Generally, the Rangemaster uses a 102" whip. I've always used 102" fiberglass whips because they can take the wind and dont rust. Well I need a new one and was just shopping trying to find a bargain and I came across these 92" fiberglass whips, thats a full ten inches shorter than what we commonly use but it's only $38 - which is a lot cheaper than I've ever bought.
https://www.wearecb.com/8x5-16-fiberglass-whip-white.html
It makes this curious statement: "FR96-W - 92" Fiberglass CB Antenna (White) with Standard Thread. The length is approximate and may vary per the manufacturer."
I've never actually measured my antennas, presumably a ant marketed at 102" is just that, but I dont know, consider a 2x4. Anyway, don't know what they charge for shipping but I do see the exact same antennas on ebay for $47 with free shipping - which seems an incredible bargain to me. intent://www.ebay.com/itm/167423101905
No big deal about it being 10 inches shorter, just extend the ground lead to compensate.
What do you think?
Since the tuned loading coil on board is designed for the 104 inch antenna same as the Procaster you *may* create a mismatch and tuning for peak signal may not be quite as good. Don't know if adding ground lead would compensate one way or another, or how much range would be affected. What if you contact Rangemaster and see what he says? If you normally get a mile just for discussion, and with the shorter antenna get 4/5ths of a mile if that doesn't matter than yes it's a good deal. It may be a bit more convenient to have a little more ground lead room.
@mark I'm not sure if your interpretation is accurate. From what I understand a 6ft whip and a 4ft ground lead equals a 10ft antenna. Does not the Rangemasters tuning adjustment actually tune for the length of the antenna? For example if you elevate your transmitter (thus extend the lead/antenna length, that in turn requires a retune, correct? I'm not sure how it works with a Procaster but everytime you change the height or location of a Rangemaster you have to absolutely retune it.
Take for example the front cover of the Part15 introduction pdf that HB had created. The Rangemaster shown has a very short whip - this had been done to raise the transmitter a few feet but still keep it within the 3 meter limitation for compliance - it's still an eight foot antenna, it's just that the top whip section is only about 4 foot, the ground lead constitutes the other 4ft.
Is this not correct? Had R Fry been incorrect?
Since the tuned loading coil on board is designed for the 104 inch antenna ..
Are they usually 104"? I thought it was usually 102" - the 92" whip description includes a disclaimer that the antennas actuall length may vary (which I still find curious).
The FCC permits you up to a 118.11 inches of antenna, they dont make the 110" cb whips anymore but they used to be common from what I understand.
@richpowers Ok this from Gerry at Procaster whom I am friends with here in Toronto, who engineers the Procaster.
A loading coil whether on board or externally at the base of the antenna is in series with the antenna and has a certain number of windings and a certain value for a given frequency or range of frequencies that is "peaked" with a trimmer capacitor and is there to make the shorter than ideal antennas used for part 15 AM act like a longer one. For the 104" antenna the coil chosen has a specific value to cause resonance with a particular antenna length. If you make the antenna shorter or longer and not changing the inductor coil also you create a mismatch and the tuning will not peak for resonance as well and less range. The Stock length on the Rangemaster may be 102" or 104", I don't know but whatever the coil and ATU has been chosen for the stock length. The Procaster is 104"
I don't know what Rich fry said about this and I remember I had a discussion with him on this several years ago on this forum as he said if you change the 104" antenna to 300" for example it would be much better and I said no not true as there now is a mismatch with the loading coil and will not make it better.
As for making up the length with ground lead to get the same range I can't answer that as I don't know. I don't know if a shorter antenna and longer ground lead equals a 104" antenna.
You should ask Rangemaster about it. Maybe I can ask Gerry about this a post the answer.
But I do know that for a given frequency all those jumpers you have on the Rangemaster to fine tune first and the final trimmer for peak will be affected negatively by changing antenna length. A way to see is use the correct length and ground length and peak it and see what you get on the meter and then do what you want to do all things being equal, same frequency, other than reducing the antenna length and increasing the ground length and go through the tuning procedure and see if the final result is the same on the meter. Even if it is not quite as good but close would it matter?
Here's some info on antennas, loading coils, and resonance
https://en.wikipedia.org/wiki/Loading_coil
My primary point is - in my understanding, based on past discussions, the terms "antenna" and "ground lead" are basically interchangeable. You can use a 8 foot ground lead and no whip antenna at all and tune it to perform with the same legth 8 foot radiator - or you can tune it to perform with a 100ft ground lead like KENC had done on the water tower.
10ft Ground lead + 8ft Whip = 18ft antenna
No?
@richpowers I know what you are saying but I don't think so.
I have a procaster here. I will power it, not today, no antenna, and connect a 9ft wire to the ground lug and see what happens when I tune it, with no antenna.
