkscopes.com/PDF_image/Pascall%20PDF/AC701_AC702.pdf
RS components retailed these for many years so that may be another
source for an older data sheet
Giuseppi, with any old attenuator its worth a DC resistance check to see
if one of the attenuator sections has not been fried over the years.
Should be easy enough to fix if somebody has been careless, I recall it
being made with standard wire ended resistors, 1.8 W or something similar.
David
--
Message: 5
Date: Tue, 7 Jan 2014 00:01:35 -
From: "Alan Melia"
To: "Discussion of precise time and frequency measurement"
Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Message-ID: <5A50B59B6A42487F8AEF9AF2AF8A7001@gnat>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Hi agn Giuseppi that may indicate your units date from later, after the
company were acquired by Pascall
Alan
- Original Message -
From: "Giuseppe Marullo"
To: "Discussion of precise time and frequency measurement"
Sent: Monday, January 06, 2014 4:05 PM
Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
On 07/01/2014 00:03, time-nuts-requ...@febo.com wrote:
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
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Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Hi agn Giuseppi that may indicate your units date from later, after the company were acquired by Pascall Alan - Original Message - From: "Giuseppe Marullo" To: "Discussion of precise time and frequency measurement" Sent: Monday, January 06, 2014 4:05 PM Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs Alan, thank you for your answer. >. If you are refering to the units in blue crackle diecast case with miniature toggle Sort of, but "mine" is orange: http://thumbs3.ebaystatic.com/d/l225/m/mkbCnoRgl8RNnxvJdy9phAw.jpg Seems pretty close, I was hoping for some better figure but I plan to use it for HF bands, so no big deal if the Fmax is 150MHz. Thank you again. Giuseppe Marullo IW2JWW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Alan, thank you for your answer. >. If you are refering to the units in blue crackle diecast case with miniature toggle Sort of, but "mine" is orange: http://thumbs3.ebaystatic.com/d/l225/m/mkbCnoRgl8RNnxvJdy9phAw.jpg Seems pretty close, I was hoping for some better figure but I plan to use it for HF bands, so no big deal if the Fmax is 150MHz. Thank you again. Giuseppe Marullo IW2JWW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Hi Guiseppi I think I have some papers on them somewhere.I cant remember the model numbers. If you are refering to the units in blue crackle diecast case with miniature toggle switches the spec max frequency is 150MHz from memory. I did plot one some time ago on my Spectrum Analyser and TG, They are usable to 200MHz with reduced accuracy. Alan G3NYK. - Original Message - From: "Giuseppe Marullo" To: "Discussion of precise time and frequency measurement" Sent: Monday, January 06, 2014 1:13 PM Subject: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs Hello to all, and Happy New Year. I would like to know the specs for this attenuator, especially the maximum frequency, if any good folk has a ballpark idea... I was not able to locate any info about it. Thanks in advance. Giuseppe Marullo IW2JWW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT - Old Hatfield 2105 Step attenuator specs
Hello to all, and Happy New Year. I would like to know the specs for this attenuator, especially the maximum frequency, if any good folk has a ballpark idea... I was not able to locate any info about it. Thanks in advance. Giuseppe Marullo IW2JWW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
