Comprod UHF 66-40-44 duplexer review

[WB4JGI]

I'm looking at getting one of these for either ham or commercial use, I haven't decided which route to go at this site yet. Looking at Tessco it has a wide split 406-512mhz. I'm thinking that's a little wide for a duplexer and curious if the specs listed hold true from 440 up to 470MHZ.

If anyone can chime in on this set of duplexers that would be great, or any other Comprod filters for that matter. They look like the old TX/RX filters which I thought were great products.

[Bill_G]

According to the specs, it can be tuned across that range. I am not familiar with it. So, cannot comment on how well it works. But, it is a pass-reject. It's a real duplexer for a high site with moderate activity, and not adjacent channel users.

[FMROB]

That 406-512 listing is just that. I am certain that they have individual units for a specified less bandwidth unit. I was under the impression the comprod was a tx/rx sister company. Their equipment seems very similar.

Stick with the EMR 526 style 6 cavity duplexer. They are decent units.

[WB4JGI]

I was looking at their website just a second ago and their specs are the same 406-512 but the only duplexer listing they have states it's bandsplit is 406-470. Guess I'll have to call them next week and see.

I was able to find a duplexer while going through my dads barn it's model number was 526 something, it does have six cavities, but the company name on it says Phelps Dodge. It does have a dent on it from being in storage for around 20 years or more and is missing the cables that connect all the cavities together on one side of the unit. I wonder if Phelps Dodge/EMR could make some cables for it?

My dad was explaining to me that the cables are supposed to be exactly 11 12" long between the cavities and I can't make a cable that precise. Then I don't know if that length is supposed to be frequency specific or not either.

Thanks for the replies thus far.

[kcbooboo]

Phelps Dodge was bought by Celwave. The PD526-series of duplexers work very well. They DO need cables of 11-1/2 inches and I think two of the six cables that go to the TEE connector are 1/2 inch shorter. Further information can be found on the web. The length of the cable is critical and is definitely frequency-specific; the PD526 will TUNE over the 403-512 MHz range but you need the right cable length to make it WORK on the 440-450 MHz range.

I had one and I bought a new cable set in 2002 for $250. It's far cheaper to make your own. A male N crimp connector adds exactly 1/2 inch to the end-to-end length of the cable, so to make an 11-1/2 inch cable, you cut the RG214 to exactly 10-1/2 inches long, prepare the ends according to the connector manufacturer, and crimp two male N connectors to it, being careful not to shorten the cable at all; now you have an assembly that's exactly 11-1/2 inches long. The connectors cost about $4 each and the RG214 can be found for between $1 and $2 per foot. That's about $10 in materials per cable and you need six.

Bob M.

[wavetar]

I can vouch for Comprod product, it's very good stuff. They are the 'official' filter provider for Kenwood NexEdge digital systems, here in Canada at least. Quality on par with Sinclair, but typically 20-30% less money for comparable product.

[WB4JGI]

Quality on par with Sinclair, but typically 20-30% less money for comparable product.

On my Tessco account the Sinclair Q3220 is a whopping $57 cheaper and has almost the same specs.

Only difference between Sinclair and the Comprod is the Sinclair handles 350 watts and has a 2 year warranty. While the Comprod handles 125 watts and has a 5 year warranty.

The amount of wattage doesn't matter in my case as I will be running a TRBO repeater at 45 watts. If I can't make my old Phepls Dodge duplexers work I guess I'll look at these 2 duplexers as a replacement. As these 2 are within my budget for this project.

Thanks for the replies thus far.

[wavetar]

Quality on par with Sinclair, but typically 20-30% less money for comparable product.

On my Tessco account the Sinclair Q3220 is a whopping $57 cheaper and has almost the same specs.

Only difference between Sinclair and the Comprod is the Sinclair handles 350 watts and has a 2 year warranty. While the Comprod handles 125 watts and has a 5 year warranty.

The amount of wattage doesn't matter in my case as I will be running a TRBO repeater at 45 watts. If I can't make my old Phepls Dodge duplexers work I guess I'll look at these 2 duplexers as a replacement. As these 2 are within my budget for this project.

Thanks for the replies thus far.

Hmmm, apparently we get a heck of a deal on Comprod product as we buy it direct & they are Canadian based, so no border fees/hassle. Price being equal, you'd do well with either one.

[motorola_otaku]

I recently recabled a Celwave/Phelps-Dodge PD526 with RG400 cable (which is what they're shipped with now IIRC.) I don't have the exact measurements in front of me but I was able to find them in a Google search of the repeater_builder mailing list archive. Barring that, if you can get someone to measure the length of a factory RG214 jumper you can calculate the velocity factor-adjusted length for RG400.