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stareagle

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Join date : 2012-12-17

PostSubject: frequency counter and signal gen   2013-01-19, 11:36 pm

I have an old trustworthy EICO 324 sig gen. It wasn't working quite right. Hooked it up to a B&K 1801 Freq counter and a B&K 1820. I tryed both. Same reaction. Everything worked perfect untill I got to the higher freqs. I cannot get the counters to read the higher freqs. I must be doing something wrong, but what? The eico 324 works fine on my short wave receiver but why won't the counters show the higher freqs? I need the counter to show the freqs.
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-01-20, 10:02 pm

Don't hook up the counter directly to a signal generator. You are looking at a lot of problems. instead You need to just take a hank of coax and make a tiny loop at the end of the coax, center wire, (loop needs to be insulated) and use a connector to wire it up to, this will be your counter probe. Put the loop next to the output of the signal generator wire. The generator wire can be nothing more than a wire about 1-3 foot insulated connected to the center of the output jack of your generator. don't connect the signal generator and the counters directly together.

you need to measure the signal generator output with a voltmeter such as a HP 410A.or B, or C. They have an RF voltage probe and will measure up to 800 Mhz. They are very accurate.

Then adjust your signal generator to just over about .7 volts output. You may be putting too much signal into the counters and swamping the counter input. Most have some kind of protection on the input but it may have been damaged. (by using it wrong in both cases).

Do you have the minimum input voltages for the counters? (should be in the microvolt range) At both lowest and highest frequencies?

Also the maximum input voltages, At both lowest and highest frequencies? If so what are they?

Do you have any other signal source, such as a hand held transceiver that you could use to see if they register on both counters?

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Last edited by Cliff Jones on 2013-01-20, 10:53 pm; edited 1 time in total
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stareagle

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PostSubject: Re: frequency Counters   2013-01-20, 10:51 pm

OK, I only have a HP 412A VTVM. Maybe that will suffice? I don't think I have an RF Probe but I remember making some kind of a probe homemade. It might be an RF probe. I still have it. I did try to measure the output V with a DVM and it read 0 v. Yes,I have transceivers (both am & fm) I will try that too and let you all know.I am not Douglas MacAurther but "I shall return"
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-01-20, 11:14 pm

i DON'T THINK THAT WILL WORK as its a DC meter. That would limit it's frequency. Even with a homemade probe it would have to have a diode in it to convert the RF to DC. But if the circuitry wasn't designed for RF it may give erroneous readings. You may be better off using a O'scope. It should have the same range as your counters. That way you have something to compare against.

By the way exactly what are the higher frequencies you mentioned?

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stareagle

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PostSubject: Re: frequency Counters   2013-01-22, 6:18 pm

I opened both counters. Both have 82ohm R at the BNC input. One was burned so I replaced it - no difference. The counters are loaded with IC chips! The Sig Gen must be good as I pick up all the sigs on my short wave. I could zero beat the gen to a known freq on the short wave and align the Gen (a pain). I also have a Gertsch FM 7 zero beat freq counter but the Gen is AM. I do have an EICO mod 460 and a Ramsey 2200 dual trace oscilloscope - both with probes. The Ramsey seems to work well but I am not sure how to use it for this application. The counters don't pick up the Gen signal unless I connect them direct to the Gen. Evidently something needs replacing in the counters. I'm not going to get into the IC's but it looks like the sig feeds into some caps, diodes, resistors etc. prior to the chips. The freqs that I can't count are 37-145 MC. But the radio receives them easily. I want my counters !! I want to do an alignment on the SX-71 and as accurately as possable. And I can't trust the counters.
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stareagle

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PostSubject: Re: frequency Counters   2013-01-23, 3:45 pm

my-O-my ! I must be going senile. I havn't used the Gertsch in many years. I saw the model FM 7 and thought it was frequency modulation! ( I guess FM stands for frequency meter ). And why not? A carrier is a carrier. I hope it still works.

Well I hooked up the Gertsch and turned her on for the first time in about 20 years or so. Not too good Sad There seems to be 60 hz filter hum and the switches and pots need cleaning and who knows what else. I guess the dampness sitting in the basement all these years did it no good. I do remember that it did work as I used it many years ago. Another someday maybe project Question
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-01-23, 11:19 pm

The B&K 1801 is only rated for 40 Mhz Tops and I'm sure it starts to drop before that. The other counter is good up to 80 Mhz.

Do you have a digital shortwave?, you can get some very cheap and use it as a counter to check your signal generator without any connections to the Sig-gen..

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stareagle

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PostSubject: Re: frequency Counters   2013-01-24, 8:12 pm

I do not have dig short wave. All of mine are anolog. IE, dials. Might be worth buying one. What an awsome idea. One question : does your brain ever rest? lol
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stareagle

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PostSubject: Re: frequency Counters   2013-01-27, 5:26 pm

Guess what I found! I am sure I have more counters hidden in the basement. Hidden in the basement I found a Dosy. Heres the link to the meter. [You must be registered and logged in to see this link.] Very Happy
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-01-27, 8:28 pm

That may work if your signal generator can put out any small measurable wattage.
Does the tester have a built in dummy load? I cannot tell from that link.
try it and see, it can't hurt as the signal generator doesn't put out anything much in the way of power.
hook up an antenna to the input and set the output insulated wire wrapped around that antenna or as close as you can get.

