I believe there are 50 ohm BNC connectors that fit 75 ohm cable, which
are interchangeable as you say, but there are also true 75 ohm BNC's
that do not intermate with garden variety BNC's.
Rick N6RK
k8gt@mi.rr.com wrote:
> With all due respect, Frank, but 50 and 75 Ohm BNC connectors are very
> compatible and in the TV and Video production businesses, we have been using
> them since the '60's. When we changed from UHF connectors to BNCs, we only
> had 50 Ohm types, it was a little later that the 75 Ohm connectors were
> available. In analog video it didn't make any difference, but when we got to
> SD video and now HD video, it definitely did make a difference. Obviously at
> VHF anf UHF RF, it makes a great difference.
>
> Your description of the difference in connectors is spot on.
>
> 73, Gerry, K8GT
>
>
>
> ---- donovanf@starpower.net wrote:
>
> =============
> 75 ohm BNC connectors are specialized connectors used primarily above 100 MHz
> by in high definition television production studios, telephone, and satellite
> communications industries. Unless you work in those industries, you're not
> likely to need them. 50 ohm BNCs work fine with 75 ohm cables for
> applications below about 100 MHz where the connector is very short compared
> to a wavelength.
>
> The dielectric in 75 ohm BNCs connectors has a obvious different
> configuration than the dielectric in 50 ohm connectors. The dielectric in a
> 50 ohm BNC is extends along the inner surface of the shield. The dielectric
> in a 75 ohm BNC does not extend along the inner surface of the shield.
>
> http://www.lifebeforelandfill.com/item/cameras_photo/professional_video_equipment/cables_wires/canare_bnc_cable_m-m_75ohm_lv-61s_45-ft/images/00179_canare_bnc_cable_m-m_75ohm_lv-61s_45-ft_img_01_gall.jpg
>
>
> IMPORTANT: 50 and 75 ohm BNC connectors are not usually compatible or
> interchangeable.
>
> 73
> Frank
> W3LPL
>
> ---- Original message ----
>> Date: Thu, 19 Nov 2009 14:38:03 -0800 (PST)
>> From: Julius Fazekas <phriendly1@yahoo.com>
>> Subject: Topband: F connector question
>> To: topband@contesting.com
>>
>> Anyone have any idea what type of F connector I need for this? Didn't
>> realize there were so many flavors.
>>
>> And what's the difference between a 50 ohm BNC and a 75 ohm BNC, other than
>> the impedance?
>>
>> Commscope 22790 Quality High Performance HDTV Cable 9700851 18AWG CMR(ETL)
>> C(ETL) 002112
>> Center Conductor: 18AWG Solid Copper
>> Dielectric: Foamed Polyetheylene (FPE) Approx. Dia. Over Dielectric: 0.144:
>> +/- 0.004"
>> Shield: Foil: Aluminum/Poly Tape, Braid: 34 AWG Tinned Copper, 90% Coverage
>> Jacket: Flame Retardant Polyvinylchloride (FR-PVC)
>>
>> Mucho gracias in advance,
>> Julius
>>
>>
>> Julius Fazekas
>> N2WN
>>
>> Tennessee Contest Group
>> http://www.k4ro.net/tcg/index.html
>> http://groups.google.com/group/tcg1?hl=en
>>
>> Tennessee QSO Party
>> http://www.tnqp.org/
>>
>> Elecraft K2/100 #4455
>> Elecraft K3/100 #366
>> Elecraft K3/100 #1875
>> _______________________________________________
>> 160 meters is a serious band, it should be treated with respect. - TF4M
> _______________________________________________
> 160 meters is a serious band, it should be treated with respect. - TF4M
>
> _______________________________________________
> 160 meters is a serious band, it should be treated with respect. - TF4M
>
>
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
|
