Looking For A Base Antenna For 39.3 - 39.6 Range

[mm]

An ok low band antenna.

WPC39S0B-001: Larid Wideband, Lowband Antenna operating in 39-46 MHz with NMO Connector | Arcadian Antenna

and any of these nmo to base conversion mounts with 3 or 4, 6 foot wire or similar radialls in place of whatever radiall kit is supplied with the mount.

https://www.theantennafarm.com/catalog/base-antenna-mounts-1289/mobile-to-base-convertor-kits-1243/

 

[cmdrwill]

YUP... NO groundplane.

 

[mm]

Some more info on this antenna, sweeping with a RIG EXPERT 230 HANDHELD ANALYZER the worst case return loss in my base setup was -12db and typically -16 or better from my old notes.

I have this model wideband mobile antenna with a homebrew nmo base mount on a 10 foot mast.

I use 4 counterpoise radialls which are part of a guy system.

These 4 guy wires are 6 foot long and made from #14 pvc coated uv protected stranded copper wire.

These radialls are coming off at a 45 degree angle with egg insulators at the 6 foot ends then the remaining length of these guy wire assemblies are made from uv resistant nylon rope which does double duty as the guy wires.

This works very well for monitoring chp and other low band systems between 39-49 MHz with a GE ORION radio.

My only concern is that a similar 27-30 MHz model of this antenna had an issue running a 29 MHZ GE Orion at 110 watts around 29 MHZ and one capacitor was replaced with a similar value porcelain, but with a higher 500 volt cap which resolved high power tx failures.

What I'm saying is that you should observe a maximum tx power rating of <=100 watts and preferably 90 watts or less and you shouldn't have any issues transmitting.

 

[W5lz]

An antenna used over a wide frequency range is going to be a compromise unless it has traps to "separate" it into segments tuned for each band of use. In general scanners arent very picky about antennas. Also in general, a too long antenna will work out better than one too short. An antenna resonant on a frequency will "hear" better than one that isnt. That difference is typically not very big, so don't get carried away, you know?

 

[N5TWB]

If you can find one at an army surplus store or hamfest, the old military RC-292 ground plane worked, with adjustments, from 30 - 80 MHz.

 

[prcguy]

The base insulator/mounts for RC-292s come up on Epay all the time and you can thread the element holes for 3/8-24 and stick in store bought whips or thread some aluminum rod for a nice sturdy ground plane. The center hubs for the military OE-254s come up also and with some aluminum rods or tubing you can make a great broad band no tune 30 to 88MHz range omni.

If you can find one at an army surplus store or hamfest, the old military RC-292 ground plane worked, with adjustments, from 30 - 80 MHz.

 

[k8zgw]

A coaxial dipole, , about 12 feet long ( a half wave on 38 mhz) should work
as good as anything you can buy, google coaxial dipole, and build one for WAY less then $300.00 !!

 

[951ryan]

I went to Ham Radio Outlet yesterday and paid about $200 for a Diamond D-130J and 50ft of new cable... After the 2hr round trip drive, I got home, spent 45min setting everything up and still having issues picking up our local CHP on 39.6 yet am picking up a much further CHP station on 39.3 pretty strong.

Because I'm not really techy with RF stuff and really wanted something pre-made I opted to buy a custom 1/4 Wave Ground Plane antenna from Arrow Antenna for $84 with shipping tuned to the frequency I requested. Hopefully, that arrives next week and does the trick.

 

[allend]

To the OP. All of these people chiming in is going to cost you a lot of money and headache. I have been pulling in CHP for years now on low band and its never perfect depending on what frequencies you are trying to pull in. I have discone antenna's 10 to 15 feet apart and for no reason some antenna's pull in signals different and better.

Your biggest problem is where you live and where your antenna is going to be placed. This is # 1 hurdle you can't change where you live.

I live 50 miles from Riverside 39.68 mhz and I am pulling in Riverside CHP with full bar and full quieting on a Diamond Discone 3000N up at 40 ft.

Let me give you this scenario. At 40 ft with metal in the air I can't for the love of GOD pull in 39.22 The Copper. Just can't. But if I use a whip antenna on my car down the street like 1 block I can pull in the Copper.

With my discone I can pull in everything from LA and OC and RC and Riverside. That is pretty freaking good for a 100 dollar D3000N. You ain't going to do any better. Where you live you will be able to pull in repeaters where I can't. See where I am going with this. Its all where you live and radio waves only travel so far and bounce certains ways. You are just going to have to do trial and error.

 

[allend]

I went to Ham Radio Outlet yesterday and paid about $200 for a Diamond D-130J and 50ft of new cable... After the 2hr round trip drive, I got home, spent 45min setting everything up and still having issues picking up our local CHP on 39.6 yet am picking up a much further CHP station on 39.3 pretty strong.

