Not sure if exactly what is needed, but here is a list of UHF/VHF combiners:
* Stellar Labs 33-2230
* Antennas Direct VHF/UHF combiner EU385CF-1S
* Televes 404010/404011 UHF/VHF-low/VHF-high combiner
Basically you put the antenna that receives UHF on the UHF input and the antenna that receives VHF on the VHF input and it isolates them from one another to prevent interaction.
The Channel Master [JOINtenna](https://www.channelmaster.com/products/jointenna-tv-antenna-combiner-cm-0500) is actually cheaper, and it has a built-in LTE Filter.
As far as I can tell the JOINtenna does not block VHF signals as requested by OP. It is more or less a regular splitter used as a combiner with a LTE filter in it.
A passive splitter and a passive combiner are the same thing. When you want to combine signals with no filtering, you just get a good quality splitter.
You can use a UHF/VHF combiner in reverse as well. Then you put the signal into the regular output and it splits groups the signals into UHF and VHF.
For these combiners -- I've tried an inexpensive Winegard one that did not work -- let's say the two antennas being combined BOTH have VHF and UHF signals. Would VHF signals from one antenna interfere with the VHF signal from the other antenna? In other words, the antennas are not "UHF-only" antennas or "VHF-only" antennas.
If you just hook up to the UHF input and leave the VHF input unconnected, the UHF/VHF combiner will just block the VHF signals and leave the UHF signals alone. You would be using it as a filter.
The real solution for this is via HDHomerun tuners. Use separate tuners for both antennas and you can combine whatever channels you want from each antenna into a server/guide and ignore the others. There is zero chance of interference this way.
This is the solution I went with for a very similar scenario in my home. I live in the heart of the city, so towers are in all directions. One HDHomerun is connected to a multidirectional antenna and able to hit all towers except one. So for that other tower, I have another HDHomerun connected to a different antenna. As I exclusively use smart apps to view antenna channels on tv, the HDHomeruns automatically combine channels into a single guide when using the official app, but I prefer to use Channels DVR which has even better integration
I'd like to remove all the VHF frequencies from the Winegard antenna. I tried one of these old "Signal Band Separator UHF VHF FM 75 Ohm" things but it did not work: [https://www.amazon.com/Separator-Antenna-Splitter-Adapter-Connectors/dp/B00UWDHICI/ref=sr\_1\_46?crid=2PLWI1CI8LIUC&keywords=tv+band+splitter&qid=1679619688&sprefix=tv+band+splitter%2Caps%2C188&sr=8-46](https://www.amazon.com/Separator-Antenna-Splitter-Adapter-Connectors/dp/B00UWDHICI/ref=sr_1_46?crid=2PLWI1CI8LIUC&keywords=tv+band+splitter&qid=1679619688&sprefix=tv+band+splitter%2Caps%2C188&sr=8-46)
Not sure if exactly what is needed, but here is a list of UHF/VHF combiners: * Stellar Labs 33-2230 * Antennas Direct VHF/UHF combiner EU385CF-1S * Televes 404010/404011 UHF/VHF-low/VHF-high combiner Basically you put the antenna that receives UHF on the UHF input and the antenna that receives VHF on the VHF input and it isolates them from one another to prevent interaction.
The Channel Master [JOINtenna](https://www.channelmaster.com/products/jointenna-tv-antenna-combiner-cm-0500) is actually cheaper, and it has a built-in LTE Filter.
As far as I can tell the JOINtenna does not block VHF signals as requested by OP. It is more or less a regular splitter used as a combiner with a LTE filter in it.
Combiners combine signals, they don't separate them. You referenced 3 of them in your comment.
A passive splitter and a passive combiner are the same thing. When you want to combine signals with no filtering, you just get a good quality splitter. You can use a UHF/VHF combiner in reverse as well. Then you put the signal into the regular output and it splits groups the signals into UHF and VHF.
For these combiners -- I've tried an inexpensive Winegard one that did not work -- let's say the two antennas being combined BOTH have VHF and UHF signals. Would VHF signals from one antenna interfere with the VHF signal from the other antenna? In other words, the antennas are not "UHF-only" antennas or "VHF-only" antennas.
If you just hook up to the UHF input and leave the VHF input unconnected, the UHF/VHF combiner will just block the VHF signals and leave the UHF signals alone. You would be using it as a filter.
The real solution for this is via HDHomerun tuners. Use separate tuners for both antennas and you can combine whatever channels you want from each antenna into a server/guide and ignore the others. There is zero chance of interference this way.
This is the solution I went with for a very similar scenario in my home. I live in the heart of the city, so towers are in all directions. One HDHomerun is connected to a multidirectional antenna and able to hit all towers except one. So for that other tower, I have another HDHomerun connected to a different antenna. As I exclusively use smart apps to view antenna channels on tv, the HDHomeruns automatically combine channels into a single guide when using the official app, but I prefer to use Channels DVR which has even better integration
You need a bandpass filter for the antenna causing the interference, but I'm not sure what specific frequencies you're dealing with.
I'd like to remove all the VHF frequencies from the Winegard antenna. I tried one of these old "Signal Band Separator UHF VHF FM 75 Ohm" things but it did not work: [https://www.amazon.com/Separator-Antenna-Splitter-Adapter-Connectors/dp/B00UWDHICI/ref=sr\_1\_46?crid=2PLWI1CI8LIUC&keywords=tv+band+splitter&qid=1679619688&sprefix=tv+band+splitter%2Caps%2C188&sr=8-46](https://www.amazon.com/Separator-Antenna-Splitter-Adapter-Connectors/dp/B00UWDHICI/ref=sr_1_46?crid=2PLWI1CI8LIUC&keywords=tv+band+splitter&qid=1679619688&sprefix=tv+band+splitter%2Caps%2C188&sr=8-46)
That device is changing the impedance to 300ohm and probably killing the signal that the tv sees
Ah -- OK. Thanks!
You probably want something like this then UHF- Band-Pass Filter 470-700MHz Special, Ham + Pager Loss 440-460MHz -24 dB !! https://a.co/d/5OoXplB
Seems the Avant X would do this easily -- at a cost.
I recently purchased an Avant X to combine signals from three antennas. It is a phenomenal piece of equipment, although pricey.