49:1 vs. 9:1 Transformer for RX only?

[MTScannerNut]

I've been looking at end-fed antennas at myantennas.com. I see that they sell antennas with various length wire with both 9:1 and 49:1 ununs. The 49:1 are labeled as resonant antennas. What I cannot seem to get a clear answer in all my reading is which is superior for a receive only antenna? I would like to hear all the ham bands as well as the shortwave bands. I will not be transmitting. I have the room to install a 130-150' wire, so that is not the problem. Which is best for my application? Thanks in advance.

 

[900mhz]

Resonant with an antenna tuner I would imagine...and that is for TX and depending on which band. Since you just want receive only, I am sure a random length would suffice for your circumstance. You got room for 150 feet...string out 150 feet...

 

[popnokick]

Put up the longest antenna you have room for. For receive only don't be concerned about the ratio of the ununs. More wire in the air = more bands = more signal capture.

 

[prcguy]

A 49:1 or 64:1 is used only for a resonant end fed antenna cut for a half wavelength at its lowest frequency and it will operate with a good match on all harmonic freqs. It would not be good for general SW use due to the very specific and narrow frequency ranges it covers. A 49:1 would match 50 ohms to about 2,450 ohms and a 64:1 matches to 3,200 ohms, typical of a 1/2 wave end fed.

A 9:1 matches 50 ohms to 450 ohms and that turns out to be an ok compromise for feeding 50-100ft of wire for general purpose SW receive. That type of wire antenna could be lower than 50 ohms at some frequencies and over 2,000 ohms at other freqs, so 450 ohms smooths out many of the impedance bumps across the HF bands. The popular PAR SW end fed is about 45ft of wire and a custom 9:1 balun with some grounding options.

 

[ka3jjz]

And you can change out that 45 foot of wire the Vibroplex PAR gives you with more if you want.

But at 150 foot of space - something we cave dwellers would kill for - you can do much better than 'string out a piece of wire'. My viewpoint is biased, of course, but I would lean to a G5RV type antenna and a good transmatch (notice I didn't say antenna tuner - they aren't the same thing) since I'd be on the air with it. For just receiving, depending on the frequency being used and the radio, you might not need a transmatch at all..

If you have the green and the space, having more than 1 different type of antenna can often work to your advantage. What one antenna is hearing so well, another might bring in better. Propagation can be that way sometimes. As an example...

EWE Antenna review :: DXing.info

Mike

 

[prcguy]

The G5RV is a 20m antenna with a little gain and on other bands its a random length doublet that needs a good common mode choke at the coax/balanced line junction.

And you can change out that 45 foot of wire the Vibroplex PAR gives you with more if you want.

But at 150 foot of space - something we cave dwellers would kill for - you can do much better than 'string out a piece of wire'. My viewpoint is biased, of course, but I would lean to a G5RV type antenna and a good transmatch (notice I didn't say antenna tuner - they aren't the same thing) since I'd be on the air with it. For just receiving, depending on the frequency being used and the radio, you might not need a transmatch at all..

If you have the green and the space, having more than 1 different type of antenna can often work to your advantage. What one antenna is hearing so well, another might bring in better. Propagation can be that way sometimes. As an example...

EWE Antenna review :: DXing.info

Mike

 

[900mhz]

The G5RV is a 20m antenna with a little gain and on other bands its a random length doublet that needs a good common mode choke at the coax/balanced line junction.

honestly, A G5RV is an overrated antenna. There are better solutions, depending on real estate

 

[ka3jjz]

The G5RV is a 20m antenna with a little gain and on other bands its a random length doublet that needs a good common mode choke at the coax/balanced line junction.

Yes, and there are a couple of versions of that antenna floating around (like one by ZS6 something or other) which would perform just fine as a receive only antenna. There are numerous other antennas out there that would fit easily in 150 foot of space; the point here is that being a bit more scientific about your antenna choices would help bring better results, depending on the radio being used and your local RF environs, of course..

 

[WA8ZTZ]

For your purposes, HF ham and shortwave bands RX only, a 50' to 100' run of wire with a 9:1 unun matching device will
provide a close enough match to a typical 50 ohm receiver input over the HF band. Keep it away from power lines, HID lighting, bug zappers and the like for safety and to minimize noise pickup. Be sure to consider lightning protection.