Mixer as freuency doubler

I don't know about the circuit you have however, my experience tells me you should have a trimmer there somewhere that should be aligned at your highest operating point.

It sounds like capacitance and other elements of are not matched very wall.

Jamie

Geesh, I don't know. (I usually don't care.) We get the cables from RF Industries. Pretty blue cable with BNC ends, it says RG58A/U. Does that help? (We list the part number as RFW-1982) I tried a 4 foot length of RG58C/U (Belden 8262) (made by pomona) and that was slower.

George H.

=A0 =A0(Richard Feynman)

I was going on the propagation velocity. It's too high, at 0.8, for solid polyethylene, or PTFE, indicative of partial air dielectric, foam or cellular.

RG58X is supposed to be solid polyethylene, VP 0.66. Belden 8262 is specced as RG58C/U, and conforms.

There are lots of cables sold as RG-whatever that don't conform.

RF Industries' RFW1982 appears to be one of those, stated to be double shield, which RG58 isn't. More like RG223, but that's 0.66 as well. Couldn't find a detailed specification, which says it all to me.

Moral: Buy cables of known specification, and terminate them yourself, if you are interested in calculating performance.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I've got an Eico 322 RF generator which even has a 3rd harmonic scale! The waveform isn't real pretty on the highest range, squashed a bit.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

That's how they get the harmonics. The top band is a distorted sine wave. I have three or four Preciision E200 signal generators. I see them for $5 at hamfests, and pick them up. Considering the time they were built, they are not bad designs. Replace the electrolytic, a couple paper caps and the celuloid strip over the dail and they are good for another 50 years. :)

bama.edebris.com/download/paco/e200/PrecE200.pdf

om RF

hat

Grin... I couldn't find anything either.

George H.

=A0 =A0(Richard Feynman)

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

every analog TEK scope had a delay line to slow the vertical signal until the trigger could get the sweep running,so you could see the leading edge of the signal.In the old tube scopes,you had to tweak the delay line to get a flat pulse response.

--
Jim Yanik
jyanik
at
localnet
dot com

My Tek 475 has a nice spiral of dual hardline in the bottom. I've seen schematics of the oldies -- delay line was sort-of lumped constant. Yuck!

20+ trimmer caps for one spiral of wire, was that really cheaper than coax, even back in the day?

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

That's a spiral balanced delay line. I believe it's 125 ohm line (from old memory).

The problem with most signal generators of that ilk is lack of screening. More comes out down the mains lead and every spindle hole than comes out of the socket. You can hear them a hundred feet away. That and spurious FM on AM.

Maybe OK for aligning consumer radios, hopeless for serious communications receivers.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

Three forward, two back, repeat for ever?

The interesting thing about those lumped constant lines was the way they used the CRT interplate capacitance as part of the final section.

Distributed plates were interesting, too.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

The case is all steel and welded, with a lot of screws to hold the front panel in place. It had a line filter, as well. They have very little leakage, and were used to align a lot of shortwave radios. It was top of the line in it's day. Long before lab grade equipment was smaller than a bread box. The only thing it didn't have was a calibrated attenuator.

That unit evolved over the years into the solid state B&K E200 signal generator.

Offerings from GR, and Marconi Instruments come to mind.

How many layers of screening? Some 1940s/1950s vintage instruments had three, a box, in a box, in a box, all silver plated inside and out. Wipers on all shafts. Anybody who's taken a Marconi TF801D to pieces, to get to the oscillator tube, will know what I mean.

I would hope so.

How much?

Depends what you mean by "shortwave radio". I mean things like AR88Ds, National HROs, Racal RA17s, Collins military stuff. Certifying performance to makers' specifications.

Not much use for sensitivity measurements, then.

I've never used anything from B&K. Always regarded their stuff as low-end. (For the benefit of Europeon readers, I don't mean Bruel and Kjaer, their stuff *is* lab grade).

My requirements for a signal generator always have been:

Frequency stability. Accuracy of output level. Low leakage. Low spurious and harmonic content. Low residual FM on AM.

