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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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13th Dec 2014, 3:47 pm | #1 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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1-500MHz frequency counter
I've just bought one of those 1-500MHz frequency counters on ebay for £7.59 and it looks to be just the job but I don't recognise the small coax socket at the interface. Has anyone else bought one who can advise me on this please?
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13th Dec 2014, 3:53 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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Re: 1-500MHz frequency counter
Which one?
I'm suspecting it will be a "SMA" connector - as used on mobile phones and wireless-routers. |
13th Dec 2014, 4:49 pm | #3 | |
Guest
Posts: n/a
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Re: 1-500MHz frequency counter
If it is the one that Google popped up searching for
Quote:
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13th Dec 2014, 6:25 pm | #4 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
Thanks guys. I've ordered an SMA male to male connector with 1.5m of coax in between so I'll cut one of the males off and attach a suitable probe. It was not knowing what to call it that was the problem as is often the case.
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13th Dec 2014, 6:53 pm | #5 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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Re: 1-500MHz frequency counter
Good grief, the SMA torque spanner will cost far more that the counter
B
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13th Dec 2014, 9:42 pm | #6 | |
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Re: 1-500MHz frequency counter
Quote:
I do like the SMA, a small (large ish) connector that is common and therefore cheap, very good for internal stuff. |
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14th Dec 2014, 12:18 am | #7 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
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14th Dec 2014, 2:09 am | #8 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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Re: 1-500MHz frequency counter
Yes, tongue in cheek, though I have seen torque spanners used on SMA. I thought my 99MHz counter was good value at £15, but that was some time ago. Has yours been supplied with any guidance on the usable input level; too little or too much can upset them.
B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
14th Dec 2014, 11:59 am | #9 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
No Bazz, no info at all. I was thinking of adding a zener to the input but need to know what the max is.
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15th Dec 2014, 12:56 pm | #10 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
Have you any advice at all on what the max input voltage is likely to be Bazz? I have an old RS counter that will take inputs up into the hundreds of volts depending on frequency so I will only be using the new one for low level transistor circuits; checking oscillator frequencies, etc. I've trawled the net but surprisingly can find no info on this, considering the thousands that have been sold. There isn't even a manufacturer's logo on it!
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15th Dec 2014, 1:29 pm | #11 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
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Re: 1-500MHz frequency counter
These look quite good and I'm thinking of getting one myself as I don't have one and my 'friend' decided to sell his for next to nothing without offering it to me first!
Shall I risk it or wait for yours to arrive so you can report on how good it is - probably risk it. I think I noticed one with an even higher resolution for something like £24. Maybe not the same frequency range. |
15th Dec 2014, 2:02 pm | #12 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
I've just given it a try with a 10MHz crystal oscillator and it shows that as 10.0016MHz but I don't know how accurate the oscillator frequency is (It's just a 7490 divider unit).
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16th Dec 2014, 8:49 am | #13 |
Pentode
Join Date: May 2014
Location: Amsterdam, Netherlands
Posts: 202
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Re: 1-500MHz frequency counter
Beat it against a 10 MHz source (WWV) using a shortwave receiver. If it's just a loose HC49/U XTAL the accuracy will be low.
It's odd to have an SMA connector as a test socket. A BNC is much more convenient and way more common. Tjerk, 9ZZ |
16th Dec 2014, 6:15 pm | #14 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
Cheers Tjerk,
Yes, I'm going to do that. I'm just waiting for the male connector and coax to arrive. I'll report back when i've done that. Many thanks Jim M0JBJ |
17th Dec 2014, 3:46 pm | #15 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
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Re: 1-500MHz frequency counter
I've got one on order - worth a punt at that price!
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17th Dec 2014, 4:45 pm | #16 |
Guest
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Re: 1-500MHz frequency counter
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17th Dec 2014, 5:02 pm | #17 |
Pentode
Join Date: May 2014
Location: Amsterdam, Netherlands
Posts: 202
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Re: 1-500MHz frequency counter
I disagree. I use SMA connectors a lot and it's a hassle to tighten the nut. Not a problem for (semi-)permanent connections. But the twist'n'lock bayonet of the BNC ("Bayonet Navy Connector") beats this over and over again, hands down. Usually I'm not going over 4 GHz, the limit for BNC.
Tjerk, 9ZZ |
17th Dec 2014, 6:12 pm | #19 | |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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Re: 1-500MHz frequency counter
Quote:
I did ask the question previously on the forum about affective ways of protecting the input but don't recall any exceptional suggestions. A pair of Schottkies side by side may be a basic approach. Something more elaborate would probably be nice in terms of keeping the input impedance high . B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
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17th Dec 2014, 6:19 pm | #20 |
Heptode
Join Date: Nov 2004
Location: Ripon, N.Yorkshire, UK.
Posts: 782
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Re: 1-500MHz frequency counter
It is quite sensitive Bazz. I've just hooked it up to this little oscillator I put together to test RF Germanium transistors (It goes from 8 to 20 MHz) and it worked quite nicely when connected to the 6-turn green coupling coil. As I said earlier I don't intend using it with high amplitude RF.
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