The definitive answer is below, from Garey K4OAH (SK).
________
All original cables were 38" long tip-to-tip.
The INJ, (and CAR OSC in the C-Line,) cables used a foam inner dielectric and phono connectors
with a white insulation. This cable measures 60 pF total capacity.
All other cables used the standard for the day clear polyethelene inner dielectric and phenolic
(brown) insulated phono connectors and measure ~100 pF.
Original Drake INJ and CAR OSC Cables = 19 pF/ft = .160" o.d. (foam poly)
RG-62 = 93R = 13.5 pF/ft = 0.240" o.d.
RG-59 = 75R = 14.8 pF/ft = 0.242" o.d.
RG-6 = 75R = 16.2 pF/ft = 0.270" o.d.
RG-174= 50R = 30.8 pF/ft = 0.110" o.d.
Mic Cable (Belden 8410) = Hi-Z = 33 pf/ft = 0.160" o.d. (foam poly)
Mic Cable (Belden 8421) = Hi-Z = 16 pf/ft = 0.180" o.d. (foam poly)
R/S Audio Patch Cable = 28 pF/ft = 0.165" o.d. (poly)
The best choice is the Belden 8421 Audio cable from their "Brilliance" line. It looks just like
the other cables, and is very flexible. K0UYA, another list member, had some 8421 at one time
that he was selling by the foot. The RG-62 is OK, but it is 50% larger and far less flexible.
RG-62 is also prone to shorting if bent over too small a radius, and is susceptible to heat
damage when soldering connectors. The best "feature" of RG-62 is that it is often FREE, since
there have been many miles of it pulled out of old computer networks.
The only pertinent factor is the total capacity. Impedance and "loss" are not important.
Any _reasonably low capacity_ coax will work if the units are cabled together for the
adjustment of the INJ trimmers.
The cable type ONLY affects the LEVEL of the PreMix signal, (5.645 MHz ABOVE the
transmit/receive frequency,) and a small DC control voltage between the two. If the shunt
capacity is too high, insufficient LO level for the first mixer will reduce the sensitivity of
the receiver and the output power of the transmitter.
Some of the "commercial" cable mfrs use RG-59A, but it's a little larger and also prone to
shorting if bent over too tight a radius.
The ANT lead to the receiver is too short to matter, but you want good shield integrity, which
usually eliminates R/S cables.
The best connectors I've found are the Switchcraft 3502 plugs, available from just about anyone,
Digikey, Mouser, Allied, Newark and just about any reputable parts place.
Garey Barrell, K4OAH
August 21, 2015
_______
73
-Jim
NU0C
On Sun, 08 Mar 2020 08:47:30 -0700
Bent J?rgensen <BentJoe@...> wrote:
Hello to the Group
Is someone able to inform me about the correct type of cable for Carrier Osc. an Injection for the T-4XC and R-4C.
I have heard about RG59 and RG62.
What is correct ?
What is the important factors / parameters for this cable ?
And why ?
Thanks in advance.
Br.
Bent
OZ5ZD
Jim Shorney