800 antenna to supplement a Discone

[prcguy]

My antenna came in today and I stuck an analyzer on it. Sorry the analyzer was set to look at the lousy match on a 900 amateur band antenna but this new 824 to 960MHz antenna looks real good in the VSWR catagory. Its under 2:1 from 700MHz to 1,000MHz and much less within its specified range. VSWR is not the only spec to look at but its a good start. Compare this plot with the one in post #15 above, its the same analyzer and settings.

Since I looked at several of these on Ebay one of the sellers sent me a special offer of $26.99 including shipping so I bought a second one.

 

[vagrant]

That looks superb compared to the Comet using the same settings. The results appear similar to my 2015 purchase, but at the current scaling it is difficult to tell. Looks like mine will be here Tuesday. I hope it sweeps just as well. Thanks for the heads up as this should help many.

 

[vagrant]

Antenna arrived today and it is not as friendly at 700 MHz, but it wasn't advertised to be either. It also has an N Male at the end, which it shows in the photographs on eBay, but the description notes that it is N Female. Not really a problem for me, but just so you know. Here is the sticker on the front of mine.


Here's a sweep comparative with prcguy.


Here's a plot with the scaling adjusted. VSWR is under 1.5 from 800 to 950 MHz. The results on this antenna would better suit my needs for TX on amateur 900 MHz.

 

[prcguy]

Interesting that mine was around 2:1 at 700MHz but I had the factory mounting bracket installed which gives it a little ground plane. Did you test on a mounting bracket? Maybe test again with some sheet metal under it?

Antenna arrived today and it is not as friendly at 700 MHz, but it wasn't advertised to be either. It also has an N Male at the end, which it shows in the photographs on eBay, but the description notes that it is N Female. Not really a problem for me, but just so you know. Here is the sticker on the front of mine.
View attachment 91858

Here's a sweep comparative with prcguy.
View attachment 91857

Here's a plot with the scaling adjusted. VSWR is under 1.5 from 800 to 950 MHz. The results on this antenna would better suit my needs for TX on amateur 900 MHz.
View attachment 91859

 

[vagrant]

Yes, it is interesting. Also, as this has an N Male, I cannot slip it into my other mount or I would have to get an accurate comparison with my other. Hmm...well I did just use a F/F barrel connector on my same mount and the numbers got ugly all over, especially at the low end and around 900. Like 6:1 at 700 MHz.

I'll probably look for another that has an N Female connector and maybe return this one. Still, I wish the results were similar to yours. I will pass on the last seller (athomemarket) as he doesn't know the difference. Which seller did you purchase from and was it N Female? I may end up having to keep it.

Anyways, I found a magnet mount with an N female and popped onto the hood of my SUV and roof. The numbers remained similar despite movement. The ground plane did help to some degree on the low and high ends. It dropped it from 5 to about 3.6 at 700 MHz and did not hit under 2:1 until 785 MHz.

 

[KC1UA]

Great thread! I was looking at similar options earlier and when I saw your comments on the HGV906U I grabbed one. Found one with hardware delivered for $49, so maybe a few more $$ but one stop shopping. Mine will be side-mounted off of my tower and fed through my antenna patch panel, not diplexed.

 

[4436time]

Would you expect this antenna to perform any better in the attic than say a Radio Shack 800Mhz antenna?

L-Com SP97177 800/900 MHz 6 dBi Omnidirectional Antenna like HGV-906U w/N-Female | eBay

(1) L-Com SP97177 800/900 MHz 6 dBi Omnidirectional Antenna. Model: SP97177. 800/900 MHz. It would require an N-Male to N-Male adapter (L-Com Part #: AXA-NMNM) to work identically. The mounting adapter is not included.

www.ebay.com

 

[w4amp]

What is the make and model of these "analyzers" ?

 

[mancow]

It looks like mine which is N1201SA

[US$149.99 36% OFF]N1201SA UV RF Vector Impedance ANT SWR Antenna Analyzer Meter Tester 140MHz - 2.7GHz Measurement & Analysis Instruments from Tools on banggood https://banggood.app.link/SVtRxwfBncb

 

[vagrant]

@4436time I would expect it to work better. If you have one and it is not working better, I am wondering if the improved gain is causing you problems while monitoring a simulcast system, or if other RFI is now getting in due to the improved antenna.

@w4amp That is an RF vector impedance analyzer model number N2061SA. We are both using the same model. I got it through Amazon for around $260 a few years back. It is extremely handy for various measurements, but it has limitations even if what you are measuring is within it's specs. For example, it will work for tuning a simple notch duplexer but not a BpBr duplexer. It is fantastic for what it does at that price. Some vastly experienced person clued me in about it. It serves me well for amateur/hobby level stuff. I later compared the tuning performed using it against an Agilent E6380A (8935 series) analyzer. The difference was extremely slight. Also, an 8935 series analyzer is not something one can fit into their pocket. There is an obvious cost difference as well. Again, for amateur/hobby use this particular analyzer does the job.

