3.7.1 Sources of Commercial Mods
A number of sources did exist for mods to this equipment. Amateurs like to change equipment around. If the equipment is popular, it is not unusual for a cottage industry to develop for some enhancements and goodies. Consider the following as reference only:
 | Sartori Associates (W5DA) Sartori offered for sale a number of accessories for the R4C and TR7 including solid state tubes (a 6BA6 was called a SBA6), crystal filters, audio low pass filters and such. No current data exists to my knowledge indicating that Sartori Associates is still providing any accessories. |
| Sherwood Engineering Similar to the above, they provide R4C rework services and crystal filters. This company is still alive and very well. Sherwood Engineering has a reputation for quality, well thought out solutions to communications problems. They were at one time quite involved with Drake equipment and specialized in the R4C and R7. Sherwood is back in the Drake business and has a Web sight. I encourage R4C owners to have a look. http://www.sherweng.com |
| Fox Tango Fox Tango was bought out by International in the early 90's. F/T originally was noted for their Yaesu FT101 filters and first mixer kit changes. Regarding the Drake R4C, they offered add-ons known as GUF-1, GUF-2 and GUD. The first 2 were filters replacements for the first IF crystal filter in the Drake R4C and were for SSB and CW respectively. The GUF-1 came in 8 and 6 kHz bandwidths. The GUD was a solid state product detector kit replacement. A filter switch kit for both the GUF-1 and '2 was available that mounted above the chassis where the first crystal filter resided. The object of the exercise was to provide switchable filters for CW and the 'other' modes. Sherwood might have done something similar also. |
| International Radio This company deals in after market crystal filters for a number of radios. The filters are about $110 and are good. Their filters for the Japanese radios are better than factory and much cheaper. This is especially true for the Icom FL-44 455 kHz model. Some of their filters are not 'drop in replacements' such as the GUF-1. The R4C optional filters are size and pin compatible. It is difficult to find a better filter for a radio than from these folks. Most of their filters for all of the radios that you could buy for are drop in replacements. Some models of the GUF-1 are not drop in replacements, but the work required to install the filter is not all that difficult. International's filters are made in Japan and subject to delivery and order delays. If you catch International between orders for new shipments, expect to wait 3 months minimum. These people are the only source for optional filters for older equipment that I am aware of. They DO NOT have AM filters for any of the 7 line. Since they are the only source, readers that want a filter for their Drakes (or older 'other') are advised very strongly NOT to hesitate.*** International Radio has been bought out. |
