[John Bartley]

Ron,

I do my alignments a bit differently than others by using inductive coupling to the radios, so how I reduce the output level when I find it's too high is that I increase the distance between the inductive coupler elements. I have the output of my generator fed to a scramble wound coil. I connect a jumper wire to the specified injection point, then drape the wire thru', over or beside the coil depending on how much signal I need. By doing that I can reduce the input signals to zero, even though the generator might not be able to.

I am sure that anyone could build a shielded coupler if it was necessary. I haven't yet needed it.

Caveat :: I mostly work on AA5, AA6 or lower end multiband receivers (like your HQ .... I had one ... loved it!)

cheers

[Ron Ramirez]

Hmmm. Interesting. So when you say "scramble wound coil" do you mean just some random wire wound by hand without regard to turns or wire gauge?

[EdHolland]

The B+K looks like a great instrument Ron. Hope you enjoy using it to get great results

[John Bartley]

Hmmm. Interesting. So when you say "scramble wound coil" do you mean just some random wire wound by hand without regard to turns or wire gauge?

Yup, that's exactly what I do. I forget how many turns I put on the T.P. tube, but I'd say about 75-100 of plain enameled copper wire.

You might want to check with the "experts" to see if you fancy that idea before doing it. I'm not known for following "rules" too closely .... your results may vary.

cheers

EDIT :: I have toyed with the idea of using a surplus variable IF transformer (and removing the capacitors) as a coupling device but I never got that far.

[Ron Ramirez]

John

I really like your idea. As I recall you're using a 4040A so if it works with your unit, I would assume it would work with a 4040 as well. I think I will try it. It seems to me that this would be a cheap, quick, and dirty answer to reducing signal to the radio under test without spending big buck$$ on a proper attenuator (yes, I've looked at some and several tend to be pricey).

Wife prefers TP without tubes inside so I'll have to go a different route. Maybe an old, unused inductor from a speaker crossover? Or maybe a now-unused 2.5 mH RF choke from the Philco 70 I converted to AVC?

[Eliot Ness]

Wife prefers TP without tubes inside so I'll have to go a different route.

Let me know and I can supply you with several empty rolls at the Lexington meet

[EdHolland]

I've done this also, to get weak coupling of a signal, and it can work a treat. Another benefit is there's no direct connection between the instrument and the radio, so avoiding the problems that can lurk there.

[John Bartley]

Well ..... hot dog !! It's nice to know that my cheese has not completely slipped off it's cracker

[W8ZV]

I REALLY cheated!  I scavenged an antenna from an old AA5 radio, the kind wound on the back of the radio, put a .05 capacitor in series with the center conductor of a length of RG-58, and soldered the ground side of the cable to the other end of the wire on the antenna.  The other end of the coax, which is about 15 feet long, has a BNC connector on it.  I can hook it up to the generator, and set it next to the console I'm working on.  Too much signal, move the antenna away.  It's got the right impedance match for the generator and it works without pulling the OSC of the radio, or overdriving the IF stages when you touch them up for the last time.  Works VERY nicely to get the IF trap tuned in.  It saves on trying to figure out how to couple the generator without blowing it up.

[John Bartley]

Not only has my cheese NOT slipped off it's cracker, but I'm in good company indeed! (patting myself on the back .. hehehe)

[Ron Ramirez]

You should pat yourself on the back, John. I appreciate your suggestion of the "TP" coil. It works very well indeed. I wound exactly 100 turns of 32 gauge wire on mine. I have found that the B+K 4040 puts out a very strong signal. While aligning my RCA T8-14, I found that I had to both turn down the gain all the way and push in the 20db CUT button to get the signal as low as possible - and it was still pretty strong even with a coupling wire connected to the radio looped around the coil only once.

[John Bartley]

I am glad that it worked for you Ron. I do some unorthodox things in the pursuit of my hobbies, and I always hesitate a bit before suggesting them to others.

cheers !!

[Ron Ramirez]

Update:

When the stimulus checks went out earlier this year, I splurged and invested in the signal generator I really wanted - a Siglent SDG1032x.

https://siglentna.com/product/sdg1032x/

Now this is what I have needed for YEARS. Punch in a frequency and it stays there. Rock solid. No drifting. What a difference it makes in alignments. I fixed up an RCA 6T5 before my last surgery and used the new Siglent to align it. Works great.

You can set everything up, then activate the channel you are using and get to work. Deactivate the channel, change frequencies, activate again and continue. Very nice.

I've been setting mine for an AM signal, modulated at 1000 kc - 30% modulation, set for 50 ohm impedance (it is switchable between 50 ohm and high Z), usually at a low enough level output to make the signal in the radio barely audible to avoid strong AVC action. Between that and the 20 dB attenuator I purchased used from the auction site, it works out well. I could set it at any level up to 100% modulation if I wish, or with no modulation.

I still use the TP coil for AC/DC radios. Only now, I have a 50 ohm resistor in series with the coil. Again, it works great.

[morzh]

Ron,

Ah, you finally have partaken of the digital goodness. I hope the euphoria will last awhile and kick in every time you use the beast.
I love my HP. If it weren't for its weight, I'd probably have commited adultery with it. Right on my bench.

Advice: do make a protector, look up what I did. The investment of this magnitude ought to be prote ted

[Ron Ramirez]

Wow Mike,

You're one crazy dude, man. And I mean that in a good way.

Totally agree on the protector, and I will. I have been, and will continue to, use a capacitor between the high side of the generator output and the radio being aligned, also.