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stareagle

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PostSubject: Re: frequency Counters   2013-01-29, 6:13 am

I tried it but not enough wattage I guess. Counter works fine with a CB when TXing Rolling Eyes Oh what to do now.
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-01-29, 11:04 pm

Well one thing you could do is find a crystal for each frequency, 455Khz, 1Mhz, 5Mhz and 10Mhz and put in line with the signal generator.

Or you could do a zero beat with a broadcast station frequency against the signal generator.

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stareagle

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PostSubject: Re: frequency Counters   2013-02-06, 3:00 pm

Best as I can tell, both counters seem OK. I am using the RF out from the Eico 324 as the freq source. In order for the counters to read the freq, I must wire direct from the out of the Eico to the counter input. I tried to measure the out voltage at the Eico and get a little over 1v AC with a DVM.
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stareagle

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PostSubject: Re: frequency Counters   2013-02-06, 9:18 pm

I hooked an antenna to a CB and an antenna on the counter. The counter measured the CB frequencies quite well.
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-02-06, 10:40 pm

CBs usually put out 5 watts max and SSB is around 7 to 10, but I'm not sure of the regs anymore. Your sig gen won't even come close.

But you said a direct connection? I would be very careful and use an isolation transformer at least on the signal generator to avoid sparks and meltdown issues.
If so, does it read correct frequencies?
From your signal generator that is?

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stareagle

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PostSubject: Re: frequency Counters   2013-02-13, 6:24 pm

Here's the update: Everything seems normal with the counters but I am not totally sure they are ok yet. I put the Sig Gen next to a Bearcat 210WX scanner . The Bearcat can scan from 29mc - 54mc and 136mc - 512mc.. The generator seems ok untill I tried the 37mc thru 435mc.. The scanner won't pick up a signal from the Sig Gen in these higher freqs, which is the same problem as when using the counters. But my short wave ( SX-71 ) will pick up the signal. Why ??? Is there some place that I can wire the counters directly into the EICO 324 sig gen Safely ?? My guess at this point is that the GEN isn't putting out a strong enough signal for the counters or the Bearcat to receive, when in the higher frequencies. At any rate today I purchased the manual and service manual with schematics for both the BK1801 and BK1820 counters. ( Ebay @ $10.00 for each counter ) They are hard to find. Exclamation I do need to use the counters with the 324 sig gen as it is not that accurate. If all else fails, I will have to buy a signal generator with a built in counter. Sad scratch [You must be registered and logged in to see this link.] --------- [You must be registered and logged in to see this link.]


Last edited by stareagle on 2013-02-13, 6:38 pm; edited 1 time in total (Reason for editing : added link)
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Cliff Jones
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PostSubject: Re: frequency Counters   2013-04-15, 1:09 pm

stareagle wrote:
Here's the update: Everything seems normal with the counters but I am not totally sure they are ok yet. I put the Sig Gen next to a Bearcat 210WX scanner . The Bearcat can scan from 29mc - 54mc and 136mc - 512mc.. The generator seems ok untill I tried the 37mc thru 435mc.. The scanner won't pick up a signal from the Sig Gen in these higher freqs, which is the same problem as when using the counters. But my short wave ( SX-71 ) will pick up the signal. Why ??? Is there some place that I can wire the counters directly into the EICO 324 sig gen Safely ?? My guess at this point is that the GEN isn't putting out a strong enough signal for the counters or the Bearcat to receive, when in the higher frequencies.




At any rate today I purchased the manual and service manual with schematics for both the BK1801 and BK1820 counters. ( Ebay @ $10.00 for each counter ) They are hard to find. Exclamation I do need to use the counters with the 324 sig gen as it is not that accurate. If all else fails, I will have to buy a signal generator with a built in counter. Sad scratch [You must be registered and logged in to see this link.] --------- [You must be registered and logged in to see this link.]

Note: sorry for the delay in answering, too many brands in the fire at this time.

The B&K 1801 only is good to 40 MHZ
The B&K 1820 is only good to 80MHZ
So you will fry the front end of the counters if you force high strength signals into their front ends.

If your signal generator can put out high frequencies (usually generated harmonics) that the SX 71 can receive, then I would suspect your scanner is faulty. To test the generator take it to a separate room and again use your SX 71. That way you won't overload the SX 71 front end. If it still can pick up the higher frequencies, from the generator then the generator is doing its job. I don't think the scanner has any kind of signal protection for strong local signals, if it does then that's why it to would block the strong signal. Try the same thing with the scanner distance wise, to find out.

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Cliff Jones
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PostSubject: frequency Counters   2013-06-24, 1:50 pm

Discussions of Frequency counters in general can be posted Here in this topic.

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