AOR Wide Band Antennas; AOR SA7000 vs Diamond D130NJ Discone

[iMONITOR]

I'm considering a new wide-band receive only antenna for my new ICOM IC-R8600 receiver. How does AOR's SA7000 compare to a Diamond D130NJ discone antenna?

SA7000



Additional info:

AOR SA7000 Super wide band base aerial system - AOR Ltd

AOR SA7000 - 30kHz-2000MHz, Receive only, Wideband whip antenna The aerial is designed for areas where space is a problem or when an "unobtrusive" installation is essential. The SA7000 is a passive arrangement providing two whip elements: a long element for short wave up to 30 MHz and a second...

radioaficion.com

 

[cmdrwill]

I would only consider the AOR SA7000 if you want the low band to 50 mhz. And NO comparison to the cheepie
discone (s).

A good quality ground plane with a VHF / UHF / 800 mobile antenna mounted in the clear.. .

 

[iMONITOR]

@prcguy Mike I'd be interested in your feedback on this antenna? I'm aware there are some compromises but for a stealthy special application what do you think? I'd be using it primairly on 2M/70Cm, VHF/UHF airbands, marine as well as 11 & 20 meters.

 

[prcguy]

I have one, it kind of works but not very well. On AM BCB and HF its better than a short length of wire stuck in the back of your radio indoors and better on HF than using a VHF/UHF Discone. I haven't played much with mine on VHF/UHF so I don't have any data. I suppose if you lived in a place that was very antenna restrictive and you could only have one small antenna for everything from VLF to UHF, its better than nothing.

The AOR SA7000 consists of a 6ft whip with a transformer that matches a very high impedance to 50 ohms and the mystery loaded VHF/UHF whip. The output of the low frequency transformer and the base of the VHF/UHF whip feed a diplexer with about a 30MHz cross over point to isolate the two antennas while combining them onto one connector.

These antennas are sometimes used by radio and TV stations to receive EAS alerts on broadcast AM, FM and NOAA frequencies to then send out over the radio or TV station. We had one at my last gig and it didn't work very well on FM broadcast band or NOAA so I took it apart and rebuilt it with a specific tuned dipole for 100MHz and 162MHz, which worked much better. The original whip did not resonate anywhere near the needed frequencies for picking up EAS and I have no idea why some companies supply these antennas with their receivers. The 6ft long whip for HF did seem to work ok for picking up AM BCB.

I bought one cheap just to measure the transformer used to match the 6ft whip for HF and its sitting in pieces in my garage at the moment. I should put it all back together and sell it since it will never get used here.

@prcguy Mike I'd be interested in your feedback on this antenna? I'm aware there are some compromises but for a stealthy special application what do you think? I'd be using it primairly on 2M/70Cm, VHF/UHF airbands, marine as well as 11 & 20 meters.

 

[buddrousa]

As expected a very good unbiased and well explained answer.

 

[iMONITOR]

I have one, it kind of works but not very well. On AM BCB and HF its better than a short length of wire stuck in the back of your radio indoors and better on HF than using a VHF/UHF Discone. I haven't played much with mine on VHF/UHF so I don't have any data. I suppose if you lived in a place that was very antenna restrictive and you could only have one small antenna for everything from VLF to UHF, its better than nothing.

The AOR SA7000 consists of a 6ft whip with a transformer that matches a very high impedance to 50 ohms and the mystery loaded VHF/UHF whip. The output of the low frequency transformer and the base of the VHF/UHF whip feed a diplexer with about a 30MHz cross over point to isolate the two antennas while combining them onto one connector.

These antennas are sometimes used by radio and TV stations to receive EAS alerts on broadcast AM, FM and NOAA frequencies to then send out over the radio or TV station. We had one at my last gig and it didn't work very well on FM broadcast band or NOAA so I took it apart and rebuilt it with a specific tuned dipole for 100MHz and 162MHz, which worked much better. The original whip did not resonate anywhere near the needed frequencies for picking up EAS and I have no idea why some companies supply these antennas with their receivers. The 6ft long whip for HF did seem to work ok for picking up AM BCB.

I bought one cheap just to measure the transformer used to match the 6ft whip for HF and its sitting in pieces in my garage at the moment. I should put it all back together and sell it since it will never get used here.

Not what I was hoping for but thanks for responding.

I had a friend that had a cottage in Lexington, Michigan. that was North of Port Huron that had one for 10+ years mounted about 20' above ground level. He claimed it worked great for Marine traffic out on Lake Huron. He also used to listen to the local fire department on 150.00 MHz band VHF.

 

[65GS]

I have had the AOR SA7000 for about one month now and so far it has worked pretty well. I may need to relocate it a bit for a better signal but will deal with that later. Will probably try something else in the future that hopefully can provide more gain.

I do have one concern though. Checking the continuity from center conductor to ground on my coax shows about 1.3 ohms. I then checked at the SA7000 RX output as seen in the picture and it reads .2 ohms. I have never seen an antenna that reads almost a dead short between the center conductor and ground. I am hoping it is the result of mixing of the two antennas and is normal but am not sure. Like I said earlier it seems to work good so this may be by design. Has any one else looked at this?

 

[Ubbe]

It's several coils in series that goes to ground and will measure 0 ohm at DC.

/Ubbe

 

[65GS]

Thanks Ubbe, I am more comfortable using the antenna now. Before I worried it could damage the radio in some way.
I plan on replacing the RG58/U it came with with something better and maybe moving the it a bit down the wall for better reception.