Because I'm not really techy with RF stuff and really wanted something pre-made I opted to buy a custom 1/4 Wave Ground Plane antenna from Arrow Antenna for $84 with shipping tuned to the frequency I requested. Hopefully, that arrives next week and does the trick.

So you did a great job with the antenna. Now keep in mind that when you get that Arrow Antenna tuned for 39.68mhz you might or might not get that frequency. That D130J should of been able to grab that signal with no problem. But with that Arrow Antenna that you ordered you might pull the signal you want but then you might lose other low band frequencies. Its a give and take situation with antenna's sometimes. I have gone through all of these scenarios and hands down the Diamond Discone tends to work the best unless you want to put up a big old mast with a boat load of metal in the air. But that's pretty not realistic for just trying to pickup 39-45 mhz. Good Luck

Also, one more piece of advice. You might want to put that antenna up higher on the Chimney. Get a directv arm mount and bolt it to the chimney and that added height might get you there. Just have to work on the placement. You might get another 10 ft of height

 

[Ubbe]

Below 80MHz a discone starts to work as a 1/4 GP antenna if it has a top element, as your antenna has. The top element are tuned for 50-55MHz so replace the top part that are held with an allen screw with an element that are something between 1 and 1/2 foot and 2 foot longer than the original element, which probably are 2 to 2 1/2 foot. So put a 4-5 foot element on the discone and it should be pretty close to what you'll get with your purchased 1/4 GP antenna.

/Ubbe

 

[RadioVoice]

Check https://childsantennas.com/omni-base-antennas I have one he built for me on 47 MHz. that works well.

 

[951ryan]

I went to Ham Radio Outlet yesterday and paid about $200 for a Diamond D-130J and 50ft of new cable... After the 2hr round trip drive, I got home, spent 45min setting everything up and still having issues picking up our local CHP on 39.6 yet am picking up a much further CHP station on 39.3 pretty strong.

Because I'm not really techy with RF stuff and really wanted something pre-made I opted to buy a custom 1/4 Wave Ground Plane antenna from Arrow Antenna for $84 with shipping tuned to the frequency I requested. Hopefully, that arrives next week and does the trick.

My custom tuned antenna came in from Arrow Antenna, this thing was HUGE. Plugged everything in and the reception is WORSE with this custom tuned antenna than it is with the Diamond D-130J. I've attached pics of both. Man, this is frustrating. Next step is to buy a chimney mount and get that sucker up a bit higher, praying that does the trick but I'm still confused how a general discone antenna is outperforming this custom tuned antenna almost triple the size.

 

[allend]

Lessons are hard to learn sometimes. The discone antenna is the best you are going to be-able to do at this point. Don't waste your time and money on trying different antenna's at this point. You have two problems at this point. #1 is where you live at this point. #2 CHP made some tweaks with their antenna's or their repeaters with that frequency you are trying to receive. Pretty much you are no options to fixes these issues.

The best you are going to be-able to do is put the Discone on a mount on the chimney and call it a day. You have no other options at this point.

 

[prcguy]

Something is definitely wrong and if the full size ground plane and Discone were at the same height and location and feedline, the ground plane should be noticeably better. Do you have anything like an antenna analyzer to check the ground plane with?

My custom tuned antenna came in from Arrow Antenna, this thing was HUGE. Plugged everything in and the reception is WORSE with this custom tuned antenna than it is with the Diamond D-130J. I've attached pics of both. Man, this is frustrating. Next step is to buy a chimney mount and get that sucker up a bit higher, praying that does the trick but I'm still confused how a general discone antenna is outperforming this custom tuned antenna almost triple the size.

 

[allend]

This is how you should mount your antenna.

 

[prcguy]

Higher, get it higher! A Directv 2" mast from a Slimline dish will easily handle another 5ft mast and that Discone.

This is how you should mount your antenna.

 

[Ubbe]

In reference to Hustler exaggerating their gain figures and general antenna gain results, I found an excellent article by Ed Kelm KD7TUN that is the best I've seen so far. Longer is Better « SJCARS

"CONCLUSIONS:

1. If you are looking at buying a VHF antenna, DON’T choose one based upon advertised gain. Determine the likely REAL gain from the antenna height and the curve above for a line source.

2. There is no magic antenna design that beats the gain vs. height curve. If an ad says there is, remember what a famous ham Yagi designer said: “P. T. Barnum is alive and well, and writing antenna advertisements.”

3. Once you have settled upon the gain (and therefore height) you need, choose the antenna based upon price, reviews of mechanical reliability, wind ratings and your location, etc. Do NOT pay any attention to reviews touting the superior RF performance of antenna A over antenna B. If they’re both about 10 feet tall, their performance should be virtually identical! Anecdotal evidence is best reserved for things like flying saucer sightings."

/Ubbe