Tram 201a or Mark IV for ssb

[ak3383]

Do either one of these radios do a good job on ssb? I've always wanted a 40-channel tube radio to talk on 38lsb but if I do I want it to sound good. I have a set of older 23-channel Brownings for AM but nothing for sideband. I have read that both of these radio had their issues, just wondered which one would sound the best and be pretty easy to you i.e. drifting and such. This site looks to be "thee" place to get opinions on these good 'ol radios.

[Sandbagger]

Aug 7, 2009 18:17:15 GMT -5 ak3383 said:

Do either one of these radios do a good job on ssb? I've always wanted a 40-channel tube radio to talk on 38lsb but if I do I want it to sound good. I have a set of older 23-channel Brownings for AM but nothing for sideband. I have read that both of these radio had their issues, just wondered which one would sound the best and be pretty easy to you i.e. drifting and such. This site looks to be "thee" place to get opinions on these good 'ol radios.

I'm doing a "head to head" shootout between my Browning MK III and my Tram D201 on a variety of situations, to see which is the true "king of the classic radios". As far a SSB goes, the Tram wins hands down. It's much easier to operate since there isn't a separate transmitter and receiver to tune, and the Tram uses a crystal filter and true product detector in the receiver, which makes for better performance. The Tram isn't totally without issue though. Operating on the manual tuner, some drift is noted. But on the crystal side, it's as rock steady as any other SSB rig.

[ak3383]

Great info thanks. I was kinda hopin the Tram was better on ssb cause I always wanted one of them.

[2600]

Believe him. He's dead on target. Agrees completely with my experience.

73

[radioreddz]

no doubt the Tram is much better on SSB. even been doing a little freebanding above ch.40 on the manual side after warm up seem pretty stable.

[2600]

So long as you don't talk too much.

The one thing they weren't thinking about when they designed the D201 was using the VFO to transmit on SSB.

When you transmit, the AC voltage to the heaters on the tubes will fall slightly. This causes the VFO to drift. So long as you only receive on SSB, the stability is not bad.

But unless you provide a separate regulated source of 6.3 Volts for the heater on the VFO tube, you will drift while talking on SSB.

That same amount of drift on AM is too small for anyone to hear on the other end.

I have seen schemes to regulated the 400 Volts DC that powers the VFO circuit, but it doesn't seem to make much difference. A 10-Watt zener diode will hold that voltage more constant, but won't affect the biggest cause of drift, that one tube's heater temperature.

73

[mark4]

Tram does better on SSB.
But the receive seems a little narrow.
I would much rather run a Cobra 2000 on SSB.
I have owned Tram and Browning. And prefer browning overall.
My browning hangs in there pretty good and the transmit is dead on SSB. But the receive of this unit is to narrow banded for the wide bander's. They end up sounding like Darth Vader.

[wd8nia]

I've never had or ran a D201A, but I've ran all versions of the D201. I didn't have a lot of success with the Mex version on SSB, and I blew out the mode switch running said US version on SSB before I could reach any conclusion. I'm now running the HW model daily, have made many DX as well as local contacts with it on SSB, and I've had no reports of it drifting on TX; but, it's marginally drifty on RX until it's warmed up for a half hour or so. So, I always turn it on and wait at least a half hour before I operate it. With all the work that's been done to this rig, I have to assume something must have been done about the drift issue if it exhibited such to begin with.

Other than checking/adjusting bias, I don't recall ever even once running my MKIV on SSB. I used it on AM only as that's what I picked it up for.

73.