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Does anyone know of a HP signal generator thats got a sweep section for
FM (87.5 - 108 MHz) tuner alignment? The old Sound technology ST1000 was ideal for that but now long out of production but seeing that in the UK at least the FM Broadcast band is to be retrained till at least 2030 and we do have some FM Rebroadcast receivers to look after, that would be a useful unit to have! Thanks if anyone can recommend an HP one... -- Tony Sayer |
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Probably hard to find these days, but an 8690 sweeper mainframe with the
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solid state 8698 100 KHz to 110 MHz plugin should do the job. The 8698/8690 combo has a full range calibrated attenuator on the output(+10 to -110 dBm) and both internal and external modulation capabilities are available. But- it IS big and heavy! DaveB, NZ -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of tony sayer Sent: Friday, February 11, 2022 08:06 To: [email protected] Subject: [HP-Agilent-Keysight-equipment] FM Tuner alignment generator?.. Does anyone know of a HP signal generator thats got a sweep section for FM (87.5 - 108 MHz) tuner alignment? The old Sound technology ST1000 was ideal for that but now long out of production but seeing that in the UK at least the FM Broadcast band is to be retrained till at least 2030 and we do have some FM Rebroadcast receivers to look after, that would be a useful unit to have! Thanks if anyone can recommend an HP one... -- Tony Sayer |
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The HP8601A is a good choice. It¡¯s old-school analog. If you¡¯re fussy about frequency accuracy, you¡¯ll want to connect a frequency counter, but that¡¯s easily done. These don¡¯t take up much bench space, and are easy to fix.
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There¡¯s also a Sencore alignment generator, whose model number escapes me at the moment. I¡¯ll post later with it if no one else chimes in. I used to use one decades ago in a TV service shop, and it got the job done. I¡¯ve since seen many at e-flea markets for a song. Not HP, but if you need a fine service-grade instrument, it¡¯s a great choice. ¡ª°ä³ó±ð±ð°ù²õ Tom Sent from my iThing, so please forgive typos and brevity. On Feb 10, 2022, at 11:07 AM, tony sayer <tony@...> wrote: |
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SG-165. That¡¯s the Sencore gen I was trying to remember.
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Slow neurons! Sent from my iThing, so please forgive typos and brevity. On Feb 10, 2022, at 12:53 PM, Tom Lee <tomlee@...> wrote: |
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HP8340B and 8341B will do it. So will the 8340A and 8341A if you can work without FM modulation
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Quoting Tom Lee <tomlee@...> The HP8601A is a good choice. It¡¯s old-school analog. If you¡¯re fussy about frequency accuracy, you¡¯ll want to connect a frequency counter, but that¡¯s easily done. These don¡¯t take up much bench space, and are easy to fix. |
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Hi Tony, Let's look at what you are doing.? Firstly, I do a lot of FM tuner alignment, and I have an ST1000A.? I don't have a great deal of luck using the double sweep feature, and it isn't a sweep as much as high modulation levels.? Your deviation is 150 KHz to 200 KHz only, and a sweeper covers far more bandwidth.? I use a spectrum analyser when I want to do that. Some times you must follow the manufactures procedure in the manual.? One method that works best is to modulate 75 KHz in mono, then align for minimum distortion.? That even makes sense!? The THD analyser would measure 0.03% for the very best tuner, many sit around 0.15% THD.? So you could use an HP 333A or 334A or better, like a 339A.? Even a Leader THD meter would be fine.? I use an 8656A, you could use an 8657A as well.? You do want an accurate frequency, which the ST1000A cannot provide.? Other signal generators might only send a signal out on odd frequencies, like the Sencore SG80, which you will quickly find not suitable for tracking alignments.? I do use that one for distortion and stereo alignment work. To do really good alignment work, you do need a good generator or two (I use two to avoid constantly changing frequency), and the same instrument will provide a low distortion modulated signal that will allow you do adjust for minimum distortion.? There are other techniques used as well, so training is critical as well.? The ST1000A is not a magic bullet and isn't always suitable.? You definitely need another generator if you intend to use an ST1000A.? In order to get accurate signal levels I bought a Keysight N9310A - they ain't cheap!? But if you get an HP 8656A or B calibrated and correct for impedance (from 50R to 75R) you should be close.? I also use an RF power meter.? There is no end to stuff you could use to do a better job! I hope that helps, Chris |
