Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Signal Generator for Hammarlund




 
The AM Forum
March 31, 2020, 08:44:33 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 [2] 3   Go Down
  Print  
Author Topic: Signal Generator for Hammarlund  (Read 16327 times)
0 Members and 1 Guest are viewing this topic.
W4AMV
Member

Offline Offline

Posts: 580


« Reply #25 on: January 18, 2012, 10:01:55 AM »

Crap cable is usually a bigger problem than 8640B leakage. RG58 leaks very bad. You really need to use double shielded cable like RG223 or RG141B. BNC connectors also suck for leakage when you want to play below -130dBM.

Agree, good cable and proper connector and dressing is important. However, the level of leakage I was addressing in the 8640 and for that manner any generator that is not properly reassembled or maintained will not be corrected by the cable or connector selection. As a simple test, Carl, if you own a 2 meter or UHF handheld you can use it as a test vehicle when you obtain your generator. Assume the generator goes to VHF or for HF construct a magnetic loop for your HF RX (this is documnted in the 8640 manual). With the generator ON, pass the loop or whip all around the generator box. Set the attenuator to its min level and terminate all generator ports (into 50 ohms). You should hear ZIP. I have seen a 8640B radiate so bad that pickup was obtained from a foot away! Not a fault of the HP, but of its care and reassembly. Incidently, there was an early version of the B which did not have an EMI screen shield in front of the digital display. Radiation from the display was horrific. Soooo, check the display see if you see the BLACK grid EMI shield embedded in the RED filter.
Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #26 on: January 18, 2012, 03:23:35 PM »

Quote
As a simple test, Carl, if you own a 2 meter or UHF handheld you can use it as a test vehicle


Carl learned about leakage almost 50 years ago in a screen room at National and later with Tempest security clearance at Sanders Associates and Wang Labs.Grin
Logged
W4AMV
Member

Offline Offline

Posts: 580


« Reply #27 on: January 18, 2012, 05:08:59 PM »

oops, I meant to say Chuck! Sorry Roll Eyes
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #28 on: January 19, 2012, 07:47:51 AM »

Does anyone have a recommendation where to look for these signal generators besides Ebay, CraigsList, Toronto Surplus Fair Radio and ham fest?

Chuck
Logged
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #29 on: January 19, 2012, 08:26:54 AM »

Just search on HP. This way you can see if there are any HP3325A/Bs around.
HP made many different generators.
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #30 on: January 20, 2012, 10:30:08 AM »

Hi to all:

Do you think this product and procedures would work when aligning the Hammarlund HQ-17A-VHF?

http://comtekk.us/sinad.htm

Chuck
Logged
w3jn
Johnny Novice
Administrator
Member

Offline Offline

Posts: 4593



« Reply #31 on: January 20, 2012, 11:38:32 AM »

That's just a SINADer.  Not needed, there's no adjustment in a HQ requiring a min reading on a SINAD meter.
Logged

FCC:  "The record is devoid of a demonstrated nexus between Morse code proficiency and on-the-air conduct."
aa5wg
Member

Offline Offline

Posts: 425


« Reply #32 on: January 20, 2012, 07:21:36 PM »

W3JN:
Thank you.
Chuck
Logged
Jim/WA2MER
Contributing
Member
*
Offline Offline

Posts: 210



« Reply #33 on: January 20, 2012, 07:58:39 PM »

I also have the HP8640B and it's been worth its weight in gold to me.  Not dirt cheap, but they're plentiful.  Just be careful to find one that has good gears...replacements are hard to find.

If you want to get a sweep generator, which I also recommend, consider a Hickok 288X.  It's late '40s design and was decent generator for the day, just the thing shops would have used for IF alignment.  I paid $10 for mine at a hamfest, and all it needed was to get a couple of controls freed up.  It's plenty stable enough for swept IF alignment.  I don't trust its analog frequency dial, so I use the '8640B to set the frequency.

All the information you could want to know about it is in the manual: http://bama.edebris.com/manuals/hickok/288x/.

73,
Jim
W2BVM
Logged

Anything worth doing is worth doing to excess.
Since you have to die anyway, you might as well die from something you like.
aa5wg
Member

Offline Offline

Posts: 425


« Reply #34 on: January 21, 2012, 08:27:10 AM »

Jim:
Thank you. 
Chuck
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #35 on: January 22, 2012, 03:13:32 AM »

Jim:

Can the HP8640B put out a non modulated (cw) signal?  The manual for the Hammarlund HQ-170A alignment mentions this?

Chuck
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #36 on: January 22, 2012, 03:30:32 AM »

What does the group think about the Marconi 2018 signal generator?

Chuck
Logged
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 7687


CQ CQ CONTEST


WWW
« Reply #37 on: January 22, 2012, 03:39:27 AM »

What does the group think about the Marconi 2018 signal generator?

Chuck

It doesn't get down to 60 KHz which is what you need for Hammarlund IF alignment:
Marconi 2018, 80KHz-520MHz
Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
Jim/WA2MER
Contributing
Member
*
Offline Offline

Posts: 210



« Reply #38 on: January 22, 2012, 07:43:58 AM »

Jim:

Can the HP8640B put out a non modulated (cw) signal?  The manual for the Hammarlund HQ-170A alignment mentions this?

Chuck

The '8640B will generate AM, FM and unmodulated signals.  However, I lost sight of the fact that you need 60 KHz for for the Hammy.  The '8640B spec only goes down to 500 KHz, but they actually go a bit lower...I've used mine for 455 KHz alignment.

