Trials of restoring Heathkit DX-35

[CK-722]

What's the difference between the 5T and the 5H? WFDF had a 5H, and it seems like it was wider, like three panels?

[audiophile]

This, exactly... Only left channel was wired up.

I installed that unit for WQON to protect STL's when it was next to bakery. It doesn't have a clipper either.

[FET-500]

This, exactly... Only left channel was wired up.

I installed that unit for WQON to protect STL's when it was next to bakery. It doesn't have a clipper either.

Please elaborate: was the signal digitized and sent out on microwave?

[audiophile]

Analog Microwave. A pair of Marti STL8's.

[FET-500]

Analog Microwave. A pair of Marti STL8's.

My friend at work (our webmaster) used to do point to point on the Mexican border. The equipment is getting so cheap, we're joking about our own network.

My brain is starting to spasm over the idea of a "man-in-the-middle" attack on this type of link.

[Ed Joseph]

At some point, this Orban was evidently moved to the AM... as I think back, the phase was probably reversed to the TX.

Honestly, I think I'd rather have analog STL over digital. That's just me. I do not trust digital, or especially the internet infrastructure, to be hardened enough if the Sun decides to flare us in a major way or an EMP occurs due to any event. I just feel if that happens, analog stuff has a better chance of surviving. It should always be a backup option at any rate.

[CK-722]

WKNX used an RCA BTA 10H, which is outwardly nearly identical to an RCA BTA 5H.

Barry Mishkind pictures of 5 kW transmitters back in the 1950s and 1960s.

https://www.oldradio.com/archives/hardware/RCA/5.htm

[Ed Joseph]

I remember actually seeing that RCA at WKNX working back in the Day. It was trashed to make room for the MW10 in around 1979-80.

Edit: Honestly, I thought the RCA sounded better than the Harris.

[k8jd]

The rectifier tube may have been a good sub. many of the 5V filament dual diode tubes were using the same pin linup for the elements, only made physically different to handle more or less Plaate current and voltage. .

[audiophile]

I remember actually seeing that RCA at WKNX working back in the Day. It was trashed to make room for the MW10 in around 1979-80.

Edit: Honestly, I thought the RCA sounded better than the Harris.

Why did they trash it, if it was working?

[Ed Joseph]

If I recall, it was having some problems with the plate transformer, it was up on woodblocks to isolate it from the cabinet because it has shorted internally. It would do low power but not high. I hope I have that right, it was like 1979.

Edit to add: I would guess, if the engineer wasn't Jim McCluskey, it probably could have been "properly" repaired and kept for backup. Then again, it was pretty big and they had to shoehorn an MW10 in that small space on Gabel rd.

[Ed Joseph]

UPDATE on DX-35

At this point, there is something in this unit which just isn't right. Something changes after it's making moderate power (45watts in CW) into dummy load a few minutes, front panel meter pins and the fuse opens.

I am tempted at this point to strip this thing down and make a simple all-band amp out of it.

[audiophile]

Bad tube ruled out?