Quote:
Originally Posted by Boobtubeman
Hehehe yeah i wasnt expecting to hear "calling all cars" 
My roof antenna was a throw together.. It consists of a stainless steel whip bolted to a copper vent pipe (ex CB) and some RG26 A/U i had lying around as sheilded cable. Im sure its not matched but my dads ZENITH trans oceanic seemed to enjoy it 
Mind ya, i just did a re-cap on it and dont have the tools or the knowlege to give it a tune-up if it needs one..
I just thought ide get some kind of reception even with a throw- together roof setup.. Trying to figure out if the rado is okay or i need to upgrade the antenna.. ?
Steve |
Hmmm.
If you can hear stations on the broadcast band and one shortwave band, the radio is basically working. If you have an outdoor antenna, even as simple as yours appears to be, as I said in my first post you should hear some stations on the 1695-4000 KHz band as well. My best guess is that the signal circuits for that frequency range may be terribly out of alignment, or there could be an open component somewhere between the antenna and the ... I want to say the grid of the RF amplifier tube, but I saw the schematic on Nostalgia Air and noticed that there is no such stage in this radio.
You might also try cleaning the contacts of the band switch; in a radio as old as yours the switch may not have been cleaned for decades, if at all, since the radio was new. Many times poor contacts on the switch will kill reception on one or more bands; I have a Zenith C845 AM/FM radio that I am almost certain has an intermittent contact on the band switch, as the signal cuts in and out when I move the shaft. This may also be the case with your Delco radio; as I said, in a radio made some 70 years ago, the controls will definitely need a good cleaning. There is also the possibillity that the band switch is just plain worn out after seven decades, but if the radio works on two bands but not the third, I would suspect dirty contacts before doing anything really drastic.
In over 35 years in amateur radio I have never heard of RG36A/U coaxial cable. The mismatch between it and the antenna input of your Delco radio, however, may be enough to cause very severe signal loss at 1.69-5 MHz.
Another thing just occurred to me: On the Nostalgia Air schematic for this set, the antenna input is shown as a terminal strip, which is definitely not meant for coax cable. You almost certainly have an incredible mismatch right there. These radios were designed to be used with a single-wire antenna and a ground.
One more thing. Full-length Citizens Band antennas are 108 inches long, so your best reception would likely be on the second shortwave band, which on your set tunes to 18.1 MHz. You may hear some signals on the 1.6-5 MHz band using just that antenna, but I would use a separate antenna for optimum reception there.
Good luck. Those older radios were made much better than today's transistor sets. Shape up the antenna, get the signal circuits aligned (professionally, if such is beyond your capabilities), and you will have an excellent set. I'm not familiar with Delco radios (the old sets in my small collection are Zenith and Sony), but generally speaking, your set should work very well once it is shaped up to specifications. Those old sets work and sound better than today's no-name or rebadged Korean/Japanese/Chinese imports. As I have said many times in these forums, they don't make them like they used to....unfortunately.
