G503 Military Vehicle Message Forums

First, I have 2 radios in a newly purchased M-20. I'm a gearhead, not a radio expert. BC683-B and BC684-B, do I need 2 antennas? I currently have 1.
Second, does anyone have an antenna whip hold down insulator they would trade or sell? I think I need an IN-86.
Third, I need a section for a whip antenna, MS-50 (yellow->green). Any available?
Thank you for your help, Jim

They use the same antenna when mounted in the FT-237.The IN-86 is correct for the tie down.

the question you need to ask is -do you want and artillery radio ? ( SCR-608), instead of an armor radio (SCR-508) ?

and do you have the manual

TM 11-2716, 44. Installation of Radio Equipment in Armored Utility Car M20, 29 pages. PB 80912 - BSIR 7(1):35; 10/03/47

BB

Only semi-related to your subject.... if you plan to do a lot of street driving with antenna up, including tied back, I don't recommend it and it's not about hitting things. I don't want to hijack your thread so feel free to email me or make a new post about driving with antennas.

trees and branches and traffic signal wires beat the hell out of the WWII antennas....

I use a 102 inch fiberglass CB antenna for my working BC-659J with PE-120 power unit, MP-57 mount. Find it more forgiving than the MS sections when contacting tree branches, no bending. SWR on 29.400 and 29.600 are well within limits.

WM,

The BC-683-(*) is a receiver and the BC-684-(*) is a transmitter. They both share the same antenna (normally) so you only need one antenna.

Unless you also have an HF set in the M20, you do not need an MS-50. Only the HF sets use MS-50 and MS-49. With the SCR-628 that you say you have, if your mast base is MP-48-A, you need MS-53, MS-52 and MS-51. If your setup is 1944 or later, you can also use AB-15/GR with one each of MS-116-A, MS-117-A and MS-118-A.

If you use the older mast sections, pay particular attention to the instructions to use MC-424 and MC-423 or cloth friction tape on the two threaded joints. And tighten the set screw at the top of the MP-48-A. If you don't, you will probably lose one MS-51 per parade, especially if you drive the vehicle to and from the parade.

I have a good supply of IN-86-A insulators, which replaced all IN-86 as they broke. Price $12.50 each plus postage. I also have the MC-424 and MC-423 clamps @ $5.00 each. And new un-died RP-5 @ $0.50 per foot. I may figure out how to die it later this year. Although not all of the original production was died.

Robert D.

A wealth of info, thank you, Jim