Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Zenith 15U270
#17

So I put this radio back on the bench.  I played with the dial lamp - it was all the way in.  I found a different 47 lamp that was slightly longer and had the filament way out at the end.  It improved the dial lighting a bit.

I hooked the IF section up to the spectrum analyzer to see what I could do with the response curve.  Here are the results:


IF peaked per alignment instructions. At 6 db down the bandwidth is about +-3.5k.

   


I looked at doing this.  At 6db down, bandwidth would be about+- 7K but the sensitivity is down a lot.

   


I settled in on this. At 6db down, bandwidth is about +- 6k.

   


At the loss of quite a bit of sensitivity, I gained a fair amount of bandwidth.  Still not as good as the Philco 37-116. The radio does sound better with my HiFi transmitter, though.  That's the way I usually use my AM sets.  If I listen to real broadcasts, it's usually talk radio so the high frequencies are not needed.

Kind of fun to play with!


Messages In This Thread
Zenith 15U270 - by rfeenstra - 05-31-2020, 04:45 PM
RE: Zenith 15U270 - by rfeenstra - 05-31-2020, 04:54 PM
RE: Zenith 15U270 - by morzh - 05-31-2020, 06:10 PM
RE: Zenith 15U270 - by rfeenstra - 05-31-2020, 08:06 PM
RE: Zenith 15U270 - by morzh - 05-31-2020, 08:39 PM
RE: Zenith 15U270 - by Eliot Ness - 06-01-2020, 08:07 AM
RE: Zenith 15U270 - by rfeenstra - 06-04-2020, 08:12 PM
RE: Zenith 15U270 - by sdradioman - 06-05-2020, 07:06 AM
RE: Zenith 15U270 - by rfeenstra - 06-05-2020, 10:12 PM
RE: Zenith 15U270 - by morzh - 06-05-2020, 11:44 PM
RE: Zenith 15U270 - by Phlogiston - 06-06-2020, 10:46 AM
RE: Zenith 15U270 - by rfeenstra - 06-06-2020, 11:23 AM
RE: Zenith 15U270 - by rfeenstra - 06-06-2020, 06:23 PM
RE: Zenith 15U270 - by Phlogiston - 06-06-2020, 08:56 PM
RE: Zenith 15U270 - by rfeenstra - 06-06-2020, 09:47 PM
RE: Zenith 15U270 - by Phlogiston - 06-06-2020, 10:34 PM
RE: Zenith 15U270 - by rfeenstra - 06-09-2020, 09:14 PM
RE: Zenith 15U270 - by PhilcoJohn - 06-10-2020, 08:27 AM
RE: Zenith 15U270 - by Phlogiston - 06-11-2020, 11:32 AM
RE: Zenith 15U270 - by rfeenstra - 06-11-2020, 03:31 PM



Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
Here are the links. 6TPZ and 5TPO The speakers are good. I've tried several known good ones. I just have to fi...R3Sons — 06:27 PM
Philco 91 Tuning Condenser
I just found a set screw. Was able to turn dial just enough to see it and loosen it. I have it off now.dconant — 06:14 PM
Philco 91 Tuning Condenser
Hello, Does anyone know how the dial plate comes off the tuning condenser shaft? The dial itself id so warped I can't...dconant — 06:01 PM
Eico 368 TV/FM Sweep Generator
Ron, for the future: In order to change the name of teh topic, 1. Go to the very first post. 2. Hit "Edit...morzh — 04:29 PM
6TPZ and 5TPO Radio Help
Transistors are easy. No converters. If you have input voltage, then just put some signal through. Or touch your fin...morzh — 04:25 PM
462ron
Hi Mike, I believe I tried different ways to change the header for my post but no luck. Anyway thanks for changing it fo...462ron — 04:02 PM
6TPZ and 5TPO Radio Help
Since these radios operated in harsh environments (temp changes and vibration) you could touch a soldering iron to all t...GarySP — 03:18 PM
6TPZ and 5TPO Radio Help
Thank you Gary. Hi Morzh. These radios are 6 transistor radios. Sadly no tubes. Thanks though.R3Sons — 02:19 PM
Heathkit Sweep Generator TS-4
Ron Instead of Quick reply, go to New Reply, then go to the title of the very first post, and change the title text the...morzh — 02:00 PM
6TPZ and 5TPO Radio Help
I am not a specialist in car radios. I suspect they might use vibrators to convert 12V to acceptable tube voltages, so ...morzh — 01:58 PM

[-]
Who's Online
There are currently 9508 online users. [Complete List]
» 1 Member(s) | 9507 Guest(s)
Avatar

>