Actually, the motorola connector has a longer pin. I have an adaptor that works with both motorola AND rca connectors.
The common auto radio connector/plug has worked well for about 80 years and does not go intermittent. A modern crimp version for RG-58/8X size cables would be far better than the RCA and possibly the BNC up to VHF. Carl
On some adapters for converting to the UHF connector, instructions in the kit are to cut off the long pin about 3/8-in. This instruction is from both use in MFJ kits and the Ramsey kits. Radio Shack sold the adapter. I found that on the Ramsey kit I built, it was not necessary to cut off the pin. It depends mainly on which type of connector is used on a specific radio as to whether the pin had to be cut. Some connectors on the radio had a problem of components mounted right back of the connector and if the long pin adapter were used on them, it could contact some other component of the wire soldered to the connector itself. This is why the instruction to cut off the pin to a shorter length.
The Philco designed auto radio style connector is indeed a good connector and did not require a twist-shell to secure the connection. Some lip-mount Hustler mobile mounts used this kind of connector I only found one failure using this on my car and it was in the coax at the connector, not the connector itself. It is relatively long but it about the size of RG-58/59 so it did not present a bad transition from coax to connector. Most of them used a paper/fiber phenolic insulator so there is relatively little danger of insulation deterioration. If you take a Heath style connector cable used on many of those QRP rigs, and it is pushed into the Philco auto radio connector, it will fit and can be used as a transition from a car radio to another kind of antenna, for example. It is a more dependable connection from the cable/coax to the connector than when using the male Philco connector where it comes to connecting the outer shell because many of those auto radio cables from the antenna does not use soldering to the coax but merely depend on dry contact without soldering. Such technology, not soldering the braided shield to the connector, invites eventual bad-connection problems. Using the Heath style connector eliminates this weakness.
So do the ones on MY open wire feedline. However, all of my EQUIPMENT is connected together with coax.
Professional tests for RF loss are made by using what is called a "network analysis" test set-up. This consists of signal generators which can scan RF bands of interest or spot RF frequencies. The generators feed a 50 ohm hardline arm, which is connected to the cable or connectors being tested. Another hardline arm goes to RF measuring devices which can be precision RF meters capable of operating flatly at the frequencies being tested for or leveled and calibrated modern digital storage displays that are scanned in sync with scanning inputs. When the two arms are connected directly to each other zero loss is referenced. In my experience using network analysis set-ups the coax cable losses measured for coax pretty much agrees with book values to be found in "Reference Data for Radio Engineers" or ARRL manuals. Now I'll talk about coax connectors. Tests are usually made with a pair of connectors, male and female. This is what engineers. refer to as INSERTION LOSS. There is always some finite insertion loss involved. It is usually less than 0.25 dB. This is not a very significant loss in most cases but it can be significant at UHF or microwave frequencies or for those who want to get every watt out of a QRP transmitter.
The tests didn't measure the loss with sufficient resolution. In my experience, connectors take about .1 dB - less than the resolution of the bandscope used in the test.
Thanks for accurate info from an engineering perspective. What type of connector did you measure? There are situations where a station installation may have a dozen or more connector pairs between the xcvr and antenna. The xcvr connection, input and output of the amp, input and output of the antenna tuner, input and output of the wattmeter, input and output of the antenna switch, input and output of the static arrestor, input and output of the balun, and the antenna connection. That adds up to 14 connector pairs. A loss of .25db per connector pair could easily add up to 3db or more loss for the entire station, both on receive and transmit. I would like to minimize this loss as much as possible.
A loss of 0.25 dB for a connector at HF doesn't make sense. At 1500 watts, it would dissipate 84 watts. But clearly folks run 1500 watts all the time without their connectors desoldering themselves.
W2ILP clearly referenced "insertion loss". Run 1500 watts CONTINUOUS power for a few minutes, then see how warm you connectors are.
