HP 8640B LF ??
 

I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1. I have
several choices and would like some user opinions if anyone has a
comparison. I can buy an HP 11710B down converter which will divide the 50
to 61 MHz band down to 10 KHz thru 11 MHz or an HP 11710A that divides 5 to
5.5 MHz to 5 KHz thru 500 KHz. The HP 11710 A&B are quite differnt in size,
appearnce and I wonder if the B is that much that I should only consider it?
In addition, I could try to find an HP 8640B with Opt 1 that includes an
internal audio oscillator that covers 20 Hz to 600 KHz, and sell my unit.
But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.
At the present time I'm using a HP 606A a sizeable beast
that goes down to 50 Kc. I also have an HP 3586C which is quite good
as a Sig Gen, I got it becasue I wanted to listen to LF! So I is it an
11710,
an Opt 1 trade or something else, I wouldn't mind recovering some space!
Any user experience with these units appreciated.
thanks
hank wd5jfr

I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1.

But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.

Hank-

I'm not that familiar with the specs, but it looks like the lowest band on the
8640B is 250 to 500 KHz, regardless of option.

The variable audio oscillator option has its own output level adjustment, but I
don't think it is calibrated like the main RF output. It certainly doesn't go
through the main attenuator except as modulation on the RF! I'm not sure, but
the variable audio oscillator's output may be 600 Ohms rather than 50.

When I've tried adjusting the frequency on the variable audio oscillator, I've
found it touchy. You definitely do NOT have phase lock on that oscillator. It
would be fine for use with AM and FM modulation, but not the greatest as an LF
RF signal where accuracy is a bit more important.

I can see using it with sufficient output to drive the counter's external
input, but with an external attenuator to set the impedance and level for your
application. It might work, but I wouldn't be happy with such an arrangement!

73, Fred, K4DII

I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1.

But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.

Hank-

I'm not that familiar with the specs, but it looks like the lowest band on the
8640B is 250 to 500 KHz, regardless of option.

The variable audio oscillator option has its own output level adjustment, but I
don't think it is calibrated like the main RF output. It certainly doesn't go
through the main attenuator except as modulation on the RF! I'm not sure, but
the variable audio oscillator's output may be 600 Ohms rather than 50.

When I've tried adjusting the frequency on the variable audio oscillator, I've
found it touchy. You definitely do NOT have phase lock on that oscillator. It
would be fine for use with AM and FM modulation, but not the greatest as an LF
RF signal where accuracy is a bit more important.

I can see using it with sufficient output to drive the counter's external
input, but with an external attenuator to set the impedance and level for your
application. It might work, but I wouldn't be happy with such an arrangement!

73, Fred, K4DII

Fred McKenzie wrote:
I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1.

But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.

Hank-

I'm not that familiar with the specs, but it looks like the lowest band on the
8640B is 250 to 500 KHz, regardless of option.

The low end on mine, with options 1, 2, and 3, is just above 447 kHz.
That appears to be the designed low end, so that the 8640B could be
used for IF alignment.

There's an option that controls whether the _high_ end is 512 MHz or
1024 MHz, but that's different.


--
"#@^&*^(@#$!!"
"What?"
"We've been decoding a 'Make Money Fast' chain letter for the last month!"
"Those *******s!" -- george william herbert, in rasfw

Fred McKenzie wrote:
I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1.

But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.

Hank-

I'm not that familiar with the specs, but it looks like the lowest band on the
8640B is 250 to 500 KHz, regardless of option.

The low end on mine, with options 1, 2, and 3, is just above 447 kHz.
That appears to be the designed low end, so that the 8640B could be
used for IF alignment.

There's an option that controls whether the _high_ end is 512 MHz or
1024 MHz, but that's different.


--
"#@^&*^(@#$!!"
"What?"
"We've been decoding a 'Make Money Fast' chain letter for the last month!"
"Those *******s!" -- george william herbert, in rasfw

Henry Kolesnik wrote:

I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1. I have
several choices and would like some user opinions if anyone has a
comparison. I can buy an HP 11710B down converter which will divide the 50
to 61 MHz band down to 10 KHz thru 11 MHz or an HP 11710A that divides 5 to
5.5 MHz to 5 KHz thru 500 KHz. The HP 11710 A&B are quite differnt in size,
appearnce and I wonder if the B is that much that I should only consider it?
In addition, I could try to find an HP 8640B with Opt 1 that includes an
internal audio oscillator that covers 20 Hz to 600 KHz, and sell my unit.
But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.
At the present time I'm using a HP 606A a sizeable beast
that goes down to 50 Kc. I also have an HP 3586C which is quite good
as a Sig Gen, I got it becasue I wanted to listen to LF! So I is it an
11710,
an Opt 1 trade or something else, I wouldn't mind recovering some space!
Any user experience with these units appreciated.
thanks
hank wd5jfr


Can you use a function generator, or a test oscillator like the H-P
651 for frequencies below the lower limit on the H-P 8640? it is
something that comes in handy for other things anyway. The test
oscillator would stack on the 8640, its in the same style H-P cabinet.


--
19 days!


Michael A. Terrell
Central Florida

Henry Kolesnik wrote:

I've got an HP 8640B Opt 2, and am quite satisfied with it's performance but
this one doesn't go below 500KHz since it doesn't have Opt 1. I have
several choices and would like some user opinions if anyone has a
comparison. I can buy an HP 11710B down converter which will divide the 50
to 61 MHz band down to 10 KHz thru 11 MHz or an HP 11710A that divides 5 to
5.5 MHz to 5 KHz thru 500 KHz. The HP 11710 A&B are quite differnt in size,
appearnce and I wonder if the B is that much that I should only consider it?
In addition, I could try to find an HP 8640B with Opt 1 that includes an
internal audio oscillator that covers 20 Hz to 600 KHz, and sell my unit.
But I don't think I'd have phase lock available which is nice but probably
not mandatory. I'm not sure how the Opt 1 works with the attenuator.
At the present time I'm using a HP 606A a sizeable beast
that goes down to 50 Kc. I also have an HP 3586C which is quite good
as a Sig Gen, I got it becasue I wanted to listen to LF! So I is it an
11710,
an Opt 1 trade or something else, I wouldn't mind recovering some space!
Any user experience with these units appreciated.
thanks
hank wd5jfr


Can you use a function generator, or a test oscillator like the H-P
651 for frequencies below the lower limit on the H-P 8640? it is
something that comes in handy for other things anyway. The test
oscillator would stack on the 8640, its in the same style H-P cabinet.


--
19 days!


Michael A. Terrell
Central Florida