Anything that amplitude modulates an oscillator is suspect from the beginning.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

The tuning & bandwitch shafts had wipers. The coarse & fine attenuators were inside another shield, and the pots came trough the front panel. If one of them were leaking, the pot was defective.

These were copper plated inside the case.

Not enough to be detected by a radio sitting next to it.

Most of those are newer that the original E200 design.

That kind of work wasn't done in Radio & TV shops. They were good enough to align 99% of AM & shortwave recievers.

B&K was never sold as lab grade, but they sold millions of dollars worth to TV shops

Good for you. I used HP 8660 & HP 3325B at Microdyne. I have a HP

606 & a HP 608 in storage, because they drift too much. I prefer synthesised generators that are phase locked to an in house frequency standard. To that end, I built a 1 in 32 out 10 MHz Distribution Amp for Microdyne.

Not every application has those requirements. Sometimes you just need to see if something is working ar the right frequency. I have a AD8950 based DDS signal generator. The user interface sucks, but it's accurate.

You're thinking of the TF144 series. The 801 is the one with the separately tunable , modulated, buffer amplifier that gave it its exceptional harmonic performance.

All silver plated, except for the attenuator piston, which was gold.

AR88 came out in 1938/39, HRO, even earlier, I think. RA17 features in "Tinker, Tailor, Soldier, Spy" movie, made last year. Supposedly set in

1963. I wonder where they got them from?

They were quite advanced, Wadley drift-canceling loop.

I don't know about radio/TV shops, but the factories certainly had better equipment.

I still use a pair of 8640Bs, locked to a GPS standard.

I don't like synthesized generators. You need to spend a great deal of money to get close to 8640 phase noise performance. I had a Racal-Dana

9-something synthesized generator for a while. My ancient, long discarded TF801D was 10-15dB better on harmonics. Close-in spectrum looked like a shaving brush. Impossible to get meaningful link noise tests with it.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I was talking about the E200. I've never seen the inside of any Marconi equipment.

Which factories? Building consumer or mil spec? You would be surprised at the equipment used in some factories. There was a photo of the early ICOM factory showing dozens of benches, all using TV shop grade equipment. Some of the lurkers and beginners don't need lab grade, or have thousands of dollars for test equipment. The E200 was better than most hobby & TV shop grade equipment, and definitely better than Heathkit. You could FM modulate their IG-102 by yelling through the vent holes. Drop a screwdriver on the bench, and you could hear it in the radio you were working on. Turn the volume up on a FM radio, and get feedback.

I've used 8640s, and didn't care for them. Without the PLL, they drifted all over the place. Still, it was a lot better than the Loggimetrics crap at Cincinnati Electronics.

I'm only doing personal projects these days, and not many of those. I did a lot of work to reduce the phase noise in the PLL synthesiser design at Microdyne.

You've missed a treat, there. Some of it was beautifully made. Their last Q meter made Boonton look like junk.

Mil and civil aeronautical.

That's why you're supposed to use the PLL ;-)

I'll put up with that inconvenience for the rest of the performance.

I hope they thanked you. It's a dying art.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I never liked the Boonton Q meter.

That's what we built at Cincinatti Electronics. I did QA on the PRC/77, and the GRC/106 line was next to us.

They sure did. They laid me off, claiming that I was no longer a team player because I was too sick to work overtime. I lost my healthcare and it was another two years before I found out that I was diabetic.

BTW I just had my 8640B repaired at ERevisited. A couple of hundred bucks for a flat rate repair--including return shipping--and they basically jacked up the nameplate and slid a new sig generator in underneath. I now know why everyone likes the 8640B: the close-in phase noise isn't that wonderful compared to a DDS, but as you go out it keeps dropping, and dropping, and dropping, rather than flattening out into mediocrity. If you have one that needs some TLC, you could do a lot worse than dropping $200 at ERevisited.

(And no, they aren't paying me to say that--certainly not at $200 a pop!)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net