The model mancow noted may be from the same factory. I expect it would work just as well for sweeping an antenna. I needed the other model for the additional features it has.

 

[Hit_Factor]

What is the make and model of these "analyzers" ?

Here is the link to Amazon for the tool mentioned earlier. Amazon.com: PS100 UV RF Vector Impedance ANT SWR Antenna Analyzer Meter Tester 140MHz - 2.7GHz N1201SA New Version: Electronics

Here is another tool, NanoVNA is the general name for them. Various sizes and capabilities. Start at $50 or so and go up to $150 or so for the larger screen models.

This is the one I have. NanoVNA-F Handheld Vector network analyzer – Hangzhou Minghong Electronic Technology Co., Ltd.

 

[w4amp]

NanoVNA is the general name for them. Various sizes and capabilities. Start at $50 or so and go up to $150 or so for the larger screen models.

This is the one I have. NanoVNA-F Handheld Vector network analyzer – Hangzhou Minghong Electronic Technology Co., Ltd.

Thanks. I prefer a real spectrum analyzer myself. That's just me though.

At 1250' ASL I receive P25 systems in four states with a SDS200 and Comet KP20. Two stages of pre-amp in line also.

I will admit The KP20 is bad on 700 mhz. The only thing I like there is a Sirio UHF discone. I have yagis that will work but then you need rotation of course.

 

[4436time]

Thanks and I don't have one. But it's a good price and I will keep that in mind.

@4436time I would expect it to work better. If you have one and it is not working better, I am wondering if the improved gain is causing you problems while monitoring a simulcast system, or if other RFI is now getting in due to the improved antenna.

 

[4436time]

I picked one of these up and it does pretty decent for the price. Pro-106 gets 5 solid bars on most sites where the RS 800MHz antenna fluctuates from 3-5.

If a person wanted to mount it on the roof, painted to look like a pvc vent pipe (to keep HOA happy), how much would it affect reception and would it need to be grounded?

 

[prcguy]

I have not found any grey or white paints to affect reception below 1GHz but some black paints could have a little attenuation at those frequencies. At much higher frequencies most paints will attenuate, like we used to make attenuators for DirecTV satellite antennas under test by spray painting over the white plastic feed radome. You can spray the paint on and measure the attenuation in real time and it stays the same after drying. We then had several different attenuation covers we could swap around for different tests but this was at 12 and 20GHz.

If the antenna is exposed on a roof you should ground to NEC specs at the very least.

I picked one of these up and it does pretty decent for the price. Pro-106 gets 5 solid bars on most sites where the RS 800MHz antenna fluctuates from 3-5.

If a person wanted to mount it on the roof, painted to look like a pvc vent pipe (to keep HOA happy), how much would it affect reception and would it need to be grounded?

 

[ohiogator]

How would this antenna do in the 770-854 range? I made a $60 offer on one on eBay that came with 100' of 400 coax and they accepted. I am going to mount it on a 30' tower.

 

[prcguy]

What antenna?

How would this antenna do in the 770-854 range? I made a $60 offer on one on eBay that came with 100' of 400 coax and they accepted. I am going to mount it on a 30' tower.

 

[ohiogator]

What antenna?

The L-Com HGV-906U.

 

[prcguy]

If it came with 100ft of LMR400 for that price you did real well. I would try and use the least amount of coax possible at those frequencies like under 50ft.

The L-Com HGV-906U.

 

[prcguy]

Update! I just permanently swapped out my high frequency Discone on my dual antenna master receive system with the L-com HGV-906U and signals in the 900MHz amateur band went up right about 5dB on my Icom R8600 meter. The Discone was very small and designed for about 400MHz through about 3GHZ so it would have been near unity gain in the 700/800/900MHz range.

On another test years ago I took careful measurements in the 800/900MHz range on a full size scanner Discone, MP Antennas Super-M Ultra stupid thing and the small Discone measured about 10dB better overall in the 800/900MHz range. That is huge but mostly because the bigger Discone's radiation pattern shifts up above the horizon and this is typical for most like the Radio Shack, Diamond D-130 series, etc.

So this means if you have a typical scanner Discone and want to improve your 700/800/900MHz reception, adding an antenna like the L-com HGV-906U can improve reception by maybe 15dB. That can be a night and day improvement if your in an extreme fringe area. You can also run a diplexer so the big Discone can receive the 100-512MHz range where it does a good job then let the other antenna take over for the higher frequency stuff.