Using UHF amplifier on dual band radio?

[ClemsonSCJ]

Ok this is either going to be one of the more stupid things I’ve asked or not...BUT...here’s what I got. Currently have an Icom 2730 in my car and I recently acquired a Yaesu FT3D to have a nice handheld in addition to the Boafengs I have. I went ahead and ordered a short antenna to do a lip mount on the hood of my car where the radio antenna was so it will be a very natural look, so that I can run the HT in my car as well.

So here’s where my question comes in. Not sure if I’m going to go to these lengths or not, but I started toying with the idea of an amplifier like one of the BTech models. However they are not dual band amplifiers and I’d have to choose which band I wanted it for. The only dual band amplifier I was able to find, I’d just buy a new damn mobile radio before I invested that much money in an amp. So the issue becomes this...I’d want to have the capability of transmitting on both bands, but the amps are only designed for one. So would it be possible to go from the radio into a duplexer to split vhf and uhf, the uhf line go into the amp, the vhf line just continue without amplification, and then get a 2 way splitter to join them back to run to the antenna?

 

[buddrousa]

You would be better off to just buy the right tool for the job you forget do something wrong and fry the entire setup.

 

[mmckenna]

So would it be possible to go from the radio into a duplexer to split vhf and uhf, the uhf line go into the amp, the vhf line just continue without amplification, and then get a 2 way splitter to join them back to run to the antenna?

Yeah, it would work.


But why? By the time you buy all that hardware, you'd be better off getting a dual band radio.
Diplexers will have a bit of loss. Not a lot, but they have some.
A decent amplifier is going to cost a bit, so will the diplexers, cables, connectors, installation, etc….

 

[ClemsonSCJ]

Yeah, it would work.


But why? By the time you buy all that hardware, you'd be better off getting a dual band radio.
Diplexers will have a bit of loss. Not a lot, but they have some.
A decent amplifier is going to cost a bit, so will the diplexers, cables, connectors, installation, etc….

And that’s more or less why I’m doubting I’ll even bother trying it but I still was intrigued by the idea and had to ask. One possible issue I did find...when transmitting on UHF, the duplexer would obviously keep any rf from feeding back through the VHF line. But when transmitting VHF, there would be nothing keeping that 5 watts from back feeding into the UHF amplifier. IF (BIG IF) this setup were going to be attempted, would a duplexer be needed on the bottom and top end?

 

[ClemsonSCJ]

You would be better off to just buy the right tool for the job you forget do something wrong and fry the entire setup.

I would hope I forget to do something wrong 😅

But yeah I’m pretty much in agreement...so this is more or less asked out of sheer intrigue.

 

[mmckenna]

But when transmitting VHF, there would be nothing keeping that 5 watts from back feeding into the UHF amplifier. IF (BIG IF) this setup were going to be attempted, would a duplexer be needed on the bottom and top end?

The diplexer would isolate that from the UHF side.

Here's a dual band amp:

Mirage BD-35 Mirage VHF/UHF Amplifiers | DX Engineering

Free Shipping - Mirage VHF/UHF Amplifiers with qualifying orders of $99. Shop VHF/UHF Amplifiers at DX Engineering.

www.dxengineering.com

$300.00.

Dual band VHF/UHF radio:

Ham Radio Outlet Product Details - Item Not found

We were unable to find a product matching that product id and/or description.

www.hamradio.com

$259.00

The mobile radio will give you much louder and intelligible audio, plus it'll save you $40!

 

[mmckenna]

When I first received my ham license, I went out and bought a dual band hand held radio.

I quickly realized that 5 watts into a crappy antenna didn't do much. I built a Ramsey kits VHF amplifier that took the 5 watts on VHF and bumped it up to 35 watts. Built from a kit, I seem to remember it being around $100. Having access to a shop at work, I built it in my spare time.
I used it mobile for a while, but quickly discovered that the pip-squeak audio/speaker on the hand held made it very difficult to understand. The speaker mic didn't help much.
Plus I was dealing with a power adapter, coaxial cable, speaker mic, and it got to be a real hassle.

After about a week of trying that mobile, I went out and got 2 meter mobile with my next paycheck. Worked much better, louder audio, much easier to use.

The RF amp stayed at home hooked up to the handheld. At some point I bought a PK-232 Packet TNC and had that hooked up to the handheld and the amp. Worked pretty well, until I lost interest in packet (this was before the day of internet tubes connecting our homes…).

I think I sold the amp at a ham flea market.

 

[bharvey2]

I have to agree with the above posts. I've done the messing around with the HT and amp thing. While you can get it to work. the time and money you put in to it will never match the results you'll get with a genuine mobile radio. If the intention was to stick it all in a backpack and walk around, it might be worth it but as the intent appears to be in a car really, go with a mobile.

Oh and if stupid questions were really a thing on this site, there'd probably be a specific forum category for them. At least that's what I tell myself.

 

[KN4EHX]

Lots of good dual bands floating around eBay and QRZ for less than the price of an amplifier. Also don’t thumb your nose at brands like Anytone, Connect Systems, or TYT. Those three make excellent dual band radios that are Analog / DMR capable for excellent prices with warranties to boot.

 

[KN4EHX]

Lots of good dual bands floating around eBay and QRZ for less than the price of an amplifier. Also don’t thumb your nose at brands like Anytone, Connect Systems, or TYT. Those three make excellent dual band radios that are Analog / DMR capable for excellent prices with warranties to boot.

Should also be some decent sales on those from places like Bridgecom, HRO, and others for Memorial Day Weekend.