2008 Catalog Available
The 2008 Blonder Tongue Broadband Catalog has been completely revised and updated with all of the latest information on our full line of Broadband Products. Download or order a copy today.
Broadband Hands-On Training
Learn more about Blonder Tongue's expert training in broandband technologies. See the schedule for locations and dates.
Ask An Engineer
Blonder Tongue Laboratories is a leading manufacturer and designer of Broadband systems, voice, video, data and CATV. Use of this query capability is intended for those with questions about this industry and Blonder Tongue’s products and is not intended for general use or for questions outside of this framework.
Some of our Frequently Asked Questions
- Q. We have a new U5896 19 and it is modulating on channel 70. How do I change it to Channel 19?
- Q. Is the BAVM-z Channelized Audio/Video Modulator still available? If not, what took it's place?
- Q. What is recommended for rack spacing?
- Q. Where can I find DIP switch settings for my AM Agile Modulator?
- Q. I am designing a distribution system for 78 channels (550MHz), should I use an 860MHz amplifier for future expansion?
- Q. Why am I not getting an output on the thru-line from my multiport tap?
- Q. Can I send a sub-channel backwards through a splitter?
- Q. I'm calculating the loss in the reverse direction on a two-way system. Do I include the return-loss in the calculation?
- Q. Can you use a directional coupler in a two-way system?
- Q. What size amplifier do I need for a system with ## drops?
- Q. I changed the DIP switch settings on the MAVM and now the unit is not working?
- Q. Why am I not receiving any video out of a modulator?
- A. We have a new U5896 19 and it is modulating on channel 70. How do I change it to Channel 19?
You have to be careful, U 5896 is for UHF channel 19 which is very close to CATV channel 70. If you want CATV channel 19, you can buy a replacement Output Filter Module (OFM) for the channel you desire, they are field replaceable. Frequency charts for CATV, QAM, VHF, UHF, and FM are all located in the Blonder Tongue Broadband Reference Guide.
(Back to Top) - A. Is the BAVM-z Channelized Audio/Video Modulator still available? If not, what took it's place?
The new and improved model is the BAVM-SAW-861.
(Back to Top) - A. What is recommended for rack spacing?
If a rack is not air conditioned, you need to space all active equipment with a minimum of one rack space. Even with a closed rack it's good to do, many engineers place draw fans in the top of the rack to pull the A/C upwards and vent the heat. The closer you can keep the equipment to 68/70 degrees the better.
(Back to Top) - A. Where can I find DIP switch settings for my AM Agile Modulator?
You're in luck! We created a Web page that includes all the switch settings for not only the AM, but also the AP and AD.
(Back to Top) - A. I am designing a distribution system for 78 channels (550MHz), should I use an 860MHz amplifier for future expansion?
An 860MHz amplifier can be used only if the calculations are done at 860MHz and the tap values are specified accordingly. If the system is designed at 550MHz and an 860MHz amplifier is used, the slope-control will not function. Since it will pivot at 860MHz, the tap values will be too high for an 550MHz system.
(Back to Top) - A. Why am I not getting an output on the thru-line from my multiport tap?
When using 2, 4, or 8 port directional-couplers inline, the values of 4, 8, and 11 respectively, have no thru-put because they are terminated units. No other tap may be cascaded after these values.
(Back to Top) - A. Can I send a sub-channel backwards through a splitter?
Yes. Passive devices will pass signals in either direction. Typically, the difference in loss between the reverse direction and forward direction is negligible and can be ignored.
(Back to Top) - A. I'm calculating the loss in the reverse direction on a two-way system. Do I include the return-loss in the calculation?
No. The term "return-loss" is simply another way to express impedance match or VSWR. Return-loss does not increase loss in the reverse direction.
(Back to Top) - A. Can you use a directional coupler in a two-way system?
Yes. The term "directional" only means that the loss from the tap port is different depending on the direction of signal travel on the thru-line.
(Back to Top) - A. What size amplifier do I need for a system with ## drops?
The required amplifier output level cannot be determined without knowing the system loss and amplifier input level.
(Back to Top) - A. I changed the DIP switch settings on the MAVM and now the unit is not working?
You may not have changed the OFM to correspond with the new setting.
(Back to Top) - A. Why am I not receiving any video out of a modulator?
You may be using the RF output "F" connector from the VCR, receiver, DVD, or LD instead of the baseband video RCA jack.
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Technical Solutions Contact
Steve Hegge
732.679.4000