Dragged the Drakes back out...

[N8YX]

After a protracted period of time spent messing around with a TS-940S/R-71A and IC-751A/R-71A arrangement in the SO2R spot I decided to haul the vintage stuff out of storage and give it another go.

This morning finds 2x TR7/R7/RV75/SP75/CW75/MN2700s in the lineup. The R7s still drift a bit...and an N4YG DDS VFO kit in each should fix that.

Two of my R7s came from FCC field offices and as such were outfitted with some non-standard features: BNC Antenna Input and 3rd IF (50KHz) Output connectors. A consumer-model R7 doesn't have a way to get at the IF for monitoring purposes.

Why do I like these rigs so much? In a word: Configurability. Particularly where the IF filters are concerned. If one tallies up all of the filters - both OEM and aftermarket - which were offered for the 7 line (and the later TR5), the selection is rather impressive:

8/6/4/3/2.8/2.3/1.8/1.0/0.5/0.4/0.3 KHz B/W.

The cool thing is that ANY of those filters may be installed in any filter slot in the radios. Drake cautions against using other than the stock 2.3KHz B/W filter in the "default" transmit-enabled slot but many folks have used the 2.8 or 3.0KHz versions with great success. Radio Botswana went so far as to equip their TR7s with 4KHz filters in the TX position for use as enhanced-fidelity, remote news feeds...and they worked well in that role.

I'm looking to set one of my ex-FCC receivers up with 8 (or 6), 4, 2.3, 1.8 and 1.0KHz filters when I add the DDS unit; its companion TR7 will be equipped with a 4, 3.0 (or 2.8 ), 2.3 and 1.8KHz complement. This station will primarily be used for AM/SSB amateur/SWL/Ute work. The R7 in question has an AUX7 board fitted that's configured with programming modules for all of the popular SWBC bands, while the TR7 has an AUX7 with WARC band modules and a couple RX-only ranges installed.

The CW/FSK-position twins will have the following installed: (R7) 2.3/1.8/1.0/0.5/0.3KHz B/W; (TR7) 2.3/1.8/0.5/0.3KHz B/W.

Try that with any other rig short of a DDS-equipped unit...and even then you're into the K3/Orion/7800 tier.

Carlo, if you're reading this:

The TR7 we discussed is on the bench at the moment. I discovered a flaky capacitor in the AF Output circuit and am going to replace it...

[W1GUH]

And don't forget the "no-filter" filter option -- a resistor.

[N8YX]

And don't forget the "no-filter" filter option -- a resistor.

Roofies.

[NQ6U]

Carlo, if you're reading this:

The TR7 we discussed is on the bench at the moment. I discovered a flaky capacitor in the AF Output circuit and am going to replace it...

Okay, thanks!

[WØTKX]

[W1GUH]

I still can't put "drift" and "Drake" in the same sentence. But I don't do digital modes, never notice any.

[NQ6U]

Speaking of ducks and radios, I finally did the last tweaking on the T-4X this evening. The result: 110 watts CW out on 80, 40 and 20 meters, a bit less on 15 and 10 meters. Haven't tested on SSB yet because I don't have a suitable mic but I am a happy camper.

[N8YX]

I still can't put "drift" and "Drake" in the same sentence. But I don't do digital modes, never notice any.

I left mine on all day yesterday - most of the weekend, in fact. A little background info: Drake used a pair of #1893 incandescent bulbs (one for PTO tuning lighting; one for meter lighting) not only as illumination but for temperature stabilization purposes. That is, by keeping the inside of the rig slightly warmer than ambient any drift is minimized.

Works good but I like a cooler running rig. I also like cool blue LED lighting. Thus, both R7s and both TR7s in the lineup have LEDs for illumination.

Once the rigs reach stabilization temperature - say, after a few hours run time - they really don't drift much. I ran all the rigs on their internal PTOs from last evening onward and noticed ~100hz total drift on each by this morning. The direction of drift is predictable, too: A colder environment causes them to drift upwards and a warmer one results in a downward change in frequency.

Adding the DDS units to the R7s will fix drift issues permanently, and I can use the RV75s in conjunction with the TR7s for data work if desired.

Also wired in a pair of Timewave DSP599zx to the station yesterday. One channel of each gets audio from the TR7's rear panel "Audio" connector and the other channel processes sound from each of two non-DSP-equipped R7000s.

For vintage equipment, this stuff doesn't work bad at all.

[Jeff K1NSS]

Radio Botswana went so far as to equip their TR7s with 4KHz filters in the TX position for use as enhanced-fidelity, remote news feeds...and they worked well in that role.

I wish I wrote that. Pretty cool sentence no matter how you came by that information. Nevertheless, how did you?

Also amazing cool all the radios you have. Are there Quonset huts and a cherry Spruce Goose involved? Are you Howard Hughes?

[Jeff K1NSS]

BTW all, my latest foundling is a circa early 50s Bilious Chartreuse Crosley Dashboard Color Radio. All Crosley tubes intact and functioning. Works but needs caps, natch. No steal at 20 bucks and I broke the super narrow gauge metal halo off the tuning needle trying to pull the piece off the variable cap shaft. Paul, remember to bring along any delicate repairs next time you're up this way. Brain surgery, golf ball liquid center removal, the doctor is in. Anybody know good bakelite cleaning secret so I don't have to send away for 3-step Novus (?) plastic cleaning method from Antique Radio.com?