You can do this at your end also. I don't think the ground lead is an antenna, prove me wrong.
A stainless steel whip, a copper or aluminum pipe, or a 10AWG wire - they are all radiating elements. It doesn't matter if it extends out the top or bottom of the transmitter. The antenna and ground lead essentially are a single element. I don't think I'm wrong about this. Could be, but I think that's the gist.
Every AM NOUO involved antennas in excess of 10 feet due to their extended ground leads. The ground lead is just as much part of the antenna as the whip is.
Wish R Fry was here about now.
@mark Ahhh.. You and I have discussed this before over at mbcf when R Fry was still alive. Below is a brief excerpt of his expertise on the matter, but here's a link to the entire discussion: https://mbcf.boards.net/thread/2854/antenna-ground-lead
Antenna vs. Ground Lead - What's the actual difference?
R Fry, March 2019:
".. The conducting path(s) leading from the transmitter circuit board common bus and/or its r-f ground terminal can radiate more r-f energy than the ~3-m whip attached to the transmitter that is considered to be "the antenna."
..The output signal of a radio transmitter is an a-c waveform. Energy appearing at its "antenna" connector and its "ground" connector are identical, except for being 180° out of phase with each other.
In free space it doesn't matter to the performance of that system configuration as to which of the two output terminals of the transmitter connects to a 4" wire called "the antenna" and the other to a 102" wire called "ground," or with the wires reversed.
Remember the old days before polarized a-c power plugs were required? A radio then could be plugged into a wall socket no matter which way the plug was inserted, and the radio worked fine either way (not OSHA safe, but it worked). Same principle."
Well, sort of.
For your application, a 102 inch or 92 inch radiator should make little to no difference.
Remember that a ground itself does not radiate (although the short lead to ground might). It just forms the other half of the antenna, and makes the radiator more efficient.
However, if you had an 8 foot radiator, and a 100 foot ground lead, you no longer have a vertical antenna, but some form of offset dipole. Different tuning characteristics, different radiation patterns, etc. You might not be able to tune it, depending on the tuning circuits in the transmitter.
.... You might not be able to tune it, depending on the tuning circuits in the transmitter.
Well I know first hand you can tune an 8ft whip with 50 or more foot ground lead and acheive in excess of five miles (on the coast anyway). I know this from using the city's pavilion that had a very elaborate grounding system (lightning). I had the Rangemaster on its roof and grounded to that grounding system. It came in loud and clear the next island over and probably was receivable in Savannah..
It was not the 8ft section of whip that achieved that range, it was obviously its lead(s) radiating.
100mw into that really big antenna performed spectacularly as I was able to tune its peak
Of course it wasn't compliant, but the fact is you can most certainly tune antennas larger than 10 feet to vastly improve performance.
I dont get how this is even a question.
Just noticed this guy on facebook (Jeff Bearden Pino in Edin Oklahoma) that uses only a 4 foot antenna on his 1670AM Part 15 station, but as you notice he simply compensates the length of the lead. He uses a Talking House.
facebook.com/share/p/16QPHHSL6Y/
The ground lead is part of the antenna. No question about it.
Wow.. There's a Facebook group called 102" Whip Antennas! And here some excerpts from an interesting thread which kind of relates to this discussion here, heres a few excerpts (ok, it's more than a few...
/
■What's the difference between a 102" & 108" whip? [161 comments:
• I ran a 108" Whip on CB for many years as I didn't want to use a Spring. Back in the 60-70's the Braid inside the Spring often broke causing erratic operation as the spring flexed and the Spring acted like a Coil briefly. In 1975 I switched to 4' Fiberglass Whips, problem solved. Now I use a pair of 102's as a 10 meter Dipole.
• - I have used a 30" Hustler Mast Base Swction for Bumper Mounts with a 102" to get 11 feet for 15 meters.
• That works! Great suggestion. I might have “issues” 😉 with smacking bridges with an 11’ antenna on a 5’ tall car, especially in Pennsylvania where we have old, low bridges, but I’ll always be able to find my car in a Walmart parking lot.
Did you drive around with an 11’ antenna? If so, any concerns?
• Use a 102 whip with a 6” spring
• Actually the spring is only about 4.5”. The connections for the spring will add up to about that 6” needed for the full quarter wave. I just mention this so the novice won’t waste time looking for a full 6” spring.
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• I had to keep from laughing when that was mentioned earlier, but I kept quiet 🤫
• i guess older springs used to be a true 6 inches i had to actually make a extender for mine. No big deal then i later bought stainless rod to use and never did haha
• I’m old. First antenna was a 102” on a chain bumper mount. The spring is the same as it has always been to my knowledge. The design was for the spring to be screwed into a ball mount, giving you the other two inches. The 108” whip came along when folks wanted to just use the antenna itself right into the pl coax connector. 108” from the end of the coax to the tip of the antenna is what you are after. However you get that doesn’t really matter, a spring, or any type of conductor will work.