Jim
Logged

Anything worth doing is worth doing to excess.
Since you have to die anyway, you might as well die from something you like.
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #39 on: January 22, 2012, 09:41:35 AM »

Copied from my post on Page 1

Quote
I also have a 8640B but those damn gears are fragile so I only use it on riceboxes on another bench. Use the recommended accessory HP-11710B downconverter and it will get you down to 10KHz. Lots of junk on Fleabay so caveat emptor.
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #40 on: January 22, 2012, 12:40:41 PM »

Carl, Jim and all

Thank you for the good information.  Can the down converter, HP11710B, for the HP8640B put out a cw signal (non modulated)?

Chuck
Logged
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #41 on: January 22, 2012, 01:00:21 PM »

A double balanced mixer willl do the same thing. Take the 5MHz reference and mix it with the generator output to get a lower frequency. add a low pass fillter and done. My 8640bs get down to about 450khz. A cheap function generator with sweep function is far better for tuning an LC filtered IF. A scope will display the bandpass so you can tune it flat if the sweep out ramp controls the horizontal position of the display.
Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #42 on: January 22, 2012, 04:40:04 PM »

Can you recommend a function generator with sweep function?

Will the Hickok 5900A function generator work?  I don't see any reference that the Hickok 5900A has the sweep function?  Does anyone know if it has the sweep function?  

I am not sure if the down converter for the HP8640B has the non modulated (cw) output signal capability.  

Thus far I have not found an HP606B for under $700.00.  This is to  much.  The least expensive working HP8640B has been about $2600.00.  This is to much.  

I have not given up.  Thank you for your help and patience.

Chuck

Logged
aa5wg
Member

Offline Offline

Posts: 425


« Reply #43 on: January 22, 2012, 08:53:19 PM »

I just watched a video showing the alignment of the IF's of an old radio.  The gentleman was using a function generator that had sweeping ability.
He plugged the output into a an oscilloscope for visual.  I also read a bit about this and it seems using a function generator with sweeping ability and with markers along with a scope would be a better approach than my first thoughts of obtaining just a signal generator.

My question is, do I still use a non modulated (cw) signal from the function generator or do I use a modulated signal?  What type of modulation, if needed, should one use (am, FM etc.)?  The Hammralund HQ-170A-VHF manual says to use a non modulated signal (cw)l from a signal generator.  However, I think the use of a function generator along with the scope would be better.  I think a frequency counter would be needed?

Anyone have a follow up to my thoughts.  Am I on the right track?

What would be a good choice for this function generator.  That is, if this is the correct way to go?

Thank you for any and all help with this challenge.

Chuck

 
Logged
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 7687


CQ CQ CONTEST


WWW
« Reply #44 on: January 22, 2012, 09:05:47 PM »

How do you plan to align the RF section of the receiver with a function generator?
Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
Jim, W5JO
Member

Offline Offline

Posts: 2456


« Reply #45 on: January 22, 2012, 10:04:52 PM »

Chuck there were several versions of function generators that have (had) the sweep function.  You choose a frequency with the analog output as you saw then the sweep function will alter the frequency back and forth at the setting you choose.  I have one made in Israel that I paid 10 dollars for at a hamfest that is solid state and very stable.  To avoid paying a lot, I suggest you go to some of the bigger fests and look rather than shop ebay if you can.  The sellers on eBay sometimes are a bit exravent in their listings and I don't want to buy something I haven't held or seen.

The things are not in favor because not many people do this type of thing so don't be afraid to dicker on the price.  There were 3 on the table where I found the one I have and it was marked 25 dollars the other two cheaper.  It will tune from near zero to 10 megacycles so you could use it for all IF frequencies and, even RF up to 10 megacycles.

The HP equipment is usually very expensive and I don't own any, mostly because of that.  I have an old AN/URM 25F that I have used successfully for years.   Mine is stable enough to do an aligment at 10 meters.  On AM, much below 3 microvolts is great on most old equipment so the leakage doesn't bother much.  If you will watch you may find one, get a D or F version, in good condition and they probably won't be much.  I also have a CM-1 that is digital and will sweep frequency.  One of the early service monitors, it is nice to have, but with a cheap frequency counter attached to the 25F high output and the receiver attached to the attenuated output, I can do all the RF alignment I want it is just a bit more tedious.  Altogether I spent near 50 dollars for that equipment and got my 100 meg scope for another 50.   For me, this is a hobby and I don't want to spend a lot of money.
Logged
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #46 on: January 22, 2012, 10:53:30 PM »

This thread is going in circles
Logged
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 7687


CQ CQ CONTEST


WWW
« Reply #47 on: January 22, 2012, 11:07:22 PM »

Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
aa5wg
Member

Offline Offline

Posts: 425


« Reply #48 on: January 23, 2012, 12:12:21 AM »

Jim and all:

Thank you for the advice.  At present, I think I will look for the sweep generator (and maybe a diode detector) to use with my scope to align the IF section of the receiver.  Not sure if I need the diode detector?

Chuck
Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #49 on: January 24, 2012, 01:04:15 PM »

Quote
Thank you for the good information.  Can the down converter, HP11710B, for the HP8640B put out a cw signal (non modulated)?

Of course. All it does is convert the 8640B output to a different range, you use all the regular functions and simply do the frequency conversion between your ears.

It will work with most any other sig gen that has a stable output from 50-60MHz. Also see this for some sweeping info using one.
http://www.cliftonlaboratories.com/adventure_of_the_hp_11710b.htm

I bought mine for $75 when the market was flooded with them by the USAF and the surplus bandits were having a price war Tongue
Logged
Pages: 1 [2] 3   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.076 seconds with 18 queries.