¿ªÔÆÌåÓýI worked at a boutique hifi shop for a few years around 2015. I had an 8640 and it was fime for aligning FM tuners, as well as AM/SW and the occasional communications receiver. The shop had a Sound Technologies ST-1000, but the other technician laid total claim to it. I got a Heathkit generator for working on? stereo FM decoders. Considering the technical standards and audio processing of stations in this area, a tip top quality alignment with a sweep generator would? be a waste of time.? I did borrow and use a spectrum analyzer with a tracking generator to repair a really beaten up Marantz 10 tuner. Trying to align an IF with Butterworth filters can drive you crazy, especially if you don't have the secret factory repair manual. I never had an unhappy customer. ?? Bruce Gentry, KA2IVY On 2/10/22 15:47, Dave Brown wrote:
Probably hard to find these days, but an 8690 sweeper mainframe with the solid state 8698 100 KHz to 110 MHz plugin should do the job. The 8698/8690 combo has a full range calibrated attenuator on the output(+10 to -110 dBm) and both internal and external modulation capabilities are available. But- it IS big and heavy! DaveB, NZ -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of tony sayer Sent: Friday, February 11, 2022 08:06 To: [email protected] Subject: [HP-Agilent-Keysight-equipment] FM Tuner alignment generator?.. Does anyone know of a HP signal generator thats got a sweep section for FM (87.5 - 108 MHz) tuner alignment? The old Sound technology ST1000 was ideal for that but now long out of production but seeing that in the UK at least the FM Broadcast band is to be retrained till at least 2030 and we do have some FM Rebroadcast receivers to look after, that would be a useful unit to have! Thanks if anyone can recommend an HP one... -- Tony Sayer |
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On Thu, Feb 10, 2022 at 11:06 AM, tony sayer wrote:
Does anyone know of a HP signal generator thats got a sweep section forUnless you've got your heart set on spending a lot of money, there are several pieces of non-HP equipment that should do the task just fine: the NanoVNA and the tinySA.? Both about the size of a deck of cards,? price runs fifty bucks and up.? There are some bad tinySA clones out there, so if you buy one, buy it from one of the recommended vendors.? Recommended vendors here: https://tinysa.org/wiki/pmwiki.php?n=Main.Buying |
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Hi,
Recently I was using my 8645A for tuner alignment (a Mcintsh MR71 tube tune). I tried all sorts of methods - the 8645 can sweep the FM range with an FM modulated signal on top of it. Finally, for IF alignment, I used fixed RF frequency with FM modulation of 100Hz and 500kHz deviation. Really versatile piece of equipment... its repair gave me a lot of headaches but it was worth it. I got plenty of? valuable support from this group... cheers Martin |
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To do a comprehensive job of aligning FM tuners you really want a generator designed for that job - especially if you want to verify or align FM stereo multiplex decoders.
One example of a relatively modern unit is the Sencore SG80.? Unfortunately, because it is so good for the task, the asking and selling prices for them are rather high. There are other generators specifically made for the task as well.? There is a class of generators - sometimes called "standard" signal generators - specifically intended for servicing radios. They are modern, solid state, accurate, and reliable. There are many models from companies like Leader, Panasonic, Kenwood, Kikusui, Meguro and others. Alternatively, if you like lab grade equipment and envision general use of the generator as well - particularly if you want frequency coverage to 1 GHz or more,, there is one good choice - the Rohde & Schwarz SML/SMV series with option B5. |
Jim Allyn - N7JA
Martin