• I have found if I use a 102" SS whip + barrel spring + chrome ball I get the best SWR consistently ... ... That setup gives me the longest range with clearest audio of all the mobile antennas I have tried since the late 60's and I'm still looking for a better antenna..... ... Some other folks find that just a 102" SS whip works best for them... I've tried every different combination I can think of with a variety of antennas including extra grounding.... I was told in the beginning by a CB Shopp Owner that was the best setup back then and he showed me how to do the installation.... He also told me to keep looking for the next best antenna and when I found something better to let him know.... That was his fee for helping me and teaching me about equipment selection and proper installation.... .... Good Luck 👍 Out On The Bandwaves...... 73 .... ....
• Fortyfour Dan its designed to use a spring to make it 108.
• Fortyfour Dan actually tests have shown the 7 ft skipshooter can sometimes outdo a stainless steel whip in certain situations by design as the stainless steel whip goes up and out and straight up into space, while a top load like the 7ft skip shooter goes up and spreads out more. It has been mentioned before over the years that I read and I found out when I pulled up with my new 7-foot skip shooter with a several of my ham friends decades ago and mentioned it to them and they laughed as usual about my antenna but then they tested it. Lol Four of them next to me with their ham rigs and trunk mounted 102s, testing both antennas in each vehicle to three base stations and the skipshooter came out ahead on receive end on all, although just by a hair, it was the winner. We didn't test distance cuz then you get into skip and stuff and it was mentioned tested locally. Not an accurate test but it was a test. We are all pretty sure the whip would win for distance by design as well. Great learning experience for everyone that day.
• 102 inch = 27.9 -29.4 Mhz
108 inch = 26.2 - 27.7 Mhz.
Springs lower your frequency
Attaching a 2 foot to 5 ft stainless wrapped around the 102 inch whip gets to 23-25 Nhz and even down to 21 Mhz,,If your a hammer guy,,
• Your mom prefers the extra 6 inches
• 102 in. Is for ham 10 meter 108 is for CB 11 meter band
• I use a 12 inch whip adjuster before I bought that I couldn’t get below 2 now I’m at .1-.1 They work amazing. No snapping springs
• Run it yourself, universal 1/4 wave formula, (except for CB) 234/Freq
• do you make this shit up as you go?
• Retired engineer, FCC licensed I worked on antenna systems.
• 102” whip + 2” ball and 4” spring = 108.” Bottom line!
• Just use an 18.6ft coax instead of a spring. Works great
• Greg Tolman Sr. 6 inches of spring I vs 6 inches of coax. I'll take the coax
• 102 is cut for 10m and 108 is cut for 11m. Realy hard to find 108" ss now days so you use a 6in spring or raiser. I made 5, 6, 7 and 8in solid risers to help tune my whips
• 108 inches is for 11 meter cb band and 102 is shorter for above ch 40
Higher frequency range takes a shorter antenna.
• 6 inch.
Seriosly all this antennas are ¼ wave considering velocity factor. Velocity factor depend of material you use, most thickness. That's all. Spring in base is pure for mechanical reasons. Nothing else.
• 102 is for 10 meters 108 is for CB. They dont make 108s anymore, it was easier and cost effective to make the 102 and add a 6in spring. Nowadays people use a 10 or 12 inch ss whip "riser/aduster/ extension, as pictured.
• Remember the universal formula for a 1/4 wave antenna is 234/F, comes to 103.2 inches for CB band center.
• That's because a quarter wavelength on 11 m is 108 in
• 108 inch is 1/4 wave ...102 inch is the length you normally need when velocity factor of the material the antenna is made out of is taken into account ...test your swr to determine if the antenna is to short at 102, it is the only way .....the old fiberglass 1/4 wave whips used to be only 98 inch
• You can get a whip adjuster from ICA manufacturing
The points to be derived from the many comments is that - yes, you most certainly can compensate for a shorter whip by simply extending your ground lead - or use a riser or whatever..
It's also interesting to note that the when 102" whips came out it was due to compensate for the 6" height of the mounting ball so that the total length would still equal 108" (otherwise it would be 114" which threw off the proper resonance).
So.. for our purposes the 102" whips are actually too short as is. it should be 108" for a 1/4 wave.
However, if you had an 8 foot radiator, and a 100 foot ground lead, you no longer have a vertical antenna, but some form of offset dipole.
I just noticed you said that, I think that described configuration becomes a form of offset dipole ONLY IF that 100ft ground lead IS NOT connected to ground but hanging free
At least that's how I've come to understand it - but perhaps I misinterpreted that somewhere along the way.