|
Hi Dave,
toggle quoted message
Show quoted text
Remember Tek gold plated their PC boards until gold skyrocketed in in price in 1972 or 1973 so I think it was an easy way for Tek to "color code" the adapters so engineers would know which way to connect them. It is definitely not solid gold. Even an idiot could tell that by the weight. There would be a very big difference in mass from the non-gold end to the gold end if it were solid gold. Dennis -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Dave Seiter Sent: Monday, August 12, 2019 4:41 PM To: [email protected] Subject: Re: [TekScopes] General Radio 874 Connector, inner conductor "bendies" Hi Dennis, Yes, the inner conductor for the 125ohm version is considerably smaller than the normal version. I've always wondered if there was another use for them because some of the people selling them think they are made from pure gold (apparently). The box that's on ebay now has been there since at least 2008. When I was actively looking for them, they were easy to spot from far away at swap meets due to the gold. If there was a bin of 874s, I always did a quick scan of all of them because just as you occasionally run across a "normal" 874 that is gold plated, I have found 125 ohm versions that are not gold plated. (I have a "T" connector sitting on the couch next to me which has no gold at all, even though all three ends are 125 ohm). Also, the oldest 519 I have has no gold plated connectors at all. Seems odd to use gold plating as a visual key, but I guess if you're buying a 519, it's nice to have some bling instead of colored plastic. -Dave On Monday, August 12, 2019, 09:40:29 AM PDT, Dennis Tillman W7PF <dennis@...> wrote: Hi Dave, If I remember correctly the reason for the 125 ohm connectors was because that was the impedance of the vertical deflection plates. The input signal went directly to the plates. So I would guess the answer is no - there was no other use for 125 ohm connectors To get 125 ohm characteristic impedance the size of the inner conductor has to be different than for a 50 ohm characteristic impedance so Tek made special 50 ohm to 125 ohm adapters. The 50 ohm GR 874 connector was on one end and the 125 ohm GR connector was at the other end. The 50 ohm end was the standard color of all GR connectors. The 125 ohm end was plated with gold. Because of the gold they were quite eye catching and "unique". The entire set of adapters Tek made for the 519 came in a really beautiful mahogany box. I had one of those boxes with most of the 519 adapters. The box, the adapters, and the 519 are now in Barrie Gilbert's collection of scopes. Dennis Tillman W7PF -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Dave Seiter Sent: Monday, August 12, 2019 9:03 AM Speaking of the 874 connectors, were the 125 ohm versions ever used for anything unrelated to the 519s, or by anyone outside of Tek? -Dave On Sunday, August 11, 2019, 05:12:44 PM PDT, Dale H. Cook <bridgewaterma@...> wrote: On 8/11/2019 4:08 PM, Bruce Hunter wrote: The 774-series connectors were the predecessors of the 874-type and best described as a banana plug encased with an outer shield. They were not hermaphroditic. -- Dennis Tillman W7PF TekScopes Moderator -- Dennis Tillman W7PF TekScopes Moderator |
